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Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
Linus Torvalds1da177e2005-04-16 15:20:36 -07003
4The following is a consolidated list of the kernel parameters as implemented
5(mostly) by the __setup() macro and sorted into English Dictionary order
6(defined as ignoring all punctuation and sorting digits before letters in a
7case insensitive manner), and with descriptions where known.
8
9Module parameters for loadable modules are specified only as the
10parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14Module parameters for modules that are built into the kernel image
15are specified on the kernel command line with the module name plus
16'.' plus parameter name, with '=' and value if appropriate, such as:
17
18 usbcore.blinkenlights=1
19
Randy Dunlapca1eda22009-05-06 16:02:58 -070020Hyphens (dashes) and underscores are equivalent in parameter names, so
21 log_buf_len=1M print-fatal-signals=1
22can also be entered as
23 log-buf-len=1M print_fatal_signals=1
24
25
Stefan Richtera901ebb2006-04-01 01:43:18 +020026This document may not be entirely up to date and comprehensive. The command
27"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
28module. Loadable modules, after being loaded into the running kernel, also
29reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
30parameters may be changed at runtime by the command
31"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
32
Stefan Richter6585fa82006-04-01 01:44:30 +020033The parameters listed below are only valid if certain kernel build options were
34enabled and if respective hardware is present. The text in square brackets at
35the beginning of each description states the restrictions within which a
36parameter is applicable:
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38 ACPI ACPI support is enabled.
Chuck Ebbertc99c1082007-07-27 10:46:20 +100039 AGP AGP (Accelerated Graphics Port) is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 ALSA ALSA sound support is enabled.
41 APIC APIC support is enabled.
42 APM Advanced Power Management support is enabled.
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +020043 AVR32 AVR32 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 AX25 Appropriate AX.25 support is enabled.
Robin Getz0ae53642007-10-09 17:24:49 +080045 BLACKFIN Blackfin architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070046 DRM Direct Rendering Management support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
48 EFI EFI Partitioning (GPT) is enabled
49 EIDE EIDE/ATAPI support is enabled.
50 FB The frame buffer device is enabled.
51 HW Appropriate hardware is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 IA-64 IA-64 architecture is enabled.
Mimi Zohar6146f0d2009-02-04 09:06:57 -050053 IMA Integrity measurement architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070055 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 ISAPNP ISA PnP code is enabled.
57 ISDN Appropriate ISDN support is enabled.
58 JOY Appropriate joystick support is enabled.
Eduard - Gabriel Munteanub9ce08c2008-08-10 20:14:03 +030059 KMEMTRACE kmemtrace is enabled.
Kristen Carlson Accardi11ef6972006-09-28 11:29:01 -070060 LIBATA Libata driver is enabled
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 LP Printer support is enabled.
62 LOOP Loopback device support is enabled.
63 M68k M68k architecture is enabled.
64 These options have more detailed description inside of
65 Documentation/m68k/kernel-options.txt.
66 MCA MCA bus support is enabled.
67 MDA MDA console support is enabled.
68 MOUSE Appropriate mouse support is enabled.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070069 MSI Message Signaled Interrupts (PCI).
Randy Dunlapc8facbb2007-07-31 00:37:40 -070070 MTD MTD (Memory Technology Device) support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 NET Appropriate network support is enabled.
72 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070073 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 NFS Appropriate NFS support is enabled.
75 OSS OSS sound support is enabled.
Randy Dunlapc8facbb2007-07-31 00:37:40 -070076 PV_OPS A paravirtualized kernel is enabled.
77 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 PARISC The PA-RISC architecture is enabled.
79 PCI PCI bus support is enabled.
Randy Dunlap7f785762007-10-05 13:17:58 -070080 PCIE PCI Express support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 PCMCIA The PCMCIA subsystem is enabled.
82 PNP Plug & Play support is enabled.
83 PPC PowerPC architecture is enabled.
84 PPT Parallel port support is enabled.
85 PS2 Appropriate PS/2 support is enabled.
86 RAM RAM disk support is enabled.
James Morris20510f22007-10-16 23:31:32 -070087 ROOTPLUG The example Root Plug LSM is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 S390 S390 architecture is enabled.
89 SCSI Appropriate SCSI support is enabled.
90 A lot of drivers has their options described inside of
91 Documentation/scsi/.
James Morris20510f22007-10-16 23:31:32 -070092 SECURITY Different security models are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 SELINUX SELinux support is enabled.
94 SERIAL Serial support is enabled.
Paul Mundte523d932007-02-28 18:30:01 +090095 SH SuperH architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 SMP The kernel is an SMP kernel.
97 SPARC Sparc architecture is enabled.
David Brownell77437fd2008-07-23 21:28:33 -070098 SWSUSP Software suspend (hibernation) is enabled.
99 SUSPEND System suspend states are enabled.
Steven Rostedtf38f1d22008-12-16 23:06:40 -0500100 FTRACE Function tracing enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 TS Appropriate touchscreen support is enabled.
Alan Sternd4f373e2008-11-10 14:07:45 -0500102 UMS USB Mass Storage support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 USB USB support is enabled.
104 USBHID USB Human Interface Device support is enabled.
105 V4L Video For Linux support is enabled.
106 VGA The VGA console has been enabled.
107 VT Virtual terminal support is enabled.
108 WDT Watchdog support is enabled.
109 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700110 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 X86-64 X86-64 architecture is enabled.
112 More X86-64 boot options can be found in
Uwe Hermann71cced62008-10-20 09:32:21 -0700113 Documentation/x86/x86_64/boot-options.txt .
Andi Kleenc0115602008-08-22 09:53:39 +0200114 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
116In addition, the following text indicates that the option:
117
118 BUGS= Relates to possible processor bugs on the said processor.
119 KNL Is a kernel start-up parameter.
120 BOOT Is a boot loader parameter.
121
122Parameters denoted with BOOT are actually interpreted by the boot
123loader, and have no meaning to the kernel directly.
124Do not modify the syntax of boot loader parameters without extreme
Kyle McMartin954a8b82009-02-19 16:48:14 -0500125need or coordination with <Documentation/x86/boot.txt>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126
Karsten Weiss55588702007-02-13 13:26:21 +0100127There are also arch-specific kernel-parameters not documented here.
Uwe Hermann71cced62008-10-20 09:32:21 -0700128See for example <Documentation/x86/x86_64/boot-options.txt>.
Karsten Weiss55588702007-02-13 13:26:21 +0100129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
131a trailing = on the name of any parameter states that that parameter will
132be entered as an environment variable, whereas its absence indicates that
133it will appear as a kernel argument readable via /proc/cmdline by programs
134running once the system is up.
135
jens m. noedler9c4751f2006-09-29 02:00:27 -0700136The number of kernel parameters is not limited, but the length of the
137complete command line (parameters including spaces etc.) is limited to
138a fixed number of characters. This limit depends on the architecture
139and is between 256 and 4096 characters. It is defined in the file
140./include/asm/setup.h as COMMAND_LINE_SIZE.
141
142
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530143 acpi= [HW,ACPI,X86]
Bernhard Walle03d926f2007-03-06 02:29:44 -0800144 Advanced Configuration and Power Interface
Randy Dunlapaf23f572009-02-22 17:05:22 -0800145 Format: { force | off | ht | strict | noirq | rsdt }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 force -- enable ACPI if default was off
147 off -- disable ACPI if default was on
148 noirq -- do not use ACPI for IRQ routing
149 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700150 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 strictly ACPI specification compliant.
Zhao Yakui237889b2008-12-17 16:55:18 +0800152 rsdt -- prefer RSDT over (default) XSDT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Randy Dunlap53471122008-03-12 18:10:51 -0400154 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
Len Browna1fdcc02007-03-11 03:26:14 -0400156 acpi_apic_instance= [ACPI, IOAPIC]
157 Format: <int>
158 2: use 2nd APIC table, if available
159 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400160 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400161
Thomas Renningerc3d6de62008-08-01 17:37:55 +0200162 acpi_backlight= [HW,ACPI]
163 acpi_backlight=vendor
164 acpi_backlight=video
165 If set to vendor, prefer vendor specific driver
166 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
167 of the ACPI video.ko driver.
168
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700169 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
170 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 Format: <int>
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700172 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
173 debug output. Bits in debug_layer correspond to a
174 _COMPONENT in an ACPI source file, e.g.,
175 #define _COMPONENT ACPI_PCI_COMPONENT
176 Bits in debug_level correspond to a level in
177 ACPI_DEBUG_PRINT statements, e.g.,
178 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
Bjorn Helgaase76f4272008-11-13 17:30:13 -0600179 The debug_level mask defaults to "info". See
180 Documentation/acpi/debug.txt for more information about
181 debug layers and levels.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
Bjorn Helgaase76f4272008-11-13 17:30:13 -0600183 Enable processor driver info messages:
184 acpi.debug_layer=0x20000000
185 Enable PCI/PCI interrupt routing info messages:
186 acpi.debug_layer=0x400000
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700187 Enable AML "Debug" output, i.e., stores to the Debug
188 object while interpreting AML:
189 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700190 Enable all messages related to ACPI hardware:
191 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
Thomas Renninger36eec5e2008-08-11 15:03:20 +0200192
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700193 Some values produce so much output that the system is
194 unusable. The "log_buf_len" parameter may be useful
195 if you need to capture more output.
Zhang Ruif9891062007-04-24 13:53:22 +0800196
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700197 acpi_display_output= [HW,ACPI]
198 acpi_display_output=vendor
199 acpi_display_output=video
200 See above.
201
202 acpi_irq_balance [HW,ACPI]
203 ACPI will balance active IRQs
204 default in APIC mode
205
206 acpi_irq_nobalance [HW,ACPI]
207 ACPI will not move active IRQs (default)
208 default in PIC mode
209
210 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
211 Format: <irq>,<irq>...
212
213 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
214 use by PCI
215 Format: <irq>,<irq>...
216
217 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
218
219 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
220 Format: To spoof as Windows 98: ="Microsoft Windows"
221
222 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
223 acpi_osi="string1" # add string1 -- only one string
224 acpi_osi="!string2" # remove built-in string2
225 acpi_osi= # disable all strings
226
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530227 acpi_pm_good [X86]
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700228 Override the pmtimer bug detection: force the kernel
229 to assume that this machine's pmtimer latches its value
230 and always returns good values.
231
Zhao Yakuif5adfaa2008-08-11 14:57:50 +0800232 acpi.power_nocheck= [HW,ACPI]
233 Format: 1/0 enable/disable the check of power state.
234 On some bogus BIOS the _PSC object/_STA object of
235 power resource can't return the correct device power
236 state. In such case it is unneccessary to check its
237 power state again in power transition.
238 1 : disable the power state check
239
Randy Dunlap4af94f32009-04-17 18:30:28 -0700240 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
241 Format: { level | edge | high | low }
242
243 acpi_serialize [HW,ACPI] force serialization of AML methods
244
245 acpi_skip_timer_override [HW,ACPI]
246 Recognize and ignore IRQ0/pin2 Interrupt Override.
247 For broken nForce2 BIOS resulting in XT-PIC timer.
248
249 acpi_sleep= [HW,ACPI] Sleep options
250 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
251 old_ordering, s4_nonvs }
252 See Documentation/power/video.txt for information on
253 s3_bios and s3_mode.
254 s3_beep is for debugging; it makes the PC's speaker beep
255 as soon as the kernel's real-mode entry point is called.
256 s4_nohwsig prevents ACPI hardware signature from being
257 used during resume from hibernation.
258 old_ordering causes the ACPI 1.0 ordering of the _PTS
259 control method, with respect to putting devices into
260 low power states, to be enforced (the ACPI 2.0 ordering
261 of _PTS is used by default).
262 s4_nonvs prevents the kernel from saving/restoring the
263 ACPI NVS memory during hibernation.
264
265 acpi_use_timer_override [HW,ACPI]
266 Use timer override. For some broken Nvidia NF5 boards
267 that require a timer override, but don't have HPET
268
Luca Tettamanti7e905602009-03-30 00:01:27 +0200269 acpi_enforce_resources= [ACPI]
270 { strict | lax | no }
271 Check for resource conflicts between native drivers
272 and ACPI OperationRegions (SystemIO and SystemMemory
273 only). IO ports and memory declared in ACPI might be
274 used by the ACPI subsystem in arbitrary AML code and
275 can interfere with legacy drivers.
276 strict (default): access to resources claimed by ACPI
277 is denied; legacy drivers trying to access reserved
278 resources will fail to bind to device using them.
279 lax: access to resources claimed by ACPI is allowed;
280 legacy drivers trying to access reserved resources
281 will bind successfully but a warning message is logged.
282 no: ACPI OperationRegions are not marked as reserved,
283 no further checks are performed.
284
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 ad1848= [HW,OSS]
286 Format: <io>,<irq>,<dma>,<dma2>,<type>
287
Randy Dunlap4af94f32009-04-17 18:30:28 -0700288 add_efi_memmap [EFI; X86] Include EFI memory map in
289 kernel's map of available physical RAM.
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 advansys= [HW,SCSI]
292 See header of drivers/scsi/advansys.c.
293
294 advwdt= [HW,WDT] Advantech WDT
295 Format: <iostart>,<iostop>
296
297 aedsp16= [HW,OSS] Audio Excel DSP 16
298 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
299 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700300
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700301 agp= [AGP]
302 { off | try_unsupported }
303 off: disable AGP support
304 try_unsupported: try to drive unsupported chipsets
305 (may crash computer or cause data corruption)
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 aha152x= [HW,SCSI]
308 See Documentation/scsi/aha152x.txt.
309
310 aha1542= [HW,SCSI]
311 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
312
313 aic7xxx= [HW,SCSI]
314 See Documentation/scsi/aic7xxx.txt.
315
316 aic79xx= [HW,SCSI]
317 See Documentation/scsi/aic79xx.txt.
318
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200319 amd_iommu= [HW,X86-84]
320 Pass parameters to the AMD IOMMU driver in the system.
321 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200322 isolate - enable device isolation (each device, as far
323 as possible, will get its own protection
Joerg Roedel3ce1f932008-11-17 15:09:20 +0100324 domain) [default]
Joerg Roedele5e1f602008-11-17 15:07:17 +0100325 share - put every device behind one IOMMU into the
326 same protection domain
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900327 fullflush - enable flushing of IO/TLB entries when
328 they are unmapped. Otherwise they are
329 flushed before they will be reused, which
330 is a lot of faster
331
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200332 amd_iommu_size= [HW,X86-64]
333 Define the size of the aperture for the AMD IOMMU
334 driver. Possible values are:
335 '32M', '64M' (default), '128M', '256M', '512M', '1G'
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 amijoy.map= [HW,JOY] Amiga joystick support
338 Map of devices attached to JOY0DAT and JOY1DAT
339 Format: <a>,<b>
340 See also Documentation/kernel/input/joystick.txt
341
342 analog.map= [HW,JOY] Analog joystick and gamepad support
343 Specifies type or capabilities of an analog joystick
344 connected to one of 16 gameports
345 Format: <type1>,<type2>,..<type16>
346
Randy Dunlapa9913042005-10-23 12:57:11 -0700347 apc= [HW,SPARC]
348 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 Format: noidle
350 Disable APC CPU standby support. SPARCstation-Fox does
351 not play well with APC CPU idle - disable it if you have
352 APC and your system crashes randomly.
353
Randy Dunlapca1eda22009-05-06 16:02:58 -0700354 apic= [APIC,X86-32] Advanced Programmable Interrupt Controller
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700355 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 Format: { quiet (default) | verbose | debug }
357 Change the amount of debugging information output
358 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700359
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700361 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
364 Format: <io>,<irq>,<nodeID>
365
366 ataflop= [HW,M68k]
367
368 atarimouse= [HW,MOUSE] Atari Mouse
369
370 atascsi= [HW,SCSI] Atari SCSI
371
372 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
373 EzKey and similar keyboards
374
375 atkbd.reset= [HW] Reset keyboard during initialization
376
Randy Dunlapa9913042005-10-23 12:57:11 -0700377 atkbd.set= [HW] Select keyboard code set
378 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379
380 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
381 keyboards
382
383 atkbd.softraw= [HW] Choose between synthetic and real raw mode
384 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700385
386 atkbd.softrepeat= [HW]
387 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
389 autotest [IA64]
390
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 baycom_epp= [HW,AX25]
392 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700393
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
395 Format: <io>,<mode>
396 See header of drivers/net/hamradio/baycom_par.c.
397
Randy Dunlapa9913042005-10-23 12:57:11 -0700398 baycom_ser_fdx= [HW,AX25]
399 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 Format: <io>,<irq>,<mode>[,<baud>]
401 See header of drivers/net/hamradio/baycom_ser_fdx.c.
402
Randy Dunlapa9913042005-10-23 12:57:11 -0700403 baycom_ser_hdx= [HW,AX25]
404 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 Format: <io>,<irq>,<mode>
406 See header of drivers/net/hamradio/baycom_ser_hdx.c.
407
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700408 boot_delay= Milliseconds to delay each printk during boot.
409 Values larger than 10 seconds (10000) are changed to
410 no delay (0).
411 Format: integer
412
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700413 bootmem_debug [KNL] Enable bootmem allocator debug messages.
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700416 bttv.radio= Most important insmod options are available as
417 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
419 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
420
421 BusLogic= [HW,SCSI]
422 See drivers/scsi/BusLogic.c, comment before function
423 BusLogic_ParseDriverOptions().
424
425 c101= [NET] Moxa C101 synchronous serial card
426
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700427 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 Sometimes CPU hardware bugs make them report the cache
429 size incorrectly. The kernel will attempt work arounds
430 to fix known problems, but for some CPUs it is not
431 possible to determine what the correct size should be.
432 This option provides an override for these situations.
433
James Morris20510f22007-10-16 23:31:32 -0700434 capability.disable=
435 [SECURITY] Disable capabilities. This would normally
436 be used only if an alternative security model is to be
437 configured. Potentially dangerous and should only be
438 used if you are entirely sure of the consequences.
439
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100440 ccw_timeout_log [S390]
441 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442
Paul Menage8bab8dd2008-04-04 14:29:57 -0700443 cgroup_disable= [KNL] Disable a particular controller
444 Format: {name of the controller(s) to disable}
445 {Currently supported controllers - "memory"}
446
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 checkreqprot [SELINUX] Set initial checkreqprot flag value.
448 Format: { "0" | "1" }
449 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700450 0 -- check protection applied by kernel (includes
451 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 1 -- check protection requested by application.
453 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700454 Value can be changed at runtime via
455 /selinux/checkreqprot.
456
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100457 cio_ignore= [S390]
458 See Documentation/s390/CommonIO for details.
459
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700460 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700461 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200462 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700463 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200464 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 Format: { pit | tsc | cyclone | pmtmr }
466
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700467 clocksource= [GENERIC_TIME] Override the default clocksource
468 Format: <string>
469 Override the default clocksource and use the clocksource
470 with the name specified.
471 Some clocksource names to choose from, depending on
472 the platform:
473 [all] jiffies (this is the base, fallback clocksource)
474 [ACPI] acpi_pm
475 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
476 pxa_timer,timer3,32k_counter,timer0_1
477 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700478 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700479 scx200_hrt on Geode; cyclone on IBM x440
480 [MIPS] MIPS
481 [PARISC] cr16
482 [S390] tod
483 [SH] SuperH
484 [SPARC64] tick
485 [X86-64] hpet,tsc
486
Andi Kleenac72e782008-01-30 13:33:21 +0100487 clearcpuid=BITNUM [X86]
488 Disable CPUID feature X for the kernel. See
Randy Dunlap07983f02009-01-06 14:42:41 -0800489 arch/x86/include/asm/cpufeature.h for the valid bit
490 numbers. Note the Linux specific bits are not necessarily
Andi Kleenac72e782008-01-30 13:33:21 +0100491 stable over kernel options, but the vendor specific
492 ones should be.
493 Also note that user programs calling CPUID directly
494 or using the feature without checking anything
495 will still see it. This just prevents it from
496 being used by the kernel or shown in /proc/cpuinfo.
497 Also note the kernel might malfunction if you disable
498 some critical bits.
499
Robert Jennings14f966e2009-04-15 05:55:32 +0000500 cmo_free_hint= [PPC] Format: { yes | no }
501 Specify whether pages are marked as being inactive
502 when they are freed. This is used in CMO environments
503 to determine OS memory pressure for page stealing by
504 a hypervisor.
505 Default: yes
506
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530507 code_bytes [X86] How many bytes of object code to print
Arjan van de Vena25bd942008-01-30 13:33:08 +0100508 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100509 Range: 0 - 8192
510 Default: 64
511
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700513 Format:
514 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
516 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
517 Format: <io>[,<irq>]
518
Randy Dunlapa9913042005-10-23 12:57:11 -0700519 com90xx= [HW,NET]
520 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 Format: <io>[,<irq>[,<memstart>]]
522
523 condev= [HW,S390] console device
524 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 console= [KNL] Output console device and options.
527
528 tty<n> Use the virtual console device <n>.
529
530 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800531 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800533 the form "bbbbpnf", where "bbbb" is the baud rate,
534 "p" is parity ("n", "o", or "e"), "n" is number of
535 bits, and "f" is flow control ("r" for RTS or
536 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800538 See Documentation/serial-console.txt for more
539 information. See
540 Documentation/networking/netconsole.txt for an
541 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700543 uart[8250],io,<addr>[,options]
544 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 Start an early, polled-mode console on the 8250/16550
546 UART at the specified I/O port or MMIO address,
547 switching to the matching ttyS device later. The
548 options are the same as for ttyS, above.
549
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700550 If the device connected to the port is not a TTY but a braille
551 device, prepend "brl," before the device type, for instance
552 console=brl,ttyS0
553 For now, only VisioBraille is supported.
554
Hidehiro Kawai4cb0e112009-01-06 14:42:47 -0800555 coredump_filter=
556 [KNL] Change the default value for
557 /proc/<pid>/coredump_filter.
558 See also Documentation/filesystems/proc.txt.
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700561 Format:
562 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700564 crashkernel=nn[KMG]@ss[KMG]
565 [KNL] Reserve a chunk of physical memory to
566 hold a kernel to switch to with kexec on panic.
567
Bernhard Wallefb391592007-10-18 23:41:02 -0700568 crashkernel=range1:size1[,range2:size2,...][@offset]
569 [KNL] Same as above, but depends on the memory
570 in the running system. The syntax of range is
571 start-[end] where start and end are both
572 a memory unit (amount[KMG]). See also
573 Documentation/kdump/kdump.txt for a example.
574
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 cs89x0_dma= [HW,NET]
576 Format: <dma>
577
578 cs89x0_media= [HW,NET]
579 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700580
Randy Dunlapa9913042005-10-23 12:57:11 -0700581 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 See header of drivers/s390/block/dasd_devmap.c.
583
584 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
585 (one device per port)
586 Format: <port#>,<type>
587 See also Documentation/input/joystick-parport.txt
588
589 debug [KNL] Enable kernel debugging (events log level).
590
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700591 debug_locks_verbose=
592 [KNL] verbose self-tests
593 Format=<0|1>
594 Print debugging info while doing the locking API
595 self-tests.
596 We default to 0 (no extra messages), setting it to
597 1 will print _a lot_ more information - normally
598 only useful to kernel developers.
599
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700600 debug_objects [KNL] Enable object debugging
601
Kyle McMartin3e8ebb52009-03-01 20:41:41 -0500602 no_debug_objects
603 [KNL] Disable object debugging
604
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200605 debugpat [X86] Enable PAT debugging
606
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200607 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 Format: <area>[,<node>]
609 See also Documentation/networking/decnet.txt.
610
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700611 default_hugepagesz=
612 [same as hugepagesz=] The size of the default
613 HugeTLB page size. This is the size represented by
614 the legacy /proc/ hugepages APIs, used for SHM, and
615 default size when mounting hugetlbfs filesystems.
616 Defaults to the default architecture's huge page size
617 if not specified.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700618
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 dhash_entries= [KNL]
620 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700621
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 digi= [HW,SERIAL]
623 IO parameters + enable/disable command.
624
625 digiepca= [HW,SERIAL]
626 See drivers/char/README.epca and
Randy Dunlap31c00fc2008-11-13 21:33:24 +0000627 Documentation/serial/digiepca.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628
Yinghai Lu95ffa242008-04-29 03:52:33 -0700629 disable_mtrr_cleanup [X86]
Yinghai Lu95ffa242008-04-29 03:52:33 -0700630 The kernel tries to adjust MTRR layout from continuous
631 to discrete, to make X server driver able to add WB
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700632 entry later. This parameter disables that.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700633
Yinghai Lu093af8d2008-01-30 13:33:32 +0100634 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100635 By default the kernel will trim any uncacheable
636 memory out of your available memory pool based on
637 MTRR settings. This parameter disables that behavior,
638 possibly causing your machine to run very slowly.
639
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530640 disable_timer_pin_1 [X86]
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700641 Disable PIN 1 of APIC timer
642 Can be useful to work around chipset bugs.
643
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 dmasound= [HW,OSS] Sound subsystem buffers
645
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700646 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support,
647 this option disables the debugging code at boot.
648
649 dma_debug_entries=<number>
650 This option allows to tune the number of preallocated
651 entries for DMA-API debugging code. One entry is
652 required per DMA-API allocation. Use this if the
653 DMA-API debugging code disables itself because the
654 architectural default is too low.
655
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 dscc4.setup= [NET]
657
658 dtc3181e= [HW,SCSI]
659
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700660 dynamic_printk Enables pr_debug()/dev_dbg() calls if
661 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
662 These can also be switched on/off via
663 <debugfs>/dynamic_printk/modules
664
665 earlycon= [KNL] Output early console device and options.
666 uart[8250],io,<addr>[,options]
667 uart[8250],mmio,<addr>[,options]
668 Start an early, polled-mode console on the 8250/16550
669 UART at the specified I/O port or MMIO address.
670 The options are the same as for ttyS, above.
671
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530672 earlyprintk= [X86,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 earlyprintk=vga
674 earlyprintk=serial[,ttySn[,baudrate]]
Yinghai Lu5c059172008-07-24 17:29:40 -0700675 earlyprintk=dbgp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676
Randy Dunlapa9913042005-10-23 12:57:11 -0700677 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 takes over.
679
Yinghai Lu5c059172008-07-24 17:29:40 -0700680 Only vga or serial or usb debug port at a time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
682 Currently only ttyS0 and ttyS1 are supported.
683
684 Interaction with the standard serial driver is not
685 very good.
686
687 The VGA output is eventually overwritten by the real
688 console.
689
690 eata= [HW,SCSI]
691
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700693 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 eisa_irq_edge= [PARISC,HW]
696 See header of drivers/parisc/eisa.c.
697
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700698 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700700 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
702 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800703 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700704 See Documentation/block/as-iosched.txt and
705 Documentation/block/deadline-iosched.txt for details.
706
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530707 elfcorehdr= [IA64,PPC,SH,X86]
Randy Dunlapa9913042005-10-23 12:57:11 -0700708 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800709 image elf header. Generally kexec loader will
710 pass this option to capture kernel.
711 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700713 enable_mtrr_cleanup [X86]
714 The kernel tries to adjust MTRR layout from continuous
715 to discrete, to make X server driver able to add WB
716 entry later. This parameter enables that.
717
Randy Dunlapca1eda22009-05-06 16:02:58 -0700718 enable_timer_pin_1 [X86]
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700719 Enable PIN 1 of APIC timer
720 Can be useful to work around chipset bugs
721 (in particular on some ATI chipsets).
722 The kernel tries to set a reasonable default.
723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 enforcing [SELINUX] Set initial enforcing status.
725 Format: {"0" | "1"}
726 See security/selinux/Kconfig help text.
727 0 -- permissive (log only, no denials).
728 1 -- enforcing (deny and log).
729 Default value is 0.
730 Value can be changed at runtime via /selinux/enforce.
731
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 ether= [HW,NET] Ethernet cards parameters
733 This option is obsoleted by the "netdev=" option, which
734 has equivalent usage. See its documentation for details.
735
736 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
737 Format: <io>[,<irq>]
738
Akinobu Mitade1ba092006-12-08 02:39:42 -0800739 failslab=
740 fail_page_alloc=
741 fail_make_request=[KNL]
742 General fault injection mechanism.
743 Format: <interval>,<probability>,<space>,<times>
744 See also /Documentation/fault-injection/.
745
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 fd_mcs= [HW,SCSI]
747 See header of drivers/scsi/fd_mcs.c.
748
749 fdomain= [HW,SCSI]
750 See header of drivers/scsi/fdomain.c.
751
752 floppy= [HW]
Randy Dunlap31c00fc2008-11-13 21:33:24 +0000753 See Documentation/blockdev/floppy.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754
Alex Chiangf13ae302008-05-08 14:03:23 -0600755 force_pal_cache_flush
756 [IA-64] Avoid check_sal_cache_flush which may hang on
757 buggy SAL_CACHE_FLUSH implementations. Using this
758 parameter will force ia64_sal_cache_flush to call
759 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
760
Peter Zijlstrad9e54072008-11-01 19:57:37 +0100761 ftrace=[tracer]
762 [ftrace] will set and start the specified tracer
763 as early as possible in order to facilitate early
764 boot debugging.
765
766 ftrace_dump_on_oops
767 [ftrace] will dump the trace buffers on oops.
768
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 gamecon.map[2|3]=
770 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
771 support via parallel port (up to 5 devices per port)
772 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
773 See also Documentation/input/joystick-parport.txt
774
775 gamma= [HW,DRM]
776
Yinghai Luaaf23042008-01-30 13:33:09 +0100777 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
778 Format: off | on
779 default: on
780
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 gdth= [HW,SCSI]
782 See header of drivers/scsi/gdth.c.
783
784 gpt [EFI] Forces disk with valid GPT signature but
785 invalid Protective MBR to be treated as GPT.
786
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 gvp11= [HW,SCSI]
788
789 hashdist= [KNL,NUMA] Large hashes allocated during boot
790 are distributed across NUMA nodes. Defaults on
Hugh Dickins429aa0f2009-05-06 16:02:51 -0700791 for 64bit NUMA, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700792 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793
794 hcl= [IA-64] SGI's Hardware Graph compatibility layer
795
796 hd= [EIDE] (E)IDE hard drive subsystem geometry
797 Format: <cyl>,<head>,<sect>
798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
800 size of <nn>. This works even on boxes that have no
801 highmem otherwise. This also works to reduce highmem
802 size on bigger boxes.
803
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800804 highres= [KNL] Enable/disable high resolution timer mode.
805 Valid parameters: "on", "off"
806 Default: "on"
807
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 hisax= [HW,ISDN]
809 See Documentation/isdn/README.HiSax.
810
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700811 hlt [BUGS=ARM,SH]
812
813 hpet= [X86-32,HPET] option to control HPET usage
814 Format: { enable (default) | disable | force |
815 verbose }
816 disable: disable HPET and use PIT instead
817 force: allow force enabled of undocumented chips (ICH4,
818 VIA, nVidia)
819 verbose: show contents of HPET registers during setup
820
Andi Kleenb4718e62008-07-23 21:27:51 -0700821 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
822 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700823 On x86-64 and powerpc, this option can be specified
824 multiple times interleaved with hugepages= to reserve
825 huge pages of different sizes. Valid pages sizes on
826 x86-64 are 2M (when the CPU supports "pse") and 1G
827 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700828 Note that 1GB pages can only be allocated at boot time
829 using hugepages= and not freed afterwards.
Paul Mundt6902aa82008-09-21 17:14:42 +0900830
Hendrik Brueckner555d61d2009-01-09 12:15:02 +0100831 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
832 terminal devices. Valid values: 0..8
Hendrik Brueckner431429f2009-03-26 15:23:55 +0100833 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
834 If specified, z/VM IUCV HVC accepts connections
835 from listed z/VM user IDs only.
Hendrik Bruecknercef71252008-12-25 13:39:55 +0100836
Jarkko Nikula3a853fb2009-03-23 18:07:47 -0700837 i2c_bus= [HW] Override the default board specific I2C bus speed
Jarkko Nikula79547632009-03-23 18:07:48 -0700838 or register an additional I2C bus that is not
839 registered from board initialization code.
Jarkko Nikula3a853fb2009-03-23 18:07:47 -0700840 Format:
841 <bus_id>,<clkrate>
842
Jiri Kosina36d95732008-10-06 02:51:09 -0400843 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200845 i8042.dumbkbd [HW] Pretend that controller can only read data from
846 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 (Don't attempt to blink the leds)
848 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500849 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400850 i8042.noloop [HW] Disable the AUX Loopback command while probing
851 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 i8042.nomux [HW] Don't check presence of an active multiplexing
853 controller
854 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
855 controllers
856 i8042.panicblink=
857 [HW] Frequency with which keyboard LEDs should blink
858 when kernel panics (default is 0.5 sec)
859 i8042.reset [HW] Reset the controller during init and cleanup
860 i8042.unlock [HW] Unlock (ignore) the keylock
861
862 i810= [HW,DRM]
863
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700864 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
865 indicates that the driver is running on unsupported
866 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
868 does not match list of supported models.
869 i8k.power_status
870 [HW] Report power status in /proc/i8k
871 (disabled by default)
872 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
873 capability is set.
874
875 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
876 See Documentation/mca.txt.
877
878 icn= [HW,ISDN]
879 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
880
David Fries0af80c02009-02-25 20:28:21 +0100881 ide-core.nodma= [HW] (E)IDE subsystem
882 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
883 .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
884 .chs .ignore_cable are additional options
Randy Dunlap1c10e932008-03-07 21:53:50 +0100885 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100888 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700890 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
891 Claim all unknown PCI IDE storage controllers.
892
Andi Kleenf039b752007-05-02 19:27:12 +0200893 idle= [X86]
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800894 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
895 Poll forces a polling idle loop that can slightly
896 improve the performance of waking up a idle CPU, but
897 will use a lot of power and make the system run hot.
898 Not recommended.
899 idle=mwait: On systems which support MONITOR/MWAIT but
900 the kernel chose to not use it because it doesn't save
901 as much power as a normal idle loop, use the
902 MONITOR/MWAIT idle loop anyways. Performance should be
903 the same as idle=poll.
904 idle=halt: Halt is forced to be used for CPU idle.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800905 In such case C2/C3 won't be used again.
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800906 idle=nomwait: Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700907
Ingo Molnar792908222006-12-06 20:40:51 -0800908 ignore_loglevel [KNL]
909 Ignore loglevel setting - this will print /all/
910 kernel messages to the console. Useful for debugging.
911
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 ihash_entries= [KNL]
913 Set number of hash buckets for inode cache.
914
Mimi Zohar3323eec2009-02-04 09:06:58 -0500915 ima_audit= [IMA]
916 Format: { "0" | "1" }
917 0 -- integrity auditing messages. (Default)
918 1 -- enable informational integrity auditing messages.
919
920 ima_hash= [IMA]
921 Formt: { "sha1" | "md5" }
922 default: "sha1"
923
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 in2000= [HW,SCSI]
925 See header of drivers/scsi/in2000.c.
926
927 init= [KNL]
928 Format: <full_path>
929 Run specified binary instead of /sbin/init as init
930 process.
931
932 initcall_debug [KNL] Trace initcalls as they are executed. Useful
933 for working out where the kernel is dying during
934 startup.
935
936 initrd= [BOOT] Specify the location of the initial ramdisk
937
938 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
939 Format: <irq>
940
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700941 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
Kyle McMartin0cd5c3c2009-02-04 14:29:19 -0800942 on
943 Enable intel iommu driver.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700944 off
945 Disable intel iommu driver.
946 igfx_off [Default Off]
947 By default, gfx is mapped as normal device. If a gfx
948 device has a dedicated DMAR unit, the DMAR unit is
949 bypassed by not enabling DMAR with this option. In
950 this case, gfx device will use physical address for
951 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700952 forcedac [x86_64]
953 With this option iommu will not optimize to look
954 for io virtual address below 32 bit forcing dual
955 address cycle on pci bus for cards supporting greater
956 than 32 bit addressing. The default is to look
957 for translation below 32 bit and if not available
958 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800959 strict [Default Off]
960 With this option on every unmap_single operation will
961 result in a hardware IOTLB flush operation as opposed
962 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700963
Randy Dunlap0cb55ad2009-04-05 15:55:22 -0700964 inttest= [IA64]
965
966 iomem= Disable strict checking of access to MMIO memory
967 strict regions from userspace.
968 relaxed
969
970 iommu= [x86]
971 off
972 force
973 noforce
974 biomerge
975 panic
976 nopanic
977 merge
978 nomerge
979 forcesac
980 soft
981
982 io7= [HW] IO7 for Marvel based alpha systems
983 See comment before marvel_specify_io7 in
984 arch/alpha/kernel/core_marvel.c.
985
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +0530986 io_delay= [X86] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100987 0x80
988 Standard port 0x80 based delay
989 0xed
990 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100991 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100992 Simple two microseconds delay
993 none
994 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100995
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400997 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998
999 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001000 See comment before ip2_setup() in
1001 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002
1003 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
1004 See header of drivers/scsi/ips.c.
1005
Alan Cox200803d2005-06-28 20:45:18 -07001006 irqfixup [HW]
1007 When an interrupt is not handled search all handlers
1008 for it. Intended to get systems with badly broken
1009 firmware running.
1010
1011 irqpoll [HW]
1012 When an interrupt is not handled search all handlers
1013 for it. Also check all handlers each timer
1014 interrupt. Intended to get systems with badly broken
1015 firmware running.
1016
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -07001018 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019
1020 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -08001021 Format:
1022 <cpu number>,...,<cpu number>
1023 or
Li Zefanb225d442008-11-06 12:53:39 -08001024 <cpu number>-<cpu number>
1025 (must be a positive range in ascending order)
Derek Fults22f2e282006-12-06 20:37:11 -08001026 or a mixture
1027 <cpu number>,...,<cpu number>-<cpu number>
Li Zefanb225d442008-11-06 12:53:39 -08001028
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 This option can be used to specify one or more CPUs
1030 to isolate from the general SMP balancing and scheduling
Li Zefanb225d442008-11-06 12:53:39 -08001031 algorithms. You can move a process onto or off an
1032 "isolated" CPU via the CPU affinity syscalls or cpuset.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033 <cpu number> begins at 0 and the maximum value is
1034 "number of CPUs in system - 1".
1035
1036 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -07001037 alternative -- manually setting the CPU mask of all
1038 tasks in the system -- can cause problems and
1039 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040
Randy Dunlapa9913042005-10-23 12:57:11 -07001041 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042
1043 js= [HW,JOY] Analog joystick
1044 See Documentation/input/joystick.txt.
1045
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001046 keepinitrd [HW,ARM]
1047
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301048 kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -07001049 specifies the amount of memory usable by the kernel
1050 for non-movable allocations. The requested amount is
1051 spread evenly throughout all nodes in the system. The
1052 remaining memory in each node is used for Movable
1053 pages. In the event, a node is too small to have both
1054 kernelcore and Movable pages, kernelcore pages will
1055 take priority and other nodes will have a larger number
1056 of kernelcore pages. The Movable zone is used for the
1057 allocation of pages that may be reclaimed or moved
1058 by the page migration subsystem. This means that
1059 HugeTLB pages may not be allocated from this zone.
1060 Note that allocations like PTEs-from-HighMem still
1061 use the HighMem zone if it exists, and the Normal
1062 zone if it does not.
1063
Eduard - Gabriel Munteanub9ce08c2008-08-10 20:14:03 +03001064 kmemtrace.enable= [KNL,KMEMTRACE] Format: { yes | no }
1065 Controls whether kmemtrace is enabled
1066 at boot-time.
1067
1068 kmemtrace.subbufs=n [KNL,KMEMTRACE] Overrides the number of
1069 subbufs kmemtrace's relay channel has. Set this
1070 higher than default (KMEMTRACE_N_SUBBUFS in code) if
1071 you experience buffer overruns.
1072
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001073 kgdboc= [HW] kgdb over consoles.
1074 Requires a tty driver that supports console polling.
1075 (only serial suported for now)
1076 Format: <serial_device>[,baud]
1077
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001078 kmac= [MIPS] korina ethernet MAC address.
1079 Configure the RouterBoard 532 series on-chip
1080 Ethernet adapter MAC address.
1081
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301082 kstack=N [X86] Print N words from the kernel stack
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001083 in oops dumps.
1084
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 l2cr= [PPC]
1086
Robert Brosea78bfbf2008-03-29 07:20:23 +11001087 l3cr= [PPC]
1088
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001089 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001090 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301092 lapic_timer_c2_ok [X86,APIC] trust the local apic timer
Randy Dunlapada9cfd2008-12-19 10:57:32 -08001093 in C2 power state.
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001094
FD Camifcb71f62008-01-06 19:08:56 +01001095 libata.dma= [LIBATA] DMA control
1096 libata.dma=0 Disable all PATA and SATA DMA
1097 libata.dma=1 PATA and SATA Disk DMA only
1098 libata.dma=2 ATAPI (CDROM) DMA only
1099 libata.dma=4 Compact Flash DMA only
1100 Combinations also work, so libata.dma=3 enables DMA
1101 for disks and CDROMs, but not CFs.
1102
Dave Jones78e70c22007-09-27 11:50:13 -04001103 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1104 when set.
1105 Format: <int>
1106
Tejun Heo33267322008-02-13 09:15:09 +09001107 libata.force= [LIBATA] Force configurations. The format is comma
1108 separated list of "[ID:]VAL" where ID is
1109 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1110 matching port, link or device. Basically, it matches
1111 the ATA ID string printed on console by libata. If
1112 the whole ID part is omitted, the last PORT and DEVICE
1113 values are used. If ID hasn't been specified yet, the
1114 configuration applies to all ports, links and devices.
1115
1116 If only DEVICE is omitted, the parameter applies to
1117 the port and all links and devices behind it. DEVICE
1118 number of 0 either selects the first device or the
1119 first fan-out link behind PMP device. It does not
1120 select the host link. DEVICE number of 15 selects the
1121 host link and device attached to it.
1122
1123 The VAL specifies the configuration to force. As long
1124 as there's no ambiguity shortcut notation is allowed.
1125 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1126 The following configurations can be forced.
1127
1128 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1129 Any ID with matching PORT is used.
1130
1131 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1132
1133 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1134 udma[/][16,25,33,44,66,100,133] notation is also
1135 allowed.
1136
1137 * [no]ncq: Turn on or off NCQ.
1138
Tejun Heo05944bd2008-08-13 20:19:09 +09001139 * nohrst, nosrst, norst: suppress hard, soft
1140 and both resets.
1141
Tejun Heo33267322008-02-13 09:15:09 +09001142 If there are multiple matching configurations changing
1143 the same attribute, the last one is used.
1144
Randy Dunlap7c4be252009-01-06 14:42:44 -08001145 lmb=debug [KNL] Enable lmb debug messages.
1146
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 load_ramdisk= [RAM] List of ramdisks to load from floppy
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001148 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001150 lockd.nlm_grace_period=P [NFS] Assign grace period.
1151 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001153 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1154 Format: <integer>
1155
1156 lockd.nlm_timeout=T [NFS] Assign timeout value.
1157 Format: <integer>
1158
1159 lockd.nlm_udpport=M [NFS] Assign UDP port.
1160 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
1162 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1163 Format: <irq>
1164
1165 loglevel= All Kernel Messages with a loglevel smaller than the
1166 console loglevel will be printed to the console. It can
1167 also be changed with klogd or other programs. The
1168 loglevels are defined as follows:
1169
1170 0 (KERN_EMERG) system is unusable
1171 1 (KERN_ALERT) action must be taken immediately
1172 2 (KERN_CRIT) critical conditions
1173 3 (KERN_ERR) error conditions
1174 4 (KERN_WARNING) warning conditions
1175 5 (KERN_NOTICE) normal but significant condition
1176 6 (KERN_INFO) informational
1177 7 (KERN_DEBUG) debug-level messages
1178
1179 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001180 Format: { n | nk | nM }
1181 n must be a power of two. The default size
1182 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183
Randy Dunlapaccaa242007-10-16 01:29:37 -07001184 logo.nologo [FB] Disables display of the built-in Linux logo.
1185 This may be used to provide more screen space for
1186 kernel log messages and is useful when debugging
1187 kernel boot problems.
1188
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 lp=0 [LP] Specify parallel ports to use, e.g,
1190 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1191 lp=reset first parallel port). 'lp=0' disables the
1192 lp=auto printer driver. 'lp=reset' (which can be
1193 specified in addition to the ports) causes
1194 attached printers to be reset. Using
1195 lp=port1,port2,... specifies the parallel ports
1196 to associate lp devices with, starting with
1197 lp0. A port specification may be 'none' to skip
1198 that lp device, or a parport name such as
1199 'parport0'. Specifying 'lp=auto' instead of a
1200 port specification list means that device IDs
1201 from each port should be examined, to see if
1202 an IEEE 1284-compliant printer is attached; if
1203 so, the driver will manage that printer.
1204 See also header of drivers/char/lp.c.
1205
1206 lpj=n [KNL]
1207 Sets loops_per_jiffy to given constant, thus avoiding
1208 time-consuming boot-time autodetection (up to 250 ms per
1209 CPU). 0 enables autodetection (default). To determine
1210 the correct value for your kernel, boot with normal
1211 autodetection and see what value is printed. Note that
1212 on SMP systems the preset will be applied to all CPUs,
1213 which is likely to cause problems if your CPUs need
1214 significantly divergent settings. An incorrect value
1215 will cause delays in the kernel to be wrong, leading to
1216 unpredictable I/O errors and other breakage. Although
1217 unlikely, in the extreme case this might damage your
1218 hardware.
1219
1220 ltpc= [NET]
1221 Format: <io>,<irq>,<dma>
1222
Randy Dunlapa9913042005-10-23 12:57:11 -07001223 mac5380= [HW,SCSI] Format:
1224 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
Randy Dunlapa9913042005-10-23 12:57:11 -07001226 machvec= [IA64] Force the use of a particular machine-vector
1227 (machvec) in a generic kernel.
1228 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001230 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater
1231 than or equal to this physical address is ignored.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232
1233 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001234 should make use of. maxcpus=n : n >= 0 limits the
1235 kernel to using 'n' processors. n=0 is a special case,
1236 it is equivalent to "nosmp", which also disables
1237 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001239 max_loop= [LOOP] Maximum number of loopback devices that can
1240 be mounted
1241 Format: <1-256>
Bob Picco2b2c3752005-06-29 18:00:00 -07001242
Randy Dunlapa9913042005-10-23 12:57:11 -07001243 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 Should be between 1 and 2^32-1.
1245
1246 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001247 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 Should be between 1 and 16384.
1249
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 mcatest= [IA-64]
1251
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001252 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253
Uwe Hermann71cced62008-10-20 09:32:21 -07001254 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
Andi Kleen909dd322007-10-17 18:04:38 +02001255
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 md= [HW] RAID subsystems devices and level
1257 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001258
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 mdacon= [MDA]
1260 Format: <first>,<last>
1261 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001262
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1264 Amount of memory to be used when the kernel is not able
1265 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001266 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 address space collisions. Without memmap= PCI devices
1268 could be placed at addresses belonging to unused RAM.
1269
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001270 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 memory.
1272
Paul Mundt6902aa82008-09-21 17:14:42 +09001273 memchunk=nn[KMG]
1274 [KNL,SH] Allow user to override the default size for
1275 per-device physically contiguous DMA buffers.
1276
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301277 memmap=exactmap [KNL,X86] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 E820 memory map, as specified by the user.
1279 Such memmap=exactmap lines can be constructed based on
1280 BIOS output or other requirements. See the memmap=nn@ss
1281 option description.
1282
1283 memmap=nn[KMG]@ss[KMG]
1284 [KNL] Force usage of a specific region of memory
1285 Region of memory to be used, from ss to ss+nn.
1286
1287 memmap=nn[KMG]#ss[KMG]
1288 [KNL,ACPI] Mark specific memory as ACPI data.
1289 Region of memory to be used, from ss to ss+nn.
1290
1291 memmap=nn[KMG]$ss[KMG]
1292 [KNL,ACPI] Mark specific memory as reserved.
1293 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001294 Example: Exclude memory from 0x18690000-0x1869ffff
1295 memmap=64K$0x18690000
1296 or
1297 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001299 memory_corruption_check=0/1 [X86]
1300 Some BIOSes seem to corrupt the first 64k of
1301 memory when doing things like suspend/resume.
1302 Setting this option will scan the memory
1303 looking for corruption. Enabling this will
1304 both detect corruption and prevent the kernel
1305 from using the memory being corrupted.
1306 However, its intended as a diagnostic tool; if
1307 repeatable BIOS-originated corruption always
1308 affects the same memory, you can use memmap=
1309 to prevent the kernel from using that memory.
1310
1311 memory_corruption_check_size=size [X86]
1312 By default it checks for corruption in the low
1313 64k, making this memory unavailable for normal
1314 use. Use this parameter to scan for
1315 corruption in more or less memory.
1316
1317 memory_corruption_check_period=seconds [X86]
1318 By default it checks for corruption every 60
1319 seconds. Use this parameter to check at some
1320 other rate. 0 disables periodic checking.
1321
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001322 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001323 Format: <integer>
Yinghai Luc64df702008-03-21 18:56:19 -07001324 default : 0 <disable>
Andreas Herrmann9e5f6cf2009-02-25 11:30:45 +01001325 Specifies the number of memtest passes to be
1326 performed. Each pass selects another test
1327 pattern from a given set of patterns. Memtest
1328 fills the memory with this pattern, validates
1329 memory contents and reserves bad memory
1330 regions that are detected.
Yinghai Luc64df702008-03-21 18:56:19 -07001331
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 meye.*= [HW] Set MotionEye Camera parameters
1333 See Documentation/video4linux/meye.txt.
1334
Andres Salomon8f368812007-10-12 23:04:06 +02001335 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1336 Multi-Function General Purpose Timers on AMD Geode
1337 platforms.
1338
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001339 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1340 the BIOS has incorrectly applied a workaround. TinyBIOS
1341 version 0.98 is known to be affected, 0.99 fixes the
1342 problem by letting the user disable the workaround.
1343
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 mga= [HW,DRM]
1345
Randy Dunlap1c207f952008-11-19 15:36:16 -08001346 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1347 physical address is ignored.
1348
Mel Gorman6b74ab92008-07-23 21:26:49 -07001349 mminit_loglevel=
1350 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1351 parameter allows control of the logging verbosity for
1352 the additional memory initialisation checks. A value
1353 of 0 disables mminit logging and a level of 4 will
1354 log everything. Information is printed at KERN_DEBUG
1355 so loglevel=8 may also need to be specified.
1356
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 mousedev.tap_time=
1358 [MOUSE] Maximum time between finger touching and
1359 leaving touchpad surface for touch to be considered
1360 a tap and be reported as a left button click (for
1361 touchpads working in absolute mode only).
1362 Format: <msecs>
1363 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1364 reporting absolute coordinates, such as tablets
1365 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1366 reporting absolute coordinates, such as tablets
1367
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301368 movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001369 is similar to kernelcore except it specifies the
1370 amount of memory used for migratable allocations.
1371 If both kernelcore and movablecore is specified,
1372 then kernelcore will be at *least* the specified
1373 value but may be more. If movablecore on its own
1374 is specified, the administrator must be careful
1375 that the amount of memory usable for all allocations
1376 is not too small.
1377
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378 mpu401= [HW,OSS]
1379 Format: <io>,<irq>
1380
1381 MTD_Partition= [MTD]
1382 Format: <name>,<region-number>,<size>,<offset>
1383
Randy Dunlapa9913042005-10-23 12:57:11 -07001384 MTD_Region= [MTD] Format:
1385 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386
1387 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001388 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389
Ben Dooks9db829f2008-07-03 11:24:29 +01001390 mtdset= [ARM]
1391 ARM/S3C2412 JIVE boot control
1392
1393 See arch/arm/mach-s3c2412/mach-jive.c
1394
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001396 [HW] Make the MicroTouch USB driver use raw coordinates
1397 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001399 mtrr_chunk_size=nn[KMG] [X86]
1400 used for mtrr cleanup. It is largest continous chunk
1401 that could hold holes aka. UC entries.
1402
1403 mtrr_gran_size=nn[KMG] [X86]
1404 Used for mtrr cleanup. It is granularity of mtrr block.
1405 Default is 1.
1406 Large value could prevent small alignment from
1407 using up MTRRs.
1408
1409 mtrr_spare_reg_nr=n [X86]
1410 Format: <integer>
1411 Range: 0,7 : spare reg number
1412 Default : 1
1413 Used for mtrr cleanup. It is spare mtrr entries number.
1414 Set to 2 or more if your graphical card needs more.
1415
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1417
1418 NCR_D700= [HW,SCSI]
1419 See header of drivers/scsi/NCR_D700.c.
1420
1421 ncr5380= [HW,SCSI]
1422
1423 ncr53c400= [HW,SCSI]
1424
1425 ncr53c400a= [HW,SCSI]
1426
1427 ncr53c406a= [HW,SCSI]
1428
1429 ncr53c8xx= [HW,SCSI]
1430
1431 netdev= [NET] Network devices parameters
1432 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1433 Note that mem_start is often overloaded to mean
1434 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001435 This usage is only documented in each driver source
1436 file if at all.
1437
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001438 nf_conntrack.acct=
1439 [NETFILTER] Enable connection tracking flow accounting
1440 0 to disable accounting
1441 1 to enable accounting
1442 Default value depends on CONFIG_NF_CT_ACCT that is
1443 going to be removed in 2.6.29.
1444
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001446 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447
1448 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001449 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450
Trond Myklebusta72b4422006-01-03 09:55:41 +01001451 nfs.callback_tcpport=
1452 [NFS] set the TCP port on which the NFSv4 callback
1453 channel should listen.
1454
Trond Myklebust58df0952006-01-03 09:55:57 +01001455 nfs.idmap_cache_timeout=
1456 [NFS] set the maximum lifetime for idmapper cache
1457 entries.
1458
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001459 nfs.enable_ino64=
1460 [NFS] enable 64-bit inode numbers.
1461 If zero, the NFS client will fake up a 32-bit inode
1462 number for the readdir() and stat() syscalls instead
1463 of returning the full 64-bit number.
1464 The default is to return 64-bit inode numbers.
1465
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001466 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1467 when a NMI is triggered.
1468 Format: [state][,regs][,debounce][,die]
1469
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301470 nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
Cyrill Gorcunov5b9a0e12008-11-01 18:06:51 +03001471 Format: [panic,][num]
1472 Valid num: 0,1,2
1473 0 - turn nmi_watchdog off
1474 1 - use the IO-APIC timer for the NMI watchdog
1475 2 - use the local APIC for the NMI watchdog using
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001476 a performance counter. Note: This will use one
1477 performance counter and the local APIC's performance
1478 vector.
1479 When panic is specified, panic when an NMI watchdog
1480 timeout occurs.
1481 This is useful when you use a panic=... timeout and
1482 need the box quickly up again.
Cyrill Gorcunov5b9a0e12008-11-01 18:06:51 +03001483 Instead of 1 and 2 it is possible to use the following
1484 symbolic names: lapic and ioapic
1485 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001487 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 emulation library even if a 387 maths coprocessor
1489 is present.
1490
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001491 no_console_suspend
1492 [HW] Never suspend the console
1493 Disable suspending of consoles during suspend and
1494 hibernate operations. Once disabled, debugging
1495 messages can reach various consoles while the rest
1496 of the system is being put to sleep (ie, while
1497 debugging driver suspend/resume hooks). This may
1498 not work reliably with all consoles, but is known
1499 to work with serial and VGA consoles.
1500
Christoph Lameterc1aee212007-05-31 00:40:47 -07001501 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1502 caches in the slab allocator. Saves per-node memory,
1503 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001504
Randy Dunlapa9913042005-10-23 12:57:11 -07001505 noalign [KNL,ARM]
1506
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507 noapic [SMP,APIC] Tells the kernel to not make use of any
1508 IOAPICs that may be present in the system.
1509
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 nobats [PPC] Do not use BATs for mapping kernel lowmem
1511 on "Classic" PPC cores.
1512
1513 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001514
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001515 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1516
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001517 nodelayacct [KNL] Disable per-task delay accounting
1518
Linus Torvalds1da177e2005-04-16 15:20:36 -07001519 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1520
Paul Mundt6902aa82008-09-21 17:14:42 +09001521 nodsp [SH] Disable hardware DSP at boot time.
1522
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301523 noefi [X86] Disable EFI runtime services support.
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001524
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525 noexec [IA-64]
1526
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301527 noexec [X86]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001528 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001530 noexec=off: disable non-executable mappings
1531
1532 noexec32 [X86-64]
1533 This affects only 32-bit executables.
1534 noexec32=on: enable non-executable mappings (default)
1535 read doesn't imply executable mappings
1536 noexec32=off: disable non-executable mappings
1537 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538
Paul Mundt6902aa82008-09-21 17:14:42 +09001539 nofpu [SH] Disable hardware FPU at boot time.
1540
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001541 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001542 register save and restore. The kernel will only save
1543 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544
Paulius Zaleckas01a24d22009-03-31 13:55:44 +01001545 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1546 wfi(ARM) instruction doesn't work correctly and not to
1547 use it. This is also useful when using JTAG debugger.
Randy Dunlapa9913042005-10-23 12:57:11 -07001548
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001549 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550 instruction doesn't work correctly and not to
1551 use it.
1552
Serge E. Hallyn1f29fae2008-11-05 16:08:52 -06001553 no_file_caps Tells the kernel not to honor file capabilities. The
1554 only way then for a file to be executed with privilege
1555 is to be setuid root or executed by root.
1556
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 nohalt [IA-64] Tells the kernel not to use the power saving
1558 function PAL_HALT_LIGHT when idle. This increases
1559 power-consumption. On the positive side, it reduces
1560 interrupt wake-up latency, which may improve performance
1561 in certain environments such as networked servers or
1562 real-time systems.
1563
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001564 nohz= [KNL] Boottime enable/disable dynamic ticks
1565 Valid arguments: on, off
1566 Default: on
1567
Paul Mundteeee7852009-04-02 12:31:16 +09001568 noiotrap [SH] Disables trapped I/O port accesses.
1569
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001570 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 disable unhandled interrupt sources.
1572
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301573 no_timer_check [X86,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001574 broken timer IRQ sources.
1575
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 noisapnp [ISAPNP] Disables ISA PnP code.
1577
1578 noinitrd [RAM] Tells the kernel not to load any configured
1579 initial RAM disk.
1580
1581 nointroute [IA-64]
1582
Tony Luck0aa366f2007-07-20 11:22:30 -07001583 nojitter [IA64] Disables jitter checking for ITC timers.
1584
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001585 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001587 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001588
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 noltlbs [PPC] Do not use large page/tlb entries for kernel
1590 lowmem mapping on PPC40x.
1591
Horms312f1f02006-02-22 09:57:55 +09001592 nomca [IA-64] Disable machine check abort handling
1593
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001594 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001595
Andres Salomon83d73842007-10-12 23:04:06 +02001596 nomfgpt [X86-32] Disable Multi-Function General Purpose
1597 Timer usage (for AMD Geode machines).
1598
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001599 norandmaps Don't use address space randomization. Equivalent to
1600 echo 0 > /proc/sys/kernel/randomize_va_space
1601
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001602 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001603
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001604 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001605 with UP alternatives
1606
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607 noresidual [PPC] Don't use residual data on PReP machines.
1608
Randy Dunlapa9913042005-10-23 12:57:11 -07001609 noresume [SWSUSP] Disables resume and restores original swap
1610 space.
1611
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 no-scroll [VGA] Disables scrollback.
1613 This is required for the Braillex ib80-piezo Braille
1614 reader made by F.H. Papenmeier (Germany).
1615
1616 nosbagart [IA-64]
1617
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001618 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001619
Len Brown61ec7562007-08-16 03:34:22 -04001620 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1621 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001622
Dave Jones97842212007-07-15 23:41:05 -07001623 nosoftlockup [KNL] Disable the soft-lockup detector.
1624
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001625 noswapaccount [KNL] Disable accounting of swap in memory resource
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +01001626 controller. (See Documentation/cgroups/memory.txt)
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001627
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628 nosync [HW,M68K] Disables sync negotiation for all devices.
1629
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001630 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631
1632 nousb [USB] Disable the USB subsystem
1633
1634 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001635
Weidong Han8b5b94e2009-04-17 16:42:12 +08001636 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1637
Fenghua Yua6c75b862008-03-14 13:57:08 -07001638 nptcg= [IA64] Override max number of concurrent global TLB
1639 purges which is reported from either PAL_VM_SUMMARY or
1640 SAL PALO.
1641
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001642 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1643
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001644 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1645 one of ['zone', 'node', 'default'] can be specified
1646 This can be set from sysctl after boot.
1647 See Documentation/sysctl/vm.txt for details.
1648
Randy Dunlap7c4be252009-01-06 14:42:44 -08001649 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1650 See Documentation/debugging-via-ohci1394.txt for more
1651 info.
1652
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001653 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1654 Rather than timing out after 20 ms if an EC
1655 command is not properly ACKed, override the length
1656 of the timeout. We have interrupts disabled while
1657 waiting for the ACK, so if this is set too high
1658 interrupts *may* be lost!
1659
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660 opl3= [HW,OSS]
1661 Format: <io>
1662
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 oprofile.timer= [HW]
1664 Use timer interrupt instead of performance counters
1665
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 osst= [HW,SCSI] SCSI Tape Driver
1667 Format: <buffer_size>,<write_threshold>
1668 See also Documentation/scsi/st.txt.
1669
1670 panic= [KNL] Kernel behaviour on panic
1671 Format: <timeout>
1672
1673 parkbd.port= [HW] Parallel port number the keyboard adapter is
1674 connected to, default is 0.
1675 Format: <parport#>
1676 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1677 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001678 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679
Randy Dunlapa9913042005-10-23 12:57:11 -07001680 parport= [HW,PPT] Specify parallel ports. 0 disables.
1681 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1682 Use 'auto' to force the driver to use any
1683 IRQ/DMA settings detected (the default is to
1684 ignore detected IRQ/DMA settings because of
1685 possible conflicts). You can specify the base
1686 address, IRQ, and DMA settings; IRQ and DMA
1687 should be numbers, or 'auto' (for using detected
1688 settings on that particular port), or 'nofifo'
1689 (to avoid using a FIFO even if it is detected).
1690 Parallel ports are assigned in the order they
1691 are specified on the command line, starting
1692 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001693
Randy Dunlapa9913042005-10-23 12:57:11 -07001694 parport_init_mode= [HW,PPT]
1695 Configure VIA parallel port to operate in
1696 a specific mode. This is necessary on Pegasos
1697 computer where firmware has no options for setting
1698 up parallel port mode and sets it to spp.
1699 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700 Format: [spp|ps2|epp|ecp|ecpepp]
1701
Randy Dunlapa9913042005-10-23 12:57:11 -07001702 pas2= [HW,OSS] Format:
1703 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1704
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705 pas16= [HW,SCSI]
1706 See header of drivers/scsi/pas16.c.
1707
Andrew Mortondd287792006-03-23 03:00:57 -08001708 pause_on_oops=
1709 Halt all CPUs after the first oops has been printed for
1710 the specified number of seconds. This is to be used if
1711 your oopses keep scrolling off the screen.
1712
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 pcbit= [HW,ISDN]
1714
1715 pcd. [PARIDE]
1716 See header of drivers/block/paride/pcd.c.
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001717 See also Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718
Randy Dunlapa9913042005-10-23 12:57:11 -07001719 pci=option[,option...] [PCI] various PCI subsystem options:
Bjorn Helgaas1cc0ca22009-01-14 10:04:36 -07001720 earlydump [X86] dump PCI config space before the kernel
1721 changes anything
Andi Kleenc0115602008-08-22 09:53:39 +02001722 off [X86] don't probe for the PCI bus
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001723 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001724 the hardware directly. Use this if your machine
1725 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001726 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001727 hardware access methods are allowed. Use this
1728 if you experience crashes upon bootup and you
1729 suspect they are caused by the BIOS.
Andi Kleenc0115602008-08-22 09:53:39 +02001730 conf1 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001731 Mechanism 1.
Andi Kleenc0115602008-08-22 09:53:39 +02001732 conf2 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001733 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001734 noaer [PCIE] If the PCIEAER kernel config parameter is
1735 enabled, this kernel boot option can be used to
1736 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001737 nodomains [PCI] Disable support for multiple PCI
1738 root domains (aka PCI segments, in ACPI-speak).
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05301739 nommconf [X86] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001740 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001741 nomsi [MSI] If the PCI_MSI kernel config parameter is
1742 enabled, this kernel boot option can be used to
1743 disable the use of MSI interrupts system-wide.
Stefan Assmanna9322f62008-06-11 16:35:14 +02001744 noioapicquirk [APIC] Disable all boot interrupt quirks.
1745 Safety option to keep boot IRQs enabled. This
1746 should never be necessary.
Stefan Assmann91979792008-06-11 16:35:15 +02001747 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1748 primary IO-APIC for bridges that cannot disable
1749 boot IRQs. This fixes a source of spurious IRQs
1750 when the system masks IRQs.
Stefan Assmann41b9eb22008-07-15 13:48:55 +02001751 noioapicreroute [APIC] Disable workaround that uses the
1752 boot IRQ equivalent of an IRQ that connects to
1753 a chipset where boot IRQs cannot be disabled.
1754 The opposite of ioapicreroute.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001755 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001756 routing table. These calls are known to be buggy
1757 on several machines and they hang the machine
1758 when used, but on other computers it's the only
1759 way to get the interrupt routing table. Try
1760 this option if the kernel is unable to allocate
1761 IRQs or discover secondary PCI buses on your
1762 motherboard.
Andi Kleenc0115602008-08-22 09:53:39 +02001763 rom [X86] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001764 Use with caution as certain devices share
1765 address decoders between ROMs and other
1766 resources.
Andi Kleenc0115602008-08-22 09:53:39 +02001767 norom [X86] Do not assign address space to
Gary Hadebb71ad82008-05-12 13:57:46 -07001768 expansion ROMs that do not already have
1769 BIOS assigned address ranges.
Andi Kleenc0115602008-08-22 09:53:39 +02001770 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001771 assigned automatically to PCI devices. You can
1772 make the kernel exclude IRQs of your ISA cards
1773 this way.
Andi Kleenc0115602008-08-22 09:53:39 +02001774 pirqaddr=0xAAAAA [X86] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001775 of the PIRQ table (normally generated
1776 by the BIOS) if it is outside the
1777 F0000h-100000h range.
Andi Kleenc0115602008-08-22 09:53:39 +02001778 lastbus=N [X86] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001779 useful if the kernel is unable to find your
1780 secondary buses and you want to tell it
1781 explicitly which ones they are.
Andi Kleenc0115602008-08-22 09:53:39 +02001782 assign-busses [X86] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001783 numbers ourselves, overriding
1784 whatever the firmware may have done.
Andi Kleenc0115602008-08-22 09:53:39 +02001785 usepirqmask [X86] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001786 in the BIOS $PIR table. This is needed on
1787 some systems with broken BIOSes, notably
1788 some HP Pavilion N5400 and Omnibook XE3
1789 notebooks. This will have no effect if ACPI
1790 IRQ routing is enabled.
Andi Kleenc0115602008-08-22 09:53:39 +02001791 noacpi [X86] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001792 or for PCI scanning.
Andi Kleenc0115602008-08-22 09:53:39 +02001793 use_crs [X86] Use _CRS for PCI resource
Gary Hade62f420f2007-10-03 15:56:51 -07001794 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001795 routeirq Do IRQ routing for all PCI devices.
1796 This is normally done in pci_enable_device(),
1797 so this option is a temporary workaround
1798 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001799 skip_isa_align [X86] do not align io start addr, so can
1800 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001801 firmware [ARM] Do not re-enumerate the bus but instead
1802 just use the configuration from the
1803 bootloader. This is currently used on
1804 IXP2000 systems where the bus has to be
1805 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001806 noearly [X86] Don't do any early type 1 scanning.
1807 This might help on some broken boards which
1808 machine check when some devices' config space
1809 is read. But various workarounds are disabled
1810 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001811 bfsort Sort PCI devices into breadth-first order.
1812 This sorting is done to get a device
1813 order compatible with older (<= 2.4) kernels.
1814 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001815 cbiosize=nn[KMG] The fixed amount of bus space which is
1816 reserved for the CardBus bridge's IO window.
1817 The default value is 256 bytes.
1818 cbmemsize=nn[KMG] The fixed amount of bus space which is
1819 reserved for the CardBus bridge's memory
1820 window. The default value is 64 megabytes.
Yuji Shimada32a9a6822009-03-16 17:13:39 +09001821 resource_alignment=
1822 Format:
1823 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
1824 Specifies alignment and device to reassign
1825 aligned memory resources.
1826 If <order of align> is not specified,
1827 PAGE_SIZE is used as alignment.
1828 PCI-PCI bridge can be specified, if resource
1829 windows need to be expanded.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001830
Chuck Ebberte5665a42008-09-24 20:40:34 -04001831 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1832 Management.
1833 off Disable ASPM.
1834 force Enable ASPM even on devices that claim not to support it.
1835 WARNING: Forcing ASPM on may cause system lockups.
1836
Linus Torvalds1da177e2005-04-16 15:20:36 -07001837 pcmv= [HW,PCMCIA] BadgePAD 4
1838
1839 pd. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001840 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841
1842 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1843 boot time.
1844 Format: { 0 | 1 }
1845 See arch/parisc/kernel/pdc_chassis.c
1846
1847 pf. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001848 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849
1850 pg. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001851 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852
1853 pirq= [SMP,APIC] Manual mp-table setup
Uwe Hermann71cced62008-10-20 09:32:21 -07001854 See Documentation/x86/i386/IO-APIC.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855
1856 plip= [PPT,NET] Parallel port network link
1857 Format: { parport<nr> | timid | 0 }
1858 See also Documentation/parport.txt.
1859
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001860 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1861 Override pmtimer IOPort with a hex value.
1862 e.g. pmtmr=0x508
1863
Bjorn Helgaas97ef0622008-08-19 16:53:41 -06001864 pnp.debug [PNP]
1865 Enable PNP debug messages. This depends on the
1866 CONFIG_PNP_DEBUG_MESSAGES option.
1867
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868 pnpacpi= [ACPI]
1869 { off }
1870
1871 pnpbios= [ISAPNP]
1872 { on | off | curr | res | no-curr | no-res }
1873
1874 pnp_reserve_irq=
1875 [ISAPNP] Exclude IRQs for the autoconfiguration
1876
1877 pnp_reserve_dma=
1878 [ISAPNP] Exclude DMAs for the autoconfiguration
1879
1880 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001881 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882
1883 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001884 [ISAPNP] Exclude memory regions for the
1885 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001886 Ranges are in pairs (memory base and size).
1887
Randy Dunlap4af94f32009-04-17 18:30:28 -07001888 ports= [IP_VS_FTP] IPVS ftp helper module
1889 Default is 21.
1890 Up to 8 (IP_VS_APP_MAX_PORTS) ports
1891 may be specified.
1892 Format: <port>,<port>....
1893
Ingo Molnar45807a12007-07-15 23:40:10 -07001894 print-fatal-signals=
1895 [KNL] debug: print fatal signals
1896 print-fatal-signals=1: print segfault info to
1897 the kernel console.
1898 default: off.
1899
Randy Dunlape84845c2007-07-15 23:40:25 -07001900 printk.time= Show timing data prefixed to each printk message line
1901 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1902
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07001903 processor.max_cstate= [HW,ACPI]
1904 Limit processor to maximum C-state
1905 max_cstate=9 overrides any DMI blacklist limit.
1906
1907 processor.nocst [HW,ACPI]
1908 Ignore the _CST method to determine C-states,
1909 instead using the legacy FADT method
1910
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001912 Format: [schedule,]<number>
1913 Param: "schedule" - profile schedule points.
1914 Param: <number> - step/bucket size as a power of 2 for
1915 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001916 Param: "sleep" - profile D-state sleeping (millisecs).
1917 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001918 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1921 before loading.
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001922 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923
Randy Dunlapa9913042005-10-23 12:57:11 -07001924 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1925 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1927 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001928 psmouse.resetafter= [HW,MOUSE]
1929 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 (0 = never).
1931 psmouse.resolution=
1932 [HW,MOUSE] Set desired mouse resolution, in dpi.
1933 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001934 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935 0 = disabled, 1 = enabled (default).
1936
1937 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001938 Format:
1939 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940
1941 pt. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001942 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943
Kay Sieversdc8c8582007-08-15 12:25:38 +02001944 pty.legacy_count=
1945 [KNL] Number of legacy pty's. Overwrites compiled-in
1946 default number.
1947
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001948 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001949
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 r128= [HW,DRM]
1951
1952 raid= [HW,RAID]
1953 See Documentation/md.txt.
1954
Randy Dunlapa9913042005-10-23 12:57:11 -07001955 ramdisk_blocksize= [RAM]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001956 See Documentation/blockdev/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001957
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001959 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001960
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001961 rcupdate.blimit= [KNL,BOOT]
1962 Set maximum number of finished RCU callbacks to process
1963 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001964
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001965 rcupdate.qhimark= [KNL,BOOT]
1966 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001967 RCU callbacks over which batch limiting is disabled.
1968
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001969 rcupdate.qlowmark= [KNL,BOOT]
1970 Set threshold of queued RCU callbacks below which
1971 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001972
Olof Johanssonffdfc402005-09-06 15:17:19 -07001973 rdinit= [KNL]
1974 Format: <full_path>
1975 Run specified binary instead of /init from the ramdisk,
1976 used for early userspace startup. See initrd.
1977
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001978 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Randy Dunlapecb08d82009-01-06 14:42:44 -08001980 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981
Paul Jackson46b6d942008-07-04 10:00:09 -07001982 relax_domain_level=
1983 [KNL, SMP] Set scheduler's default relax_domain_level.
Thadeu Lima de Souza Cascardo21acb9c2009-02-04 10:12:08 +01001984 See Documentation/cgroups/cpusets.txt.
Paul Jackson46b6d942008-07-04 10:00:09 -07001985
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1987
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001988 reservetop= [X86-32]
Zachary Amsden461a9aff2006-09-25 23:32:25 -07001989 Format: nn[KMG]
1990 Reserves a hole at the top of the kernel virtual
1991 address space.
1992
Vivek Goyal7e962872006-09-27 01:50:44 -07001993 reset_devices [KNL] Force drivers to reset the underlying device
1994 during initialization.
1995
Randy Dunlapa9913042005-10-23 12:57:11 -07001996 resume= [SWSUSP]
1997 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001999 resume_offset= [SWSUSP]
2000 Specify the offset from the beginning of the partition
2001 given by "resume=" at which the swap header is located,
2002 in <PAGE_SIZE> units (needed only for swap files).
2003 See Documentation/power/swsusp-and-swap-files.txt
2004
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08002005 retain_initrd [RAM] Keep initrd memory after extraction
2006
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007 rhash_entries= [KNL,NET]
2008 Set number of hash buckets for route cache
2009
2010 riscom8= [HW,SERIAL]
2011 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
2012
2013 ro [KNL] Mount root device read-only on boot
2014
2015 root= [KNL] Root filesystem
2016
2017 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
2018 mount the root filesystem
2019
2020 rootflags= [KNL] Set root filesystem mount option string
2021
2022 rootfstype= [KNL] Set root filesystem type
2023
Pierre Ossmancc1ed752007-07-15 23:40:35 -07002024 rootwait [KNL] Wait (indefinitely) for root device to show up.
2025 Useful for devices that are detected asynchronously
2026 (e.g. USB and MMC devices).
2027
James Morris20510f22007-10-16 23:31:32 -07002028 root_plug.vendor_id=
2029 [ROOTPLUG] Override the default vendor ID
2030
2031 root_plug.product_id=
2032 [ROOTPLUG] Override the default product ID
2033
2034 root_plug.debug=
2035 [ROOTPLUG] Enable debugging output
2036
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 rw [KNL] Mount root device read-write on boot
2038
2039 S [KNL] Run init in single mode
2040
2041 sa1100ir [NET]
2042 See drivers/net/irda/sa1100_ir.c.
2043
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07002045
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
2047 Format: <io>[,<timeout>[,<isapnp>]]
2048
2049 scsi_debug_*= [SCSI]
2050 See drivers/scsi/scsi_debug.c.
2051
2052 scsi_default_dev_flags=
2053 [SCSI] SCSI default device flags
2054 Format: <integer>
2055
2056 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
2057 Format: <vendor>:<model>:<flags>
2058 (flags are integer value)
2059
Randy Dunlap6af66322007-11-14 16:52:25 -08002060 scsi_logging_level= [SCSI] a bit mask of logging levels
2061 See drivers/scsi/scsi_logging.h for bits. Also
2062 settable via sysctl at dev.scsi.logging_level
2063 (/proc/sys/dev/scsi/logging_level).
2064 There is also a nice 'scsi_logging_level' script in the
2065 S390-tools package, available for download at
2066 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067
Matthew Wilcox3e082a92006-09-28 15:19:20 -06002068 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
2069 discovered. async scans them in kernel threads,
2070 allowing boot to proceed. none ignores them, expecting
2071 user space to do the scan.
2072
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07002073 security= [SECURITY] Choose a security module to enable at boot.
2074 If this boot parameter is not specified, only the first
2075 security module asking for security registration will be
2076 loaded. An invalid security module name will be treated
2077 as if no module has been chosen.
2078
2079 selinux= [SELINUX] Disable or enable SELinux at boot time.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 Format: { "0" | "1" }
2081 See security/selinux/Kconfig help text.
2082 0 -- disable.
2083 1 -- enable.
2084 Default value is set via kernel config option.
2085 If enabled at boot time, /selinux/disable can be used
2086 later to disable prior to initial policy load.
2087
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002088 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089
Linus Torvalds1da177e2005-04-16 15:20:36 -07002090 shapers= [NET]
2091 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07002092
Yinghai Lub05f78f2008-08-22 01:32:50 -07002093 show_msr= [x86] show boot-time MSR settings
2094 Format: { <integer> }
2095 Show boot-time (BIOS-initialized) MSR settings.
2096 The parameter means the number of CPUs to show,
2097 for example 1 means boot CPU only.
2098
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099 sim710= [SCSI,HW]
2100 See header of drivers/scsi/sim710.c.
2101
2102 simeth= [IA-64]
2103 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07002104
Linus Torvalds1da177e2005-04-16 15:20:36 -07002105 slram= [HW,MTD]
2106
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002107 slub_debug[=options[,slabs]] [MM, SLUB]
2108 Enabling slub_debug allows one to determine the
2109 culprit if slab objects become corrupted. Enabling
2110 slub_debug can create guard zones around objects and
2111 may poison objects when not in use. Also tracks the
2112 last alloc / free. For more information see
2113 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002114
2115 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002116 Determines the maximum allowed order for slabs.
2117 A high setting may cause OOMs due to memory
2118 fragmentation. For more information see
2119 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002120
2121 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002122 The minimum number of objects per slab. SLUB will
2123 increase the slab order up to slub_max_order to
2124 generate a sufficiently large slab able to contain
2125 the number of objects indicated. The higher the number
2126 of objects the smaller the overhead of tracking slabs
2127 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002128 For more information see Documentation/vm/slub.txt.
2129
2130 slub_min_order= [MM, SLUB]
2131 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002132 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002133 For more information see Documentation/vm/slub.txt.
2134
2135 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002136 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07002137 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002138 allocs to different slabs. Debug options disable
2139 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002140 For more information see Documentation/vm/slub.txt.
2141
Linus Torvalds1da177e2005-04-16 15:20:36 -07002142 smart2= [HW]
2143 Format: <io1>[,<io2>[,...,<io8>]]
2144
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002145 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02002146 attempt to substitute SMP alternatives once at boot.
2147
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07002148 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2149 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2150 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2151 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2152 smsc-ircc2.ircc_irq= [HW] IRQ line
2153 smsc-ircc2.ircc_dma= [HW] DMA channel
2154 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2155 0: Toshiba Satellite 1800 (GP data pin select)
2156 1: Fast pin select (default)
2157 2: ATC IRMode
2158
Linus Torvalds1da177e2005-04-16 15:20:36 -07002159 snd-ad1816a= [HW,ALSA]
2160
2161 snd-ad1848= [HW,ALSA]
2162
2163 snd-ali5451= [HW,ALSA]
2164
2165 snd-als100= [HW,ALSA]
2166
2167 snd-als4000= [HW,ALSA]
2168
2169 snd-azt2320= [HW,ALSA]
2170
2171 snd-cmi8330= [HW,ALSA]
2172
2173 snd-cmipci= [HW,ALSA]
2174
2175 snd-cs4231= [HW,ALSA]
2176
2177 snd-cs4232= [HW,ALSA]
2178
2179 snd-cs4236= [HW,ALSA]
2180
2181 snd-cs4281= [HW,ALSA]
2182
2183 snd-cs46xx= [HW,ALSA]
2184
2185 snd-dt019x= [HW,ALSA]
2186
2187 snd-dummy= [HW,ALSA]
2188
2189 snd-emu10k1= [HW,ALSA]
2190
2191 snd-ens1370= [HW,ALSA]
2192
2193 snd-ens1371= [HW,ALSA]
2194
2195 snd-es968= [HW,ALSA]
2196
2197 snd-es1688= [HW,ALSA]
2198
2199 snd-es18xx= [HW,ALSA]
2200
2201 snd-es1938= [HW,ALSA]
2202
2203 snd-es1968= [HW,ALSA]
2204
2205 snd-fm801= [HW,ALSA]
2206
2207 snd-gusclassic= [HW,ALSA]
2208
2209 snd-gusextreme= [HW,ALSA]
2210
2211 snd-gusmax= [HW,ALSA]
2212
2213 snd-hdsp= [HW,ALSA]
2214
2215 snd-ice1712= [HW,ALSA]
2216
2217 snd-intel8x0= [HW,ALSA]
2218
2219 snd-interwave= [HW,ALSA]
2220
2221 snd-interwave-stb=
2222 [HW,ALSA]
2223
2224 snd-korg1212= [HW,ALSA]
2225
2226 snd-maestro3= [HW,ALSA]
2227
2228 snd-mpu401= [HW,ALSA]
2229
2230 snd-mtpav= [HW,ALSA]
2231
2232 snd-nm256= [HW,ALSA]
2233
2234 snd-opl3sa2= [HW,ALSA]
2235
2236 snd-opti92x-ad1848=
2237 [HW,ALSA]
2238
2239 snd-opti92x-cs4231=
2240 [HW,ALSA]
2241
2242 snd-opti93x= [HW,ALSA]
2243
2244 snd-pmac= [HW,ALSA]
2245
2246 snd-rme32= [HW,ALSA]
2247
2248 snd-rme96= [HW,ALSA]
2249
2250 snd-rme9652= [HW,ALSA]
2251
2252 snd-sb8= [HW,ALSA]
2253
2254 snd-sb16= [HW,ALSA]
2255
2256 snd-sbawe= [HW,ALSA]
2257
2258 snd-serial= [HW,ALSA]
2259
2260 snd-sgalaxy= [HW,ALSA]
2261
2262 snd-sonicvibes= [HW,ALSA]
2263
2264 snd-sun-amd7930=
2265 [HW,ALSA]
2266
2267 snd-sun-cs4231= [HW,ALSA]
2268
2269 snd-trident= [HW,ALSA]
2270
2271 snd-usb-audio= [HW,ALSA,USB]
2272
2273 snd-via82xx= [HW,ALSA]
2274
2275 snd-virmidi= [HW,ALSA]
2276
2277 snd-wavefront= [HW,ALSA]
2278
2279 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002280
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002281 softlockup_panic=
2282 [KNL] Should the soft-lockup detector generate panics.
2283
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2285 See Documentation/sonypi.txt
2286
2287 specialix= [HW,SERIAL] Specialix multi-serial port adapter
Randy Dunlap31c00fc2008-11-13 21:33:24 +00002288 See Documentation/serial/specialix.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289
2290 spia_io_base= [HW,MTD]
2291 spia_fio_base=
2292 spia_pedr=
2293 spia_peddr=
2294
2295 sscape= [HW,OSS]
2296 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002297
Linus Torvalds1da177e2005-04-16 15:20:36 -07002298 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2299 See Documentation/scsi/st.txt.
2300
Steven Rostedtf38f1d22008-12-16 23:06:40 -05002301 stacktrace [FTRACE]
2302 Enabled the stack tracer on boot up.
2303
Linus Torvalds1da177e2005-04-16 15:20:36 -07002304 sti= [PARISC,HW]
2305 Format: <num>
2306 Set the STI (builtin display/keyboard on the HP-PARISC
2307 machines) console (graphic card) which should be used
2308 as the initial boot-console.
2309 See also comment in drivers/video/console/sticore.c.
2310
2311 sti_font= [HW]
2312 See comment in drivers/video/console/sticore.c.
2313
2314 stifb= [HW]
2315 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2316
Greg Banks42a7fc42007-03-06 01:42:23 -08002317 sunrpc.pool_mode=
2318 [NFS]
2319 Control how the NFS server code allocates CPUs to
2320 service thread pools. Depending on how many NICs
2321 you have and where their interrupts are bound, this
2322 option will affect which CPUs will do NFS serving.
2323 Note: this parameter cannot be changed while the
2324 NFS server is running.
2325
2326 auto the server chooses an appropriate mode
2327 automatically using heuristics
2328 global a single global pool contains all CPUs
2329 percpu one pool for each CPU
2330 pernode one pool for each NUMA node (equivalent
2331 to global on non-NUMA machines)
2332
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002334
Linus Torvalds1da177e2005-04-16 15:20:36 -07002335 switches= [HW,M68k]
2336
2337 sym53c416= [HW,SCSI]
2338 See header of drivers/scsi/sym53c416.c.
2339
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002340 sysrq_always_enabled
2341 [KNL]
2342 Ignore sysrq setting - this boot parameter will
2343 neutralize any effect of /proc/sys/kernel/sysrq.
2344 Useful for debugging.
2345
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346 t128= [HW,SCSI]
2347 See header of drivers/scsi/t128.c.
2348
2349 tdfx= [HW,DRM]
2350
David Brownell77437fd2008-07-23 21:28:33 -07002351 test_suspend= [SUSPEND]
2352 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2353 standby suspend) as the system sleep state to briefly
2354 enter during system startup. The system is woken from
2355 this state using a wakeup-capable RTC alarm.
2356
Linus Torvalds1da177e2005-04-16 15:20:36 -07002357 thash_entries= [KNL,NET]
2358 Set number of hash buckets for TCP connection
2359
Len Brownf8707ec2007-08-12 00:12:54 -04002360 thermal.act= [HW,ACPI]
2361 -1: disable all active trip points in all thermal zones
2362 <degrees C>: override all lowest active trip points
2363
Len Brownc52a7412007-08-14 15:49:32 -04002364 thermal.crt= [HW,ACPI]
2365 -1: disable all critical trip points in all thermal zones
Zhang Rui22a94d72008-10-17 02:41:20 -04002366 <degrees C>: override all critical trip points
Len Brownc52a7412007-08-14 15:49:32 -04002367
Len Brownf5487142007-08-12 00:12:44 -04002368 thermal.nocrt= [HW,ACPI]
2369 Set to disable actions on ACPI thermal zone
2370 critical and hot trip points.
2371
Len Brown72b33ef2007-08-12 00:12:17 -04002372 thermal.off= [HW,ACPI]
2373 1: disable ACPI thermal control
2374
Len Browna70cdc52007-08-12 00:12:35 -04002375 thermal.psv= [HW,ACPI]
2376 -1: disable all passive trip points
Randy Dunlapada9cfd2008-12-19 10:57:32 -08002377 <degrees C>: override all passive trip points to this
2378 value
Len Browna70cdc52007-08-12 00:12:35 -04002379
Len Brown730ff342007-08-12 00:12:26 -04002380 thermal.tzp= [HW,ACPI]
2381 Specify global default ACPI thermal zone polling rate
2382 <deci-seconds>: poll all this frequency
2383 0: no polling (default)
2384
Linus Torvalds1da177e2005-04-16 15:20:36 -07002385 tmscsim= [HW,SCSI]
2386 See comment before function dc390_setup() in
2387 drivers/scsi/tmscsim.c.
2388
Heiko Carstens2b1a61f2008-12-25 13:39:23 +01002389 topology= [S390]
2390 Format: {off | on}
2391 Specify if the kernel should make use of the cpu
2392 topology informations if the hardware supports these.
2393 The scheduler will make use of these informations and
2394 e.g. base its process migration decisions on it.
2395 Default is off.
2396
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397 tp720= [HW,PS2]
2398
KOSAKI Motohiro631595f2009-03-10 13:57:10 +09002399 trace_buf_size=nn[KMG] [ftrace] will set tracing buffer size.
2400
Linus Torvalds1da177e2005-04-16 15:20:36 -07002401 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002402 Format:
2403 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2404
Alok Kataria395628e2008-10-24 17:22:01 -07002405 tsc= Disable clocksource-must-verify flag for TSC.
2406 Format: <string>
2407 [x86] reliable: mark tsc clocksource as reliable, this
2408 disables clocksource verification at runtime.
2409 Used to enable high-resolution timer mode on older
2410 hardware, and in virtualized environment.
2411
Randy Dunlapa9913042005-10-23 12:57:11 -07002412 turbografx.map[2|3]= [HW,JOY]
2413 TurboGraFX parallel port interface
2414 Format:
2415 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002416 See also Documentation/input/joystick-parport.txt
2417
2418 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2419 See header of drivers/scsi/u14-34f.c.
2420
2421 uart401= [HW,OSS]
2422 Format: <io>,<irq>
2423
2424 uart6850= [HW,OSS]
2425 Format: <io>,<irq>
2426
Alan Stern5f8364b2006-12-05 16:29:55 -05002427 uhci-hcd.ignore_oc=
2428 [USB] Ignore overcurrent events (default N).
2429 Some badly-designed motherboards generate lots of
2430 bogus events, for ports that aren't wired to
2431 anything. Set this parameter to avoid log spamming.
2432 Note that genuine overcurrent events won't be
2433 reported either.
2434
Simon Arlotte3a61b02008-07-19 23:32:54 +01002435 unknown_nmi_panic
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05302436 [X86]
Simon Arlotte3a61b02008-07-19 23:32:54 +01002437 Set unknown_nmi_panic=1 early on boot.
2438
Alan Sternb5e795f2007-02-20 15:00:53 -05002439 usbcore.autosuspend=
2440 [USB] The autosuspend time delay (in seconds) used
2441 for newly-detected USB devices (default 2). This
2442 is the time required before an idle device will be
2443 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002444 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002445
Jaroslav Kyselafd7c5192008-10-10 16:24:45 +02002446 usbcore.usbfs_snoop=
2447 [USB] Set to log all usbfs traffic (default 0 = off).
2448
2449 usbcore.blinkenlights=
2450 [USB] Set to cycle leds on hubs (default 0 = off).
2451
2452 usbcore.old_scheme_first=
2453 [USB] Start with the old device initialization
2454 scheme (default 0 = off).
2455
2456 usbcore.use_both_schemes=
2457 [USB] Try the other device initialization scheme
2458 if the first one fails (default 1 = enabled).
2459
2460 usbcore.initial_descriptor_timeout=
2461 [USB] Specifies timeout for the initial 64-byte
2462 USB_REQ_GET_DESCRIPTOR request in milliseconds
2463 (default 5000 = 5.0 seconds).
2464
Linus Torvalds1da177e2005-04-16 15:20:36 -07002465 usbhid.mousepoll=
2466 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002467
Alan Sternd4f373e2008-11-10 14:07:45 -05002468 usb-storage.delay_use=
2469 [UMS] The delay in seconds before a new device is
2470 scanned for Logical Units (default 5).
2471
2472 usb-storage.quirks=
2473 [UMS] A list of quirks entries to supplement or
2474 override the built-in unusual_devs list. List
2475 entries are separated by commas. Each entry has
2476 the form VID:PID:Flags where VID and PID are Vendor
2477 and Product ID values (4-digit hex numbers) and
2478 Flags is a set of characters, each corresponding
2479 to a common usb-storage quirk flag as follows:
Alan Sternc838ea42008-12-15 10:40:06 -05002480 a = SANE_SENSE (collect more than 18 bytes
2481 of sense data);
Alan Sternd4f373e2008-11-10 14:07:45 -05002482 c = FIX_CAPACITY (decrease the reported
2483 device capacity by one sector);
Alan Sternc838ea42008-12-15 10:40:06 -05002484 h = CAPACITY_HEURISTICS (decrease the
2485 reported device capacity by one
2486 sector if the number is odd);
Alan Sternd4f373e2008-11-10 14:07:45 -05002487 i = IGNORE_DEVICE (don't bind to this
2488 device);
2489 l = NOT_LOCKABLE (don't try to lock and
2490 unlock ejectable media);
2491 m = MAX_SECTORS_64 (don't transfer more
2492 than 64 sectors = 32 KB at a time);
Alan Sternc838ea42008-12-15 10:40:06 -05002493 o = CAPACITY_OK (accept the capacity
2494 reported by the device);
Alan Sternd4f373e2008-11-10 14:07:45 -05002495 r = IGNORE_RESIDUE (the device reports
2496 bogus residue values);
2497 s = SINGLE_LUN (the device has only one
2498 Logical Unit);
2499 w = NO_WP_DETECT (don't test whether the
2500 medium is write-protected).
2501 Example: quirks=0419:aaf5:rl,0421:0433:rc
2502
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05302503 vdso= [X86,SH]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002504 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002505 vdso=1: enable VDSO (default)
2506 vdso=0: disable VDSO mapping
2507
Jaswinder Singh Rajput6cececf2009-04-14 14:03:43 +05302508 vdso32= [X86]
Roland McGrathaf65d642008-01-30 13:30:43 +01002509 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2510 vdso32=1: enable 32-bit VDSO (default)
2511 vdso32=0: disable 32-bit VDSO mapping
2512
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002513 vector= [IA-64,SMP]
2514 vector=percpu: enable percpu vector domain
2515
Linus Torvalds1da177e2005-04-16 15:20:36 -07002516 video= [FB] Frame buffer configuration
2517 See Documentation/fb/modedb.txt.
2518
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002519 vga= [BOOT,X86-32] Select a particular video mode
Kyle McMartin954a8b82009-02-19 16:48:14 -05002520 See Documentation/x86/boot.txt and
Randy Dunlapa9913042005-10-23 12:57:11 -07002521 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002522 Use vga=ask for menu.
2523 This is actually a boot loader parameter; the value is
2524 passed to the kernel using a special protocol.
2525
Randy Dunlapa9913042005-10-23 12:57:11 -07002526 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002527 size of <nn>. This can be used to increase the
2528 minimum size (128MB on x86). It can also be used to
2529 decrease the size and leave more room for directly
2530 mapped kernel RAM.
2531
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002532 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2533 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002534
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002535 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2536 Format: <command>
2537
2538 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2539 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002540
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07002541 vt.default_blu= [VT]
2542 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
2543 Change the default blue palette of the console.
2544 This is a 16-member array composed of values
2545 ranging from 0-255.
2546
2547 vt.default_grn= [VT]
2548 Format: <green0>,<green1>,<green2>,...,<green15>
2549 Change the default green palette of the console.
2550 This is a 16-member array composed of values
2551 ranging from 0-255.
2552
2553 vt.default_red= [VT]
2554 Format: <red0>,<red1>,<red2>,...,<red15>
2555 Change the default red palette of the console.
2556 This is a 16-member array composed of values
2557 ranging from 0-255.
2558
2559 vt.default_utf8=
2560 [VT]
2561 Format=<0|1>
2562 Set system-wide default UTF-8 mode for all tty's.
2563 Default is 1, i.e. UTF-8 mode is enabled for all
2564 newly opened terminals.
2565
Linus Torvalds1da177e2005-04-16 15:20:36 -07002566 waveartist= [HW,OSS]
2567 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002568
Linus Torvalds1da177e2005-04-16 15:20:36 -07002569 wd33c93= [HW,SCSI]
2570 See header of drivers/scsi/wd33c93.c.
2571
2572 wd7000= [HW,SCSI]
2573 See header of drivers/scsi/wd7000.c.
2574
2575 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002576 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577
Randy Dunlap0cb55ad2009-04-05 15:55:22 -07002578 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
2579 default x2apic cluster mode on platforms
2580 supporting x2apic.
2581
Linus Torvalds1da177e2005-04-16 15:20:36 -07002582 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2583 xd_geo= See header of drivers/block/xd.c.
2584
2585 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002586 Format:
2587 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002588
Randy Dunlapa9913042005-10-23 12:57:11 -07002589______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002590
2591TODO:
2592
2593 Add documentation for ALSA options.
2594 Add more DRM drivers.