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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.
47 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070048 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
Kristen Carlson Accardi11ef6972006-09-28 11:29:01 -070052 LIBATA Libata driver is enabled
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070061 MSI Message Signaled Interrupts (PCI).
Randy Dunlapc8facbb2007-07-31 00:37:40 -070062 MTD MTD (Memory Technology Device) support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070065 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
Randy Dunlapc8facbb2007-07-31 00:37:40 -070068 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
Randy Dunlap7f785762007-10-05 13:17:58 -070072 PCIE PCI Express support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
James Morris20510f22007-10-16 23:31:32 -070079 ROOTPLUG The example Root Plug LSM is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
83 Documentation/scsi/.
James Morris20510f22007-10-16 23:31:32 -070084 SECURITY Different security models are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
Paul Mundte523d932007-02-28 18:30:01 +090087 SH SuperH architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
David Brownell77437fd2008-07-23 21:28:33 -070090 SWSUSP Software suspend (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700100 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
Uwe Hermann71cced62008-10-20 09:32:21 -0700103 Documentation/x86/x86_64/boot-options.txt .
Andi Kleenc0115602008-08-22 09:53:39 +0200104 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
106In addition, the following text indicates that the option:
107
108 BUGS= Relates to possible processor bugs on the said processor.
109 KNL Is a kernel start-up parameter.
110 BOOT Is a boot loader parameter.
111
112Parameters denoted with BOOT are actually interpreted by the boot
113loader, and have no meaning to the kernel directly.
114Do not modify the syntax of boot loader parameters without extreme
Uwe Hermann71cced62008-10-20 09:32:21 -0700115need or coordination with <Documentation/x86/i386/boot.txt>.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116
Karsten Weiss55588702007-02-13 13:26:21 +0100117There are also arch-specific kernel-parameters not documented here.
Uwe Hermann71cced62008-10-20 09:32:21 -0700118See for example <Documentation/x86/x86_64/boot-options.txt>.
Karsten Weiss55588702007-02-13 13:26:21 +0100119
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
121a trailing = on the name of any parameter states that that parameter will
122be entered as an environment variable, whereas its absence indicates that
123it will appear as a kernel argument readable via /proc/cmdline by programs
124running once the system is up.
125
jens m. noedler9c4751f2006-09-29 02:00:27 -0700126The number of kernel parameters is not limited, but the length of the
127complete command line (parameters including spaces etc.) is limited to
128a fixed number of characters. This limit depends on the architecture
129and is between 256 and 4096 characters. It is defined in the file
130./include/asm/setup.h as COMMAND_LINE_SIZE.
131
132
Bernhard Walle03d926f2007-03-06 02:29:44 -0800133 acpi= [HW,ACPI,X86-64,i386]
134 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700135 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 force -- enable ACPI if default was off
137 off -- disable ACPI if default was on
138 noirq -- do not use ACPI for IRQ routing
139 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700140 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 strictly ACPI specification compliant.
142
Randy Dunlap53471122008-03-12 18:10:51 -0400143 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
Len Browna1fdcc02007-03-11 03:26:14 -0400145 acpi_apic_instance= [ACPI, IOAPIC]
146 Format: <int>
147 2: use 2nd APIC table, if available
148 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400149 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400150
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 acpi_sleep= [HW,ACPI] Sleep options
Shaohua Libdfe6b72008-07-23 21:28:41 -0700152 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
Pavel Machek23b168d2008-02-05 19:27:12 +0100153 See Documentation/power/video.txt for s3_bios and s3_mode.
154 s3_beep is for debugging; it makes the PC's speaker beep
155 as soon as the kernel's real-mode entry point is called.
Shaohua Libdfe6b72008-07-23 21:28:41 -0700156 s4_nohwsig prevents ACPI hardware signature from being
157 used during resume from hibernation.
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200158 old_ordering causes the ACPI 1.0 ordering of the _PTS
159 control method, wrt putting devices into low power
160 states, to be enforced (the ACPI 2.0 ordering of _PTS is
161 used by default).
Randy Dunlapa9913042005-10-23 12:57:11 -0700162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700164 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Randy Dunlapa9913042005-10-23 12:57:11 -0700166 acpi_irq_balance [HW,ACPI]
167 ACPI will balance active IRQs
168 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
Randy Dunlapa9913042005-10-23 12:57:11 -0700170 acpi_irq_nobalance [HW,ACPI]
171 ACPI will not move active IRQs (default)
172 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Randy Dunlapa9913042005-10-23 12:57:11 -0700174 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
175 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 Format: <irq>,<irq>...
177
Randy Dunlapa9913042005-10-23 12:57:11 -0700178 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 Format: <irq>,<irq>...
180
Len Brown67effe82007-07-26 00:50:06 -0400181 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
182
Len Browna1f9e652006-01-25 23:47:36 -0500183 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
184 Format: To spoof as Windows 98: ="Microsoft Windows"
185
Len Brownae00d812007-05-29 18:43:33 -0400186 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
187 acpi_osi="string1" # add string1 -- only one string
188 acpi_osi="!string2" # remove built-in string2
189 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
191 acpi_serialize [HW,ACPI] force serialization of AML methods
192
193 acpi_skip_timer_override [HW,ACPI]
194 Recognize and ignore IRQ0/pin2 Interrupt Override.
195 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100196 acpi_use_timer_override [HW,ACPI}
197 Use timer override. For some broken Nvidia NF5 boards
198 that require a timer override, but don't have
199 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Thomas Renningerc3d6de62008-08-01 17:37:55 +0200201 acpi_backlight= [HW,ACPI]
202 acpi_backlight=vendor
203 acpi_backlight=video
204 If set to vendor, prefer vendor specific driver
205 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
206 of the ACPI video.ko driver.
207
208 acpi_display_output= [HW,ACPI]
209 acpi_display_output=vendor
210 acpi_display_output=video
211 See above.
212
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700213 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
214 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 Format: <int>
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700216 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
217 debug output. Bits in debug_layer correspond to a
218 _COMPONENT in an ACPI source file, e.g.,
219 #define _COMPONENT ACPI_PCI_COMPONENT
220 Bits in debug_level correspond to a level in
221 ACPI_DEBUG_PRINT statements, e.g.,
222 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
223 See Documentation/acpi/debug.txt for more information
224 about debug layers and levels.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700226 Enable AML "Debug" output, i.e., stores to the Debug
227 object while interpreting AML:
228 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
229 Enable PCI/PCI interrupt routing info messages:
230 acpi.debug_layer=0x400000 acpi.debug_level=0x4
231 Enable all messages related to ACPI hardware:
232 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
Thomas Renninger36eec5e2008-08-11 15:03:20 +0200233
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700234 Some values produce so much output that the system is
235 unusable. The "log_buf_len" parameter may be useful
236 if you need to capture more output.
Zhang Ruif9891062007-04-24 13:53:22 +0800237
Zhao Yakuif5adfaa2008-08-11 14:57:50 +0800238 acpi.power_nocheck= [HW,ACPI]
239 Format: 1/0 enable/disable the check of power state.
240 On some bogus BIOS the _PSC object/_STA object of
241 power resource can't return the correct device power
242 state. In such case it is unneccessary to check its
243 power state again in power transition.
244 1 : disable the power state check
245
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700246 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700247 Override the pmtimer bug detection: force the kernel
248 to assume that this machine's pmtimer latches its value
249 and always returns good values.
250
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000251 agp= [AGP]
252 { off | try_unsupported }
253 off: disable AGP support
254 try_unsupported: try to drive unsupported chipsets
255 (may crash computer or cause data corruption)
256
Chuck Ebbert66759a02005-09-12 18:49:25 +0200257 enable_timer_pin_1 [i386,x86-64]
258 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700259 Can be useful to work around chipset bugs
260 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200261 The kernel tries to set a reasonable default.
262
263 disable_timer_pin_1 [i386,x86-64]
264 Disable PIN 1 of APIC timer
265 Can be useful to work around chipset bugs.
266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 ad1848= [HW,OSS]
268 Format: <io>,<irq>,<dma>,<dma2>,<type>
269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 advansys= [HW,SCSI]
271 See header of drivers/scsi/advansys.c.
272
273 advwdt= [HW,WDT] Advantech WDT
274 Format: <iostart>,<iostop>
275
276 aedsp16= [HW,OSS] Audio Excel DSP 16
277 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
278 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700279
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 aha152x= [HW,SCSI]
281 See Documentation/scsi/aha152x.txt.
282
283 aha1542= [HW,SCSI]
284 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
285
286 aic7xxx= [HW,SCSI]
287 See Documentation/scsi/aic7xxx.txt.
288
289 aic79xx= [HW,SCSI]
290 See Documentation/scsi/aic79xx.txt.
291
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200292 amd_iommu= [HW,X86-84]
293 Pass parameters to the AMD IOMMU driver in the system.
294 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200295 isolate - enable device isolation (each device, as far
296 as possible, will get its own protection
Joerg Roedel3ce1f932008-11-17 15:09:20 +0100297 domain) [default]
Joerg Roedele5e1f602008-11-17 15:07:17 +0100298 share - put every device behind one IOMMU into the
299 same protection domain
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900300 fullflush - enable flushing of IO/TLB entries when
301 they are unmapped. Otherwise they are
302 flushed before they will be reused, which
303 is a lot of faster
304
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200305 amd_iommu_size= [HW,X86-64]
306 Define the size of the aperture for the AMD IOMMU
307 driver. Possible values are:
308 '32M', '64M' (default), '128M', '256M', '512M', '1G'
309
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 amijoy.map= [HW,JOY] Amiga joystick support
311 Map of devices attached to JOY0DAT and JOY1DAT
312 Format: <a>,<b>
313 See also Documentation/kernel/input/joystick.txt
314
315 analog.map= [HW,JOY] Analog joystick and gamepad support
316 Specifies type or capabilities of an analog joystick
317 connected to one of 16 gameports
318 Format: <type1>,<type2>,..<type16>
319
Randy Dunlapa9913042005-10-23 12:57:11 -0700320 apc= [HW,SPARC]
321 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 Format: noidle
323 Disable APC CPU standby support. SPARCstation-Fox does
324 not play well with APC CPU idle - disable it if you have
325 APC and your system crashes randomly.
326
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700327 apic= [APIC,i386] Advanced Programmable Interrupt Controller
328 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 Format: { quiet (default) | verbose | debug }
330 Change the amount of debugging information output
331 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700332
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700334 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
337 Format: <io>,<irq>,<nodeID>
338
339 ataflop= [HW,M68k]
340
341 atarimouse= [HW,MOUSE] Atari Mouse
342
343 atascsi= [HW,SCSI] Atari SCSI
344
345 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
346 EzKey and similar keyboards
347
348 atkbd.reset= [HW] Reset keyboard during initialization
349
Randy Dunlapa9913042005-10-23 12:57:11 -0700350 atkbd.set= [HW] Select keyboard code set
351 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352
353 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
354 keyboards
355
356 atkbd.softraw= [HW] Choose between synthetic and real raw mode
357 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700358
359 atkbd.softrepeat= [HW]
360 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361
362 autotest [IA64]
363
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 baycom_epp= [HW,AX25]
365 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700366
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
368 Format: <io>,<mode>
369 See header of drivers/net/hamradio/baycom_par.c.
370
Randy Dunlapa9913042005-10-23 12:57:11 -0700371 baycom_ser_fdx= [HW,AX25]
372 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 Format: <io>,<irq>,<mode>[,<baud>]
374 See header of drivers/net/hamradio/baycom_ser_fdx.c.
375
Randy Dunlapa9913042005-10-23 12:57:11 -0700376 baycom_ser_hdx= [HW,AX25]
377 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 Format: <io>,<irq>,<mode>
379 See header of drivers/net/hamradio/baycom_ser_hdx.c.
380
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700381 boot_delay= Milliseconds to delay each printk during boot.
382 Values larger than 10 seconds (10000) are changed to
383 no delay (0).
384 Format: integer
385
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700386 bootmem_debug [KNL] Enable bootmem allocator debug messages.
387
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700389 bttv.radio= Most important insmod options are available as
390 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
392 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
393
394 BusLogic= [HW,SCSI]
395 See drivers/scsi/BusLogic.c, comment before function
396 BusLogic_ParseDriverOptions().
397
398 c101= [NET] Moxa C101 synchronous serial card
399
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700400 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 Sometimes CPU hardware bugs make them report the cache
402 size incorrectly. The kernel will attempt work arounds
403 to fix known problems, but for some CPUs it is not
404 possible to determine what the correct size should be.
405 This option provides an override for these situations.
406
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200407 security= [SECURITY] Choose a security module to enable at boot.
408 If this boot parameter is not specified, only the first
409 security module asking for security registration will be
410 loaded. An invalid security module name will be treated
411 as if no module has been chosen.
412
James Morris20510f22007-10-16 23:31:32 -0700413 capability.disable=
414 [SECURITY] Disable capabilities. This would normally
415 be used only if an alternative security model is to be
416 configured. Potentially dangerous and should only be
417 used if you are entirely sure of the consequences.
418
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100419 ccw_timeout_log [S390]
420 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421
Paul Menage8bab8dd2008-04-04 14:29:57 -0700422 cgroup_disable= [KNL] Disable a particular controller
423 Format: {name of the controller(s) to disable}
424 {Currently supported controllers - "memory"}
425
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 checkreqprot [SELINUX] Set initial checkreqprot flag value.
427 Format: { "0" | "1" }
428 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700429 0 -- check protection applied by kernel (includes
430 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 1 -- check protection requested by application.
432 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700433 Value can be changed at runtime via
434 /selinux/checkreqprot.
435
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100436 cio_ignore= [S390]
437 See Documentation/s390/CommonIO for details.
438
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700439 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700440 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200441 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700442 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200443 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 Format: { pit | tsc | cyclone | pmtmr }
445
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700446 clocksource= [GENERIC_TIME] Override the default clocksource
447 Format: <string>
448 Override the default clocksource and use the clocksource
449 with the name specified.
450 Some clocksource names to choose from, depending on
451 the platform:
452 [all] jiffies (this is the base, fallback clocksource)
453 [ACPI] acpi_pm
454 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
455 pxa_timer,timer3,32k_counter,timer0_1
456 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700457 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700458 scx200_hrt on Geode; cyclone on IBM x440
459 [MIPS] MIPS
460 [PARISC] cr16
461 [S390] tod
462 [SH] SuperH
463 [SPARC64] tick
464 [X86-64] hpet,tsc
465
Andi Kleenac72e782008-01-30 13:33:21 +0100466 clearcpuid=BITNUM [X86]
467 Disable CPUID feature X for the kernel. See
468 include/asm-x86/cpufeature.h for the valid bit numbers.
469 Note the Linux specific bits are not necessarily
470 stable over kernel options, but the vendor specific
471 ones should be.
472 Also note that user programs calling CPUID directly
473 or using the feature without checking anything
474 will still see it. This just prevents it from
475 being used by the kernel or shown in /proc/cpuinfo.
476 Also note the kernel might malfunction if you disable
477 some critical bits.
478
Arjan van de Vena25bd942008-01-30 13:33:08 +0100479 code_bytes [IA32/X86_64] How many bytes of object code to print
480 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100481 Range: 0 - 8192
482 Default: 64
483
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200484 hpet= [X86-32,HPET] option to control HPET usage
485 Format: { enable (default) | disable | force }
486 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100487 force: allow force enabled of undocumented chips (ICH4,
488 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700491 Format:
492 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493
494 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
495 Format: <io>[,<irq>]
496
Randy Dunlapa9913042005-10-23 12:57:11 -0700497 com90xx= [HW,NET]
498 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 Format: <io>[,<irq>[,<memstart>]]
500
501 condev= [HW,S390] console device
502 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700503
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 console= [KNL] Output console device and options.
505
506 tty<n> Use the virtual console device <n>.
507
508 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800509 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800511 the form "bbbbpnf", where "bbbb" is the baud rate,
512 "p" is parity ("n", "o", or "e"), "n" is number of
513 bits, and "f" is flow control ("r" for RTS or
514 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800516 See Documentation/serial-console.txt for more
517 information. See
518 Documentation/networking/netconsole.txt for an
519 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700521 uart[8250],io,<addr>[,options]
522 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 Start an early, polled-mode console on the 8250/16550
524 UART at the specified I/O port or MMIO address,
525 switching to the matching ttyS device later. The
526 options are the same as for ttyS, above.
527
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700528 If the device connected to the port is not a TTY but a braille
529 device, prepend "brl," before the device type, for instance
530 console=brl,ttyS0
531 For now, only VisioBraille is supported.
532
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700533 earlycon= [KNL] Output early console device and options.
534 uart[8250],io,<addr>[,options]
535 uart[8250],mmio,<addr>[,options]
536 Start an early, polled-mode console on the 8250/16550
537 UART at the specified I/O port or MMIO address.
538 The options are the same as for ttyS, above.
539
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700540 no_console_suspend
541 [HW] Never suspend the console
542 Disable suspending of consoles during suspend and
543 hibernate operations. Once disabled, debugging
544 messages can reach various consoles while the rest
545 of the system is being put to sleep (ie, while
546 debugging driver suspend/resume hooks). This may
547 not work reliably with all consoles, but is known
548 to work with serial and VGA consoles.
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700551 Format:
552 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700554 crashkernel=nn[KMG]@ss[KMG]
555 [KNL] Reserve a chunk of physical memory to
556 hold a kernel to switch to with kexec on panic.
557
Bernhard Wallefb391592007-10-18 23:41:02 -0700558 crashkernel=range1:size1[,range2:size2,...][@offset]
559 [KNL] Same as above, but depends on the memory
560 in the running system. The syntax of range is
561 start-[end] where start and end are both
562 a memory unit (amount[KMG]). See also
563 Documentation/kdump/kdump.txt for a example.
564
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 cs4232= [HW,OSS]
566 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
567
568 cs89x0_dma= [HW,NET]
569 Format: <dma>
570
571 cs89x0_media= [HW,NET]
572 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700573
Randy Dunlapa9913042005-10-23 12:57:11 -0700574 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 See header of drivers/s390/block/dasd_devmap.c.
576
577 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
578 (one device per port)
579 Format: <port#>,<type>
580 See also Documentation/input/joystick-parport.txt
581
582 debug [KNL] Enable kernel debugging (events log level).
583
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700584 debug_locks_verbose=
585 [KNL] verbose self-tests
586 Format=<0|1>
587 Print debugging info while doing the locking API
588 self-tests.
589 We default to 0 (no extra messages), setting it to
590 1 will print _a lot_ more information - normally
591 only useful to kernel developers.
592
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700593 debug_objects [KNL] Enable object debugging
594
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200595 debugpat [X86] Enable PAT debugging
596
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200597 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 Format: <area>[,<node>]
599 See also Documentation/networking/decnet.txt.
600
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000601 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700602 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
603 Change the default blue palette of the console.
604 This is a 16-member array composed of values
605 ranging from 0-255.
606
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000607 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700608 Format: <green0>,<green1>,<green2>,...,<green15>
609 Change the default green palette of the console.
610 This is a 16-member array composed of values
611 ranging from 0-255.
612
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000613 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700614 Format: <red0>,<red1>,<red2>,...,<red15>
615 Change the default red palette of the console.
616 This is a 16-member array composed of values
617 ranging from 0-255.
618
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000619 vt.default_utf8=
620 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700621 Format=<0|1>
622 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000623 Default is 1, i.e. UTF-8 mode is enabled for all
624 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700625
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 dhash_entries= [KNL]
627 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700628
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 digi= [HW,SERIAL]
630 IO parameters + enable/disable command.
631
632 digiepca= [HW,SERIAL]
633 See drivers/char/README.epca and
Randy Dunlap31c00fc2008-11-13 21:33:24 +0000634 Documentation/serial/digiepca.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635
Yinghai Lu95ffa242008-04-29 03:52:33 -0700636 disable_mtrr_cleanup [X86]
637 enable_mtrr_cleanup [X86]
638 The kernel tries to adjust MTRR layout from continuous
639 to discrete, to make X server driver able to add WB
640 entry later. This parameter enables/disables that.
641
642 mtrr_chunk_size=nn[KMG] [X86]
643 used for mtrr cleanup. It is largest continous chunk
644 that could hold holes aka. UC entries.
645
646 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700647 Used for mtrr cleanup. It is granularity of mtrr block.
648 Default is 1.
649 Large value could prevent small alignment from
650 using up MTRRs.
651
652 mtrr_spare_reg_nr=n [X86]
653 Format: <integer>
654 Range: 0,7 : spare reg number
655 Default : 1
656 Used for mtrr cleanup. It is spare mtrr entries number.
657 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700658
Yinghai Lu093af8d2008-01-30 13:33:32 +0100659 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100660 By default the kernel will trim any uncacheable
661 memory out of your available memory pool based on
662 MTRR settings. This parameter disables that behavior,
663 possibly causing your machine to run very slowly.
664
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 dmasound= [HW,OSS] Sound subsystem buffers
666
667 dscc4.setup= [NET]
668
669 dtc3181e= [HW,SCSI]
670
Robin Getz0ae53642007-10-09 17:24:49 +0800671 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 earlyprintk=vga
673 earlyprintk=serial[,ttySn[,baudrate]]
Yinghai Lu5c059172008-07-24 17:29:40 -0700674 earlyprintk=dbgp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
Randy Dunlapa9913042005-10-23 12:57:11 -0700676 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 takes over.
678
Yinghai Lu5c059172008-07-24 17:29:40 -0700679 Only vga or serial or usb debug port at a time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680
681 Currently only ttyS0 and ttyS1 are supported.
682
683 Interaction with the standard serial driver is not
684 very good.
685
686 The VGA output is eventually overwritten by the real
687 console.
688
689 eata= [HW,SCSI]
690
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700692 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 eisa_irq_edge= [PARISC,HW]
695 See header of drivers/parisc/eisa.c.
696
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700697 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700699 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700
701 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800702 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700703 See Documentation/block/as-iosched.txt and
704 Documentation/block/deadline-iosched.txt for details.
705
Simon Hormane515a0d2008-10-18 20:28:27 -0700706 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700707 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800708 image elf header. Generally kexec loader will
709 pass this option to capture kernel.
710 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711
712 enforcing [SELINUX] Set initial enforcing status.
713 Format: {"0" | "1"}
714 See security/selinux/Kconfig help text.
715 0 -- permissive (log only, no denials).
716 1 -- enforcing (deny and log).
717 Default value is 0.
718 Value can be changed at runtime via /selinux/enforce.
719
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 es1371= [HW,OSS]
721 Format: <spdif>,[<nomix>,[<amplifier>]]
722 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 ether= [HW,NET] Ethernet cards parameters
725 This option is obsoleted by the "netdev=" option, which
726 has equivalent usage. See its documentation for details.
727
728 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
729 Format: <io>[,<irq>]
730
Akinobu Mitade1ba092006-12-08 02:39:42 -0800731 failslab=
732 fail_page_alloc=
733 fail_make_request=[KNL]
734 General fault injection mechanism.
735 Format: <interval>,<probability>,<space>,<times>
736 See also /Documentation/fault-injection/.
737
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 fd_mcs= [HW,SCSI]
739 See header of drivers/scsi/fd_mcs.c.
740
741 fdomain= [HW,SCSI]
742 See header of drivers/scsi/fdomain.c.
743
744 floppy= [HW]
Randy Dunlap31c00fc2008-11-13 21:33:24 +0000745 See Documentation/blockdev/floppy.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746
Alex Chiangf13ae302008-05-08 14:03:23 -0600747 force_pal_cache_flush
748 [IA-64] Avoid check_sal_cache_flush which may hang on
749 buggy SAL_CACHE_FLUSH implementations. Using this
750 parameter will force ia64_sal_cache_flush to call
751 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 gamecon.map[2|3]=
754 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
755 support via parallel port (up to 5 devices per port)
756 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
757 See also Documentation/input/joystick-parport.txt
758
759 gamma= [HW,DRM]
760
Yinghai Luaaf23042008-01-30 13:33:09 +0100761 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
762 Format: off | on
763 default: on
764
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 gdth= [HW,SCSI]
766 See header of drivers/scsi/gdth.c.
767
768 gpt [EFI] Forces disk with valid GPT signature but
769 invalid Protective MBR to be treated as GPT.
770
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 gvp11= [HW,SCSI]
772
773 hashdist= [KNL,NUMA] Large hashes allocated during boot
774 are distributed across NUMA nodes. Defaults on
775 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700776 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778 hcl= [IA-64] SGI's Hardware Graph compatibility layer
779
780 hd= [EIDE] (E)IDE hard drive subsystem geometry
781 Format: <cyl>,<head>,<sect>
782
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
784 size of <nn>. This works even on boxes that have no
785 highmem otherwise. This also works to reduce highmem
786 size on bigger boxes.
787
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800788 highres= [KNL] Enable/disable high resolution timer mode.
789 Valid parameters: "on", "off"
790 Default: "on"
791
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 hisax= [HW,ISDN]
793 See Documentation/isdn/README.HiSax.
794
Andi Kleenb4718e62008-07-23 21:27:51 -0700795 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
796 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700797 On x86-64 and powerpc, this option can be specified
798 multiple times interleaved with hugepages= to reserve
799 huge pages of different sizes. Valid pages sizes on
800 x86-64 are 2M (when the CPU supports "pse") and 1G
801 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700802 Note that 1GB pages can only be allocated at boot time
803 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700804 default_hugepagesz=
805 [same as hugepagesz=] The size of the default
806 HugeTLB page size. This is the size represented by
807 the legacy /proc/ hugepages APIs, used for SHM, and
808 default size when mounting hugetlbfs filesystems.
809 Defaults to the default architecture's huge page size
810 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
Paul Mundt6902aa82008-09-21 17:14:42 +0900812 hlt [BUGS=ARM,SH]
813
Jiri Kosina36d95732008-10-06 02:51:09 -0400814 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200816 i8042.dumbkbd [HW] Pretend that controller can only read data from
817 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 (Don't attempt to blink the leds)
819 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500820 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400821 i8042.noloop [HW] Disable the AUX Loopback command while probing
822 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 i8042.nomux [HW] Don't check presence of an active multiplexing
824 controller
825 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
826 controllers
827 i8042.panicblink=
828 [HW] Frequency with which keyboard LEDs should blink
829 when kernel panics (default is 0.5 sec)
830 i8042.reset [HW] Reset the controller during init and cleanup
831 i8042.unlock [HW] Unlock (ignore) the keylock
832
833 i810= [HW,DRM]
834
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700835 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
836 indicates that the driver is running on unsupported
837 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
839 does not match list of supported models.
840 i8k.power_status
841 [HW] Report power status in /proc/i8k
842 (disabled by default)
843 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
844 capability is set.
845
846 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
847 See Documentation/mca.txt.
848
849 icn= [HW,ISDN]
850 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
851
852 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200853 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100854 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100857 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858
Andi Kleenf039b752007-05-02 19:27:12 +0200859 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800860 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200861 Poll forces a polling idle loop that can slightly improves the performance
862 of waking up a idle CPU, but will use a lot of power and make the system
863 run hot. Not recommended.
864 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
865 to not use it because it doesn't save as much power as a normal idle
866 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
867 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800868 idle=halt. Halt is forced to be used for CPU idle.
869 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800870 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700871
Denis Cheng594765a2008-02-06 02:57:49 +0100872 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
873 Claim all unknown PCI IDE storage controllers.
874
Ingo Molnar792908222006-12-06 20:40:51 -0800875 ignore_loglevel [KNL]
876 Ignore loglevel setting - this will print /all/
877 kernel messages to the console. Useful for debugging.
878
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 ihash_entries= [KNL]
880 Set number of hash buckets for inode cache.
881
882 in2000= [HW,SCSI]
883 See header of drivers/scsi/in2000.c.
884
885 init= [KNL]
886 Format: <full_path>
887 Run specified binary instead of /sbin/init as init
888 process.
889
890 initcall_debug [KNL] Trace initcalls as they are executed. Useful
891 for working out where the kernel is dying during
892 startup.
893
894 initrd= [BOOT] Specify the location of the initial ramdisk
895
896 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
897 Format: <irq>
898
899 inttest= [IA64]
900
Pavel Machekb552da82008-03-19 15:58:11 +0100901 iommu= [x86]
902 off
903 force
904 noforce
905 biomerge
906 panic
907 nopanic
908 merge
909 nomerge
910 forcesac
911 soft
912
913
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700914 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
915 off
916 Disable intel iommu driver.
917 igfx_off [Default Off]
918 By default, gfx is mapped as normal device. If a gfx
919 device has a dedicated DMAR unit, the DMAR unit is
920 bypassed by not enabling DMAR with this option. In
921 this case, gfx device will use physical address for
922 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700923 forcedac [x86_64]
924 With this option iommu will not optimize to look
925 for io virtual address below 32 bit forcing dual
926 address cycle on pci bus for cards supporting greater
927 than 32 bit addressing. The default is to look
928 for translation below 32 bit and if not available
929 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800930 strict [Default Off]
931 With this option on every unmap_single operation will
932 result in a hardware IOTLB flush operation as opposed
933 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700934
Rene Hermanb02aae92008-01-30 13:30:05 +0100935 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100936 0x80
937 Standard port 0x80 based delay
938 0xed
939 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100940 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100941 Simple two microseconds delay
942 none
943 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100944
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 io7= [HW] IO7 for Marvel based alpha systems
946 See comment before marvel_specify_io7 in
947 arch/alpha/kernel/core_marvel.c.
948
949 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400950 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951
952 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700953 See comment before ip2_setup() in
954 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955
956 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
957 See header of drivers/scsi/ips.c.
958
Simon Horman72c4a132006-09-13 19:57:18 -0700959 ports= [IP_VS_FTP] IPVS ftp helper module
960 Default is 21.
961 Up to 8 (IP_VS_APP_MAX_PORTS) ports
962 may be specified.
963 Format: <port>,<port>....
964
Alan Cox200803d2005-06-28 20:45:18 -0700965 irqfixup [HW]
966 When an interrupt is not handled search all handlers
967 for it. Intended to get systems with badly broken
968 firmware running.
969
970 irqpoll [HW]
971 When an interrupt is not handled search all handlers
972 for it. Also check all handlers each timer
973 interrupt. Intended to get systems with badly broken
974 firmware running.
975
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700977 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978
979 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800980 Format:
981 <cpu number>,...,<cpu number>
982 or
Li Zefanb225d442008-11-06 12:53:39 -0800983 <cpu number>-<cpu number>
984 (must be a positive range in ascending order)
Derek Fults22f2e282006-12-06 20:37:11 -0800985 or a mixture
986 <cpu number>,...,<cpu number>-<cpu number>
Li Zefanb225d442008-11-06 12:53:39 -0800987
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 This option can be used to specify one or more CPUs
989 to isolate from the general SMP balancing and scheduling
Li Zefanb225d442008-11-06 12:53:39 -0800990 algorithms. You can move a process onto or off an
991 "isolated" CPU via the CPU affinity syscalls or cpuset.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 <cpu number> begins at 0 and the maximum value is
993 "number of CPUs in system - 1".
994
995 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700996 alternative -- manually setting the CPU mask of all
997 tasks in the system -- can cause problems and
998 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999
Randy Dunlapa9913042005-10-23 12:57:11 -07001000 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001
1002 js= [HW,JOY] Analog joystick
1003 See Documentation/input/joystick.txt.
1004
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001005 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -07001006 specifies the amount of memory usable by the kernel
1007 for non-movable allocations. The requested amount is
1008 spread evenly throughout all nodes in the system. The
1009 remaining memory in each node is used for Movable
1010 pages. In the event, a node is too small to have both
1011 kernelcore and Movable pages, kernelcore pages will
1012 take priority and other nodes will have a larger number
1013 of kernelcore pages. The Movable zone is used for the
1014 allocation of pages that may be reclaimed or moved
1015 by the page migration subsystem. This means that
1016 HugeTLB pages may not be allocated from this zone.
1017 Note that allocations like PTEs-from-HighMem still
1018 use the HighMem zone if it exists, and the Normal
1019 zone if it does not.
1020
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001021 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001022 is similar to kernelcore except it specifies the
1023 amount of memory used for migratable allocations.
1024 If both kernelcore and movablecore is specified,
1025 then kernelcore will be at *least* the specified
1026 value but may be more. If movablecore on its own
1027 is specified, the administrator must be careful
1028 that the amount of memory usable for all allocations
1029 is not too small.
1030
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 keepinitrd [HW,ARM]
1032
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001033 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 in oops dumps.
1035
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001036 kgdboc= [HW] kgdb over consoles.
1037 Requires a tty driver that supports console polling.
1038 (only serial suported for now)
1039 Format: <serial_device>[,baud]
1040
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001041 kmac= [MIPS] korina ethernet MAC address.
1042 Configure the RouterBoard 532 series on-chip
1043 Ethernet adapter MAC address.
1044
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 l2cr= [PPC]
1046
Robert Brosea78bfbf2008-03-29 07:20:23 +11001047 l3cr= [PPC]
1048
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001049 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001050 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001052 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001053 C2 power state.
1054
FD Camifcb71f62008-01-06 19:08:56 +01001055 libata.dma= [LIBATA] DMA control
1056 libata.dma=0 Disable all PATA and SATA DMA
1057 libata.dma=1 PATA and SATA Disk DMA only
1058 libata.dma=2 ATAPI (CDROM) DMA only
1059 libata.dma=4 Compact Flash DMA only
1060 Combinations also work, so libata.dma=3 enables DMA
1061 for disks and CDROMs, but not CFs.
1062
Dave Jones78e70c22007-09-27 11:50:13 -04001063 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1064 when set.
1065 Format: <int>
1066
Tejun Heo33267322008-02-13 09:15:09 +09001067 libata.force= [LIBATA] Force configurations. The format is comma
1068 separated list of "[ID:]VAL" where ID is
1069 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1070 matching port, link or device. Basically, it matches
1071 the ATA ID string printed on console by libata. If
1072 the whole ID part is omitted, the last PORT and DEVICE
1073 values are used. If ID hasn't been specified yet, the
1074 configuration applies to all ports, links and devices.
1075
1076 If only DEVICE is omitted, the parameter applies to
1077 the port and all links and devices behind it. DEVICE
1078 number of 0 either selects the first device or the
1079 first fan-out link behind PMP device. It does not
1080 select the host link. DEVICE number of 15 selects the
1081 host link and device attached to it.
1082
1083 The VAL specifies the configuration to force. As long
1084 as there's no ambiguity shortcut notation is allowed.
1085 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1086 The following configurations can be forced.
1087
1088 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1089 Any ID with matching PORT is used.
1090
1091 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1092
1093 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1094 udma[/][16,25,33,44,66,100,133] notation is also
1095 allowed.
1096
1097 * [no]ncq: Turn on or off NCQ.
1098
Tejun Heo05944bd2008-08-13 20:19:09 +09001099 * nohrst, nosrst, norst: suppress hard, soft
1100 and both resets.
1101
Tejun Heo33267322008-02-13 09:15:09 +09001102 If there are multiple matching configurations changing
1103 the same attribute, the last one is used.
1104
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 load_ramdisk= [RAM] List of ramdisks to load from floppy
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001106 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001108 lockd.nlm_grace_period=P [NFS] Assign grace period.
1109 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001111 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1112 Format: <integer>
1113
1114 lockd.nlm_timeout=T [NFS] Assign timeout value.
1115 Format: <integer>
1116
1117 lockd.nlm_udpport=M [NFS] Assign UDP port.
1118 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119
1120 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1121 Format: <irq>
1122
1123 loglevel= All Kernel Messages with a loglevel smaller than the
1124 console loglevel will be printed to the console. It can
1125 also be changed with klogd or other programs. The
1126 loglevels are defined as follows:
1127
1128 0 (KERN_EMERG) system is unusable
1129 1 (KERN_ALERT) action must be taken immediately
1130 2 (KERN_CRIT) critical conditions
1131 3 (KERN_ERR) error conditions
1132 4 (KERN_WARNING) warning conditions
1133 5 (KERN_NOTICE) normal but significant condition
1134 6 (KERN_INFO) informational
1135 7 (KERN_DEBUG) debug-level messages
1136
1137 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001138 Format: { n | nk | nM }
1139 n must be a power of two. The default size
1140 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141
Randy Dunlapaccaa242007-10-16 01:29:37 -07001142 logo.nologo [FB] Disables display of the built-in Linux logo.
1143 This may be used to provide more screen space for
1144 kernel log messages and is useful when debugging
1145 kernel boot problems.
1146
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 lp=0 [LP] Specify parallel ports to use, e.g,
1148 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1149 lp=reset first parallel port). 'lp=0' disables the
1150 lp=auto printer driver. 'lp=reset' (which can be
1151 specified in addition to the ports) causes
1152 attached printers to be reset. Using
1153 lp=port1,port2,... specifies the parallel ports
1154 to associate lp devices with, starting with
1155 lp0. A port specification may be 'none' to skip
1156 that lp device, or a parport name such as
1157 'parport0'. Specifying 'lp=auto' instead of a
1158 port specification list means that device IDs
1159 from each port should be examined, to see if
1160 an IEEE 1284-compliant printer is attached; if
1161 so, the driver will manage that printer.
1162 See also header of drivers/char/lp.c.
1163
1164 lpj=n [KNL]
1165 Sets loops_per_jiffy to given constant, thus avoiding
1166 time-consuming boot-time autodetection (up to 250 ms per
1167 CPU). 0 enables autodetection (default). To determine
1168 the correct value for your kernel, boot with normal
1169 autodetection and see what value is printed. Note that
1170 on SMP systems the preset will be applied to all CPUs,
1171 which is likely to cause problems if your CPUs need
1172 significantly divergent settings. An incorrect value
1173 will cause delays in the kernel to be wrong, leading to
1174 unpredictable I/O errors and other breakage. Although
1175 unlikely, in the extreme case this might damage your
1176 hardware.
1177
1178 ltpc= [NET]
1179 Format: <io>,<irq>,<dma>
1180
Randy Dunlapa9913042005-10-23 12:57:11 -07001181 mac5380= [HW,SCSI] Format:
1182 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183
Randy Dunlapa9913042005-10-23 12:57:11 -07001184 machvec= [IA64] Force the use of a particular machine-vector
1185 (machvec) in a generic kernel.
1186 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187
Randy Dunlapa9913042005-10-23 12:57:11 -07001188 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 be mounted
1190 Format: <1-256>
1191
1192 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001193 should make use of. maxcpus=n : n >= 0 limits the
1194 kernel to using 'n' processors. n=0 is a special case,
1195 it is equivalent to "nosmp", which also disables
1196 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197
Randy Dunlap1c207f92008-11-19 15:36:16 -08001198 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
1199 or equal to this physical address is ignored.
Bob Picco2b2c3752005-06-29 18:00:00 -07001200
Randy Dunlapa9913042005-10-23 12:57:11 -07001201 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 Should be between 1 and 2^32-1.
1203
1204 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001205 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 Should be between 1 and 16384.
1207
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208 mcatest= [IA-64]
1209
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001210 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211
Uwe Hermann71cced62008-10-20 09:32:21 -07001212 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
Andi Kleen909dd322007-10-17 18:04:38 +02001213
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 md= [HW] RAID subsystems devices and level
1215 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001216
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 mdacon= [MDA]
1218 Format: <first>,<last>
1219 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001220
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1222 Amount of memory to be used when the kernel is not able
1223 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001224 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 address space collisions. Without memmap= PCI devices
1226 could be placed at addresses belonging to unused RAM.
1227
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001228 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 memory.
1230
Paul Mundt6902aa82008-09-21 17:14:42 +09001231 memchunk=nn[KMG]
1232 [KNL,SH] Allow user to override the default size for
1233 per-device physically contiguous DMA buffers.
1234
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001235 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 E820 memory map, as specified by the user.
1237 Such memmap=exactmap lines can be constructed based on
1238 BIOS output or other requirements. See the memmap=nn@ss
1239 option description.
1240
1241 memmap=nn[KMG]@ss[KMG]
1242 [KNL] Force usage of a specific region of memory
1243 Region of memory to be used, from ss to ss+nn.
1244
1245 memmap=nn[KMG]#ss[KMG]
1246 [KNL,ACPI] Mark specific memory as ACPI data.
1247 Region of memory to be used, from ss to ss+nn.
1248
1249 memmap=nn[KMG]$ss[KMG]
1250 [KNL,ACPI] Mark specific memory as reserved.
1251 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001252 Example: Exclude memory from 0x18690000-0x1869ffff
1253 memmap=64K$0x18690000
1254 or
1255 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001257 memory_corruption_check=0/1 [X86]
1258 Some BIOSes seem to corrupt the first 64k of
1259 memory when doing things like suspend/resume.
1260 Setting this option will scan the memory
1261 looking for corruption. Enabling this will
1262 both detect corruption and prevent the kernel
1263 from using the memory being corrupted.
1264 However, its intended as a diagnostic tool; if
1265 repeatable BIOS-originated corruption always
1266 affects the same memory, you can use memmap=
1267 to prevent the kernel from using that memory.
1268
1269 memory_corruption_check_size=size [X86]
1270 By default it checks for corruption in the low
1271 64k, making this memory unavailable for normal
1272 use. Use this parameter to scan for
1273 corruption in more or less memory.
1274
1275 memory_corruption_check_period=seconds [X86]
1276 By default it checks for corruption every 60
1277 seconds. Use this parameter to check at some
1278 other rate. 0 disables periodic checking.
1279
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001280 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001281 Format: <integer>
1282 range: 0,4 : pattern number
1283 default : 0 <disable>
1284
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 meye.*= [HW] Set MotionEye Camera parameters
1286 See Documentation/video4linux/meye.txt.
1287
Andres Salomon8f368812007-10-12 23:04:06 +02001288 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1289 Multi-Function General Purpose Timers on AMD Geode
1290 platforms.
1291
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001292 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1293 the BIOS has incorrectly applied a workaround. TinyBIOS
1294 version 0.98 is known to be affected, 0.99 fixes the
1295 problem by letting the user disable the workaround.
1296
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 mga= [HW,DRM]
1298
Randy Dunlap1c207f92008-11-19 15:36:16 -08001299 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1300 physical address is ignored.
1301
Mel Gorman6b74ab92008-07-23 21:26:49 -07001302 mminit_loglevel=
1303 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1304 parameter allows control of the logging verbosity for
1305 the additional memory initialisation checks. A value
1306 of 0 disables mminit logging and a level of 4 will
1307 log everything. Information is printed at KERN_DEBUG
1308 so loglevel=8 may also need to be specified.
1309
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 mousedev.tap_time=
1311 [MOUSE] Maximum time between finger touching and
1312 leaving touchpad surface for touch to be considered
1313 a tap and be reported as a left button click (for
1314 touchpads working in absolute mode only).
1315 Format: <msecs>
1316 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1317 reporting absolute coordinates, such as tablets
1318 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1319 reporting absolute coordinates, such as tablets
1320
1321 mpu401= [HW,OSS]
1322 Format: <io>,<irq>
1323
1324 MTD_Partition= [MTD]
1325 Format: <name>,<region-number>,<size>,<offset>
1326
Randy Dunlapa9913042005-10-23 12:57:11 -07001327 MTD_Region= [MTD] Format:
1328 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329
1330 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001331 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332
Ben Dooks9db829f2008-07-03 11:24:29 +01001333 mtdset= [ARM]
1334 ARM/S3C2412 JIVE boot control
1335
1336 See arch/arm/mach-s3c2412/mach-jive.c
1337
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001339 [HW] Make the MicroTouch USB driver use raw coordinates
1340 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341
1342 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1343
1344 NCR_D700= [HW,SCSI]
1345 See header of drivers/scsi/NCR_D700.c.
1346
1347 ncr5380= [HW,SCSI]
1348
1349 ncr53c400= [HW,SCSI]
1350
1351 ncr53c400a= [HW,SCSI]
1352
1353 ncr53c406a= [HW,SCSI]
1354
1355 ncr53c8xx= [HW,SCSI]
1356
1357 netdev= [NET] Network devices parameters
1358 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1359 Note that mem_start is often overloaded to mean
1360 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001361 This usage is only documented in each driver source
1362 file if at all.
1363
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001364 nf_conntrack.acct=
1365 [NETFILTER] Enable connection tracking flow accounting
1366 0 to disable accounting
1367 1 to enable accounting
1368 Default value depends on CONFIG_NF_CT_ACCT that is
1369 going to be removed in 2.6.29.
1370
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001372 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373
1374 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001375 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376
Trond Myklebusta72b4422006-01-03 09:55:41 +01001377 nfs.callback_tcpport=
1378 [NFS] set the TCP port on which the NFSv4 callback
1379 channel should listen.
1380
Trond Myklebust58df0952006-01-03 09:55:57 +01001381 nfs.idmap_cache_timeout=
1382 [NFS] set the maximum lifetime for idmapper cache
1383 entries.
1384
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001385 nfs.enable_ino64=
1386 [NFS] enable 64-bit inode numbers.
1387 If zero, the NFS client will fake up a 32-bit inode
1388 number for the readdir() and stat() syscalls instead
1389 of returning the full 64-bit number.
1390 The default is to return 64-bit inode numbers.
1391
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001392 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1393 when a NMI is triggered.
1394 Format: [state][,regs][,debounce][,die]
1395
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001396 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001398 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 emulation library even if a 387 maths coprocessor
1400 is present.
1401
Christoph Lameterc1aee212007-05-31 00:40:47 -07001402 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1403 caches in the slab allocator. Saves per-node memory,
1404 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001405
Randy Dunlapa9913042005-10-23 12:57:11 -07001406 noalign [KNL,ARM]
1407
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 noapic [SMP,APIC] Tells the kernel to not make use of any
1409 IOAPICs that may be present in the system.
1410
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 nobats [PPC] Do not use BATs for mapping kernel lowmem
1412 on "Classic" PPC cores.
1413
1414 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001415
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001416 nodelayacct [KNL] Disable per-task delay accounting
1417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1419
Paul Mundt6902aa82008-09-21 17:14:42 +09001420 nodsp [SH] Disable hardware DSP at boot time.
1421
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001422 noefi [X86-32,X86-64] Disable EFI runtime services support.
1423
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 noexec [IA-64]
1425
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001426 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001427 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001429 noexec=off: disable non-executable mappings
1430
1431 noexec32 [X86-64]
1432 This affects only 32-bit executables.
1433 noexec32=on: enable non-executable mappings (default)
1434 read doesn't imply executable mappings
1435 noexec32=off: disable non-executable mappings
1436 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437
Paul Mundt6902aa82008-09-21 17:14:42 +09001438 nofpu [SH] Disable hardware FPU at boot time.
1439
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001440 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001441 register save and restore. The kernel will only save
1442 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443
Andi Kleen191679f2008-01-30 13:33:21 +01001444 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1445
Paul Mundt6902aa82008-09-21 17:14:42 +09001446 nohlt [BUGS=ARM,SH]
Randy Dunlapa9913042005-10-23 12:57:11 -07001447
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001448 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 instruction doesn't work correctly and not to
1450 use it.
1451
1452 nohalt [IA-64] Tells the kernel not to use the power saving
1453 function PAL_HALT_LIGHT when idle. This increases
1454 power-consumption. On the positive side, it reduces
1455 interrupt wake-up latency, which may improve performance
1456 in certain environments such as networked servers or
1457 real-time systems.
1458
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001459 nohz= [KNL] Boottime enable/disable dynamic ticks
1460 Valid arguments: on, off
1461 Default: on
1462
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001463 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 disable unhandled interrupt sources.
1465
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001466 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001467 broken timer IRQ sources.
1468
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 noisapnp [ISAPNP] Disables ISA PnP code.
1470
1471 noinitrd [RAM] Tells the kernel not to load any configured
1472 initial RAM disk.
1473
1474 nointroute [IA-64]
1475
Tony Luck0aa366f2007-07-20 11:22:30 -07001476 nojitter [IA64] Disables jitter checking for ITC timers.
1477
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001478 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001480 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001481
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001482 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1483
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001484 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1485 default x2apic cluster mode on platforms
1486 supporting x2apic.
1487
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 noltlbs [PPC] Do not use large page/tlb entries for kernel
1489 lowmem mapping on PPC40x.
1490
Horms312f1f02006-02-22 09:57:55 +09001491 nomca [IA-64] Disable machine check abort handling
1492
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001493 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001494
Andres Salomon83d73842007-10-12 23:04:06 +02001495 nomfgpt [X86-32] Disable Multi-Function General Purpose
1496 Timer usage (for AMD Geode machines).
1497
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001498 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001499
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001500 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001501 with UP alternatives
1502
Linus Torvalds1da177e2005-04-16 15:20:36 -07001503 noresidual [PPC] Don't use residual data on PReP machines.
1504
Randy Dunlapa9913042005-10-23 12:57:11 -07001505 noresume [SWSUSP] Disables resume and restores original swap
1506 space.
1507
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 no-scroll [VGA] Disables scrollback.
1509 This is required for the Braillex ib80-piezo Braille
1510 reader made by F.H. Papenmeier (Germany).
1511
1512 nosbagart [IA-64]
1513
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001514 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001515
Len Brown61ec7562007-08-16 03:34:22 -04001516 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1517 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518
Dave Jones97842212007-07-15 23:41:05 -07001519 nosoftlockup [KNL] Disable the soft-lockup detector.
1520
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521 nosync [HW,M68K] Disables sync negotiation for all devices.
1522
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001523 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524
1525 nousb [USB] Disable the USB subsystem
1526
1527 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001528
Fenghua Yua6c75b862008-03-14 13:57:08 -07001529 nptcg= [IA64] Override max number of concurrent global TLB
1530 purges which is reported from either PAL_VM_SUMMARY or
1531 SAL PALO.
1532
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001533 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1534 one of ['zone', 'node', 'default'] can be specified
1535 This can be set from sysctl after boot.
1536 See Documentation/sysctl/vm.txt for details.
1537
Dave Jonesa61c2d72006-01-07 23:18:19 +00001538 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1539
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001540 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1541 Rather than timing out after 20 ms if an EC
1542 command is not properly ACKed, override the length
1543 of the timeout. We have interrupts disabled while
1544 waiting for the ACK, so if this is set too high
1545 interrupts *may* be lost!
1546
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547 opl3= [HW,OSS]
1548 Format: <io>
1549
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550 oprofile.timer= [HW]
1551 Use timer interrupt instead of performance counters
1552
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 osst= [HW,SCSI] SCSI Tape Driver
1554 Format: <buffer_size>,<write_threshold>
1555 See also Documentation/scsi/st.txt.
1556
1557 panic= [KNL] Kernel behaviour on panic
1558 Format: <timeout>
1559
1560 parkbd.port= [HW] Parallel port number the keyboard adapter is
1561 connected to, default is 0.
1562 Format: <parport#>
1563 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1564 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001565 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566
Randy Dunlapa9913042005-10-23 12:57:11 -07001567 parport= [HW,PPT] Specify parallel ports. 0 disables.
1568 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1569 Use 'auto' to force the driver to use any
1570 IRQ/DMA settings detected (the default is to
1571 ignore detected IRQ/DMA settings because of
1572 possible conflicts). You can specify the base
1573 address, IRQ, and DMA settings; IRQ and DMA
1574 should be numbers, or 'auto' (for using detected
1575 settings on that particular port), or 'nofifo'
1576 (to avoid using a FIFO even if it is detected).
1577 Parallel ports are assigned in the order they
1578 are specified on the command line, starting
1579 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580
Randy Dunlapa9913042005-10-23 12:57:11 -07001581 parport_init_mode= [HW,PPT]
1582 Configure VIA parallel port to operate in
1583 a specific mode. This is necessary on Pegasos
1584 computer where firmware has no options for setting
1585 up parallel port mode and sets it to spp.
1586 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587 Format: [spp|ps2|epp|ecp|ecpepp]
1588
Randy Dunlapa9913042005-10-23 12:57:11 -07001589 pas2= [HW,OSS] Format:
1590 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1591
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592 pas16= [HW,SCSI]
1593 See header of drivers/scsi/pas16.c.
1594
Andrew Mortondd287792006-03-23 03:00:57 -08001595 pause_on_oops=
1596 Halt all CPUs after the first oops has been printed for
1597 the specified number of seconds. This is to be used if
1598 your oopses keep scrolling off the screen.
1599
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600 pcbit= [HW,ISDN]
1601
1602 pcd. [PARIDE]
1603 See header of drivers/block/paride/pcd.c.
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001604 See also Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605
Randy Dunlapa9913042005-10-23 12:57:11 -07001606 pci=option[,option...] [PCI] various PCI subsystem options:
Andi Kleenc0115602008-08-22 09:53:39 +02001607 off [X86] don't probe for the PCI bus
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001608 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001609 the hardware directly. Use this if your machine
1610 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001611 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001612 hardware access methods are allowed. Use this
1613 if you experience crashes upon bootup and you
1614 suspect they are caused by the BIOS.
Andi Kleenc0115602008-08-22 09:53:39 +02001615 conf1 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001616 Mechanism 1.
Andi Kleenc0115602008-08-22 09:53:39 +02001617 conf2 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001618 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001619 noaer [PCIE] If the PCIEAER kernel config parameter is
1620 enabled, this kernel boot option can be used to
1621 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001622 nodomains [PCI] Disable support for multiple PCI
1623 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001624 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001625 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001626 nomsi [MSI] If the PCI_MSI kernel config parameter is
1627 enabled, this kernel boot option can be used to
1628 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001629 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001630 routing table. These calls are known to be buggy
1631 on several machines and they hang the machine
1632 when used, but on other computers it's the only
1633 way to get the interrupt routing table. Try
1634 this option if the kernel is unable to allocate
1635 IRQs or discover secondary PCI buses on your
1636 motherboard.
Andi Kleenc0115602008-08-22 09:53:39 +02001637 rom [X86] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001638 Use with caution as certain devices share
1639 address decoders between ROMs and other
1640 resources.
Andi Kleenc0115602008-08-22 09:53:39 +02001641 norom [X86] Do not assign address space to
Gary Hadebb71ad82008-05-12 13:57:46 -07001642 expansion ROMs that do not already have
1643 BIOS assigned address ranges.
Andi Kleenc0115602008-08-22 09:53:39 +02001644 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001645 assigned automatically to PCI devices. You can
1646 make the kernel exclude IRQs of your ISA cards
1647 this way.
Andi Kleenc0115602008-08-22 09:53:39 +02001648 pirqaddr=0xAAAAA [X86] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001649 of the PIRQ table (normally generated
1650 by the BIOS) if it is outside the
1651 F0000h-100000h range.
Andi Kleenc0115602008-08-22 09:53:39 +02001652 lastbus=N [X86] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001653 useful if the kernel is unable to find your
1654 secondary buses and you want to tell it
1655 explicitly which ones they are.
Andi Kleenc0115602008-08-22 09:53:39 +02001656 assign-busses [X86] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001657 numbers ourselves, overriding
1658 whatever the firmware may have done.
Andi Kleenc0115602008-08-22 09:53:39 +02001659 usepirqmask [X86] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001660 in the BIOS $PIR table. This is needed on
1661 some systems with broken BIOSes, notably
1662 some HP Pavilion N5400 and Omnibook XE3
1663 notebooks. This will have no effect if ACPI
1664 IRQ routing is enabled.
Andi Kleenc0115602008-08-22 09:53:39 +02001665 noacpi [X86] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001666 or for PCI scanning.
Andi Kleenc0115602008-08-22 09:53:39 +02001667 use_crs [X86] Use _CRS for PCI resource
Gary Hade62f420f2007-10-03 15:56:51 -07001668 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001669 routeirq Do IRQ routing for all PCI devices.
1670 This is normally done in pci_enable_device(),
1671 so this option is a temporary workaround
1672 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001673 skip_isa_align [X86] do not align io start addr, so can
1674 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001675 firmware [ARM] Do not re-enumerate the bus but instead
1676 just use the configuration from the
1677 bootloader. This is currently used on
1678 IXP2000 systems where the bus has to be
1679 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001680 noearly [X86] Don't do any early type 1 scanning.
1681 This might help on some broken boards which
1682 machine check when some devices' config space
1683 is read. But various workarounds are disabled
1684 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001685 bfsort Sort PCI devices into breadth-first order.
1686 This sorting is done to get a device
1687 order compatible with older (<= 2.4) kernels.
1688 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001689 cbiosize=nn[KMG] The fixed amount of bus space which is
1690 reserved for the CardBus bridge's IO window.
1691 The default value is 256 bytes.
1692 cbmemsize=nn[KMG] The fixed amount of bus space which is
1693 reserved for the CardBus bridge's memory
1694 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001695
Chuck Ebberte5665a42008-09-24 20:40:34 -04001696 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1697 Management.
1698 off Disable ASPM.
1699 force Enable ASPM even on devices that claim not to support it.
1700 WARNING: Forcing ASPM on may cause system lockups.
1701
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 pcmv= [HW,PCMCIA] BadgePAD 4
1703
1704 pd. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001705 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706
1707 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1708 boot time.
1709 Format: { 0 | 1 }
1710 See arch/parisc/kernel/pdc_chassis.c
1711
1712 pf. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001713 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714
1715 pg. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001716 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717
1718 pirq= [SMP,APIC] Manual mp-table setup
Uwe Hermann71cced62008-10-20 09:32:21 -07001719 See Documentation/x86/i386/IO-APIC.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720
1721 plip= [PPT,NET] Parallel port network link
1722 Format: { parport<nr> | timid | 0 }
1723 See also Documentation/parport.txt.
1724
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001725 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1726 Override pmtimer IOPort with a hex value.
1727 e.g. pmtmr=0x508
1728
Bjorn Helgaas97ef0622008-08-19 16:53:41 -06001729 pnp.debug [PNP]
1730 Enable PNP debug messages. This depends on the
1731 CONFIG_PNP_DEBUG_MESSAGES option.
1732
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 pnpacpi= [ACPI]
1734 { off }
1735
1736 pnpbios= [ISAPNP]
1737 { on | off | curr | res | no-curr | no-res }
1738
1739 pnp_reserve_irq=
1740 [ISAPNP] Exclude IRQs for the autoconfiguration
1741
1742 pnp_reserve_dma=
1743 [ISAPNP] Exclude DMAs for the autoconfiguration
1744
1745 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001746 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747
1748 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001749 [ISAPNP] Exclude memory regions for the
1750 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 Ranges are in pairs (memory base and size).
1752
Jason Baron346e15b2008-08-12 16:46:19 -04001753 dynamic_printk
1754 Enables pr_debug()/dev_dbg() calls if
1755 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1756 be switched on/off via <debugfs>/dynamic_printk/modules
1757
Ingo Molnar45807a12007-07-15 23:40:10 -07001758 print-fatal-signals=
1759 [KNL] debug: print fatal signals
1760 print-fatal-signals=1: print segfault info to
1761 the kernel console.
1762 default: off.
1763
Randy Dunlape84845c2007-07-15 23:40:25 -07001764 printk.time= Show timing data prefixed to each printk message line
1765 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1766
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001768 Format: [schedule,]<number>
1769 Param: "schedule" - profile schedule points.
1770 Param: <number> - step/bucket size as a power of 2 for
1771 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001772 Param: "sleep" - profile D-state sleeping (millisecs).
1773 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001774 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775
Randy Dunlapa9913042005-10-23 12:57:11 -07001776 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 Limit processor to maximum C-state
1778 max_cstate=9 overrides any DMI blacklist limit.
1779
Len Brown41c0d862005-12-28 12:43:51 -05001780 processor.nocst [HW,ACPI]
1781 Ignore the _CST method to determine C-states,
1782 instead using the legacy FADT method
1783
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1785 before loading.
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001786 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787
Randy Dunlapa9913042005-10-23 12:57:11 -07001788 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1789 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1791 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001792 psmouse.resetafter= [HW,MOUSE]
1793 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 (0 = never).
1795 psmouse.resolution=
1796 [HW,MOUSE] Set desired mouse resolution, in dpi.
1797 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001798 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 0 = disabled, 1 = enabled (default).
1800
1801 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001802 Format:
1803 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804
1805 pt. [PARIDE]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001806 See Documentation/blockdev/paride.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807
Kay Sieversdc8c8582007-08-15 12:25:38 +02001808 pty.legacy_count=
1809 [KNL] Number of legacy pty's. Overwrites compiled-in
1810 default number.
1811
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001812 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001813
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 r128= [HW,DRM]
1815
1816 raid= [HW,RAID]
1817 See Documentation/md.txt.
1818
Randy Dunlapa9913042005-10-23 12:57:11 -07001819 ramdisk_blocksize= [RAM]
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001820 See Documentation/blockdev/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001821
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Randy Dunlap31c00fc2008-11-13 21:33:24 +00001823 See Documentation/blockdev/ramdisk.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001825 rcupdate.blimit= [KNL,BOOT]
1826 Set maximum number of finished RCU callbacks to process
1827 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001828
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001829 rcupdate.qhimark= [KNL,BOOT]
1830 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001831 RCU callbacks over which batch limiting is disabled.
1832
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001833 rcupdate.qlowmark= [KNL,BOOT]
1834 Set threshold of queued RCU callbacks below which
1835 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001836
Olof Johanssonffdfc402005-09-06 15:17:19 -07001837 rdinit= [KNL]
1838 Format: <full_path>
1839 Run specified binary instead of /init from the ramdisk,
1840 used for early userspace startup. See initrd.
1841
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001842 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001844 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845
Paul Jackson46b6d942008-07-04 10:00:09 -07001846 relax_domain_level=
1847 [KNL, SMP] Set scheduler's default relax_domain_level.
1848 See Documentation/cpusets.txt.
1849
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1851
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001852 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001853 Format: nn[KMG]
1854 Reserves a hole at the top of the kernel virtual
1855 address space.
1856
Vivek Goyal7e962872006-09-27 01:50:44 -07001857 reset_devices [KNL] Force drivers to reset the underlying device
1858 during initialization.
1859
Randy Dunlapa9913042005-10-23 12:57:11 -07001860 resume= [SWSUSP]
1861 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001863 resume_offset= [SWSUSP]
1864 Specify the offset from the beginning of the partition
1865 given by "resume=" at which the swap header is located,
1866 in <PAGE_SIZE> units (needed only for swap files).
1867 See Documentation/power/swsusp-and-swap-files.txt
1868
Michael Neuling0a7b35c2007-02-10 01:44:33 -08001869 retain_initrd [RAM] Keep initrd memory after extraction
1870
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871 rhash_entries= [KNL,NET]
1872 Set number of hash buckets for route cache
1873
1874 riscom8= [HW,SERIAL]
1875 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1876
1877 ro [KNL] Mount root device read-only on boot
1878
1879 root= [KNL] Root filesystem
1880
1881 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1882 mount the root filesystem
1883
1884 rootflags= [KNL] Set root filesystem mount option string
1885
1886 rootfstype= [KNL] Set root filesystem type
1887
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001888 rootwait [KNL] Wait (indefinitely) for root device to show up.
1889 Useful for devices that are detected asynchronously
1890 (e.g. USB and MMC devices).
1891
James Morris20510f22007-10-16 23:31:32 -07001892 root_plug.vendor_id=
1893 [ROOTPLUG] Override the default vendor ID
1894
1895 root_plug.product_id=
1896 [ROOTPLUG] Override the default product ID
1897
1898 root_plug.debug=
1899 [ROOTPLUG] Enable debugging output
1900
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 rw [KNL] Mount root device read-write on boot
1902
1903 S [KNL] Run init in single mode
1904
1905 sa1100ir [NET]
1906 See drivers/net/irda/sa1100_ir.c.
1907
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001909
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1911 Format: <io>[,<timeout>[,<isapnp>]]
1912
1913 scsi_debug_*= [SCSI]
1914 See drivers/scsi/scsi_debug.c.
1915
1916 scsi_default_dev_flags=
1917 [SCSI] SCSI default device flags
1918 Format: <integer>
1919
1920 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1921 Format: <vendor>:<model>:<flags>
1922 (flags are integer value)
1923
Randy Dunlap6af66322007-11-14 16:52:25 -08001924 scsi_logging_level= [SCSI] a bit mask of logging levels
1925 See drivers/scsi/scsi_logging.h for bits. Also
1926 settable via sysctl at dev.scsi.logging_level
1927 (/proc/sys/dev/scsi/logging_level).
1928 There is also a nice 'scsi_logging_level' script in the
1929 S390-tools package, available for download at
1930 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001932 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1933 discovered. async scans them in kernel threads,
1934 allowing boot to proceed. none ignores them, expecting
1935 user space to do the scan.
1936
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 selinux [SELINUX] Disable or enable SELinux at boot time.
1938 Format: { "0" | "1" }
1939 See security/selinux/Kconfig help text.
1940 0 -- disable.
1941 1 -- enable.
1942 Default value is set via kernel config option.
1943 If enabled at boot time, /selinux/disable can be used
1944 later to disable prior to initial policy load.
1945
James Morris4e5ab4c2006-06-09 00:33:33 -07001946 selinux_compat_net =
1947 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001948 Format: { "0" | "1" }
1949 0 -- use new secmark-based packet controls
1950 1 -- use legacy packet controls
1951 Default value is 0 (preferred).
1952 Value can be changed at runtime via
1953 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001954
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001955 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957 shapers= [NET]
1958 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001959
Yinghai Lub05f78f2008-08-22 01:32:50 -07001960 show_msr= [x86] show boot-time MSR settings
1961 Format: { <integer> }
1962 Show boot-time (BIOS-initialized) MSR settings.
1963 The parameter means the number of CPUs to show,
1964 for example 1 means boot CPU only.
1965
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966 sim710= [SCSI,HW]
1967 See header of drivers/scsi/sim710.c.
1968
1969 simeth= [IA-64]
1970 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001971
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 slram= [HW,MTD]
1973
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001974 slub_debug[=options[,slabs]] [MM, SLUB]
1975 Enabling slub_debug allows one to determine the
1976 culprit if slab objects become corrupted. Enabling
1977 slub_debug can create guard zones around objects and
1978 may poison objects when not in use. Also tracks the
1979 last alloc / free. For more information see
1980 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001981
1982 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001983 Determines the maximum allowed order for slabs.
1984 A high setting may cause OOMs due to memory
1985 fragmentation. For more information see
1986 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001987
1988 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001989 The minimum number of objects per slab. SLUB will
1990 increase the slab order up to slub_max_order to
1991 generate a sufficiently large slab able to contain
1992 the number of objects indicated. The higher the number
1993 of objects the smaller the overhead of tracking slabs
1994 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001995 For more information see Documentation/vm/slub.txt.
1996
1997 slub_min_order= [MM, SLUB]
1998 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001999 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002000 For more information see Documentation/vm/slub.txt.
2001
2002 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002003 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07002004 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002005 allocs to different slabs. Debug options disable
2006 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002007 For more information see Documentation/vm/slub.txt.
2008
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009 smart2= [HW]
2010 Format: <io1>[,<io2>[,...,<io8>]]
2011
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002012 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02002013 attempt to substitute SMP alternatives once at boot.
2014
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07002015 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2016 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2017 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2018 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2019 smsc-ircc2.ircc_irq= [HW] IRQ line
2020 smsc-ircc2.ircc_dma= [HW] DMA channel
2021 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2022 0: Toshiba Satellite 1800 (GP data pin select)
2023 1: Fast pin select (default)
2024 2: ATC IRMode
2025
Linus Torvalds1da177e2005-04-16 15:20:36 -07002026 snd-ad1816a= [HW,ALSA]
2027
2028 snd-ad1848= [HW,ALSA]
2029
2030 snd-ali5451= [HW,ALSA]
2031
2032 snd-als100= [HW,ALSA]
2033
2034 snd-als4000= [HW,ALSA]
2035
2036 snd-azt2320= [HW,ALSA]
2037
2038 snd-cmi8330= [HW,ALSA]
2039
2040 snd-cmipci= [HW,ALSA]
2041
2042 snd-cs4231= [HW,ALSA]
2043
2044 snd-cs4232= [HW,ALSA]
2045
2046 snd-cs4236= [HW,ALSA]
2047
2048 snd-cs4281= [HW,ALSA]
2049
2050 snd-cs46xx= [HW,ALSA]
2051
2052 snd-dt019x= [HW,ALSA]
2053
2054 snd-dummy= [HW,ALSA]
2055
2056 snd-emu10k1= [HW,ALSA]
2057
2058 snd-ens1370= [HW,ALSA]
2059
2060 snd-ens1371= [HW,ALSA]
2061
2062 snd-es968= [HW,ALSA]
2063
2064 snd-es1688= [HW,ALSA]
2065
2066 snd-es18xx= [HW,ALSA]
2067
2068 snd-es1938= [HW,ALSA]
2069
2070 snd-es1968= [HW,ALSA]
2071
2072 snd-fm801= [HW,ALSA]
2073
2074 snd-gusclassic= [HW,ALSA]
2075
2076 snd-gusextreme= [HW,ALSA]
2077
2078 snd-gusmax= [HW,ALSA]
2079
2080 snd-hdsp= [HW,ALSA]
2081
2082 snd-ice1712= [HW,ALSA]
2083
2084 snd-intel8x0= [HW,ALSA]
2085
2086 snd-interwave= [HW,ALSA]
2087
2088 snd-interwave-stb=
2089 [HW,ALSA]
2090
2091 snd-korg1212= [HW,ALSA]
2092
2093 snd-maestro3= [HW,ALSA]
2094
2095 snd-mpu401= [HW,ALSA]
2096
2097 snd-mtpav= [HW,ALSA]
2098
2099 snd-nm256= [HW,ALSA]
2100
2101 snd-opl3sa2= [HW,ALSA]
2102
2103 snd-opti92x-ad1848=
2104 [HW,ALSA]
2105
2106 snd-opti92x-cs4231=
2107 [HW,ALSA]
2108
2109 snd-opti93x= [HW,ALSA]
2110
2111 snd-pmac= [HW,ALSA]
2112
2113 snd-rme32= [HW,ALSA]
2114
2115 snd-rme96= [HW,ALSA]
2116
2117 snd-rme9652= [HW,ALSA]
2118
2119 snd-sb8= [HW,ALSA]
2120
2121 snd-sb16= [HW,ALSA]
2122
2123 snd-sbawe= [HW,ALSA]
2124
2125 snd-serial= [HW,ALSA]
2126
2127 snd-sgalaxy= [HW,ALSA]
2128
2129 snd-sonicvibes= [HW,ALSA]
2130
2131 snd-sun-amd7930=
2132 [HW,ALSA]
2133
2134 snd-sun-cs4231= [HW,ALSA]
2135
2136 snd-trident= [HW,ALSA]
2137
2138 snd-usb-audio= [HW,ALSA,USB]
2139
2140 snd-via82xx= [HW,ALSA]
2141
2142 snd-virmidi= [HW,ALSA]
2143
2144 snd-wavefront= [HW,ALSA]
2145
2146 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002147
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002148 softlockup_panic=
2149 [KNL] Should the soft-lockup detector generate panics.
2150
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2152 See Documentation/sonypi.txt
2153
2154 specialix= [HW,SERIAL] Specialix multi-serial port adapter
Randy Dunlap31c00fc2008-11-13 21:33:24 +00002155 See Documentation/serial/specialix.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156
2157 spia_io_base= [HW,MTD]
2158 spia_fio_base=
2159 spia_pedr=
2160 spia_peddr=
2161
2162 sscape= [HW,OSS]
2163 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002164
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2166 See Documentation/scsi/st.txt.
2167
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168 sti= [PARISC,HW]
2169 Format: <num>
2170 Set the STI (builtin display/keyboard on the HP-PARISC
2171 machines) console (graphic card) which should be used
2172 as the initial boot-console.
2173 See also comment in drivers/video/console/sticore.c.
2174
2175 sti_font= [HW]
2176 See comment in drivers/video/console/sticore.c.
2177
2178 stifb= [HW]
2179 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2180
Greg Banks42a7fc42007-03-06 01:42:23 -08002181 sunrpc.pool_mode=
2182 [NFS]
2183 Control how the NFS server code allocates CPUs to
2184 service thread pools. Depending on how many NICs
2185 you have and where their interrupts are bound, this
2186 option will affect which CPUs will do NFS serving.
2187 Note: this parameter cannot be changed while the
2188 NFS server is running.
2189
2190 auto the server chooses an appropriate mode
2191 automatically using heuristics
2192 global a single global pool contains all CPUs
2193 percpu one pool for each CPU
2194 pernode one pool for each NUMA node (equivalent
2195 to global on non-NUMA machines)
2196
Linus Torvalds1da177e2005-04-16 15:20:36 -07002197 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002198
Linus Torvalds1da177e2005-04-16 15:20:36 -07002199 switches= [HW,M68k]
2200
2201 sym53c416= [HW,SCSI]
2202 See header of drivers/scsi/sym53c416.c.
2203
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002204 sysrq_always_enabled
2205 [KNL]
2206 Ignore sysrq setting - this boot parameter will
2207 neutralize any effect of /proc/sys/kernel/sysrq.
2208 Useful for debugging.
2209
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 t128= [HW,SCSI]
2211 See header of drivers/scsi/t128.c.
2212
2213 tdfx= [HW,DRM]
2214
David Brownell77437fd2008-07-23 21:28:33 -07002215 test_suspend= [SUSPEND]
2216 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2217 standby suspend) as the system sleep state to briefly
2218 enter during system startup. The system is woken from
2219 this state using a wakeup-capable RTC alarm.
2220
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221 thash_entries= [KNL,NET]
2222 Set number of hash buckets for TCP connection
2223
Len Brownf8707ec2007-08-12 00:12:54 -04002224 thermal.act= [HW,ACPI]
2225 -1: disable all active trip points in all thermal zones
2226 <degrees C>: override all lowest active trip points
2227
Len Brownc52a7412007-08-14 15:49:32 -04002228 thermal.crt= [HW,ACPI]
2229 -1: disable all critical trip points in all thermal zones
Zhang Rui22a94d72008-10-17 02:41:20 -04002230 <degrees C>: override all critical trip points
Len Brownc52a7412007-08-14 15:49:32 -04002231
Len Brownf5487142007-08-12 00:12:44 -04002232 thermal.nocrt= [HW,ACPI]
2233 Set to disable actions on ACPI thermal zone
2234 critical and hot trip points.
2235
Len Brown72b33ef2007-08-12 00:12:17 -04002236 thermal.off= [HW,ACPI]
2237 1: disable ACPI thermal control
2238
Len Browna70cdc52007-08-12 00:12:35 -04002239 thermal.psv= [HW,ACPI]
2240 -1: disable all passive trip points
2241 <degrees C>: override all passive trip points to this value
2242
Len Brown730ff342007-08-12 00:12:26 -04002243 thermal.tzp= [HW,ACPI]
2244 Specify global default ACPI thermal zone polling rate
2245 <deci-seconds>: poll all this frequency
2246 0: no polling (default)
2247
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248 tmscsim= [HW,SCSI]
2249 See comment before function dc390_setup() in
2250 drivers/scsi/tmscsim.c.
2251
2252 tp720= [HW,PS2]
2253
2254 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002255 Format:
2256 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2257
Randy Dunlapa9913042005-10-23 12:57:11 -07002258 turbografx.map[2|3]= [HW,JOY]
2259 TurboGraFX parallel port interface
2260 Format:
2261 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 See also Documentation/input/joystick-parport.txt
2263
2264 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2265 See header of drivers/scsi/u14-34f.c.
2266
2267 uart401= [HW,OSS]
2268 Format: <io>,<irq>
2269
2270 uart6850= [HW,OSS]
2271 Format: <io>,<irq>
2272
Alan Stern5f8364b2006-12-05 16:29:55 -05002273 uhci-hcd.ignore_oc=
2274 [USB] Ignore overcurrent events (default N).
2275 Some badly-designed motherboards generate lots of
2276 bogus events, for ports that aren't wired to
2277 anything. Set this parameter to avoid log spamming.
2278 Note that genuine overcurrent events won't be
2279 reported either.
2280
Simon Arlotte3a61b02008-07-19 23:32:54 +01002281 unknown_nmi_panic
2282 [X86-32,X86-64]
2283 Set unknown_nmi_panic=1 early on boot.
2284
Alan Sternb5e795f2007-02-20 15:00:53 -05002285 usbcore.autosuspend=
2286 [USB] The autosuspend time delay (in seconds) used
2287 for newly-detected USB devices (default 2). This
2288 is the time required before an idle device will be
2289 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002290 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002291
Jaroslav Kyselafd7c5192008-10-10 16:24:45 +02002292 usbcore.usbfs_snoop=
2293 [USB] Set to log all usbfs traffic (default 0 = off).
2294
2295 usbcore.blinkenlights=
2296 [USB] Set to cycle leds on hubs (default 0 = off).
2297
2298 usbcore.old_scheme_first=
2299 [USB] Start with the old device initialization
2300 scheme (default 0 = off).
2301
2302 usbcore.use_both_schemes=
2303 [USB] Try the other device initialization scheme
2304 if the first one fails (default 1 = enabled).
2305
2306 usbcore.initial_descriptor_timeout=
2307 [USB] Specifies timeout for the initial 64-byte
2308 USB_REQ_GET_DESCRIPTOR request in milliseconds
2309 (default 5000 = 5.0 seconds).
2310
Linus Torvalds1da177e2005-04-16 15:20:36 -07002311 usbhid.mousepoll=
2312 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002313
Paul Jackson200001e2008-06-25 05:44:46 -07002314 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2315 kernel's map of available physical RAM.
2316
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002317 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf5272007-05-02 19:27:12 +02002318 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002319 vdso=1: enable VDSO (default)
2320 vdso=0: disable VDSO mapping
2321
Roland McGrathaf65d642008-01-30 13:30:43 +01002322 vdso32= [X86-32,X86-64]
2323 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2324 vdso32=1: enable 32-bit VDSO (default)
2325 vdso32=0: disable 32-bit VDSO mapping
2326
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002327 vector= [IA-64,SMP]
2328 vector=percpu: enable percpu vector domain
2329
Linus Torvalds1da177e2005-04-16 15:20:36 -07002330 video= [FB] Frame buffer configuration
2331 See Documentation/fb/modedb.txt.
2332
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002333 vga= [BOOT,X86-32] Select a particular video mode
Uwe Hermann71cced62008-10-20 09:32:21 -07002334 See Documentation/x86/i386/boot.txt and
Randy Dunlapa9913042005-10-23 12:57:11 -07002335 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336 Use vga=ask for menu.
2337 This is actually a boot loader parameter; the value is
2338 passed to the kernel using a special protocol.
2339
Randy Dunlapa9913042005-10-23 12:57:11 -07002340 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341 size of <nn>. This can be used to increase the
2342 minimum size (128MB on x86). It can also be used to
2343 decrease the size and leave more room for directly
2344 mapped kernel RAM.
2345
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002346 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2347 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002349 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2350 Format: <command>
2351
2352 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2353 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002354
Linus Torvalds1da177e2005-04-16 15:20:36 -07002355 waveartist= [HW,OSS]
2356 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002357
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358 wd33c93= [HW,SCSI]
2359 See header of drivers/scsi/wd33c93.c.
2360
2361 wd7000= [HW,SCSI]
2362 See header of drivers/scsi/wd7000.c.
2363
2364 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002365 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002366
2367 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2368 xd_geo= See header of drivers/block/xd.c.
2369
2370 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002371 Format:
2372 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373
Andi Kleena62eaf12006-02-16 23:41:58 +01002374 norandmaps Don't use address space randomization
2375 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2376
Randy Dunlapa9913042005-10-23 12:57:11 -07002377______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378
2379TODO:
2380
2381 Add documentation for ALSA options.
2382 Add more DRM drivers.