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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
Stefan Richtera901ebb2006-04-01 01:43:18 +020020This document may not be entirely up to date and comprehensive. The command
21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22module. Loadable modules, after being loaded into the running kernel, also
23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24parameters may be changed at runtime by the command
25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
Stefan Richter6585fa82006-04-01 01:44:30 +020027The parameters listed below are only valid if certain kernel build options were
28enabled and if respective hardware is present. The text in square brackets at
29the beginning of each description states the restrictions within which a
30parameter is applicable:
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32 ACPI ACPI support is enabled.
Chuck Ebbertc99c1082007-07-27 10:46:20 +100033 AGP AGP (Accelerated Graphics Port) is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +020037 AVR32 AVR32 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 AX25 Appropriate AX.25 support is enabled.
Robin Getz0ae53642007-10-09 17:24:49 +080039 BLACKFIN Blackfin architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070040 DRM Direct Rendering Management support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 IA-64 IA-64 architecture is enabled.
Mimi Zohar6146f0d2009-02-04 09:06:57 -050047 IMA Integrity measurement architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070049 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 ISAPNP ISA PnP code is enabled.
51 ISDN Appropriate ISDN support is enabled.
52 JOY Appropriate joystick support is enabled.
Kristen Carlson Accardi11ef6972006-09-28 11:29:01 -070053 LIBATA Libata driver is enabled
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 LP Printer support is enabled.
55 LOOP Loopback device support is enabled.
56 M68k M68k architecture is enabled.
57 These options have more detailed description inside of
58 Documentation/m68k/kernel-options.txt.
59 MCA MCA bus support is enabled.
60 MDA MDA console support is enabled.
61 MOUSE Appropriate mouse support is enabled.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070062 MSI Message Signaled Interrupts (PCI).
Randy Dunlapc8facbb2007-07-31 00:37:40 -070063 MTD MTD (Memory Technology Device) support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 NET Appropriate network support is enabled.
65 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070066 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 NFS Appropriate NFS support is enabled.
68 OSS OSS sound support is enabled.
Randy Dunlapc8facbb2007-07-31 00:37:40 -070069 PV_OPS A paravirtualized kernel is enabled.
70 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 PARISC The PA-RISC architecture is enabled.
72 PCI PCI bus support is enabled.
Randy Dunlap7f785762007-10-05 13:17:58 -070073 PCIE PCI Express support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 PCMCIA The PCMCIA subsystem is enabled.
75 PNP Plug & Play support is enabled.
76 PPC PowerPC architecture is enabled.
77 PPT Parallel port support is enabled.
78 PS2 Appropriate PS/2 support is enabled.
79 RAM RAM disk support is enabled.
James Morris20510f22007-10-16 23:31:32 -070080 ROOTPLUG The example Root Plug LSM is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 S390 S390 architecture is enabled.
82 SCSI Appropriate SCSI support is enabled.
83 A lot of drivers has their options described inside of
84 Documentation/scsi/.
James Morris20510f22007-10-16 23:31:32 -070085 SECURITY Different security models are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 SELINUX SELinux support is enabled.
87 SERIAL Serial support is enabled.
Paul Mundte523d932007-02-28 18:30:01 +090088 SH SuperH architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 SMP The kernel is an SMP kernel.
90 SPARC Sparc architecture is enabled.
David Brownell77437fd2008-07-23 21:28:33 -070091 SWSUSP Software suspend (hibernation) is enabled.
92 SUSPEND System suspend states are enabled.
Steven Rostedtf38f1d22008-12-16 23:06:40 -050093 FTRACE Function tracing enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 TS Appropriate touchscreen support is enabled.
Alan Sternd4f373e2008-11-10 14:07:45 -050095 UMS USB Mass Storage support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 USB USB support is enabled.
97 USBHID USB Human Interface Device support is enabled.
98 V4L Video For Linux support is enabled.
99 VGA The VGA console has been enabled.
100 VT Virtual terminal support is enabled.
101 WDT Watchdog support is enabled.
102 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700103 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 X86-64 X86-64 architecture is enabled.
105 More X86-64 boot options can be found in
Uwe Hermann71cced62008-10-20 09:32:21 -0700106 Documentation/x86/x86_64/boot-options.txt .
Andi Kleenc0115602008-08-22 09:53:39 +0200107 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109In addition, the following text indicates that the option:
110
111 BUGS= Relates to possible processor bugs on the said processor.
112 KNL Is a kernel start-up parameter.
113 BOOT Is a boot loader parameter.
114
115Parameters denoted with BOOT are actually interpreted by the boot
116loader, and have no meaning to the kernel directly.
117Do not modify the syntax of boot loader parameters without extreme
Kyle McMartin954a8b82009-02-19 16:48:14 -0500118need or coordination with <Documentation/x86/boot.txt>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
Karsten Weiss55588702007-02-13 13:26:21 +0100120There are also arch-specific kernel-parameters not documented here.
Uwe Hermann71cced62008-10-20 09:32:21 -0700121See for example <Documentation/x86/x86_64/boot-options.txt>.
Karsten Weiss55588702007-02-13 13:26:21 +0100122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
124a trailing = on the name of any parameter states that that parameter will
125be entered as an environment variable, whereas its absence indicates that
126it will appear as a kernel argument readable via /proc/cmdline by programs
127running once the system is up.
128
jens m. noedler9c4751f2006-09-29 02:00:27 -0700129The number of kernel parameters is not limited, but the length of the
130complete command line (parameters including spaces etc.) is limited to
131a fixed number of characters. This limit depends on the architecture
132and is between 256 and 4096 characters. It is defined in the file
133./include/asm/setup.h as COMMAND_LINE_SIZE.
134
135
Bernhard Walle03d926f2007-03-06 02:29:44 -0800136 acpi= [HW,ACPI,X86-64,i386]
137 Advanced Configuration and Power Interface
Randy Dunlapaf23f572009-02-22 17:05:22 -0800138 Format: { force | off | ht | strict | noirq | rsdt }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 force -- enable ACPI if default was off
140 off -- disable ACPI if default was on
141 noirq -- do not use ACPI for IRQ routing
142 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700143 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 strictly ACPI specification compliant.
Zhao Yakui237889b2008-12-17 16:55:18 +0800145 rsdt -- prefer RSDT over (default) XSDT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
Randy Dunlap53471122008-03-12 18:10:51 -0400147 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148
Len Browna1fdcc02007-03-11 03:26:14 -0400149 acpi_apic_instance= [ACPI, IOAPIC]
150 Format: <int>
151 2: use 2nd APIC table, if available
152 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400153 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 acpi_sleep= [HW,ACPI] Sleep options
Rafael J. Wysockiba84ed92008-10-26 20:56:30 +0100156 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
157 old_ordering, s4_nonvs }
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800158 See Documentation/power/video.txt for information on
159 s3_bios and s3_mode.
Pavel Machek23b168d2008-02-05 19:27:12 +0100160 s3_beep is for debugging; it makes the PC's speaker beep
161 as soon as the kernel's real-mode entry point is called.
Shaohua Libdfe6b72008-07-23 21:28:41 -0700162 s4_nohwsig prevents ACPI hardware signature from being
163 used during resume from hibernation.
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200164 old_ordering causes the ACPI 1.0 ordering of the _PTS
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800165 control method, with respect to putting devices into
166 low power states, to be enforced (the ACPI 2.0 ordering
167 of _PTS is used by default).
Rafael J. Wysockiba84ed92008-10-26 20:56:30 +0100168 s4_nonvs prevents the kernel from saving/restoring the
169 ACPI NVS memory during hibernation.
Randy Dunlapa9913042005-10-23 12:57:11 -0700170
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700172 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Randy Dunlapa9913042005-10-23 12:57:11 -0700174 acpi_irq_balance [HW,ACPI]
175 ACPI will balance active IRQs
176 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
Randy Dunlapa9913042005-10-23 12:57:11 -0700178 acpi_irq_nobalance [HW,ACPI]
179 ACPI will not move active IRQs (default)
180 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181
Randy Dunlapa9913042005-10-23 12:57:11 -0700182 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
183 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 Format: <irq>,<irq>...
185
Randy Dunlapa9913042005-10-23 12:57:11 -0700186 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 Format: <irq>,<irq>...
188
Len Brown67effe82007-07-26 00:50:06 -0400189 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
190
Len Browna1f9e652006-01-25 23:47:36 -0500191 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
192 Format: To spoof as Windows 98: ="Microsoft Windows"
193
Len Brownae00d812007-05-29 18:43:33 -0400194 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
195 acpi_osi="string1" # add string1 -- only one string
196 acpi_osi="!string2" # remove built-in string2
197 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
199 acpi_serialize [HW,ACPI] force serialization of AML methods
200
201 acpi_skip_timer_override [HW,ACPI]
202 Recognize and ignore IRQ0/pin2 Interrupt Override.
203 For broken nForce2 BIOS resulting in XT-PIC timer.
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800204 acpi_use_timer_override [HW,ACPI]
Andi Kleenfa18f472006-11-14 16:57:46 +0100205 Use timer override. For some broken Nvidia NF5 boards
206 that require a timer override, but don't have
207 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208
Thomas Renningerc3d6de62008-08-01 17:37:55 +0200209 acpi_backlight= [HW,ACPI]
210 acpi_backlight=vendor
211 acpi_backlight=video
212 If set to vendor, prefer vendor specific driver
213 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
214 of the ACPI video.ko driver.
215
216 acpi_display_output= [HW,ACPI]
217 acpi_display_output=vendor
218 acpi_display_output=video
219 See above.
220
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700221 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
222 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 Format: <int>
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700224 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
225 debug output. Bits in debug_layer correspond to a
226 _COMPONENT in an ACPI source file, e.g.,
227 #define _COMPONENT ACPI_PCI_COMPONENT
228 Bits in debug_level correspond to a level in
229 ACPI_DEBUG_PRINT statements, e.g.,
230 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
Bjorn Helgaase76f4272008-11-13 17:30:13 -0600231 The debug_level mask defaults to "info". See
232 Documentation/acpi/debug.txt for more information about
233 debug layers and levels.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
Bjorn Helgaase76f4272008-11-13 17:30:13 -0600235 Enable processor driver info messages:
236 acpi.debug_layer=0x20000000
237 Enable PCI/PCI interrupt routing info messages:
238 acpi.debug_layer=0x400000
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700239 Enable AML "Debug" output, i.e., stores to the Debug
240 object while interpreting AML:
241 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700242 Enable all messages related to ACPI hardware:
243 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
Thomas Renninger36eec5e2008-08-11 15:03:20 +0200244
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700245 Some values produce so much output that the system is
246 unusable. The "log_buf_len" parameter may be useful
247 if you need to capture more output.
Zhang Ruif9891062007-04-24 13:53:22 +0800248
Zhao Yakuif5adfaa2008-08-11 14:57:50 +0800249 acpi.power_nocheck= [HW,ACPI]
250 Format: 1/0 enable/disable the check of power state.
251 On some bogus BIOS the _PSC object/_STA object of
252 power resource can't return the correct device power
253 state. In such case it is unneccessary to check its
254 power state again in power transition.
255 1 : disable the power state check
256
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700257 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700258 Override the pmtimer bug detection: force the kernel
259 to assume that this machine's pmtimer latches its value
260 and always returns good values.
261
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000262 agp= [AGP]
263 { off | try_unsupported }
264 off: disable AGP support
265 try_unsupported: try to drive unsupported chipsets
266 (may crash computer or cause data corruption)
267
Chuck Ebbert66759a02005-09-12 18:49:25 +0200268 enable_timer_pin_1 [i386,x86-64]
269 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700270 Can be useful to work around chipset bugs
271 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200272 The kernel tries to set a reasonable default.
273
274 disable_timer_pin_1 [i386,x86-64]
275 Disable PIN 1 of APIC timer
276 Can be useful to work around chipset bugs.
277
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 ad1848= [HW,OSS]
279 Format: <io>,<irq>,<dma>,<dma2>,<type>
280
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 advansys= [HW,SCSI]
282 See header of drivers/scsi/advansys.c.
283
284 advwdt= [HW,WDT] Advantech WDT
285 Format: <iostart>,<iostop>
286
287 aedsp16= [HW,OSS] Audio Excel DSP 16
288 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
289 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 aha152x= [HW,SCSI]
292 See Documentation/scsi/aha152x.txt.
293
294 aha1542= [HW,SCSI]
295 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
296
297 aic7xxx= [HW,SCSI]
298 See Documentation/scsi/aic7xxx.txt.
299
300 aic79xx= [HW,SCSI]
301 See Documentation/scsi/aic79xx.txt.
302
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200303 amd_iommu= [HW,X86-84]
304 Pass parameters to the AMD IOMMU driver in the system.
305 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200306 isolate - enable device isolation (each device, as far
307 as possible, will get its own protection
Joerg Roedel3ce1f932008-11-17 15:09:20 +0100308 domain) [default]
Joerg Roedele5e1f602008-11-17 15:07:17 +0100309 share - put every device behind one IOMMU into the
310 same protection domain
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900311 fullflush - enable flushing of IO/TLB entries when
312 they are unmapped. Otherwise they are
313 flushed before they will be reused, which
314 is a lot of faster
315
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200316 amd_iommu_size= [HW,X86-64]
317 Define the size of the aperture for the AMD IOMMU
318 driver. Possible values are:
319 '32M', '64M' (default), '128M', '256M', '512M', '1G'
320
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 amijoy.map= [HW,JOY] Amiga joystick support
322 Map of devices attached to JOY0DAT and JOY1DAT
323 Format: <a>,<b>
324 See also Documentation/kernel/input/joystick.txt
325
326 analog.map= [HW,JOY] Analog joystick and gamepad support
327 Specifies type or capabilities of an analog joystick
328 connected to one of 16 gameports
329 Format: <type1>,<type2>,..<type16>
330
Randy Dunlapa9913042005-10-23 12:57:11 -0700331 apc= [HW,SPARC]
332 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 Format: noidle
334 Disable APC CPU standby support. SPARCstation-Fox does
335 not play well with APC CPU idle - disable it if you have
336 APC and your system crashes randomly.
337
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700338 apic= [APIC,i386] Advanced Programmable Interrupt Controller
339 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 Format: { quiet (default) | verbose | debug }
341 Change the amount of debugging information output
342 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700343
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700345 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
348 Format: <io>,<irq>,<nodeID>
349
350 ataflop= [HW,M68k]
351
352 atarimouse= [HW,MOUSE] Atari Mouse
353
354 atascsi= [HW,SCSI] Atari SCSI
355
356 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
357 EzKey and similar keyboards
358
359 atkbd.reset= [HW] Reset keyboard during initialization
360
Randy Dunlapa9913042005-10-23 12:57:11 -0700361 atkbd.set= [HW] Select keyboard code set
362 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
364 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
365 keyboards
366
367 atkbd.softraw= [HW] Choose between synthetic and real raw mode
368 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700369
370 atkbd.softrepeat= [HW]
371 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372
373 autotest [IA64]
374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 baycom_epp= [HW,AX25]
376 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700377
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
379 Format: <io>,<mode>
380 See header of drivers/net/hamradio/baycom_par.c.
381
Randy Dunlapa9913042005-10-23 12:57:11 -0700382 baycom_ser_fdx= [HW,AX25]
383 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 Format: <io>,<irq>,<mode>[,<baud>]
385 See header of drivers/net/hamradio/baycom_ser_fdx.c.
386
Randy Dunlapa9913042005-10-23 12:57:11 -0700387 baycom_ser_hdx= [HW,AX25]
388 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 Format: <io>,<irq>,<mode>
390 See header of drivers/net/hamradio/baycom_ser_hdx.c.
391
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700392 boot_delay= Milliseconds to delay each printk during boot.
393 Values larger than 10 seconds (10000) are changed to
394 no delay (0).
395 Format: integer
396
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700397 bootmem_debug [KNL] Enable bootmem allocator debug messages.
398
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700400 bttv.radio= Most important insmod options are available as
401 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
403 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
404
405 BusLogic= [HW,SCSI]
406 See drivers/scsi/BusLogic.c, comment before function
407 BusLogic_ParseDriverOptions().
408
409 c101= [NET] Moxa C101 synchronous serial card
410
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700411 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 Sometimes CPU hardware bugs make them report the cache
413 size incorrectly. The kernel will attempt work arounds
414 to fix known problems, but for some CPUs it is not
415 possible to determine what the correct size should be.
416 This option provides an override for these situations.
417
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200418 security= [SECURITY] Choose a security module to enable at boot.
419 If this boot parameter is not specified, only the first
420 security module asking for security registration will be
421 loaded. An invalid security module name will be treated
422 as if no module has been chosen.
423
James Morris20510f22007-10-16 23:31:32 -0700424 capability.disable=
425 [SECURITY] Disable capabilities. This would normally
426 be used only if an alternative security model is to be
427 configured. Potentially dangerous and should only be
428 used if you are entirely sure of the consequences.
429
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100430 ccw_timeout_log [S390]
431 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
Paul Menage8bab8dd2008-04-04 14:29:57 -0700433 cgroup_disable= [KNL] Disable a particular controller
434 Format: {name of the controller(s) to disable}
435 {Currently supported controllers - "memory"}
436
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 checkreqprot [SELINUX] Set initial checkreqprot flag value.
438 Format: { "0" | "1" }
439 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700440 0 -- check protection applied by kernel (includes
441 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 1 -- check protection requested by application.
443 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700444 Value can be changed at runtime via
445 /selinux/checkreqprot.
446
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100447 cio_ignore= [S390]
448 See Documentation/s390/CommonIO for details.
449
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700450 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700451 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200452 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700453 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200454 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 Format: { pit | tsc | cyclone | pmtmr }
456
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700457 clocksource= [GENERIC_TIME] Override the default clocksource
458 Format: <string>
459 Override the default clocksource and use the clocksource
460 with the name specified.
461 Some clocksource names to choose from, depending on
462 the platform:
463 [all] jiffies (this is the base, fallback clocksource)
464 [ACPI] acpi_pm
465 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
466 pxa_timer,timer3,32k_counter,timer0_1
467 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700468 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700469 scx200_hrt on Geode; cyclone on IBM x440
470 [MIPS] MIPS
471 [PARISC] cr16
472 [S390] tod
473 [SH] SuperH
474 [SPARC64] tick
475 [X86-64] hpet,tsc
476
Andi Kleenac72e782008-01-30 13:33:21 +0100477 clearcpuid=BITNUM [X86]
478 Disable CPUID feature X for the kernel. See
Randy Dunlap07983f02009-01-06 14:42:41 -0800479 arch/x86/include/asm/cpufeature.h for the valid bit
480 numbers. Note the Linux specific bits are not necessarily
Andi Kleenac72e782008-01-30 13:33:21 +0100481 stable over kernel options, but the vendor specific
482 ones should be.
483 Also note that user programs calling CPUID directly
484 or using the feature without checking anything
485 will still see it. This just prevents it from
486 being used by the kernel or shown in /proc/cpuinfo.
487 Also note the kernel might malfunction if you disable
488 some critical bits.
489
Arjan van de Vena25bd942008-01-30 13:33:08 +0100490 code_bytes [IA32/X86_64] How many bytes of object code to print
491 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100492 Range: 0 - 8192
493 Default: 64
494
Joerg Roedel59d3daa2009-01-09 13:01:56 +0100495 dma_debug=off If the kernel is compiled with DMA_API_DEBUG support
496 this option disables the debugging code at boot.
497
498 dma_debug_entries=<number>
499 This option allows to tune the number of preallocated
500 entries for DMA-API debugging code. One entry is
501 required per DMA-API allocation. Use this if the
502 DMA-API debugging code disables itself because the
503 architectural default is too low.
504
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200505 hpet= [X86-32,HPET] option to control HPET usage
Andreas Herrmannb98103a2009-02-21 00:09:47 +0100506 Format: { enable (default) | disable | force |
507 verbose }
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200508 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100509 force: allow force enabled of undocumented chips (ICH4,
510 VIA, nVidia)
Andreas Herrmannb98103a2009-02-21 00:09:47 +0100511 verbose: show contents of HPET registers during setup
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700514 Format:
515 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516
517 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
518 Format: <io>[,<irq>]
519
Randy Dunlapa9913042005-10-23 12:57:11 -0700520 com90xx= [HW,NET]
521 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 Format: <io>[,<irq>[,<memstart>]]
523
524 condev= [HW,S390] console device
525 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700526
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 console= [KNL] Output console device and options.
528
529 tty<n> Use the virtual console device <n>.
530
531 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800532 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800534 the form "bbbbpnf", where "bbbb" is the baud rate,
535 "p" is parity ("n", "o", or "e"), "n" is number of
536 bits, and "f" is flow control ("r" for RTS or
537 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800539 See Documentation/serial-console.txt for more
540 information. See
541 Documentation/networking/netconsole.txt for an
542 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700544 uart[8250],io,<addr>[,options]
545 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 Start an early, polled-mode console on the 8250/16550
547 UART at the specified I/O port or MMIO address,
548 switching to the matching ttyS device later. The
549 options are the same as for ttyS, above.
550
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700551 If the device connected to the port is not a TTY but a braille
552 device, prepend "brl," before the device type, for instance
553 console=brl,ttyS0
554 For now, only VisioBraille is supported.
555
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700556 earlycon= [KNL] Output early console device and options.
557 uart[8250],io,<addr>[,options]
558 uart[8250],mmio,<addr>[,options]
559 Start an early, polled-mode console on the 8250/16550
560 UART at the specified I/O port or MMIO address.
561 The options are the same as for ttyS, above.
562
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700563 no_console_suspend
564 [HW] Never suspend the console
565 Disable suspending of consoles during suspend and
566 hibernate operations. Once disabled, debugging
567 messages can reach various consoles while the rest
568 of the system is being put to sleep (ie, while
569 debugging driver suspend/resume hooks). This may
570 not work reliably with all consoles, but is known
571 to work with serial and VGA consoles.
572
Hidehiro Kawai4cb0e112009-01-06 14:42:47 -0800573 coredump_filter=
574 [KNL] Change the default value for
575 /proc/<pid>/coredump_filter.
576 See also Documentation/filesystems/proc.txt.
577
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700579 Format:
580 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700582 crashkernel=nn[KMG]@ss[KMG]
583 [KNL] Reserve a chunk of physical memory to
584 hold a kernel to switch to with kexec on panic.
585
Bernhard Wallefb391592007-10-18 23:41:02 -0700586 crashkernel=range1:size1[,range2:size2,...][@offset]
587 [KNL] Same as above, but depends on the memory
588 in the running system. The syntax of range is
589 start-[end] where start and end are both
590 a memory unit (amount[KMG]). See also
591 Documentation/kdump/kdump.txt for a example.
592
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 cs89x0_dma= [HW,NET]
594 Format: <dma>
595
596 cs89x0_media= [HW,NET]
597 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700598
Randy Dunlapa9913042005-10-23 12:57:11 -0700599 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 See header of drivers/s390/block/dasd_devmap.c.
601
602 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
603 (one device per port)
604 Format: <port#>,<type>
605 See also Documentation/input/joystick-parport.txt
606
607 debug [KNL] Enable kernel debugging (events log level).
608
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700609 debug_locks_verbose=
610 [KNL] verbose self-tests
611 Format=<0|1>
612 Print debugging info while doing the locking API
613 self-tests.
614 We default to 0 (no extra messages), setting it to
615 1 will print _a lot_ more information - normally
616 only useful to kernel developers.
617
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700618 debug_objects [KNL] Enable object debugging
619
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200620 debugpat [X86] Enable PAT debugging
621
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200622 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 Format: <area>[,<node>]
624 See also Documentation/networking/decnet.txt.
625
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000626 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700627 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
628 Change the default blue palette of the console.
629 This is a 16-member array composed of values
630 ranging from 0-255.
631
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000632 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700633 Format: <green0>,<green1>,<green2>,...,<green15>
634 Change the default green palette of the console.
635 This is a 16-member array composed of values
636 ranging from 0-255.
637
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000638 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700639 Format: <red0>,<red1>,<red2>,...,<red15>
640 Change the default red palette of the console.
641 This is a 16-member array composed of values
642 ranging from 0-255.
643
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000644 vt.default_utf8=
645 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700646 Format=<0|1>
647 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000648 Default is 1, i.e. UTF-8 mode is enabled for all
649 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700650
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 dhash_entries= [KNL]
652 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700653
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 digi= [HW,SERIAL]
655 IO parameters + enable/disable command.
656
657 digiepca= [HW,SERIAL]
658 See drivers/char/README.epca and
Randy Dunlap31c00fc2008-11-13 21:33:24 +0000659 Documentation/serial/digiepca.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660
Yinghai Lu95ffa242008-04-29 03:52:33 -0700661 disable_mtrr_cleanup [X86]
662 enable_mtrr_cleanup [X86]
663 The kernel tries to adjust MTRR layout from continuous
664 to discrete, to make X server driver able to add WB
665 entry later. This parameter enables/disables that.
666
667 mtrr_chunk_size=nn[KMG] [X86]
668 used for mtrr cleanup. It is largest continous chunk
669 that could hold holes aka. UC entries.
670
671 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700672 Used for mtrr cleanup. It is granularity of mtrr block.
673 Default is 1.
674 Large value could prevent small alignment from
675 using up MTRRs.
676
677 mtrr_spare_reg_nr=n [X86]
678 Format: <integer>
679 Range: 0,7 : spare reg number
680 Default : 1
681 Used for mtrr cleanup. It is spare mtrr entries number.
682 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700683
Yinghai Lu093af8d2008-01-30 13:33:32 +0100684 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100685 By default the kernel will trim any uncacheable
686 memory out of your available memory pool based on
687 MTRR settings. This parameter disables that behavior,
688 possibly causing your machine to run very slowly.
689
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 dmasound= [HW,OSS] Sound subsystem buffers
691
692 dscc4.setup= [NET]
693
694 dtc3181e= [HW,SCSI]
695
Robin Getz0ae53642007-10-09 17:24:49 +0800696 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 earlyprintk=vga
698 earlyprintk=serial[,ttySn[,baudrate]]
Yinghai Lu5c059172008-07-24 17:29:40 -0700699 earlyprintk=dbgp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700
Randy Dunlapa9913042005-10-23 12:57:11 -0700701 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 takes over.
703
Yinghai Lu5c059172008-07-24 17:29:40 -0700704 Only vga or serial or usb debug port at a time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705
706 Currently only ttyS0 and ttyS1 are supported.
707
708 Interaction with the standard serial driver is not
709 very good.
710
711 The VGA output is eventually overwritten by the real
712 console.
713
714 eata= [HW,SCSI]
715
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700717 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 eisa_irq_edge= [PARISC,HW]
720 See header of drivers/parisc/eisa.c.
721
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700722 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700724 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725
726 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800727 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700728 See Documentation/block/as-iosched.txt and
729 Documentation/block/deadline-iosched.txt for details.
730
Simon Hormane515a0d2008-10-18 20:28:27 -0700731 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700732 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800733 image elf header. Generally kexec loader will
734 pass this option to capture kernel.
735 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736
737 enforcing [SELINUX] Set initial enforcing status.
738 Format: {"0" | "1"}
739 See security/selinux/Kconfig help text.
740 0 -- permissive (log only, no denials).
741 1 -- enforcing (deny and log).
742 Default value is 0.
743 Value can be changed at runtime via /selinux/enforce.
744
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 ether= [HW,NET] Ethernet cards parameters
746 This option is obsoleted by the "netdev=" option, which
747 has equivalent usage. See its documentation for details.
748
749 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
750 Format: <io>[,<irq>]
751
Akinobu Mitade1ba092006-12-08 02:39:42 -0800752 failslab=
753 fail_page_alloc=
754 fail_make_request=[KNL]
755 General fault injection mechanism.
756 Format: <interval>,<probability>,<space>,<times>
757 See also /Documentation/fault-injection/.
758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 fd_mcs= [HW,SCSI]
760 See header of drivers/scsi/fd_mcs.c.
761
762 fdomain= [HW,SCSI]
763 See header of drivers/scsi/fdomain.c.
764
765 floppy= [HW]
Randy Dunlap31c00fc2008-11-13 21:33:24 +0000766 See Documentation/blockdev/floppy.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
Alex Chiangf13ae302008-05-08 14:03:23 -0600768 force_pal_cache_flush
769 [IA-64] Avoid check_sal_cache_flush which may hang on
770 buggy SAL_CACHE_FLUSH implementations. Using this
771 parameter will force ia64_sal_cache_flush to call
772 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
773
Peter Zijlstrad9e54072008-11-01 19:57:37 +0100774 ftrace=[tracer]
775 [ftrace] will set and start the specified tracer
776 as early as possible in order to facilitate early
777 boot debugging.
778
779 ftrace_dump_on_oops
780 [ftrace] will dump the trace buffers on oops.
781
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 gamecon.map[2|3]=
783 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
784 support via parallel port (up to 5 devices per port)
785 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
786 See also Documentation/input/joystick-parport.txt
787
788 gamma= [HW,DRM]
789
Yinghai Luaaf23042008-01-30 13:33:09 +0100790 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
791 Format: off | on
792 default: on
793
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 gdth= [HW,SCSI]
795 See header of drivers/scsi/gdth.c.
796
797 gpt [EFI] Forces disk with valid GPT signature but
798 invalid Protective MBR to be treated as GPT.
799
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 gvp11= [HW,SCSI]
801
802 hashdist= [KNL,NUMA] Large hashes allocated during boot
803 are distributed across NUMA nodes. Defaults on
804 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700805 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
807 hcl= [IA-64] SGI's Hardware Graph compatibility layer
808
809 hd= [EIDE] (E)IDE hard drive subsystem geometry
810 Format: <cyl>,<head>,<sect>
811
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
813 size of <nn>. This works even on boxes that have no
814 highmem otherwise. This also works to reduce highmem
815 size on bigger boxes.
816
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800817 highres= [KNL] Enable/disable high resolution timer mode.
818 Valid parameters: "on", "off"
819 Default: "on"
820
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 hisax= [HW,ISDN]
822 See Documentation/isdn/README.HiSax.
823
Andi Kleenb4718e62008-07-23 21:27:51 -0700824 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
825 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700826 On x86-64 and powerpc, this option can be specified
827 multiple times interleaved with hugepages= to reserve
828 huge pages of different sizes. Valid pages sizes on
829 x86-64 are 2M (when the CPU supports "pse") and 1G
830 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700831 Note that 1GB pages can only be allocated at boot time
832 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700833 default_hugepagesz=
834 [same as hugepagesz=] The size of the default
835 HugeTLB page size. This is the size represented by
836 the legacy /proc/ hugepages APIs, used for SHM, and
837 default size when mounting hugetlbfs filesystems.
838 Defaults to the default architecture's huge page size
839 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Paul Mundt6902aa82008-09-21 17:14:42 +0900841 hlt [BUGS=ARM,SH]
842
Hendrik Brueckner555d61d2009-01-09 12:15:02 +0100843 hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
844 terminal devices. Valid values: 0..8
Hendrik Brueckner431429f2009-03-26 15:23:55 +0100845 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
846 If specified, z/VM IUCV HVC accepts connections
847 from listed z/VM user IDs only.
Hendrik Bruecknercef71252008-12-25 13:39:55 +0100848
Jarkko Nikula3a853fb2009-03-23 18:07:47 -0700849 i2c_bus= [HW] Override the default board specific I2C bus speed
Jarkko Nikula79547632009-03-23 18:07:48 -0700850 or register an additional I2C bus that is not
851 registered from board initialization code.
Jarkko Nikula3a853fb2009-03-23 18:07:47 -0700852 Format:
853 <bus_id>,<clkrate>
854
Jiri Kosina36d95732008-10-06 02:51:09 -0400855 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200857 i8042.dumbkbd [HW] Pretend that controller can only read data from
858 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 (Don't attempt to blink the leds)
860 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500861 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400862 i8042.noloop [HW] Disable the AUX Loopback command while probing
863 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 i8042.nomux [HW] Don't check presence of an active multiplexing
865 controller
866 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
867 controllers
868 i8042.panicblink=
869 [HW] Frequency with which keyboard LEDs should blink
870 when kernel panics (default is 0.5 sec)
871 i8042.reset [HW] Reset the controller during init and cleanup
872 i8042.unlock [HW] Unlock (ignore) the keylock
873
874 i810= [HW,DRM]
875
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700876 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
877 indicates that the driver is running on unsupported
878 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
880 does not match list of supported models.
881 i8k.power_status
882 [HW] Report power status in /proc/i8k
883 (disabled by default)
884 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
885 capability is set.
886
887 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
888 See Documentation/mca.txt.
889
890 icn= [HW,ISDN]
891 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
892
David Fries0af80c02009-02-25 20:28:21 +0100893 ide-core.nodma= [HW] (E)IDE subsystem
894 Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc
895 .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom
896 .chs .ignore_cable are additional options
Randy Dunlap1c10e932008-03-07 21:53:50 +0100897 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100900 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901
Andi Kleenf039b752007-05-02 19:27:12 +0200902 idle= [X86]
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800903 Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
904 Poll forces a polling idle loop that can slightly
905 improve the performance of waking up a idle CPU, but
906 will use a lot of power and make the system run hot.
907 Not recommended.
908 idle=mwait: On systems which support MONITOR/MWAIT but
909 the kernel chose to not use it because it doesn't save
910 as much power as a normal idle loop, use the
911 MONITOR/MWAIT idle loop anyways. Performance should be
912 the same as idle=poll.
913 idle=halt: Halt is forced to be used for CPU idle.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800914 In such case C2/C3 won't be used again.
Randy Dunlapada9cfd2008-12-19 10:57:32 -0800915 idle=nomwait: Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700916
Denis Cheng594765a2008-02-06 02:57:49 +0100917 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
918 Claim all unknown PCI IDE storage controllers.
919
Ingo Molnar792908222006-12-06 20:40:51 -0800920 ignore_loglevel [KNL]
921 Ignore loglevel setting - this will print /all/
922 kernel messages to the console. Useful for debugging.
923
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 ihash_entries= [KNL]
925 Set number of hash buckets for inode cache.
926
Mimi Zohar3323eec92009-02-04 09:06:58 -0500927 ima_audit= [IMA]
928 Format: { "0" | "1" }
929 0 -- integrity auditing messages. (Default)
930 1 -- enable informational integrity auditing messages.
931
932 ima_hash= [IMA]
933 Formt: { "sha1" | "md5" }
934 default: "sha1"
935
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936 in2000= [HW,SCSI]
937 See header of drivers/scsi/in2000.c.
938
939 init= [KNL]
940 Format: <full_path>
941 Run specified binary instead of /sbin/init as init
942 process.
943
944 initcall_debug [KNL] Trace initcalls as they are executed. Useful
945 for working out where the kernel is dying during
946 startup.
947
948 initrd= [BOOT] Specify the location of the initial ramdisk
949
950 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
951 Format: <irq>
952
953 inttest= [IA64]
954
Arjan van de Vene8de1482008-10-22 19:55:31 -0700955 iomem= Disable strict checking of access to MMIO memory
956 strict regions from userspace.
957 relaxed
958
Pavel Machekb552da82008-03-19 15:58:11 +0100959 iommu= [x86]
960 off
961 force
962 noforce
963 biomerge
964 panic
965 nopanic
966 merge
967 nomerge
968 forcesac
969 soft
970
971
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700972 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
Kyle McMartin0cd5c3c2009-02-04 14:29:19 -0800973 on
974 Enable intel iommu driver.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700975 off
976 Disable intel iommu driver.
977 igfx_off [Default Off]
978 By default, gfx is mapped as normal device. If a gfx
979 device has a dedicated DMAR unit, the DMAR unit is
980 bypassed by not enabling DMAR with this option. In
981 this case, gfx device will use physical address for
982 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700983 forcedac [x86_64]
984 With this option iommu will not optimize to look
985 for io virtual address below 32 bit forcing dual
986 address cycle on pci bus for cards supporting greater
987 than 32 bit addressing. The default is to look
988 for translation below 32 bit and if not available
989 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800990 strict [Default Off]
991 With this option on every unmap_single operation will
992 result in a hardware IOTLB flush operation as opposed
993 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700994
Rene Hermanb02aae92008-01-30 13:30:05 +0100995 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100996 0x80
997 Standard port 0x80 based delay
998 0xed
999 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +01001000 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +01001001 Simple two microseconds delay
1002 none
1003 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +01001004
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 io7= [HW] IO7 for Marvel based alpha systems
1006 See comment before marvel_specify_io7 in
1007 arch/alpha/kernel/core_marvel.c.
1008
1009 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001010 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011
1012 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001013 See comment before ip2_setup() in
1014 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015
1016 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
1017 See header of drivers/scsi/ips.c.
1018
Simon Horman72c4a132006-09-13 19:57:18 -07001019 ports= [IP_VS_FTP] IPVS ftp helper module
1020 Default is 21.
1021 Up to 8 (IP_VS_APP_MAX_PORTS) ports
1022 may be specified.
1023 Format: <port>,<port>....
1024
Alan Cox200803d2005-06-28 20:45:18 -07001025 irqfixup [HW]
1026 When an interrupt is not handled search all handlers
1027 for it. Intended to get systems with badly broken
1028 firmware running.
1029
1030 irqpoll [HW]
1031 When an interrupt is not handled search all handlers
1032 for it. Also check all handlers each timer
1033 interrupt. Intended to get systems with badly broken
1034 firmware running.
1035
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -07001037 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038
1039 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -08001040 Format:
1041 <cpu number>,...,<cpu number>
1042 or
Li Zefanb225d442008-11-06 12:53:39 -08001043 <cpu number>-<cpu number>
1044 (must be a positive range in ascending order)
Derek Fults22f2e282006-12-06 20:37:11 -08001045 or a mixture
1046 <cpu number>,...,<cpu number>-<cpu number>
Li Zefanb225d442008-11-06 12:53:39 -08001047
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 This option can be used to specify one or more CPUs
1049 to isolate from the general SMP balancing and scheduling
Li Zefanb225d442008-11-06 12:53:39 -08001050 algorithms. You can move a process onto or off an
1051 "isolated" CPU via the CPU affinity syscalls or cpuset.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 <cpu number> begins at 0 and the maximum value is
1053 "number of CPUs in system - 1".
1054
1055 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -07001056 alternative -- manually setting the CPU mask of all
1057 tasks in the system -- can cause problems and
1058 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059
Randy Dunlapa9913042005-10-23 12:57:11 -07001060 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061
1062 js= [HW,JOY] Analog joystick
1063 See Documentation/input/joystick.txt.
1064
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001065 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -07001066 specifies the amount of memory usable by the kernel
1067 for non-movable allocations. The requested amount is
1068 spread evenly throughout all nodes in the system. The
1069 remaining memory in each node is used for Movable
1070 pages. In the event, a node is too small to have both
1071 kernelcore and Movable pages, kernelcore pages will
1072 take priority and other nodes will have a larger number
1073 of kernelcore pages. The Movable zone is used for the
1074 allocation of pages that may be reclaimed or moved
1075 by the page migration subsystem. This means that
1076 HugeTLB pages may not be allocated from this zone.
1077 Note that allocations like PTEs-from-HighMem still
1078 use the HighMem zone if it exists, and the Normal
1079 zone if it does not.
1080
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001081 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001082 is similar to kernelcore except it specifies the
1083 amount of memory used for migratable allocations.
1084 If both kernelcore and movablecore is specified,
1085 then kernelcore will be at *least* the specified
1086 value but may be more. If movablecore on its own
1087 is specified, the administrator must be careful
1088 that the amount of memory usable for all allocations
1089 is not too small.
1090
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 keepinitrd [HW,ARM]
1092
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001093 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 in oops dumps.
1095
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001096 kgdboc= [HW] kgdb over consoles.
1097 Requires a tty driver that supports console polling.
1098 (only serial suported for now)
1099 Format: <serial_device>[,baud]
1100
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001101 kmac= [MIPS] korina ethernet MAC address.
1102 Configure the RouterBoard 532 series on-chip
1103 Ethernet adapter MAC address.
1104
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 l2cr= [PPC]
1106
Robert Brosea78bfbf2008-03-29 07:20:23 +11001107 l3cr= [PPC]
1108
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001109 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001110 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111
Randy Dunlapada9cfd2008-12-19 10:57:32 -08001112 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer
1113 in C2 power state.
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001114
FD Camifcb71f62008-01-06 19:08:56 +01001115 libata.dma= [LIBATA] DMA control
1116 libata.dma=0 Disable all PATA and SATA DMA
1117 libata.dma=1 PATA and SATA Disk DMA only
1118 libata.dma=2 ATAPI (CDROM) DMA only
1119 libata.dma=4 Compact Flash DMA only
1120 Combinations also work, so libata.dma=3 enables DMA
1121 for disks and CDROMs, but not CFs.
1122
Dave Jones78e70c22007-09-27 11:50:13 -04001123 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1124 when set.
1125 Format: <int>
1126
Tejun Heo33267322008-02-13 09:15:09 +09001127 libata.force= [LIBATA] Force configurations. The format is comma
1128 separated list of "[ID:]VAL" where ID is
1129 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1130 matching port, link or device. Basically, it matches
1131 the ATA ID string printed on console by libata. If
1132 the whole ID part is omitted, the last PORT and DEVICE
1133 values are used. If ID hasn't been specified yet, the
1134 configuration applies to all ports, links and devices.
1135
1136 If only DEVICE is omitted, the parameter applies to
1137 the port and all links and devices behind it. DEVICE
1138 number of 0 either selects the first device or the
1139 first fan-out link behind PMP device. It does not
1140 select the host link. DEVICE number of 15 selects the
1141 host link and device attached to it.
1142
1143 The VAL specifies the configuration to force. As long
1144 as there's no ambiguity shortcut notation is allowed.
1145 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1146 The following configurations can be forced.
1147
1148 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1149 Any ID with matching PORT is used.
1150
1151 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1152
1153 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1154 udma[/][16,25,33,44,66,100,133] notation is also
1155 allowed.
1156
1157 * [no]ncq: Turn on or off NCQ.
1158
Tejun Heo05944bd2008-08-13 20:19:09 +09001159 * nohrst, nosrst, norst: suppress hard, soft
1160 and both resets.
1161
Tejun Heo33267322008-02-13 09:15:09 +09001162 If there are multiple matching configurations changing
1163 the same attribute, the last one is used.
1164
Randy Dunlap7c4be2532009-01-06 14:42:44 -08001165 lmb=debug [KNL] Enable lmb debug messages.
1166
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167 load_ramdisk= [RAM] List of ramdisks to load from floppy
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001168 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001170 lockd.nlm_grace_period=P [NFS] Assign grace period.
1171 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001173 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1174 Format: <integer>
1175
1176 lockd.nlm_timeout=T [NFS] Assign timeout value.
1177 Format: <integer>
1178
1179 lockd.nlm_udpport=M [NFS] Assign UDP port.
1180 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181
1182 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1183 Format: <irq>
1184
1185 loglevel= All Kernel Messages with a loglevel smaller than the
1186 console loglevel will be printed to the console. It can
1187 also be changed with klogd or other programs. The
1188 loglevels are defined as follows:
1189
1190 0 (KERN_EMERG) system is unusable
1191 1 (KERN_ALERT) action must be taken immediately
1192 2 (KERN_CRIT) critical conditions
1193 3 (KERN_ERR) error conditions
1194 4 (KERN_WARNING) warning conditions
1195 5 (KERN_NOTICE) normal but significant condition
1196 6 (KERN_INFO) informational
1197 7 (KERN_DEBUG) debug-level messages
1198
1199 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001200 Format: { n | nk | nM }
1201 n must be a power of two. The default size
1202 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203
Randy Dunlapaccaa242007-10-16 01:29:37 -07001204 logo.nologo [FB] Disables display of the built-in Linux logo.
1205 This may be used to provide more screen space for
1206 kernel log messages and is useful when debugging
1207 kernel boot problems.
1208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 lp=0 [LP] Specify parallel ports to use, e.g,
1210 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1211 lp=reset first parallel port). 'lp=0' disables the
1212 lp=auto printer driver. 'lp=reset' (which can be
1213 specified in addition to the ports) causes
1214 attached printers to be reset. Using
1215 lp=port1,port2,... specifies the parallel ports
1216 to associate lp devices with, starting with
1217 lp0. A port specification may be 'none' to skip
1218 that lp device, or a parport name such as
1219 'parport0'. Specifying 'lp=auto' instead of a
1220 port specification list means that device IDs
1221 from each port should be examined, to see if
1222 an IEEE 1284-compliant printer is attached; if
1223 so, the driver will manage that printer.
1224 See also header of drivers/char/lp.c.
1225
1226 lpj=n [KNL]
1227 Sets loops_per_jiffy to given constant, thus avoiding
1228 time-consuming boot-time autodetection (up to 250 ms per
1229 CPU). 0 enables autodetection (default). To determine
1230 the correct value for your kernel, boot with normal
1231 autodetection and see what value is printed. Note that
1232 on SMP systems the preset will be applied to all CPUs,
1233 which is likely to cause problems if your CPUs need
1234 significantly divergent settings. An incorrect value
1235 will cause delays in the kernel to be wrong, leading to
1236 unpredictable I/O errors and other breakage. Although
1237 unlikely, in the extreme case this might damage your
1238 hardware.
1239
1240 ltpc= [NET]
1241 Format: <io>,<irq>,<dma>
1242
Randy Dunlapa9913042005-10-23 12:57:11 -07001243 mac5380= [HW,SCSI] Format:
1244 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245
Randy Dunlapa9913042005-10-23 12:57:11 -07001246 machvec= [IA64] Force the use of a particular machine-vector
1247 (machvec) in a generic kernel.
1248 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249
Randy Dunlapa9913042005-10-23 12:57:11 -07001250 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 be mounted
1252 Format: <1-256>
1253
1254 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001255 should make use of. maxcpus=n : n >= 0 limits the
1256 kernel to using 'n' processors. n=0 is a special case,
1257 it is equivalent to "nosmp", which also disables
1258 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259
Randy Dunlap1c207f92008-11-19 15:36:16 -08001260 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
1261 or equal to this physical address is ignored.
Bob Picco2b2c3752005-06-29 18:00:00 -07001262
Randy Dunlapa9913042005-10-23 12:57:11 -07001263 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 Should be between 1 and 2^32-1.
1265
1266 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001267 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268 Should be between 1 and 16384.
1269
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 mcatest= [IA-64]
1271
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001272 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273
Uwe Hermann71cced62008-10-20 09:32:21 -07001274 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
Andi Kleen909dd322007-10-17 18:04:38 +02001275
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 md= [HW] RAID subsystems devices and level
1277 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001278
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 mdacon= [MDA]
1280 Format: <first>,<last>
1281 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001282
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1284 Amount of memory to be used when the kernel is not able
1285 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001286 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 address space collisions. Without memmap= PCI devices
1288 could be placed at addresses belonging to unused RAM.
1289
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001290 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 memory.
1292
Paul Mundt6902aa82008-09-21 17:14:42 +09001293 memchunk=nn[KMG]
1294 [KNL,SH] Allow user to override the default size for
1295 per-device physically contiguous DMA buffers.
1296
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001297 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298 E820 memory map, as specified by the user.
1299 Such memmap=exactmap lines can be constructed based on
1300 BIOS output or other requirements. See the memmap=nn@ss
1301 option description.
1302
1303 memmap=nn[KMG]@ss[KMG]
1304 [KNL] Force usage of a specific region of memory
1305 Region of memory to be used, from ss to ss+nn.
1306
1307 memmap=nn[KMG]#ss[KMG]
1308 [KNL,ACPI] Mark specific memory as ACPI data.
1309 Region of memory to be used, from ss to ss+nn.
1310
1311 memmap=nn[KMG]$ss[KMG]
1312 [KNL,ACPI] Mark specific memory as reserved.
1313 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001314 Example: Exclude memory from 0x18690000-0x1869ffff
1315 memmap=64K$0x18690000
1316 or
1317 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001319 memory_corruption_check=0/1 [X86]
1320 Some BIOSes seem to corrupt the first 64k of
1321 memory when doing things like suspend/resume.
1322 Setting this option will scan the memory
1323 looking for corruption. Enabling this will
1324 both detect corruption and prevent the kernel
1325 from using the memory being corrupted.
1326 However, its intended as a diagnostic tool; if
1327 repeatable BIOS-originated corruption always
1328 affects the same memory, you can use memmap=
1329 to prevent the kernel from using that memory.
1330
1331 memory_corruption_check_size=size [X86]
1332 By default it checks for corruption in the low
1333 64k, making this memory unavailable for normal
1334 use. Use this parameter to scan for
1335 corruption in more or less memory.
1336
1337 memory_corruption_check_period=seconds [X86]
1338 By default it checks for corruption every 60
1339 seconds. Use this parameter to check at some
1340 other rate. 0 disables periodic checking.
1341
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001342 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001343 Format: <integer>
Yinghai Luc64df702008-03-21 18:56:19 -07001344 default : 0 <disable>
Andreas Herrmann9e5f6cf2009-02-25 11:30:45 +01001345 Specifies the number of memtest passes to be
1346 performed. Each pass selects another test
1347 pattern from a given set of patterns. Memtest
1348 fills the memory with this pattern, validates
1349 memory contents and reserves bad memory
1350 regions that are detected.
Yinghai Luc64df702008-03-21 18:56:19 -07001351
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 meye.*= [HW] Set MotionEye Camera parameters
1353 See Documentation/video4linux/meye.txt.
1354
Andres Salomon8f368812007-10-12 23:04:06 +02001355 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1356 Multi-Function General Purpose Timers on AMD Geode
1357 platforms.
1358
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001359 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1360 the BIOS has incorrectly applied a workaround. TinyBIOS
1361 version 0.98 is known to be affected, 0.99 fixes the
1362 problem by letting the user disable the workaround.
1363
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 mga= [HW,DRM]
1365
Randy Dunlap1c207f92008-11-19 15:36:16 -08001366 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1367 physical address is ignored.
1368
Mel Gorman6b74ab92008-07-23 21:26:49 -07001369 mminit_loglevel=
1370 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1371 parameter allows control of the logging verbosity for
1372 the additional memory initialisation checks. A value
1373 of 0 disables mminit logging and a level of 4 will
1374 log everything. Information is printed at KERN_DEBUG
1375 so loglevel=8 may also need to be specified.
1376
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 mousedev.tap_time=
1378 [MOUSE] Maximum time between finger touching and
1379 leaving touchpad surface for touch to be considered
1380 a tap and be reported as a left button click (for
1381 touchpads working in absolute mode only).
1382 Format: <msecs>
1383 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1384 reporting absolute coordinates, such as tablets
1385 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1386 reporting absolute coordinates, such as tablets
1387
1388 mpu401= [HW,OSS]
1389 Format: <io>,<irq>
1390
1391 MTD_Partition= [MTD]
1392 Format: <name>,<region-number>,<size>,<offset>
1393
Randy Dunlapa9913042005-10-23 12:57:11 -07001394 MTD_Region= [MTD] Format:
1395 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396
1397 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001398 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399
Ben Dooks9db829f2008-07-03 11:24:29 +01001400 mtdset= [ARM]
1401 ARM/S3C2412 JIVE boot control
1402
1403 See arch/arm/mach-s3c2412/mach-jive.c
1404
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001406 [HW] Make the MicroTouch USB driver use raw coordinates
1407 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408
1409 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1410
1411 NCR_D700= [HW,SCSI]
1412 See header of drivers/scsi/NCR_D700.c.
1413
1414 ncr5380= [HW,SCSI]
1415
1416 ncr53c400= [HW,SCSI]
1417
1418 ncr53c400a= [HW,SCSI]
1419
1420 ncr53c406a= [HW,SCSI]
1421
1422 ncr53c8xx= [HW,SCSI]
1423
1424 netdev= [NET] Network devices parameters
1425 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1426 Note that mem_start is often overloaded to mean
1427 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001428 This usage is only documented in each driver source
1429 file if at all.
1430
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001431 nf_conntrack.acct=
1432 [NETFILTER] Enable connection tracking flow accounting
1433 0 to disable accounting
1434 1 to enable accounting
1435 Default value depends on CONFIG_NF_CT_ACCT that is
1436 going to be removed in 2.6.29.
1437
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001439 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440
1441 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001442 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443
Trond Myklebusta72b4422006-01-03 09:55:41 +01001444 nfs.callback_tcpport=
1445 [NFS] set the TCP port on which the NFSv4 callback
1446 channel should listen.
1447
Trond Myklebust58df0952006-01-03 09:55:57 +01001448 nfs.idmap_cache_timeout=
1449 [NFS] set the maximum lifetime for idmapper cache
1450 entries.
1451
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001452 nfs.enable_ino64=
1453 [NFS] enable 64-bit inode numbers.
1454 If zero, the NFS client will fake up a 32-bit inode
1455 number for the readdir() and stat() syscalls instead
1456 of returning the full 64-bit number.
1457 The default is to return 64-bit inode numbers.
1458
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001459 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1460 when a NMI is triggered.
1461 Format: [state][,regs][,debounce][,die]
1462
Cyrill Gorcunov5b9a0e12008-11-01 18:06:51 +03001463 nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels
1464 Format: [panic,][num]
1465 Valid num: 0,1,2
1466 0 - turn nmi_watchdog off
1467 1 - use the IO-APIC timer for the NMI watchdog
1468 2 - use the local APIC for the NMI watchdog using
1469 a performance counter. Note: This will use one performance
1470 counter and the local APIC's performance vector.
1471 When panic is specified panic when an NMI watchdog timeout occurs.
1472 This is useful when you use a panic=... timeout and need the box
1473 quickly up again.
1474 Instead of 1 and 2 it is possible to use the following
1475 symbolic names: lapic and ioapic
1476 Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001478 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 emulation library even if a 387 maths coprocessor
1480 is present.
1481
Christoph Lameterc1aee212007-05-31 00:40:47 -07001482 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1483 caches in the slab allocator. Saves per-node memory,
1484 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001485
Randy Dunlapa9913042005-10-23 12:57:11 -07001486 noalign [KNL,ARM]
1487
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 noapic [SMP,APIC] Tells the kernel to not make use of any
1489 IOAPICs that may be present in the system.
1490
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 nobats [PPC] Do not use BATs for mapping kernel lowmem
1492 on "Classic" PPC cores.
1493
1494 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001495
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001496 nodelayacct [KNL] Disable per-task delay accounting
1497
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1499
Paul Mundt6902aa82008-09-21 17:14:42 +09001500 nodsp [SH] Disable hardware DSP at boot time.
1501
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001502 noefi [X86-32,X86-64] Disable EFI runtime services support.
1503
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 noexec [IA-64]
1505
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001506 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001507 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001509 noexec=off: disable non-executable mappings
1510
1511 noexec32 [X86-64]
1512 This affects only 32-bit executables.
1513 noexec32=on: enable non-executable mappings (default)
1514 read doesn't imply executable mappings
1515 noexec32=off: disable non-executable mappings
1516 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517
Paul Mundt6902aa82008-09-21 17:14:42 +09001518 nofpu [SH] Disable hardware FPU at boot time.
1519
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001520 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001521 register save and restore. The kernel will only save
1522 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523
Andi Kleen191679f2008-01-30 13:33:21 +01001524 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1525
Paulius Zaleckas01a24d22009-03-31 13:55:44 +01001526 nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
1527 wfi(ARM) instruction doesn't work correctly and not to
1528 use it. This is also useful when using JTAG debugger.
Randy Dunlapa9913042005-10-23 12:57:11 -07001529
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001530 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531 instruction doesn't work correctly and not to
1532 use it.
1533
Serge E. Hallyn1f29fae2008-11-05 16:08:52 -06001534 no_file_caps Tells the kernel not to honor file capabilities. The
1535 only way then for a file to be executed with privilege
1536 is to be setuid root or executed by root.
1537
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538 nohalt [IA-64] Tells the kernel not to use the power saving
1539 function PAL_HALT_LIGHT when idle. This increases
1540 power-consumption. On the positive side, it reduces
1541 interrupt wake-up latency, which may improve performance
1542 in certain environments such as networked servers or
1543 real-time systems.
1544
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001545 nohz= [KNL] Boottime enable/disable dynamic ticks
1546 Valid arguments: on, off
1547 Default: on
1548
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001549 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550 disable unhandled interrupt sources.
1551
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001552 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001553 broken timer IRQ sources.
1554
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555 noisapnp [ISAPNP] Disables ISA PnP code.
1556
1557 noinitrd [RAM] Tells the kernel not to load any configured
1558 initial RAM disk.
1559
1560 nointroute [IA-64]
1561
Tony Luck0aa366f2007-07-20 11:22:30 -07001562 nojitter [IA64] Disables jitter checking for ITC timers.
1563
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001564 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001566 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001567
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001568 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1569
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001570 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1571 default x2apic cluster mode on platforms
1572 supporting x2apic.
1573
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 noltlbs [PPC] Do not use large page/tlb entries for kernel
1575 lowmem mapping on PPC40x.
1576
Horms312f1f02006-02-22 09:57:55 +09001577 nomca [IA-64] Disable machine check abort handling
1578
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001579 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001580
Andres Salomon83d73842007-10-12 23:04:06 +02001581 nomfgpt [X86-32] Disable Multi-Function General Purpose
1582 Timer usage (for AMD Geode machines).
1583
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001584 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001585
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001586 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001587 with UP alternatives
1588
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 noresidual [PPC] Don't use residual data on PReP machines.
1590
Randy Dunlapa9913042005-10-23 12:57:11 -07001591 noresume [SWSUSP] Disables resume and restores original swap
1592 space.
1593
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594 no-scroll [VGA] Disables scrollback.
1595 This is required for the Braillex ib80-piezo Braille
1596 reader made by F.H. Papenmeier (Germany).
1597
1598 nosbagart [IA-64]
1599
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001600 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001601
Len Brown61ec7562007-08-16 03:34:22 -04001602 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1603 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604
Dave Jones97842212007-07-15 23:41:05 -07001605 nosoftlockup [KNL] Disable the soft-lockup detector.
1606
KAMEZAWA Hiroyukic0777192009-01-07 18:07:57 -08001607 noswapaccount [KNL] Disable accounting of swap in memory resource
1608 controller. (See Documentation/controllers/memory.txt)
1609
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 nosync [HW,M68K] Disables sync negotiation for all devices.
1611
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001612 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613
1614 nousb [USB] Disable the USB subsystem
1615
1616 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001617
Fenghua Yua6c75b862008-03-14 13:57:08 -07001618 nptcg= [IA64] Override max number of concurrent global TLB
1619 purges which is reported from either PAL_VM_SUMMARY or
1620 SAL PALO.
1621
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001622 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1623 one of ['zone', 'node', 'default'] can be specified
1624 This can be set from sysctl after boot.
1625 See Documentation/sysctl/vm.txt for details.
1626
Dave Jonesa61c2d72006-01-07 23:18:19 +00001627 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1628
Randy Dunlap7c4be2532009-01-06 14:42:44 -08001629 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
1630 See Documentation/debugging-via-ohci1394.txt for more
1631 info.
1632
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001633 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1634 Rather than timing out after 20 ms if an EC
1635 command is not properly ACKed, override the length
1636 of the timeout. We have interrupts disabled while
1637 waiting for the ACK, so if this is set too high
1638 interrupts *may* be lost!
1639
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 opl3= [HW,OSS]
1641 Format: <io>
1642
Linus Torvalds1da177e2005-04-16 15:20:36 -07001643 oprofile.timer= [HW]
1644 Use timer interrupt instead of performance counters
1645
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646 osst= [HW,SCSI] SCSI Tape Driver
1647 Format: <buffer_size>,<write_threshold>
1648 See also Documentation/scsi/st.txt.
1649
1650 panic= [KNL] Kernel behaviour on panic
1651 Format: <timeout>
1652
1653 parkbd.port= [HW] Parallel port number the keyboard adapter is
1654 connected to, default is 0.
1655 Format: <parport#>
1656 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1657 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001658 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659
Randy Dunlapa9913042005-10-23 12:57:11 -07001660 parport= [HW,PPT] Specify parallel ports. 0 disables.
1661 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1662 Use 'auto' to force the driver to use any
1663 IRQ/DMA settings detected (the default is to
1664 ignore detected IRQ/DMA settings because of
1665 possible conflicts). You can specify the base
1666 address, IRQ, and DMA settings; IRQ and DMA
1667 should be numbers, or 'auto' (for using detected
1668 settings on that particular port), or 'nofifo'
1669 (to avoid using a FIFO even if it is detected).
1670 Parallel ports are assigned in the order they
1671 are specified on the command line, starting
1672 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673
Randy Dunlapa9913042005-10-23 12:57:11 -07001674 parport_init_mode= [HW,PPT]
1675 Configure VIA parallel port to operate in
1676 a specific mode. This is necessary on Pegasos
1677 computer where firmware has no options for setting
1678 up parallel port mode and sets it to spp.
1679 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680 Format: [spp|ps2|epp|ecp|ecpepp]
1681
Randy Dunlapa9913042005-10-23 12:57:11 -07001682 pas2= [HW,OSS] Format:
1683 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1684
Linus Torvalds1da177e2005-04-16 15:20:36 -07001685 pas16= [HW,SCSI]
1686 See header of drivers/scsi/pas16.c.
1687
Andrew Mortondd287792006-03-23 03:00:57 -08001688 pause_on_oops=
1689 Halt all CPUs after the first oops has been printed for
1690 the specified number of seconds. This is to be used if
1691 your oopses keep scrolling off the screen.
1692
Linus Torvalds1da177e2005-04-16 15:20:36 -07001693 pcbit= [HW,ISDN]
1694
1695 pcd. [PARIDE]
1696 See header of drivers/block/paride/pcd.c.
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001697 See also Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698
Randy Dunlapa9913042005-10-23 12:57:11 -07001699 pci=option[,option...] [PCI] various PCI subsystem options:
Bjorn Helgaas1cc0ca22009-01-14 10:04:36 -07001700 earlydump [X86] dump PCI config space before the kernel
1701 changes anything
Andi Kleenc0115602008-08-22 09:53:39 +02001702 off [X86] don't probe for the PCI bus
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001703 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001704 the hardware directly. Use this if your machine
1705 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001706 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001707 hardware access methods are allowed. Use this
1708 if you experience crashes upon bootup and you
1709 suspect they are caused by the BIOS.
Andi Kleenc0115602008-08-22 09:53:39 +02001710 conf1 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001711 Mechanism 1.
Andi Kleenc0115602008-08-22 09:53:39 +02001712 conf2 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001713 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001714 noaer [PCIE] If the PCIEAER kernel config parameter is
1715 enabled, this kernel boot option can be used to
1716 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001717 nodomains [PCI] Disable support for multiple PCI
1718 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001719 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001720 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001721 nomsi [MSI] If the PCI_MSI kernel config parameter is
1722 enabled, this kernel boot option can be used to
1723 disable the use of MSI interrupts system-wide.
Stefan Assmanna9322f62008-06-11 16:35:14 +02001724 noioapicquirk [APIC] Disable all boot interrupt quirks.
1725 Safety option to keep boot IRQs enabled. This
1726 should never be necessary.
Stefan Assmann91979792008-06-11 16:35:15 +02001727 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1728 primary IO-APIC for bridges that cannot disable
1729 boot IRQs. This fixes a source of spurious IRQs
1730 when the system masks IRQs.
Stefan Assmann41b9eb22008-07-15 13:48:55 +02001731 noioapicreroute [APIC] Disable workaround that uses the
1732 boot IRQ equivalent of an IRQ that connects to
1733 a chipset where boot IRQs cannot be disabled.
1734 The opposite of ioapicreroute.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001735 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001736 routing table. These calls are known to be buggy
1737 on several machines and they hang the machine
1738 when used, but on other computers it's the only
1739 way to get the interrupt routing table. Try
1740 this option if the kernel is unable to allocate
1741 IRQs or discover secondary PCI buses on your
1742 motherboard.
Andi Kleenc0115602008-08-22 09:53:39 +02001743 rom [X86] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001744 Use with caution as certain devices share
1745 address decoders between ROMs and other
1746 resources.
Andi Kleenc0115602008-08-22 09:53:39 +02001747 norom [X86] Do not assign address space to
Gary Hadebb71ad82008-05-12 13:57:46 -07001748 expansion ROMs that do not already have
1749 BIOS assigned address ranges.
Andi Kleenc0115602008-08-22 09:53:39 +02001750 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001751 assigned automatically to PCI devices. You can
1752 make the kernel exclude IRQs of your ISA cards
1753 this way.
Andi Kleenc0115602008-08-22 09:53:39 +02001754 pirqaddr=0xAAAAA [X86] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001755 of the PIRQ table (normally generated
1756 by the BIOS) if it is outside the
1757 F0000h-100000h range.
Andi Kleenc0115602008-08-22 09:53:39 +02001758 lastbus=N [X86] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001759 useful if the kernel is unable to find your
1760 secondary buses and you want to tell it
1761 explicitly which ones they are.
Andi Kleenc0115602008-08-22 09:53:39 +02001762 assign-busses [X86] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001763 numbers ourselves, overriding
1764 whatever the firmware may have done.
Andi Kleenc0115602008-08-22 09:53:39 +02001765 usepirqmask [X86] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001766 in the BIOS $PIR table. This is needed on
1767 some systems with broken BIOSes, notably
1768 some HP Pavilion N5400 and Omnibook XE3
1769 notebooks. This will have no effect if ACPI
1770 IRQ routing is enabled.
Andi Kleenc0115602008-08-22 09:53:39 +02001771 noacpi [X86] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001772 or for PCI scanning.
Andi Kleenc0115602008-08-22 09:53:39 +02001773 use_crs [X86] Use _CRS for PCI resource
Gary Hade62f420f2007-10-03 15:56:51 -07001774 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001775 routeirq Do IRQ routing for all PCI devices.
1776 This is normally done in pci_enable_device(),
1777 so this option is a temporary workaround
1778 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001779 skip_isa_align [X86] do not align io start addr, so can
1780 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001781 firmware [ARM] Do not re-enumerate the bus but instead
1782 just use the configuration from the
1783 bootloader. This is currently used on
1784 IXP2000 systems where the bus has to be
1785 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001786 noearly [X86] Don't do any early type 1 scanning.
1787 This might help on some broken boards which
1788 machine check when some devices' config space
1789 is read. But various workarounds are disabled
1790 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001791 bfsort Sort PCI devices into breadth-first order.
1792 This sorting is done to get a device
1793 order compatible with older (<= 2.4) kernels.
1794 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001795 cbiosize=nn[KMG] The fixed amount of bus space which is
1796 reserved for the CardBus bridge's IO window.
1797 The default value is 256 bytes.
1798 cbmemsize=nn[KMG] The fixed amount of bus space which is
1799 reserved for the CardBus bridge's memory
1800 window. The default value is 64 megabytes.
Yuji Shimada32a9a6822009-03-16 17:13:39 +09001801 resource_alignment=
1802 Format:
1803 [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...]
1804 Specifies alignment and device to reassign
1805 aligned memory resources.
1806 If <order of align> is not specified,
1807 PAGE_SIZE is used as alignment.
1808 PCI-PCI bridge can be specified, if resource
1809 windows need to be expanded.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001810
Chuck Ebberte5665a42008-09-24 20:40:34 -04001811 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1812 Management.
1813 off Disable ASPM.
1814 force Enable ASPM even on devices that claim not to support it.
1815 WARNING: Forcing ASPM on may cause system lockups.
1816
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817 pcmv= [HW,PCMCIA] BadgePAD 4
1818
1819 pd. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001820 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821
1822 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1823 boot time.
1824 Format: { 0 | 1 }
1825 See arch/parisc/kernel/pdc_chassis.c
1826
1827 pf. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001828 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829
1830 pg. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001831 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832
1833 pirq= [SMP,APIC] Manual mp-table setup
Uwe Hermann71cced62008-10-20 09:32:21 -07001834 See Documentation/x86/i386/IO-APIC.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835
1836 plip= [PPT,NET] Parallel port network link
1837 Format: { parport<nr> | timid | 0 }
1838 See also Documentation/parport.txt.
1839
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001840 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1841 Override pmtimer IOPort with a hex value.
1842 e.g. pmtmr=0x508
1843
Bjorn Helgaas97ef0622008-08-19 16:53:41 -06001844 pnp.debug [PNP]
1845 Enable PNP debug messages. This depends on the
1846 CONFIG_PNP_DEBUG_MESSAGES option.
1847
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848 pnpacpi= [ACPI]
1849 { off }
1850
1851 pnpbios= [ISAPNP]
1852 { on | off | curr | res | no-curr | no-res }
1853
1854 pnp_reserve_irq=
1855 [ISAPNP] Exclude IRQs for the autoconfiguration
1856
1857 pnp_reserve_dma=
1858 [ISAPNP] Exclude DMAs for the autoconfiguration
1859
1860 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001861 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862
1863 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001864 [ISAPNP] Exclude memory regions for the
1865 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 Ranges are in pairs (memory base and size).
1867
Ingo Molnar45807a12007-07-15 23:40:10 -07001868 print-fatal-signals=
1869 [KNL] debug: print fatal signals
1870 print-fatal-signals=1: print segfault info to
1871 the kernel console.
1872 default: off.
1873
Randy Dunlape84845c2007-07-15 23:40:25 -07001874 printk.time= Show timing data prefixed to each printk message line
1875 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1876
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001878 Format: [schedule,]<number>
1879 Param: "schedule" - profile schedule points.
1880 Param: <number> - step/bucket size as a power of 2 for
1881 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001882 Param: "sleep" - profile D-state sleeping (millisecs).
1883 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001884 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885
Randy Dunlapa9913042005-10-23 12:57:11 -07001886 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 Limit processor to maximum C-state
1888 max_cstate=9 overrides any DMI blacklist limit.
1889
Len Brown41c0d862005-12-28 12:43:51 -05001890 processor.nocst [HW,ACPI]
1891 Ignore the _CST method to determine C-states,
1892 instead using the legacy FADT method
1893
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1895 before loading.
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001896 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001897
Randy Dunlapa9913042005-10-23 12:57:11 -07001898 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1899 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1901 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001902 psmouse.resetafter= [HW,MOUSE]
1903 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 (0 = never).
1905 psmouse.resolution=
1906 [HW,MOUSE] Set desired mouse resolution, in dpi.
1907 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001908 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909 0 = disabled, 1 = enabled (default).
1910
1911 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001912 Format:
1913 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914
1915 pt. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001916 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917
Kay Sieversdc8c8582007-08-15 12:25:38 +02001918 pty.legacy_count=
1919 [KNL] Number of legacy pty's. Overwrites compiled-in
1920 default number.
1921
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001922 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001923
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 r128= [HW,DRM]
1925
1926 raid= [HW,RAID]
1927 See Documentation/md.txt.
1928
Randy Dunlapa9913042005-10-23 12:57:11 -07001929 ramdisk_blocksize= [RAM]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001930 See Documentation/blockdev/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001931
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001933 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001935 rcupdate.blimit= [KNL,BOOT]
1936 Set maximum number of finished RCU callbacks to process
1937 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001938
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001939 rcupdate.qhimark= [KNL,BOOT]
1940 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001941 RCU callbacks over which batch limiting is disabled.
1942
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001943 rcupdate.qlowmark= [KNL,BOOT]
1944 Set threshold of queued RCU callbacks below which
1945 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001946
Olof Johanssonffdfc402005-09-06 15:17:19 -07001947 rdinit= [KNL]
1948 Format: <full_path>
1949 Run specified binary instead of /init from the ramdisk,
1950 used for early userspace startup. See initrd.
1951
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001952 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Randy Dunlapecb08d82009-01-06 14:42:44 -08001954 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955
Paul Jackson46b6d942008-07-04 10:00:09 -07001956 relax_domain_level=
1957 [KNL, SMP] Set scheduler's default relax_domain_level.
1958 See Documentation/cpusets.txt.
1959
Linus Torvalds1da177e2005-04-16 15:20:36 -07001960 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1961
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001962 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001963 Format: nn[KMG]
1964 Reserves a hole at the top of the kernel virtual
1965 address space.
1966
Vivek Goyal7e962872006-09-27 01:50:44 -07001967 reset_devices [KNL] Force drivers to reset the underlying device
1968 during initialization.
1969
Randy Dunlapa9913042005-10-23 12:57:11 -07001970 resume= [SWSUSP]
1971 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001973 resume_offset= [SWSUSP]
1974 Specify the offset from the beginning of the partition
1975 given by "resume=" at which the swap header is located,
1976 in <PAGE_SIZE> units (needed only for swap files).
1977 See Documentation/power/swsusp-and-swap-files.txt
1978
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001979 retain_initrd [RAM] Keep initrd memory after extraction
1980
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981 rhash_entries= [KNL,NET]
1982 Set number of hash buckets for route cache
1983
1984 riscom8= [HW,SERIAL]
1985 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1986
1987 ro [KNL] Mount root device read-only on boot
1988
1989 root= [KNL] Root filesystem
1990
1991 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1992 mount the root filesystem
1993
1994 rootflags= [KNL] Set root filesystem mount option string
1995
1996 rootfstype= [KNL] Set root filesystem type
1997
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001998 rootwait [KNL] Wait (indefinitely) for root device to show up.
1999 Useful for devices that are detected asynchronously
2000 (e.g. USB and MMC devices).
2001
James Morris20510f22007-10-16 23:31:32 -07002002 root_plug.vendor_id=
2003 [ROOTPLUG] Override the default vendor ID
2004
2005 root_plug.product_id=
2006 [ROOTPLUG] Override the default product ID
2007
2008 root_plug.debug=
2009 [ROOTPLUG] Enable debugging output
2010
Linus Torvalds1da177e2005-04-16 15:20:36 -07002011 rw [KNL] Mount root device read-write on boot
2012
2013 S [KNL] Run init in single mode
2014
2015 sa1100ir [NET]
2016 See drivers/net/irda/sa1100_ir.c.
2017
Linus Torvalds1da177e2005-04-16 15:20:36 -07002018 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07002019
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
2021 Format: <io>[,<timeout>[,<isapnp>]]
2022
2023 scsi_debug_*= [SCSI]
2024 See drivers/scsi/scsi_debug.c.
2025
2026 scsi_default_dev_flags=
2027 [SCSI] SCSI default device flags
2028 Format: <integer>
2029
2030 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
2031 Format: <vendor>:<model>:<flags>
2032 (flags are integer value)
2033
Randy Dunlap6af66322007-11-14 16:52:25 -08002034 scsi_logging_level= [SCSI] a bit mask of logging levels
2035 See drivers/scsi/scsi_logging.h for bits. Also
2036 settable via sysctl at dev.scsi.logging_level
2037 (/proc/sys/dev/scsi/logging_level).
2038 There is also a nice 'scsi_logging_level' script in the
2039 S390-tools package, available for download at
2040 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041
Matthew Wilcox3e082a92006-09-28 15:19:20 -06002042 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
2043 discovered. async scans them in kernel threads,
2044 allowing boot to proceed. none ignores them, expecting
2045 user space to do the scan.
2046
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047 selinux [SELINUX] Disable or enable SELinux at boot time.
2048 Format: { "0" | "1" }
2049 See security/selinux/Kconfig help text.
2050 0 -- disable.
2051 1 -- enable.
2052 Default value is set via kernel config option.
2053 If enabled at boot time, /selinux/disable can be used
2054 later to disable prior to initial policy load.
2055
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002056 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002057
Linus Torvalds1da177e2005-04-16 15:20:36 -07002058 shapers= [NET]
2059 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07002060
Yinghai Lub05f78f2008-08-22 01:32:50 -07002061 show_msr= [x86] show boot-time MSR settings
2062 Format: { <integer> }
2063 Show boot-time (BIOS-initialized) MSR settings.
2064 The parameter means the number of CPUs to show,
2065 for example 1 means boot CPU only.
2066
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067 sim710= [SCSI,HW]
2068 See header of drivers/scsi/sim710.c.
2069
2070 simeth= [IA-64]
2071 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07002072
Linus Torvalds1da177e2005-04-16 15:20:36 -07002073 slram= [HW,MTD]
2074
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002075 slub_debug[=options[,slabs]] [MM, SLUB]
2076 Enabling slub_debug allows one to determine the
2077 culprit if slab objects become corrupted. Enabling
2078 slub_debug can create guard zones around objects and
2079 may poison objects when not in use. Also tracks the
2080 last alloc / free. For more information see
2081 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002082
2083 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002084 Determines the maximum allowed order for slabs.
2085 A high setting may cause OOMs due to memory
2086 fragmentation. For more information see
2087 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002088
2089 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002090 The minimum number of objects per slab. SLUB will
2091 increase the slab order up to slub_max_order to
2092 generate a sufficiently large slab able to contain
2093 the number of objects indicated. The higher the number
2094 of objects the smaller the overhead of tracking slabs
2095 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002096 For more information see Documentation/vm/slub.txt.
2097
2098 slub_min_order= [MM, SLUB]
2099 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002100 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002101 For more information see Documentation/vm/slub.txt.
2102
2103 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002104 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07002105 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002106 allocs to different slabs. Debug options disable
2107 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002108 For more information see Documentation/vm/slub.txt.
2109
Linus Torvalds1da177e2005-04-16 15:20:36 -07002110 smart2= [HW]
2111 Format: <io1>[,<io2>[,...,<io8>]]
2112
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002113 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02002114 attempt to substitute SMP alternatives once at boot.
2115
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07002116 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2117 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2118 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2119 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2120 smsc-ircc2.ircc_irq= [HW] IRQ line
2121 smsc-ircc2.ircc_dma= [HW] DMA channel
2122 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2123 0: Toshiba Satellite 1800 (GP data pin select)
2124 1: Fast pin select (default)
2125 2: ATC IRMode
2126
Linus Torvalds1da177e2005-04-16 15:20:36 -07002127 snd-ad1816a= [HW,ALSA]
2128
2129 snd-ad1848= [HW,ALSA]
2130
2131 snd-ali5451= [HW,ALSA]
2132
2133 snd-als100= [HW,ALSA]
2134
2135 snd-als4000= [HW,ALSA]
2136
2137 snd-azt2320= [HW,ALSA]
2138
2139 snd-cmi8330= [HW,ALSA]
2140
2141 snd-cmipci= [HW,ALSA]
2142
2143 snd-cs4231= [HW,ALSA]
2144
2145 snd-cs4232= [HW,ALSA]
2146
2147 snd-cs4236= [HW,ALSA]
2148
2149 snd-cs4281= [HW,ALSA]
2150
2151 snd-cs46xx= [HW,ALSA]
2152
2153 snd-dt019x= [HW,ALSA]
2154
2155 snd-dummy= [HW,ALSA]
2156
2157 snd-emu10k1= [HW,ALSA]
2158
2159 snd-ens1370= [HW,ALSA]
2160
2161 snd-ens1371= [HW,ALSA]
2162
2163 snd-es968= [HW,ALSA]
2164
2165 snd-es1688= [HW,ALSA]
2166
2167 snd-es18xx= [HW,ALSA]
2168
2169 snd-es1938= [HW,ALSA]
2170
2171 snd-es1968= [HW,ALSA]
2172
2173 snd-fm801= [HW,ALSA]
2174
2175 snd-gusclassic= [HW,ALSA]
2176
2177 snd-gusextreme= [HW,ALSA]
2178
2179 snd-gusmax= [HW,ALSA]
2180
2181 snd-hdsp= [HW,ALSA]
2182
2183 snd-ice1712= [HW,ALSA]
2184
2185 snd-intel8x0= [HW,ALSA]
2186
2187 snd-interwave= [HW,ALSA]
2188
2189 snd-interwave-stb=
2190 [HW,ALSA]
2191
2192 snd-korg1212= [HW,ALSA]
2193
2194 snd-maestro3= [HW,ALSA]
2195
2196 snd-mpu401= [HW,ALSA]
2197
2198 snd-mtpav= [HW,ALSA]
2199
2200 snd-nm256= [HW,ALSA]
2201
2202 snd-opl3sa2= [HW,ALSA]
2203
2204 snd-opti92x-ad1848=
2205 [HW,ALSA]
2206
2207 snd-opti92x-cs4231=
2208 [HW,ALSA]
2209
2210 snd-opti93x= [HW,ALSA]
2211
2212 snd-pmac= [HW,ALSA]
2213
2214 snd-rme32= [HW,ALSA]
2215
2216 snd-rme96= [HW,ALSA]
2217
2218 snd-rme9652= [HW,ALSA]
2219
2220 snd-sb8= [HW,ALSA]
2221
2222 snd-sb16= [HW,ALSA]
2223
2224 snd-sbawe= [HW,ALSA]
2225
2226 snd-serial= [HW,ALSA]
2227
2228 snd-sgalaxy= [HW,ALSA]
2229
2230 snd-sonicvibes= [HW,ALSA]
2231
2232 snd-sun-amd7930=
2233 [HW,ALSA]
2234
2235 snd-sun-cs4231= [HW,ALSA]
2236
2237 snd-trident= [HW,ALSA]
2238
2239 snd-usb-audio= [HW,ALSA,USB]
2240
2241 snd-via82xx= [HW,ALSA]
2242
2243 snd-virmidi= [HW,ALSA]
2244
2245 snd-wavefront= [HW,ALSA]
2246
2247 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002248
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002249 softlockup_panic=
2250 [KNL] Should the soft-lockup detector generate panics.
2251
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2253 See Documentation/sonypi.txt
2254
2255 specialix= [HW,SERIAL] Specialix multi-serial port adapter
Randy Dunlap31c00fc2008-11-13 21:33:24 +00002256 See Documentation/serial/specialix.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257
2258 spia_io_base= [HW,MTD]
2259 spia_fio_base=
2260 spia_pedr=
2261 spia_peddr=
2262
2263 sscape= [HW,OSS]
2264 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002265
Linus Torvalds1da177e2005-04-16 15:20:36 -07002266 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2267 See Documentation/scsi/st.txt.
2268
Steven Rostedtf38f1d22008-12-16 23:06:40 -05002269 stacktrace [FTRACE]
2270 Enabled the stack tracer on boot up.
2271
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272 sti= [PARISC,HW]
2273 Format: <num>
2274 Set the STI (builtin display/keyboard on the HP-PARISC
2275 machines) console (graphic card) which should be used
2276 as the initial boot-console.
2277 See also comment in drivers/video/console/sticore.c.
2278
2279 sti_font= [HW]
2280 See comment in drivers/video/console/sticore.c.
2281
2282 stifb= [HW]
2283 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2284
Greg Banks42a7fc42007-03-06 01:42:23 -08002285 sunrpc.pool_mode=
2286 [NFS]
2287 Control how the NFS server code allocates CPUs to
2288 service thread pools. Depending on how many NICs
2289 you have and where their interrupts are bound, this
2290 option will affect which CPUs will do NFS serving.
2291 Note: this parameter cannot be changed while the
2292 NFS server is running.
2293
2294 auto the server chooses an appropriate mode
2295 automatically using heuristics
2296 global a single global pool contains all CPUs
2297 percpu one pool for each CPU
2298 pernode one pool for each NUMA node (equivalent
2299 to global on non-NUMA machines)
2300
Linus Torvalds1da177e2005-04-16 15:20:36 -07002301 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002302
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303 switches= [HW,M68k]
2304
2305 sym53c416= [HW,SCSI]
2306 See header of drivers/scsi/sym53c416.c.
2307
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002308 sysrq_always_enabled
2309 [KNL]
2310 Ignore sysrq setting - this boot parameter will
2311 neutralize any effect of /proc/sys/kernel/sysrq.
2312 Useful for debugging.
2313
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314 t128= [HW,SCSI]
2315 See header of drivers/scsi/t128.c.
2316
2317 tdfx= [HW,DRM]
2318
David Brownell77437fd2008-07-23 21:28:33 -07002319 test_suspend= [SUSPEND]
2320 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2321 standby suspend) as the system sleep state to briefly
2322 enter during system startup. The system is woken from
2323 this state using a wakeup-capable RTC alarm.
2324
Linus Torvalds1da177e2005-04-16 15:20:36 -07002325 thash_entries= [KNL,NET]
2326 Set number of hash buckets for TCP connection
2327
Len Brownf8707ec2007-08-12 00:12:54 -04002328 thermal.act= [HW,ACPI]
2329 -1: disable all active trip points in all thermal zones
2330 <degrees C>: override all lowest active trip points
2331
Len Brownc52a7412007-08-14 15:49:32 -04002332 thermal.crt= [HW,ACPI]
2333 -1: disable all critical trip points in all thermal zones
Zhang Rui22a94d72008-10-17 02:41:20 -04002334 <degrees C>: override all critical trip points
Len Brownc52a7412007-08-14 15:49:32 -04002335
Len Brownf5487142007-08-12 00:12:44 -04002336 thermal.nocrt= [HW,ACPI]
2337 Set to disable actions on ACPI thermal zone
2338 critical and hot trip points.
2339
Len Brown72b33ef2007-08-12 00:12:17 -04002340 thermal.off= [HW,ACPI]
2341 1: disable ACPI thermal control
2342
Len Browna70cdc52007-08-12 00:12:35 -04002343 thermal.psv= [HW,ACPI]
2344 -1: disable all passive trip points
Randy Dunlapada9cfd2008-12-19 10:57:32 -08002345 <degrees C>: override all passive trip points to this
2346 value
Len Browna70cdc52007-08-12 00:12:35 -04002347
Len Brown730ff342007-08-12 00:12:26 -04002348 thermal.tzp= [HW,ACPI]
2349 Specify global default ACPI thermal zone polling rate
2350 <deci-seconds>: poll all this frequency
2351 0: no polling (default)
2352
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353 tmscsim= [HW,SCSI]
2354 See comment before function dc390_setup() in
2355 drivers/scsi/tmscsim.c.
2356
Heiko Carstens2b1a61f2008-12-25 13:39:23 +01002357 topology= [S390]
2358 Format: {off | on}
2359 Specify if the kernel should make use of the cpu
2360 topology informations if the hardware supports these.
2361 The scheduler will make use of these informations and
2362 e.g. base its process migration decisions on it.
2363 Default is off.
2364
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 tp720= [HW,PS2]
2366
2367 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002368 Format:
2369 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2370
Alok Kataria395628e2008-10-24 17:22:01 -07002371 tsc= Disable clocksource-must-verify flag for TSC.
2372 Format: <string>
2373 [x86] reliable: mark tsc clocksource as reliable, this
2374 disables clocksource verification at runtime.
2375 Used to enable high-resolution timer mode on older
2376 hardware, and in virtualized environment.
2377
Randy Dunlapa9913042005-10-23 12:57:11 -07002378 turbografx.map[2|3]= [HW,JOY]
2379 TurboGraFX parallel port interface
2380 Format:
2381 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382 See also Documentation/input/joystick-parport.txt
2383
2384 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2385 See header of drivers/scsi/u14-34f.c.
2386
2387 uart401= [HW,OSS]
2388 Format: <io>,<irq>
2389
2390 uart6850= [HW,OSS]
2391 Format: <io>,<irq>
2392
Alan Stern5f8364b2006-12-05 16:29:55 -05002393 uhci-hcd.ignore_oc=
2394 [USB] Ignore overcurrent events (default N).
2395 Some badly-designed motherboards generate lots of
2396 bogus events, for ports that aren't wired to
2397 anything. Set this parameter to avoid log spamming.
2398 Note that genuine overcurrent events won't be
2399 reported either.
2400
Simon Arlotte3a61b02008-07-19 23:32:54 +01002401 unknown_nmi_panic
2402 [X86-32,X86-64]
2403 Set unknown_nmi_panic=1 early on boot.
2404
Alan Sternb5e795f2007-02-20 15:00:53 -05002405 usbcore.autosuspend=
2406 [USB] The autosuspend time delay (in seconds) used
2407 for newly-detected USB devices (default 2). This
2408 is the time required before an idle device will be
2409 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002410 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002411
Jaroslav Kyselafd7c5192008-10-10 16:24:45 +02002412 usbcore.usbfs_snoop=
2413 [USB] Set to log all usbfs traffic (default 0 = off).
2414
2415 usbcore.blinkenlights=
2416 [USB] Set to cycle leds on hubs (default 0 = off).
2417
2418 usbcore.old_scheme_first=
2419 [USB] Start with the old device initialization
2420 scheme (default 0 = off).
2421
2422 usbcore.use_both_schemes=
2423 [USB] Try the other device initialization scheme
2424 if the first one fails (default 1 = enabled).
2425
2426 usbcore.initial_descriptor_timeout=
2427 [USB] Specifies timeout for the initial 64-byte
2428 USB_REQ_GET_DESCRIPTOR request in milliseconds
2429 (default 5000 = 5.0 seconds).
2430
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431 usbhid.mousepoll=
2432 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002433
Alan Sternd4f373e2008-11-10 14:07:45 -05002434 usb-storage.delay_use=
2435 [UMS] The delay in seconds before a new device is
2436 scanned for Logical Units (default 5).
2437
2438 usb-storage.quirks=
2439 [UMS] A list of quirks entries to supplement or
2440 override the built-in unusual_devs list. List
2441 entries are separated by commas. Each entry has
2442 the form VID:PID:Flags where VID and PID are Vendor
2443 and Product ID values (4-digit hex numbers) and
2444 Flags is a set of characters, each corresponding
2445 to a common usb-storage quirk flag as follows:
Alan Sternc838ea42008-12-15 10:40:06 -05002446 a = SANE_SENSE (collect more than 18 bytes
2447 of sense data);
Alan Sternd4f373e2008-11-10 14:07:45 -05002448 c = FIX_CAPACITY (decrease the reported
2449 device capacity by one sector);
Alan Sternc838ea42008-12-15 10:40:06 -05002450 h = CAPACITY_HEURISTICS (decrease the
2451 reported device capacity by one
2452 sector if the number is odd);
Alan Sternd4f373e2008-11-10 14:07:45 -05002453 i = IGNORE_DEVICE (don't bind to this
2454 device);
2455 l = NOT_LOCKABLE (don't try to lock and
2456 unlock ejectable media);
2457 m = MAX_SECTORS_64 (don't transfer more
2458 than 64 sectors = 32 KB at a time);
Alan Sternc838ea42008-12-15 10:40:06 -05002459 o = CAPACITY_OK (accept the capacity
2460 reported by the device);
Alan Sternd4f373e2008-11-10 14:07:45 -05002461 r = IGNORE_RESIDUE (the device reports
2462 bogus residue values);
2463 s = SINGLE_LUN (the device has only one
2464 Logical Unit);
2465 w = NO_WP_DETECT (don't test whether the
2466 medium is write-protected).
2467 Example: quirks=0419:aaf5:rl,0421:0433:rc
2468
Paul Jackson200001e2008-06-25 05:44:46 -07002469 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2470 kernel's map of available physical RAM.
2471
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002472 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002473 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002474 vdso=1: enable VDSO (default)
2475 vdso=0: disable VDSO mapping
2476
Roland McGrathaf65d642008-01-30 13:30:43 +01002477 vdso32= [X86-32,X86-64]
2478 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2479 vdso32=1: enable 32-bit VDSO (default)
2480 vdso32=0: disable 32-bit VDSO mapping
2481
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002482 vector= [IA-64,SMP]
2483 vector=percpu: enable percpu vector domain
2484
Linus Torvalds1da177e2005-04-16 15:20:36 -07002485 video= [FB] Frame buffer configuration
2486 See Documentation/fb/modedb.txt.
2487
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002488 vga= [BOOT,X86-32] Select a particular video mode
Kyle McMartin954a8b82009-02-19 16:48:14 -05002489 See Documentation/x86/boot.txt and
Randy Dunlapa9913042005-10-23 12:57:11 -07002490 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002491 Use vga=ask for menu.
2492 This is actually a boot loader parameter; the value is
2493 passed to the kernel using a special protocol.
2494
Randy Dunlapa9913042005-10-23 12:57:11 -07002495 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002496 size of <nn>. This can be used to increase the
2497 minimum size (128MB on x86). It can also be used to
2498 decrease the size and leave more room for directly
2499 mapped kernel RAM.
2500
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002501 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2502 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002503
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002504 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2505 Format: <command>
2506
2507 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2508 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002509
Linus Torvalds1da177e2005-04-16 15:20:36 -07002510 waveartist= [HW,OSS]
2511 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002512
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513 wd33c93= [HW,SCSI]
2514 See header of drivers/scsi/wd33c93.c.
2515
2516 wd7000= [HW,SCSI]
2517 See header of drivers/scsi/wd7000.c.
2518
2519 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002520 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002521
2522 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2523 xd_geo= See header of drivers/block/xd.c.
2524
2525 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002526 Format:
2527 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002528
Randy Dunlapecb08d82009-01-06 14:42:44 -08002529 norandmaps Don't use address space randomization. Equivalent to
2530 echo 0 > /proc/sys/kernel/randomize_va_space
Andi Kleena62eaf12006-02-16 23:41:58 +01002531
Randy Dunlapa9913042005-10-23 12:57:11 -07002532______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002533
2534TODO:
2535
2536 Add documentation for ALSA options.
2537 Add more DRM drivers.