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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
Zhang Ruif9891062007-04-24 13:53:22 +0800201 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700203 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 1: enable, 0: disable. It is useful for boot time
205 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800206 via /sys/module/acpi/parameters/debug_layer.
207 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
208 Available bits (add the numbers together) to enable debug output
209 for specific parts of the ACPI subsystem:
210 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
211 0x10 namespace 0x20 parser 0x40 dispatcher
212 0x80 executer 0x100 resources 0x200 acpica debugger
213 0x400 os services 0x800 acpica disassembler.
214 The number can be in decimal or prefixed with 0x in hex.
215 Warning: Many of these options can produce a lot of
216 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217
Zhang Ruif9891062007-04-24 13:53:22 +0800218 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700220 Each bit of the <int> indicates an ACPI debug level,
Thomas Renninger36eec5e2008-08-11 15:03:20 +0200221 which corresponds to the level in an ACPI_DEBUG_PRINT
222 statement. After system has booted up, this mask
223 can be set via /sys/module/acpi/parameters/debug_level.
224
225 CONFIG_ACPI_DEBUG must be enabled for this to produce
226 any output. The number can be in decimal or prefixed
227 with 0x in hex. Some of these options produce so much
228 output that the system is unusable.
229
230 The following global components are defined by the
231 ACPI CA:
232 0x01 error
233 0x02 warn
234 0x04 init
235 0x08 debug object
236 0x10 info
237 0x20 init names
238 0x40 parse
239 0x80 load
240 0x100 dispatch
241 0x200 execute
242 0x400 names
243 0x800 operation region
244 0x1000 bfield
245 0x2000 tables
246 0x4000 values
247 0x8000 objects
248 0x10000 resources
249 0x20000 user requests
250 0x40000 package
251 The number can be in decimal or prefixed with 0x in hex.
252 Warning: Many of these options can produce a lot of
253 output and make your system unusable. Be very careful.
Zhang Ruif9891062007-04-24 13:53:22 +0800254
Zhao Yakuif5adfaa2008-08-11 14:57:50 +0800255 acpi.power_nocheck= [HW,ACPI]
256 Format: 1/0 enable/disable the check of power state.
257 On some bogus BIOS the _PSC object/_STA object of
258 power resource can't return the correct device power
259 state. In such case it is unneccessary to check its
260 power state again in power transition.
261 1 : disable the power state check
262
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700263 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700264 Override the pmtimer bug detection: force the kernel
265 to assume that this machine's pmtimer latches its value
266 and always returns good values.
267
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000268 agp= [AGP]
269 { off | try_unsupported }
270 off: disable AGP support
271 try_unsupported: try to drive unsupported chipsets
272 (may crash computer or cause data corruption)
273
Chuck Ebbert66759a02005-09-12 18:49:25 +0200274 enable_timer_pin_1 [i386,x86-64]
275 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700276 Can be useful to work around chipset bugs
277 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200278 The kernel tries to set a reasonable default.
279
280 disable_timer_pin_1 [i386,x86-64]
281 Disable PIN 1 of APIC timer
282 Can be useful to work around chipset bugs.
283
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 ad1848= [HW,OSS]
285 Format: <io>,<irq>,<dma>,<dma2>,<type>
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 advansys= [HW,SCSI]
288 See header of drivers/scsi/advansys.c.
289
290 advwdt= [HW,WDT] Advantech WDT
291 Format: <iostart>,<iostop>
292
293 aedsp16= [HW,OSS] Audio Excel DSP 16
294 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
295 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 aha152x= [HW,SCSI]
298 See Documentation/scsi/aha152x.txt.
299
300 aha1542= [HW,SCSI]
301 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
302
303 aic7xxx= [HW,SCSI]
304 See Documentation/scsi/aic7xxx.txt.
305
306 aic79xx= [HW,SCSI]
307 See Documentation/scsi/aic79xx.txt.
308
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200309 amd_iommu= [HW,X86-84]
310 Pass parameters to the AMD IOMMU driver in the system.
311 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200312 isolate - enable device isolation (each device, as far
313 as possible, will get its own protection
314 domain)
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900315 fullflush - enable flushing of IO/TLB entries when
316 they are unmapped. Otherwise they are
317 flushed before they will be reused, which
318 is a lot of faster
319
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200320 amd_iommu_size= [HW,X86-64]
321 Define the size of the aperture for the AMD IOMMU
322 driver. Possible values are:
323 '32M', '64M' (default), '128M', '256M', '512M', '1G'
324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 amijoy.map= [HW,JOY] Amiga joystick support
326 Map of devices attached to JOY0DAT and JOY1DAT
327 Format: <a>,<b>
328 See also Documentation/kernel/input/joystick.txt
329
330 analog.map= [HW,JOY] Analog joystick and gamepad support
331 Specifies type or capabilities of an analog joystick
332 connected to one of 16 gameports
333 Format: <type1>,<type2>,..<type16>
334
Randy Dunlapa9913042005-10-23 12:57:11 -0700335 apc= [HW,SPARC]
336 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 Format: noidle
338 Disable APC CPU standby support. SPARCstation-Fox does
339 not play well with APC CPU idle - disable it if you have
340 APC and your system crashes randomly.
341
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700342 apic= [APIC,i386] Advanced Programmable Interrupt Controller
343 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 Format: { quiet (default) | verbose | debug }
345 Change the amount of debugging information output
346 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700347
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700349 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
352 Format: <io>,<irq>,<nodeID>
353
354 ataflop= [HW,M68k]
355
356 atarimouse= [HW,MOUSE] Atari Mouse
357
358 atascsi= [HW,SCSI] Atari SCSI
359
360 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
361 EzKey and similar keyboards
362
363 atkbd.reset= [HW] Reset keyboard during initialization
364
Randy Dunlapa9913042005-10-23 12:57:11 -0700365 atkbd.set= [HW] Select keyboard code set
366 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367
368 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
369 keyboards
370
371 atkbd.softraw= [HW] Choose between synthetic and real raw mode
372 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700373
374 atkbd.softrepeat= [HW]
375 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376
377 autotest [IA64]
378
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 baycom_epp= [HW,AX25]
380 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700381
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
383 Format: <io>,<mode>
384 See header of drivers/net/hamradio/baycom_par.c.
385
Randy Dunlapa9913042005-10-23 12:57:11 -0700386 baycom_ser_fdx= [HW,AX25]
387 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 Format: <io>,<irq>,<mode>[,<baud>]
389 See header of drivers/net/hamradio/baycom_ser_fdx.c.
390
Randy Dunlapa9913042005-10-23 12:57:11 -0700391 baycom_ser_hdx= [HW,AX25]
392 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 Format: <io>,<irq>,<mode>
394 See header of drivers/net/hamradio/baycom_ser_hdx.c.
395
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700396 boot_delay= Milliseconds to delay each printk during boot.
397 Values larger than 10 seconds (10000) are changed to
398 no delay (0).
399 Format: integer
400
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700401 bootmem_debug [KNL] Enable bootmem allocator debug messages.
402
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700404 bttv.radio= Most important insmod options are available as
405 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
407 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
408
409 BusLogic= [HW,SCSI]
410 See drivers/scsi/BusLogic.c, comment before function
411 BusLogic_ParseDriverOptions().
412
413 c101= [NET] Moxa C101 synchronous serial card
414
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700415 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 Sometimes CPU hardware bugs make them report the cache
417 size incorrectly. The kernel will attempt work arounds
418 to fix known problems, but for some CPUs it is not
419 possible to determine what the correct size should be.
420 This option provides an override for these situations.
421
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200422 security= [SECURITY] Choose a security module to enable at boot.
423 If this boot parameter is not specified, only the first
424 security module asking for security registration will be
425 loaded. An invalid security module name will be treated
426 as if no module has been chosen.
427
James Morris20510f22007-10-16 23:31:32 -0700428 capability.disable=
429 [SECURITY] Disable capabilities. This would normally
430 be used only if an alternative security model is to be
431 configured. Potentially dangerous and should only be
432 used if you are entirely sure of the consequences.
433
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100434 ccw_timeout_log [S390]
435 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436
Paul Menage8bab8dd2008-04-04 14:29:57 -0700437 cgroup_disable= [KNL] Disable a particular controller
438 Format: {name of the controller(s) to disable}
439 {Currently supported controllers - "memory"}
440
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 checkreqprot [SELINUX] Set initial checkreqprot flag value.
442 Format: { "0" | "1" }
443 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700444 0 -- check protection applied by kernel (includes
445 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 1 -- check protection requested by application.
447 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700448 Value can be changed at runtime via
449 /selinux/checkreqprot.
450
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100451 cio_ignore= [S390]
452 See Documentation/s390/CommonIO for details.
453
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700454 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700455 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200456 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700457 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200458 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 Format: { pit | tsc | cyclone | pmtmr }
460
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700461 clocksource= [GENERIC_TIME] Override the default clocksource
462 Format: <string>
463 Override the default clocksource and use the clocksource
464 with the name specified.
465 Some clocksource names to choose from, depending on
466 the platform:
467 [all] jiffies (this is the base, fallback clocksource)
468 [ACPI] acpi_pm
469 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
470 pxa_timer,timer3,32k_counter,timer0_1
471 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700472 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700473 scx200_hrt on Geode; cyclone on IBM x440
474 [MIPS] MIPS
475 [PARISC] cr16
476 [S390] tod
477 [SH] SuperH
478 [SPARC64] tick
479 [X86-64] hpet,tsc
480
Andi Kleenac72e782008-01-30 13:33:21 +0100481 clearcpuid=BITNUM [X86]
482 Disable CPUID feature X for the kernel. See
483 include/asm-x86/cpufeature.h for the valid bit numbers.
484 Note the Linux specific bits are not necessarily
485 stable over kernel options, but the vendor specific
486 ones should be.
487 Also note that user programs calling CPUID directly
488 or using the feature without checking anything
489 will still see it. This just prevents it from
490 being used by the kernel or shown in /proc/cpuinfo.
491 Also note the kernel might malfunction if you disable
492 some critical bits.
493
Arjan van de Vena25bd942008-01-30 13:33:08 +0100494 code_bytes [IA32/X86_64] How many bytes of object code to print
495 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100496 Range: 0 - 8192
497 Default: 64
498
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200499 hpet= [X86-32,HPET] option to control HPET usage
500 Format: { enable (default) | disable | force }
501 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100502 force: allow force enabled of undocumented chips (ICH4,
503 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700506 Format:
507 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
509 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
510 Format: <io>[,<irq>]
511
Randy Dunlapa9913042005-10-23 12:57:11 -0700512 com90xx= [HW,NET]
513 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 Format: <io>[,<irq>[,<memstart>]]
515
516 condev= [HW,S390] console device
517 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700518
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 console= [KNL] Output console device and options.
520
521 tty<n> Use the virtual console device <n>.
522
523 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800524 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800526 the form "bbbbpnf", where "bbbb" is the baud rate,
527 "p" is parity ("n", "o", or "e"), "n" is number of
528 bits, and "f" is flow control ("r" for RTS or
529 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800531 See Documentation/serial-console.txt for more
532 information. See
533 Documentation/networking/netconsole.txt for an
534 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700536 uart[8250],io,<addr>[,options]
537 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 Start an early, polled-mode console on the 8250/16550
539 UART at the specified I/O port or MMIO address,
540 switching to the matching ttyS device later. The
541 options are the same as for ttyS, above.
542
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700543 If the device connected to the port is not a TTY but a braille
544 device, prepend "brl," before the device type, for instance
545 console=brl,ttyS0
546 For now, only VisioBraille is supported.
547
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700548 earlycon= [KNL] Output early console device and options.
549 uart[8250],io,<addr>[,options]
550 uart[8250],mmio,<addr>[,options]
551 Start an early, polled-mode console on the 8250/16550
552 UART at the specified I/O port or MMIO address.
553 The options are the same as for ttyS, above.
554
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700555 no_console_suspend
556 [HW] Never suspend the console
557 Disable suspending of consoles during suspend and
558 hibernate operations. Once disabled, debugging
559 messages can reach various consoles while the rest
560 of the system is being put to sleep (ie, while
561 debugging driver suspend/resume hooks). This may
562 not work reliably with all consoles, but is known
563 to work with serial and VGA consoles.
564
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700566 Format:
567 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700569 crashkernel=nn[KMG]@ss[KMG]
570 [KNL] Reserve a chunk of physical memory to
571 hold a kernel to switch to with kexec on panic.
572
Bernhard Wallefb391592007-10-18 23:41:02 -0700573 crashkernel=range1:size1[,range2:size2,...][@offset]
574 [KNL] Same as above, but depends on the memory
575 in the running system. The syntax of range is
576 start-[end] where start and end are both
577 a memory unit (amount[KMG]). See also
578 Documentation/kdump/kdump.txt for a example.
579
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 cs4232= [HW,OSS]
581 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
582
583 cs89x0_dma= [HW,NET]
584 Format: <dma>
585
586 cs89x0_media= [HW,NET]
587 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700588
Randy Dunlapa9913042005-10-23 12:57:11 -0700589 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 See header of drivers/s390/block/dasd_devmap.c.
591
592 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
593 (one device per port)
594 Format: <port#>,<type>
595 See also Documentation/input/joystick-parport.txt
596
597 debug [KNL] Enable kernel debugging (events log level).
598
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700599 debug_locks_verbose=
600 [KNL] verbose self-tests
601 Format=<0|1>
602 Print debugging info while doing the locking API
603 self-tests.
604 We default to 0 (no extra messages), setting it to
605 1 will print _a lot_ more information - normally
606 only useful to kernel developers.
607
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700608 debug_objects [KNL] Enable object debugging
609
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200610 debugpat [X86] Enable PAT debugging
611
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200612 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 Format: <area>[,<node>]
614 See also Documentation/networking/decnet.txt.
615
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000616 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700617 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
618 Change the default blue palette of the console.
619 This is a 16-member array composed of values
620 ranging from 0-255.
621
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000622 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700623 Format: <green0>,<green1>,<green2>,...,<green15>
624 Change the default green palette of the console.
625 This is a 16-member array composed of values
626 ranging from 0-255.
627
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000628 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700629 Format: <red0>,<red1>,<red2>,...,<red15>
630 Change the default red palette of the console.
631 This is a 16-member array composed of values
632 ranging from 0-255.
633
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000634 vt.default_utf8=
635 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700636 Format=<0|1>
637 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000638 Default is 1, i.e. UTF-8 mode is enabled for all
639 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700640
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 dhash_entries= [KNL]
642 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700643
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 digi= [HW,SERIAL]
645 IO parameters + enable/disable command.
646
647 digiepca= [HW,SERIAL]
648 See drivers/char/README.epca and
649 Documentation/digiepca.txt.
650
Yinghai Lu95ffa242008-04-29 03:52:33 -0700651 disable_mtrr_cleanup [X86]
652 enable_mtrr_cleanup [X86]
653 The kernel tries to adjust MTRR layout from continuous
654 to discrete, to make X server driver able to add WB
655 entry later. This parameter enables/disables that.
656
657 mtrr_chunk_size=nn[KMG] [X86]
658 used for mtrr cleanup. It is largest continous chunk
659 that could hold holes aka. UC entries.
660
661 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700662 Used for mtrr cleanup. It is granularity of mtrr block.
663 Default is 1.
664 Large value could prevent small alignment from
665 using up MTRRs.
666
667 mtrr_spare_reg_nr=n [X86]
668 Format: <integer>
669 Range: 0,7 : spare reg number
670 Default : 1
671 Used for mtrr cleanup. It is spare mtrr entries number.
672 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700673
Yinghai Lu093af8d2008-01-30 13:33:32 +0100674 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100675 By default the kernel will trim any uncacheable
676 memory out of your available memory pool based on
677 MTRR settings. This parameter disables that behavior,
678 possibly causing your machine to run very slowly.
679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 dmasound= [HW,OSS] Sound subsystem buffers
681
682 dscc4.setup= [NET]
683
684 dtc3181e= [HW,SCSI]
685
Robin Getz0ae53642007-10-09 17:24:49 +0800686 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 earlyprintk=vga
688 earlyprintk=serial[,ttySn[,baudrate]]
Yinghai Lu5c059172008-07-24 17:29:40 -0700689 earlyprintk=dbgp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690
Randy Dunlapa9913042005-10-23 12:57:11 -0700691 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 takes over.
693
Yinghai Lu5c059172008-07-24 17:29:40 -0700694 Only vga or serial or usb debug port at a time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695
696 Currently only ttyS0 and ttyS1 are supported.
697
698 Interaction with the standard serial driver is not
699 very good.
700
701 The VGA output is eventually overwritten by the real
702 console.
703
704 eata= [HW,SCSI]
705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700707 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 eisa_irq_edge= [PARISC,HW]
710 See header of drivers/parisc/eisa.c.
711
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700712 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700714 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
716 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800717 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700718 See Documentation/block/as-iosched.txt and
719 Documentation/block/deadline-iosched.txt for details.
720
Simon Hormane515a0d2008-10-18 20:28:27 -0700721 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700722 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800723 image elf header. Generally kexec loader will
724 pass this option to capture kernel.
725 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726
727 enforcing [SELINUX] Set initial enforcing status.
728 Format: {"0" | "1"}
729 See security/selinux/Kconfig help text.
730 0 -- permissive (log only, no denials).
731 1 -- enforcing (deny and log).
732 Default value is 0.
733 Value can be changed at runtime via /selinux/enforce.
734
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 es1371= [HW,OSS]
736 Format: <spdif>,[<nomix>,[<amplifier>]]
737 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700738
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 ether= [HW,NET] Ethernet cards parameters
740 This option is obsoleted by the "netdev=" option, which
741 has equivalent usage. See its documentation for details.
742
743 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
744 Format: <io>[,<irq>]
745
Akinobu Mitade1ba092006-12-08 02:39:42 -0800746 failslab=
747 fail_page_alloc=
748 fail_make_request=[KNL]
749 General fault injection mechanism.
750 Format: <interval>,<probability>,<space>,<times>
751 See also /Documentation/fault-injection/.
752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 fd_mcs= [HW,SCSI]
754 See header of drivers/scsi/fd_mcs.c.
755
756 fdomain= [HW,SCSI]
757 See header of drivers/scsi/fdomain.c.
758
759 floppy= [HW]
760 See Documentation/floppy.txt.
761
Alex Chiangf13ae302008-05-08 14:03:23 -0600762 force_pal_cache_flush
763 [IA-64] Avoid check_sal_cache_flush which may hang on
764 buggy SAL_CACHE_FLUSH implementations. Using this
765 parameter will force ia64_sal_cache_flush to call
766 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
767
Peter Zijlstrad9e54072008-11-01 19:57:37 +0100768 ftrace=[tracer]
769 [ftrace] will set and start the specified tracer
770 as early as possible in order to facilitate early
771 boot debugging.
772
773 ftrace_dump_on_oops
774 [ftrace] will dump the trace buffers on oops.
775
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 gamecon.map[2|3]=
777 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
778 support via parallel port (up to 5 devices per port)
779 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
780 See also Documentation/input/joystick-parport.txt
781
782 gamma= [HW,DRM]
783
Yinghai Luaaf23042008-01-30 13:33:09 +0100784 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
785 Format: off | on
786 default: on
787
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 gdth= [HW,SCSI]
789 See header of drivers/scsi/gdth.c.
790
791 gpt [EFI] Forces disk with valid GPT signature but
792 invalid Protective MBR to be treated as GPT.
793
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 gvp11= [HW,SCSI]
795
796 hashdist= [KNL,NUMA] Large hashes allocated during boot
797 are distributed across NUMA nodes. Defaults on
798 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700799 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
801 hcl= [IA-64] SGI's Hardware Graph compatibility layer
802
803 hd= [EIDE] (E)IDE hard drive subsystem geometry
804 Format: <cyl>,<head>,<sect>
805
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
807 size of <nn>. This works even on boxes that have no
808 highmem otherwise. This also works to reduce highmem
809 size on bigger boxes.
810
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800811 highres= [KNL] Enable/disable high resolution timer mode.
812 Valid parameters: "on", "off"
813 Default: "on"
814
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 hisax= [HW,ISDN]
816 See Documentation/isdn/README.HiSax.
817
Andi Kleenb4718e62008-07-23 21:27:51 -0700818 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
819 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700820 On x86-64 and powerpc, this option can be specified
821 multiple times interleaved with hugepages= to reserve
822 huge pages of different sizes. Valid pages sizes on
823 x86-64 are 2M (when the CPU supports "pse") and 1G
824 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700825 Note that 1GB pages can only be allocated at boot time
826 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700827 default_hugepagesz=
828 [same as hugepagesz=] The size of the default
829 HugeTLB page size. This is the size represented by
830 the legacy /proc/ hugepages APIs, used for SHM, and
831 default size when mounting hugetlbfs filesystems.
832 Defaults to the default architecture's huge page size
833 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834
Paul Mundt6902aa82008-09-21 17:14:42 +0900835 hlt [BUGS=ARM,SH]
836
Jiri Kosina36d95732008-10-06 02:51:09 -0400837 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200839 i8042.dumbkbd [HW] Pretend that controller can only read data from
840 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 (Don't attempt to blink the leds)
842 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500843 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400844 i8042.noloop [HW] Disable the AUX Loopback command while probing
845 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 i8042.nomux [HW] Don't check presence of an active multiplexing
847 controller
848 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
849 controllers
850 i8042.panicblink=
851 [HW] Frequency with which keyboard LEDs should blink
852 when kernel panics (default is 0.5 sec)
853 i8042.reset [HW] Reset the controller during init and cleanup
854 i8042.unlock [HW] Unlock (ignore) the keylock
855
856 i810= [HW,DRM]
857
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700858 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
859 indicates that the driver is running on unsupported
860 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
862 does not match list of supported models.
863 i8k.power_status
864 [HW] Report power status in /proc/i8k
865 (disabled by default)
866 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
867 capability is set.
868
869 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
870 See Documentation/mca.txt.
871
872 icn= [HW,ISDN]
873 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
874
875 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200876 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100877 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100880 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
Andi Kleenf039b752007-05-02 19:27:12 +0200882 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800883 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200884 Poll forces a polling idle loop that can slightly improves the performance
885 of waking up a idle CPU, but will use a lot of power and make the system
886 run hot. Not recommended.
887 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
888 to not use it because it doesn't save as much power as a normal idle
889 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
890 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800891 idle=halt. Halt is forced to be used for CPU idle.
892 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800893 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700894
Denis Cheng594765a2008-02-06 02:57:49 +0100895 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
896 Claim all unknown PCI IDE storage controllers.
897
Ingo Molnar792908222006-12-06 20:40:51 -0800898 ignore_loglevel [KNL]
899 Ignore loglevel setting - this will print /all/
900 kernel messages to the console. Useful for debugging.
901
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 ihash_entries= [KNL]
903 Set number of hash buckets for inode cache.
904
905 in2000= [HW,SCSI]
906 See header of drivers/scsi/in2000.c.
907
908 init= [KNL]
909 Format: <full_path>
910 Run specified binary instead of /sbin/init as init
911 process.
912
913 initcall_debug [KNL] Trace initcalls as they are executed. Useful
914 for working out where the kernel is dying during
915 startup.
916
917 initrd= [BOOT] Specify the location of the initial ramdisk
918
919 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
920 Format: <irq>
921
922 inttest= [IA64]
923
Pavel Machekb552da82008-03-19 15:58:11 +0100924 iommu= [x86]
925 off
926 force
927 noforce
928 biomerge
929 panic
930 nopanic
931 merge
932 nomerge
933 forcesac
934 soft
935
936
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700937 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
938 off
939 Disable intel iommu driver.
940 igfx_off [Default Off]
941 By default, gfx is mapped as normal device. If a gfx
942 device has a dedicated DMAR unit, the DMAR unit is
943 bypassed by not enabling DMAR with this option. In
944 this case, gfx device will use physical address for
945 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700946 forcedac [x86_64]
947 With this option iommu will not optimize to look
948 for io virtual address below 32 bit forcing dual
949 address cycle on pci bus for cards supporting greater
950 than 32 bit addressing. The default is to look
951 for translation below 32 bit and if not available
952 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800953 strict [Default Off]
954 With this option on every unmap_single operation will
955 result in a hardware IOTLB flush operation as opposed
956 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700957
Rene Hermanb02aae92008-01-30 13:30:05 +0100958 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100959 0x80
960 Standard port 0x80 based delay
961 0xed
962 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100963 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100964 Simple two microseconds delay
965 none
966 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100967
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 io7= [HW] IO7 for Marvel based alpha systems
969 See comment before marvel_specify_io7 in
970 arch/alpha/kernel/core_marvel.c.
971
972 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400973 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974
975 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700976 See comment before ip2_setup() in
977 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978
979 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
980 See header of drivers/scsi/ips.c.
981
Simon Horman72c4a132006-09-13 19:57:18 -0700982 ports= [IP_VS_FTP] IPVS ftp helper module
983 Default is 21.
984 Up to 8 (IP_VS_APP_MAX_PORTS) ports
985 may be specified.
986 Format: <port>,<port>....
987
Alan Cox200803d2005-06-28 20:45:18 -0700988 irqfixup [HW]
989 When an interrupt is not handled search all handlers
990 for it. Intended to get systems with badly broken
991 firmware running.
992
993 irqpoll [HW]
994 When an interrupt is not handled search all handlers
995 for it. Also check all handlers each timer
996 interrupt. Intended to get systems with badly broken
997 firmware running.
998
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -07001000 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001
1002 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -08001003 Format:
1004 <cpu number>,...,<cpu number>
1005 or
1006 <cpu number>-<cpu number> (must be a positive range in ascending order)
1007 or a mixture
1008 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 This option can be used to specify one or more CPUs
1010 to isolate from the general SMP balancing and scheduling
1011 algorithms. The only way to move a process onto or off
1012 an "isolated" CPU is via the CPU affinity syscalls.
1013 <cpu number> begins at 0 and the maximum value is
1014 "number of CPUs in system - 1".
1015
1016 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -07001017 alternative -- manually setting the CPU mask of all
1018 tasks in the system -- can cause problems and
1019 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020
Randy Dunlapa9913042005-10-23 12:57:11 -07001021 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
1023 js= [HW,JOY] Analog joystick
1024 See Documentation/input/joystick.txt.
1025
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001026 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -07001027 specifies the amount of memory usable by the kernel
1028 for non-movable allocations. The requested amount is
1029 spread evenly throughout all nodes in the system. The
1030 remaining memory in each node is used for Movable
1031 pages. In the event, a node is too small to have both
1032 kernelcore and Movable pages, kernelcore pages will
1033 take priority and other nodes will have a larger number
1034 of kernelcore pages. The Movable zone is used for the
1035 allocation of pages that may be reclaimed or moved
1036 by the page migration subsystem. This means that
1037 HugeTLB pages may not be allocated from this zone.
1038 Note that allocations like PTEs-from-HighMem still
1039 use the HighMem zone if it exists, and the Normal
1040 zone if it does not.
1041
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001042 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001043 is similar to kernelcore except it specifies the
1044 amount of memory used for migratable allocations.
1045 If both kernelcore and movablecore is specified,
1046 then kernelcore will be at *least* the specified
1047 value but may be more. If movablecore on its own
1048 is specified, the administrator must be careful
1049 that the amount of memory usable for all allocations
1050 is not too small.
1051
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 keepinitrd [HW,ARM]
1053
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001054 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 in oops dumps.
1056
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001057 kgdboc= [HW] kgdb over consoles.
1058 Requires a tty driver that supports console polling.
1059 (only serial suported for now)
1060 Format: <serial_device>[,baud]
1061
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001062 kmac= [MIPS] korina ethernet MAC address.
1063 Configure the RouterBoard 532 series on-chip
1064 Ethernet adapter MAC address.
1065
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 l2cr= [PPC]
1067
Robert Brosea78bfbf2008-03-29 07:20:23 +11001068 l3cr= [PPC]
1069
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001070 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001071 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001073 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001074 C2 power state.
1075
FD Camifcb71f62008-01-06 19:08:56 +01001076 libata.dma= [LIBATA] DMA control
1077 libata.dma=0 Disable all PATA and SATA DMA
1078 libata.dma=1 PATA and SATA Disk DMA only
1079 libata.dma=2 ATAPI (CDROM) DMA only
1080 libata.dma=4 Compact Flash DMA only
1081 Combinations also work, so libata.dma=3 enables DMA
1082 for disks and CDROMs, but not CFs.
1083
Dave Jones78e70c22007-09-27 11:50:13 -04001084 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1085 when set.
1086 Format: <int>
1087
Tejun Heo33267322008-02-13 09:15:09 +09001088 libata.force= [LIBATA] Force configurations. The format is comma
1089 separated list of "[ID:]VAL" where ID is
1090 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1091 matching port, link or device. Basically, it matches
1092 the ATA ID string printed on console by libata. If
1093 the whole ID part is omitted, the last PORT and DEVICE
1094 values are used. If ID hasn't been specified yet, the
1095 configuration applies to all ports, links and devices.
1096
1097 If only DEVICE is omitted, the parameter applies to
1098 the port and all links and devices behind it. DEVICE
1099 number of 0 either selects the first device or the
1100 first fan-out link behind PMP device. It does not
1101 select the host link. DEVICE number of 15 selects the
1102 host link and device attached to it.
1103
1104 The VAL specifies the configuration to force. As long
1105 as there's no ambiguity shortcut notation is allowed.
1106 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1107 The following configurations can be forced.
1108
1109 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1110 Any ID with matching PORT is used.
1111
1112 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1113
1114 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1115 udma[/][16,25,33,44,66,100,133] notation is also
1116 allowed.
1117
1118 * [no]ncq: Turn on or off NCQ.
1119
Tejun Heo05944bd2008-08-13 20:19:09 +09001120 * nohrst, nosrst, norst: suppress hard, soft
1121 and both resets.
1122
Tejun Heo33267322008-02-13 09:15:09 +09001123 If there are multiple matching configurations changing
1124 the same attribute, the last one is used.
1125
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 load_ramdisk= [RAM] List of ramdisks to load from floppy
1127 See Documentation/ramdisk.txt.
1128
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001129 lockd.nlm_grace_period=P [NFS] Assign grace period.
1130 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001132 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1133 Format: <integer>
1134
1135 lockd.nlm_timeout=T [NFS] Assign timeout value.
1136 Format: <integer>
1137
1138 lockd.nlm_udpport=M [NFS] Assign UDP port.
1139 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140
1141 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1142 Format: <irq>
1143
1144 loglevel= All Kernel Messages with a loglevel smaller than the
1145 console loglevel will be printed to the console. It can
1146 also be changed with klogd or other programs. The
1147 loglevels are defined as follows:
1148
1149 0 (KERN_EMERG) system is unusable
1150 1 (KERN_ALERT) action must be taken immediately
1151 2 (KERN_CRIT) critical conditions
1152 3 (KERN_ERR) error conditions
1153 4 (KERN_WARNING) warning conditions
1154 5 (KERN_NOTICE) normal but significant condition
1155 6 (KERN_INFO) informational
1156 7 (KERN_DEBUG) debug-level messages
1157
1158 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001159 Format: { n | nk | nM }
1160 n must be a power of two. The default size
1161 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
Randy Dunlapaccaa242007-10-16 01:29:37 -07001163 logo.nologo [FB] Disables display of the built-in Linux logo.
1164 This may be used to provide more screen space for
1165 kernel log messages and is useful when debugging
1166 kernel boot problems.
1167
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168 lp=0 [LP] Specify parallel ports to use, e.g,
1169 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1170 lp=reset first parallel port). 'lp=0' disables the
1171 lp=auto printer driver. 'lp=reset' (which can be
1172 specified in addition to the ports) causes
1173 attached printers to be reset. Using
1174 lp=port1,port2,... specifies the parallel ports
1175 to associate lp devices with, starting with
1176 lp0. A port specification may be 'none' to skip
1177 that lp device, or a parport name such as
1178 'parport0'. Specifying 'lp=auto' instead of a
1179 port specification list means that device IDs
1180 from each port should be examined, to see if
1181 an IEEE 1284-compliant printer is attached; if
1182 so, the driver will manage that printer.
1183 See also header of drivers/char/lp.c.
1184
1185 lpj=n [KNL]
1186 Sets loops_per_jiffy to given constant, thus avoiding
1187 time-consuming boot-time autodetection (up to 250 ms per
1188 CPU). 0 enables autodetection (default). To determine
1189 the correct value for your kernel, boot with normal
1190 autodetection and see what value is printed. Note that
1191 on SMP systems the preset will be applied to all CPUs,
1192 which is likely to cause problems if your CPUs need
1193 significantly divergent settings. An incorrect value
1194 will cause delays in the kernel to be wrong, leading to
1195 unpredictable I/O errors and other breakage. Although
1196 unlikely, in the extreme case this might damage your
1197 hardware.
1198
1199 ltpc= [NET]
1200 Format: <io>,<irq>,<dma>
1201
Randy Dunlapa9913042005-10-23 12:57:11 -07001202 mac5380= [HW,SCSI] Format:
1203 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204
Randy Dunlapa9913042005-10-23 12:57:11 -07001205 machvec= [IA64] Force the use of a particular machine-vector
1206 (machvec) in a generic kernel.
1207 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208
Randy Dunlapa9913042005-10-23 12:57:11 -07001209 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 be mounted
1211 Format: <1-256>
1212
1213 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001214 should make use of. maxcpus=n : n >= 0 limits the
1215 kernel to using 'n' processors. n=0 is a special case,
1216 it is equivalent to "nosmp", which also disables
1217 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218
Bob Picco2b2c3752005-06-29 18:00:00 -07001219 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1220 equal to this physical address is ignored.
1221
Randy Dunlapa9913042005-10-23 12:57:11 -07001222 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223 Should be between 1 and 2^32-1.
1224
1225 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001226 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 Should be between 1 and 16384.
1228
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229 mcatest= [IA-64]
1230
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001231 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232
Uwe Hermann71cced62008-10-20 09:32:21 -07001233 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
Andi Kleen909dd322007-10-17 18:04:38 +02001234
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235 md= [HW] RAID subsystems devices and level
1236 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001237
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238 mdacon= [MDA]
1239 Format: <first>,<last>
1240 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001241
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1243 Amount of memory to be used when the kernel is not able
1244 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001245 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 address space collisions. Without memmap= PCI devices
1247 could be placed at addresses belonging to unused RAM.
1248
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001249 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 memory.
1251
Paul Mundt6902aa82008-09-21 17:14:42 +09001252 memchunk=nn[KMG]
1253 [KNL,SH] Allow user to override the default size for
1254 per-device physically contiguous DMA buffers.
1255
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001256 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 E820 memory map, as specified by the user.
1258 Such memmap=exactmap lines can be constructed based on
1259 BIOS output or other requirements. See the memmap=nn@ss
1260 option description.
1261
1262 memmap=nn[KMG]@ss[KMG]
1263 [KNL] Force usage of a specific region of memory
1264 Region of memory to be used, from ss to ss+nn.
1265
1266 memmap=nn[KMG]#ss[KMG]
1267 [KNL,ACPI] Mark specific memory as ACPI data.
1268 Region of memory to be used, from ss to ss+nn.
1269
1270 memmap=nn[KMG]$ss[KMG]
1271 [KNL,ACPI] Mark specific memory as reserved.
1272 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001273 Example: Exclude memory from 0x18690000-0x1869ffff
1274 memmap=64K$0x18690000
1275 or
1276 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001278 memory_corruption_check=0/1 [X86]
1279 Some BIOSes seem to corrupt the first 64k of
1280 memory when doing things like suspend/resume.
1281 Setting this option will scan the memory
1282 looking for corruption. Enabling this will
1283 both detect corruption and prevent the kernel
1284 from using the memory being corrupted.
1285 However, its intended as a diagnostic tool; if
1286 repeatable BIOS-originated corruption always
1287 affects the same memory, you can use memmap=
1288 to prevent the kernel from using that memory.
1289
1290 memory_corruption_check_size=size [X86]
1291 By default it checks for corruption in the low
1292 64k, making this memory unavailable for normal
1293 use. Use this parameter to scan for
1294 corruption in more or less memory.
1295
1296 memory_corruption_check_period=seconds [X86]
1297 By default it checks for corruption every 60
1298 seconds. Use this parameter to check at some
1299 other rate. 0 disables periodic checking.
1300
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001301 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001302 Format: <integer>
1303 range: 0,4 : pattern number
1304 default : 0 <disable>
1305
Linus Torvalds1da177e2005-04-16 15:20:36 -07001306 meye.*= [HW] Set MotionEye Camera parameters
1307 See Documentation/video4linux/meye.txt.
1308
Andres Salomon8f368812007-10-12 23:04:06 +02001309 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1310 Multi-Function General Purpose Timers on AMD Geode
1311 platforms.
1312
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001313 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1314 the BIOS has incorrectly applied a workaround. TinyBIOS
1315 version 0.98 is known to be affected, 0.99 fixes the
1316 problem by letting the user disable the workaround.
1317
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 mga= [HW,DRM]
1319
Mel Gorman6b74ab92008-07-23 21:26:49 -07001320 mminit_loglevel=
1321 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1322 parameter allows control of the logging verbosity for
1323 the additional memory initialisation checks. A value
1324 of 0 disables mminit logging and a level of 4 will
1325 log everything. Information is printed at KERN_DEBUG
1326 so loglevel=8 may also need to be specified.
1327
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 mousedev.tap_time=
1329 [MOUSE] Maximum time between finger touching and
1330 leaving touchpad surface for touch to be considered
1331 a tap and be reported as a left button click (for
1332 touchpads working in absolute mode only).
1333 Format: <msecs>
1334 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1335 reporting absolute coordinates, such as tablets
1336 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1337 reporting absolute coordinates, such as tablets
1338
1339 mpu401= [HW,OSS]
1340 Format: <io>,<irq>
1341
1342 MTD_Partition= [MTD]
1343 Format: <name>,<region-number>,<size>,<offset>
1344
Randy Dunlapa9913042005-10-23 12:57:11 -07001345 MTD_Region= [MTD] Format:
1346 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347
1348 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001349 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350
Ben Dooks9db829f2008-07-03 11:24:29 +01001351 mtdset= [ARM]
1352 ARM/S3C2412 JIVE boot control
1353
1354 See arch/arm/mach-s3c2412/mach-jive.c
1355
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001357 [HW] Make the MicroTouch USB driver use raw coordinates
1358 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359
1360 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1361
1362 NCR_D700= [HW,SCSI]
1363 See header of drivers/scsi/NCR_D700.c.
1364
1365 ncr5380= [HW,SCSI]
1366
1367 ncr53c400= [HW,SCSI]
1368
1369 ncr53c400a= [HW,SCSI]
1370
1371 ncr53c406a= [HW,SCSI]
1372
1373 ncr53c8xx= [HW,SCSI]
1374
1375 netdev= [NET] Network devices parameters
1376 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1377 Note that mem_start is often overloaded to mean
1378 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001379 This usage is only documented in each driver source
1380 file if at all.
1381
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001382 nf_conntrack.acct=
1383 [NETFILTER] Enable connection tracking flow accounting
1384 0 to disable accounting
1385 1 to enable accounting
1386 Default value depends on CONFIG_NF_CT_ACCT that is
1387 going to be removed in 2.6.29.
1388
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001390 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391
1392 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001393 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394
Trond Myklebusta72b4422006-01-03 09:55:41 +01001395 nfs.callback_tcpport=
1396 [NFS] set the TCP port on which the NFSv4 callback
1397 channel should listen.
1398
Trond Myklebust58df0952006-01-03 09:55:57 +01001399 nfs.idmap_cache_timeout=
1400 [NFS] set the maximum lifetime for idmapper cache
1401 entries.
1402
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001403 nfs.enable_ino64=
1404 [NFS] enable 64-bit inode numbers.
1405 If zero, the NFS client will fake up a 32-bit inode
1406 number for the readdir() and stat() syscalls instead
1407 of returning the full 64-bit number.
1408 The default is to return 64-bit inode numbers.
1409
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001410 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1411 when a NMI is triggered.
1412 Format: [state][,regs][,debounce][,die]
1413
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001414 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001416 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 emulation library even if a 387 maths coprocessor
1418 is present.
1419
Christoph Lameterc1aee212007-05-31 00:40:47 -07001420 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1421 caches in the slab allocator. Saves per-node memory,
1422 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001423
Randy Dunlapa9913042005-10-23 12:57:11 -07001424 noalign [KNL,ARM]
1425
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 noapic [SMP,APIC] Tells the kernel to not make use of any
1427 IOAPICs that may be present in the system.
1428
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429 nobats [PPC] Do not use BATs for mapping kernel lowmem
1430 on "Classic" PPC cores.
1431
1432 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001433
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001434 nodelayacct [KNL] Disable per-task delay accounting
1435
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1437
Paul Mundt6902aa82008-09-21 17:14:42 +09001438 nodsp [SH] Disable hardware DSP at boot time.
1439
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001440 noefi [X86-32,X86-64] Disable EFI runtime services support.
1441
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 noexec [IA-64]
1443
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001444 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001445 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001447 noexec=off: disable non-executable mappings
1448
1449 noexec32 [X86-64]
1450 This affects only 32-bit executables.
1451 noexec32=on: enable non-executable mappings (default)
1452 read doesn't imply executable mappings
1453 noexec32=off: disable non-executable mappings
1454 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455
Paul Mundt6902aa82008-09-21 17:14:42 +09001456 nofpu [SH] Disable hardware FPU at boot time.
1457
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001458 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001459 register save and restore. The kernel will only save
1460 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461
Andi Kleen191679f2008-01-30 13:33:21 +01001462 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1463
Paul Mundt6902aa82008-09-21 17:14:42 +09001464 nohlt [BUGS=ARM,SH]
Randy Dunlapa9913042005-10-23 12:57:11 -07001465
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001466 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467 instruction doesn't work correctly and not to
1468 use it.
1469
1470 nohalt [IA-64] Tells the kernel not to use the power saving
1471 function PAL_HALT_LIGHT when idle. This increases
1472 power-consumption. On the positive side, it reduces
1473 interrupt wake-up latency, which may improve performance
1474 in certain environments such as networked servers or
1475 real-time systems.
1476
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001477 nohz= [KNL] Boottime enable/disable dynamic ticks
1478 Valid arguments: on, off
1479 Default: on
1480
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001481 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001482
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001483 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 disable unhandled interrupt sources.
1485
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001486 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001487 broken timer IRQ sources.
1488
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 noisapnp [ISAPNP] Disables ISA PnP code.
1490
1491 noinitrd [RAM] Tells the kernel not to load any configured
1492 initial RAM disk.
1493
1494 nointroute [IA-64]
1495
Tony Luck0aa366f2007-07-20 11:22:30 -07001496 nojitter [IA64] Disables jitter checking for ITC timers.
1497
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001498 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001500 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001501
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001502 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1503
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001504 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1505 default x2apic cluster mode on platforms
1506 supporting x2apic.
1507
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 noltlbs [PPC] Do not use large page/tlb entries for kernel
1509 lowmem mapping on PPC40x.
1510
Horms312f1f02006-02-22 09:57:55 +09001511 nomca [IA-64] Disable machine check abort handling
1512
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001513 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001514
Andres Salomon83d73842007-10-12 23:04:06 +02001515 nomfgpt [X86-32] Disable Multi-Function General Purpose
1516 Timer usage (for AMD Geode machines).
1517
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001518 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001519
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001520 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001521 with UP alternatives
1522
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 noresidual [PPC] Don't use residual data on PReP machines.
1524
Randy Dunlapa9913042005-10-23 12:57:11 -07001525 noresume [SWSUSP] Disables resume and restores original swap
1526 space.
1527
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528 no-scroll [VGA] Disables scrollback.
1529 This is required for the Braillex ib80-piezo Braille
1530 reader made by F.H. Papenmeier (Germany).
1531
1532 nosbagart [IA-64]
1533
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001534 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001535
Len Brown61ec7562007-08-16 03:34:22 -04001536 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1537 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538
Dave Jones97842212007-07-15 23:41:05 -07001539 nosoftlockup [KNL] Disable the soft-lockup detector.
1540
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 nosync [HW,M68K] Disables sync negotiation for all devices.
1542
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001543 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544
1545 nousb [USB] Disable the USB subsystem
1546
1547 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001548
Fenghua Yua6c75b862008-03-14 13:57:08 -07001549 nptcg= [IA64] Override max number of concurrent global TLB
1550 purges which is reported from either PAL_VM_SUMMARY or
1551 SAL PALO.
1552
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001553 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1554 one of ['zone', 'node', 'default'] can be specified
1555 This can be set from sysctl after boot.
1556 See Documentation/sysctl/vm.txt for details.
1557
Dave Jonesa61c2d72006-01-07 23:18:19 +00001558 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1559
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001560 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1561 Rather than timing out after 20 ms if an EC
1562 command is not properly ACKed, override the length
1563 of the timeout. We have interrupts disabled while
1564 waiting for the ACK, so if this is set too high
1565 interrupts *may* be lost!
1566
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567 opl3= [HW,OSS]
1568 Format: <io>
1569
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 oprofile.timer= [HW]
1571 Use timer interrupt instead of performance counters
1572
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 osst= [HW,SCSI] SCSI Tape Driver
1574 Format: <buffer_size>,<write_threshold>
1575 See also Documentation/scsi/st.txt.
1576
1577 panic= [KNL] Kernel behaviour on panic
1578 Format: <timeout>
1579
1580 parkbd.port= [HW] Parallel port number the keyboard adapter is
1581 connected to, default is 0.
1582 Format: <parport#>
1583 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1584 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001585 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586
Randy Dunlapa9913042005-10-23 12:57:11 -07001587 parport= [HW,PPT] Specify parallel ports. 0 disables.
1588 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1589 Use 'auto' to force the driver to use any
1590 IRQ/DMA settings detected (the default is to
1591 ignore detected IRQ/DMA settings because of
1592 possible conflicts). You can specify the base
1593 address, IRQ, and DMA settings; IRQ and DMA
1594 should be numbers, or 'auto' (for using detected
1595 settings on that particular port), or 'nofifo'
1596 (to avoid using a FIFO even if it is detected).
1597 Parallel ports are assigned in the order they
1598 are specified on the command line, starting
1599 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600
Randy Dunlapa9913042005-10-23 12:57:11 -07001601 parport_init_mode= [HW,PPT]
1602 Configure VIA parallel port to operate in
1603 a specific mode. This is necessary on Pegasos
1604 computer where firmware has no options for setting
1605 up parallel port mode and sets it to spp.
1606 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607 Format: [spp|ps2|epp|ecp|ecpepp]
1608
Randy Dunlapa9913042005-10-23 12:57:11 -07001609 pas2= [HW,OSS] Format:
1610 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1611
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 pas16= [HW,SCSI]
1613 See header of drivers/scsi/pas16.c.
1614
Andrew Mortondd287792006-03-23 03:00:57 -08001615 pause_on_oops=
1616 Halt all CPUs after the first oops has been printed for
1617 the specified number of seconds. This is to be used if
1618 your oopses keep scrolling off the screen.
1619
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620 pcbit= [HW,ISDN]
1621
1622 pcd. [PARIDE]
1623 See header of drivers/block/paride/pcd.c.
1624 See also Documentation/paride.txt.
1625
Randy Dunlapa9913042005-10-23 12:57:11 -07001626 pci=option[,option...] [PCI] various PCI subsystem options:
Andi Kleenc0115602008-08-22 09:53:39 +02001627 off [X86] don't probe for the PCI bus
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001628 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001629 the hardware directly. Use this if your machine
1630 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001631 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001632 hardware access methods are allowed. Use this
1633 if you experience crashes upon bootup and you
1634 suspect they are caused by the BIOS.
Andi Kleenc0115602008-08-22 09:53:39 +02001635 conf1 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001636 Mechanism 1.
Andi Kleenc0115602008-08-22 09:53:39 +02001637 conf2 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001638 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001639 noaer [PCIE] If the PCIEAER kernel config parameter is
1640 enabled, this kernel boot option can be used to
1641 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001642 nodomains [PCI] Disable support for multiple PCI
1643 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001644 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001645 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001646 nomsi [MSI] If the PCI_MSI kernel config parameter is
1647 enabled, this kernel boot option can be used to
1648 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001649 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001650 routing table. These calls are known to be buggy
1651 on several machines and they hang the machine
1652 when used, but on other computers it's the only
1653 way to get the interrupt routing table. Try
1654 this option if the kernel is unable to allocate
1655 IRQs or discover secondary PCI buses on your
1656 motherboard.
Andi Kleenc0115602008-08-22 09:53:39 +02001657 rom [X86] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001658 Use with caution as certain devices share
1659 address decoders between ROMs and other
1660 resources.
Andi Kleenc0115602008-08-22 09:53:39 +02001661 norom [X86] Do not assign address space to
Gary Hadebb71ad82008-05-12 13:57:46 -07001662 expansion ROMs that do not already have
1663 BIOS assigned address ranges.
Andi Kleenc0115602008-08-22 09:53:39 +02001664 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001665 assigned automatically to PCI devices. You can
1666 make the kernel exclude IRQs of your ISA cards
1667 this way.
Andi Kleenc0115602008-08-22 09:53:39 +02001668 pirqaddr=0xAAAAA [X86] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001669 of the PIRQ table (normally generated
1670 by the BIOS) if it is outside the
1671 F0000h-100000h range.
Andi Kleenc0115602008-08-22 09:53:39 +02001672 lastbus=N [X86] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001673 useful if the kernel is unable to find your
1674 secondary buses and you want to tell it
1675 explicitly which ones they are.
Andi Kleenc0115602008-08-22 09:53:39 +02001676 assign-busses [X86] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001677 numbers ourselves, overriding
1678 whatever the firmware may have done.
Andi Kleenc0115602008-08-22 09:53:39 +02001679 usepirqmask [X86] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001680 in the BIOS $PIR table. This is needed on
1681 some systems with broken BIOSes, notably
1682 some HP Pavilion N5400 and Omnibook XE3
1683 notebooks. This will have no effect if ACPI
1684 IRQ routing is enabled.
Andi Kleenc0115602008-08-22 09:53:39 +02001685 noacpi [X86] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001686 or for PCI scanning.
Andi Kleenc0115602008-08-22 09:53:39 +02001687 use_crs [X86] Use _CRS for PCI resource
Gary Hade62f420f2007-10-03 15:56:51 -07001688 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001689 routeirq Do IRQ routing for all PCI devices.
1690 This is normally done in pci_enable_device(),
1691 so this option is a temporary workaround
1692 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001693 skip_isa_align [X86] do not align io start addr, so can
1694 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001695 firmware [ARM] Do not re-enumerate the bus but instead
1696 just use the configuration from the
1697 bootloader. This is currently used on
1698 IXP2000 systems where the bus has to be
1699 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001700 noearly [X86] Don't do any early type 1 scanning.
1701 This might help on some broken boards which
1702 machine check when some devices' config space
1703 is read. But various workarounds are disabled
1704 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001705 bfsort Sort PCI devices into breadth-first order.
1706 This sorting is done to get a device
1707 order compatible with older (<= 2.4) kernels.
1708 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001709 cbiosize=nn[KMG] The fixed amount of bus space which is
1710 reserved for the CardBus bridge's IO window.
1711 The default value is 256 bytes.
1712 cbmemsize=nn[KMG] The fixed amount of bus space which is
1713 reserved for the CardBus bridge's memory
1714 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001715
Chuck Ebberte5665a42008-09-24 20:40:34 -04001716 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1717 Management.
1718 off Disable ASPM.
1719 force Enable ASPM even on devices that claim not to support it.
1720 WARNING: Forcing ASPM on may cause system lockups.
1721
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 pcmv= [HW,PCMCIA] BadgePAD 4
1723
1724 pd. [PARIDE]
1725 See Documentation/paride.txt.
1726
1727 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1728 boot time.
1729 Format: { 0 | 1 }
1730 See arch/parisc/kernel/pdc_chassis.c
1731
1732 pf. [PARIDE]
1733 See Documentation/paride.txt.
1734
1735 pg. [PARIDE]
1736 See Documentation/paride.txt.
1737
1738 pirq= [SMP,APIC] Manual mp-table setup
Uwe Hermann71cced62008-10-20 09:32:21 -07001739 See Documentation/x86/i386/IO-APIC.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740
1741 plip= [PPT,NET] Parallel port network link
1742 Format: { parport<nr> | timid | 0 }
1743 See also Documentation/parport.txt.
1744
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001745 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1746 Override pmtimer IOPort with a hex value.
1747 e.g. pmtmr=0x508
1748
Bjorn Helgaas97ef0622008-08-19 16:53:41 -06001749 pnp.debug [PNP]
1750 Enable PNP debug messages. This depends on the
1751 CONFIG_PNP_DEBUG_MESSAGES option.
1752
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753 pnpacpi= [ACPI]
1754 { off }
1755
1756 pnpbios= [ISAPNP]
1757 { on | off | curr | res | no-curr | no-res }
1758
1759 pnp_reserve_irq=
1760 [ISAPNP] Exclude IRQs for the autoconfiguration
1761
1762 pnp_reserve_dma=
1763 [ISAPNP] Exclude DMAs for the autoconfiguration
1764
1765 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001766 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767
1768 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001769 [ISAPNP] Exclude memory regions for the
1770 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 Ranges are in pairs (memory base and size).
1772
Jason Baron346e15b2008-08-12 16:46:19 -04001773 dynamic_printk
1774 Enables pr_debug()/dev_dbg() calls if
1775 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1776 be switched on/off via <debugfs>/dynamic_printk/modules
1777
Ingo Molnar45807a12007-07-15 23:40:10 -07001778 print-fatal-signals=
1779 [KNL] debug: print fatal signals
1780 print-fatal-signals=1: print segfault info to
1781 the kernel console.
1782 default: off.
1783
Randy Dunlape84845c2007-07-15 23:40:25 -07001784 printk.time= Show timing data prefixed to each printk message line
1785 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1786
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001788 Format: [schedule,]<number>
1789 Param: "schedule" - profile schedule points.
1790 Param: <number> - step/bucket size as a power of 2 for
1791 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001792 Param: "sleep" - profile D-state sleeping (millisecs).
1793 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001794 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795
Randy Dunlapa9913042005-10-23 12:57:11 -07001796 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 Limit processor to maximum C-state
1798 max_cstate=9 overrides any DMI blacklist limit.
1799
Len Brown41c0d862005-12-28 12:43:51 -05001800 processor.nocst [HW,ACPI]
1801 Ignore the _CST method to determine C-states,
1802 instead using the legacy FADT method
1803
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1805 before loading.
1806 See Documentation/ramdisk.txt.
1807
Randy Dunlapa9913042005-10-23 12:57:11 -07001808 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1809 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1811 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001812 psmouse.resetafter= [HW,MOUSE]
1813 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 (0 = never).
1815 psmouse.resolution=
1816 [HW,MOUSE] Set desired mouse resolution, in dpi.
1817 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001818 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 0 = disabled, 1 = enabled (default).
1820
1821 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001822 Format:
1823 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824
1825 pt. [PARIDE]
1826 See Documentation/paride.txt.
1827
Kay Sieversdc8c8582007-08-15 12:25:38 +02001828 pty.legacy_count=
1829 [KNL] Number of legacy pty's. Overwrites compiled-in
1830 default number.
1831
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001832 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001833
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 r128= [HW,DRM]
1835
1836 raid= [HW,RAID]
1837 See Documentation/md.txt.
1838
Randy Dunlapa9913042005-10-23 12:57:11 -07001839 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001841
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001843 See Documentation/ramdisk.txt.
1844
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001845 rcupdate.blimit= [KNL,BOOT]
1846 Set maximum number of finished RCU callbacks to process
1847 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001848
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001849 rcupdate.qhimark= [KNL,BOOT]
1850 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001851 RCU callbacks over which batch limiting is disabled.
1852
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001853 rcupdate.qlowmark= [KNL,BOOT]
1854 Set threshold of queued RCU callbacks below which
1855 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001856
Olof Johanssonffdfc402005-09-06 15:17:19 -07001857 rdinit= [KNL]
1858 Format: <full_path>
1859 Run specified binary instead of /init from the ramdisk,
1860 used for early userspace startup. See initrd.
1861
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001862 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001864 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865
Paul Jackson46b6d942008-07-04 10:00:09 -07001866 relax_domain_level=
1867 [KNL, SMP] Set scheduler's default relax_domain_level.
1868 See Documentation/cpusets.txt.
1869
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1871
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001872 reservetop= [X86-32]
Zachary Amsden461a9aff2006-09-25 23:32:25 -07001873 Format: nn[KMG]
1874 Reserves a hole at the top of the kernel virtual
1875 address space.
1876
Vivek Goyal7e962872006-09-27 01:50:44 -07001877 reset_devices [KNL] Force drivers to reset the underlying device
1878 during initialization.
1879
Randy Dunlapa9913042005-10-23 12:57:11 -07001880 resume= [SWSUSP]
1881 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001883 resume_offset= [SWSUSP]
1884 Specify the offset from the beginning of the partition
1885 given by "resume=" at which the swap header is located,
1886 in <PAGE_SIZE> units (needed only for swap files).
1887 See Documentation/power/swsusp-and-swap-files.txt
1888
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001889 retain_initrd [RAM] Keep initrd memory after extraction
1890
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 rhash_entries= [KNL,NET]
1892 Set number of hash buckets for route cache
1893
1894 riscom8= [HW,SERIAL]
1895 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1896
1897 ro [KNL] Mount root device read-only on boot
1898
1899 root= [KNL] Root filesystem
1900
1901 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1902 mount the root filesystem
1903
1904 rootflags= [KNL] Set root filesystem mount option string
1905
1906 rootfstype= [KNL] Set root filesystem type
1907
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001908 rootwait [KNL] Wait (indefinitely) for root device to show up.
1909 Useful for devices that are detected asynchronously
1910 (e.g. USB and MMC devices).
1911
James Morris20510f22007-10-16 23:31:32 -07001912 root_plug.vendor_id=
1913 [ROOTPLUG] Override the default vendor ID
1914
1915 root_plug.product_id=
1916 [ROOTPLUG] Override the default product ID
1917
1918 root_plug.debug=
1919 [ROOTPLUG] Enable debugging output
1920
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 rw [KNL] Mount root device read-write on boot
1922
1923 S [KNL] Run init in single mode
1924
1925 sa1100ir [NET]
1926 See drivers/net/irda/sa1100_ir.c.
1927
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001929
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1931 Format: <io>[,<timeout>[,<isapnp>]]
1932
1933 scsi_debug_*= [SCSI]
1934 See drivers/scsi/scsi_debug.c.
1935
1936 scsi_default_dev_flags=
1937 [SCSI] SCSI default device flags
1938 Format: <integer>
1939
1940 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1941 Format: <vendor>:<model>:<flags>
1942 (flags are integer value)
1943
Randy Dunlap6af66322007-11-14 16:52:25 -08001944 scsi_logging_level= [SCSI] a bit mask of logging levels
1945 See drivers/scsi/scsi_logging.h for bits. Also
1946 settable via sysctl at dev.scsi.logging_level
1947 (/proc/sys/dev/scsi/logging_level).
1948 There is also a nice 'scsi_logging_level' script in the
1949 S390-tools package, available for download at
1950 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001952 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1953 discovered. async scans them in kernel threads,
1954 allowing boot to proceed. none ignores them, expecting
1955 user space to do the scan.
1956
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957 selinux [SELINUX] Disable or enable SELinux at boot time.
1958 Format: { "0" | "1" }
1959 See security/selinux/Kconfig help text.
1960 0 -- disable.
1961 1 -- enable.
1962 Default value is set via kernel config option.
1963 If enabled at boot time, /selinux/disable can be used
1964 later to disable prior to initial policy load.
1965
James Morris4e5ab4c2006-06-09 00:33:33 -07001966 selinux_compat_net =
1967 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001968 Format: { "0" | "1" }
1969 0 -- use new secmark-based packet controls
1970 1 -- use legacy packet controls
1971 Default value is 0 (preferred).
1972 Value can be changed at runtime via
1973 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001974
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001975 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 shapers= [NET]
1978 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001979
Yinghai Lub05f78f2008-08-22 01:32:50 -07001980 show_msr= [x86] show boot-time MSR settings
1981 Format: { <integer> }
1982 Show boot-time (BIOS-initialized) MSR settings.
1983 The parameter means the number of CPUs to show,
1984 for example 1 means boot CPU only.
1985
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 sim710= [SCSI,HW]
1987 See header of drivers/scsi/sim710.c.
1988
1989 simeth= [IA-64]
1990 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001991
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 slram= [HW,MTD]
1993
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001994 slub_debug[=options[,slabs]] [MM, SLUB]
1995 Enabling slub_debug allows one to determine the
1996 culprit if slab objects become corrupted. Enabling
1997 slub_debug can create guard zones around objects and
1998 may poison objects when not in use. Also tracks the
1999 last alloc / free. For more information see
2000 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002001
2002 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002003 Determines the maximum allowed order for slabs.
2004 A high setting may cause OOMs due to memory
2005 fragmentation. For more information see
2006 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002007
2008 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002009 The minimum number of objects per slab. SLUB will
2010 increase the slab order up to slub_max_order to
2011 generate a sufficiently large slab able to contain
2012 the number of objects indicated. The higher the number
2013 of objects the smaller the overhead of tracking slabs
2014 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002015 For more information see Documentation/vm/slub.txt.
2016
2017 slub_min_order= [MM, SLUB]
2018 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002019 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002020 For more information see Documentation/vm/slub.txt.
2021
2022 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002023 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07002024 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07002025 allocs to different slabs. Debug options disable
2026 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07002027 For more information see Documentation/vm/slub.txt.
2028
Linus Torvalds1da177e2005-04-16 15:20:36 -07002029 smart2= [HW]
2030 Format: <io1>[,<io2>[,...,<io8>]]
2031
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002032 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02002033 attempt to substitute SMP alternatives once at boot.
2034
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07002035 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
2036 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2037 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2038 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2039 smsc-ircc2.ircc_irq= [HW] IRQ line
2040 smsc-ircc2.ircc_dma= [HW] DMA channel
2041 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2042 0: Toshiba Satellite 1800 (GP data pin select)
2043 1: Fast pin select (default)
2044 2: ATC IRMode
2045
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 snd-ad1816a= [HW,ALSA]
2047
2048 snd-ad1848= [HW,ALSA]
2049
2050 snd-ali5451= [HW,ALSA]
2051
2052 snd-als100= [HW,ALSA]
2053
2054 snd-als4000= [HW,ALSA]
2055
2056 snd-azt2320= [HW,ALSA]
2057
2058 snd-cmi8330= [HW,ALSA]
2059
2060 snd-cmipci= [HW,ALSA]
2061
2062 snd-cs4231= [HW,ALSA]
2063
2064 snd-cs4232= [HW,ALSA]
2065
2066 snd-cs4236= [HW,ALSA]
2067
2068 snd-cs4281= [HW,ALSA]
2069
2070 snd-cs46xx= [HW,ALSA]
2071
2072 snd-dt019x= [HW,ALSA]
2073
2074 snd-dummy= [HW,ALSA]
2075
2076 snd-emu10k1= [HW,ALSA]
2077
2078 snd-ens1370= [HW,ALSA]
2079
2080 snd-ens1371= [HW,ALSA]
2081
2082 snd-es968= [HW,ALSA]
2083
2084 snd-es1688= [HW,ALSA]
2085
2086 snd-es18xx= [HW,ALSA]
2087
2088 snd-es1938= [HW,ALSA]
2089
2090 snd-es1968= [HW,ALSA]
2091
2092 snd-fm801= [HW,ALSA]
2093
2094 snd-gusclassic= [HW,ALSA]
2095
2096 snd-gusextreme= [HW,ALSA]
2097
2098 snd-gusmax= [HW,ALSA]
2099
2100 snd-hdsp= [HW,ALSA]
2101
2102 snd-ice1712= [HW,ALSA]
2103
2104 snd-intel8x0= [HW,ALSA]
2105
2106 snd-interwave= [HW,ALSA]
2107
2108 snd-interwave-stb=
2109 [HW,ALSA]
2110
2111 snd-korg1212= [HW,ALSA]
2112
2113 snd-maestro3= [HW,ALSA]
2114
2115 snd-mpu401= [HW,ALSA]
2116
2117 snd-mtpav= [HW,ALSA]
2118
2119 snd-nm256= [HW,ALSA]
2120
2121 snd-opl3sa2= [HW,ALSA]
2122
2123 snd-opti92x-ad1848=
2124 [HW,ALSA]
2125
2126 snd-opti92x-cs4231=
2127 [HW,ALSA]
2128
2129 snd-opti93x= [HW,ALSA]
2130
2131 snd-pmac= [HW,ALSA]
2132
2133 snd-rme32= [HW,ALSA]
2134
2135 snd-rme96= [HW,ALSA]
2136
2137 snd-rme9652= [HW,ALSA]
2138
2139 snd-sb8= [HW,ALSA]
2140
2141 snd-sb16= [HW,ALSA]
2142
2143 snd-sbawe= [HW,ALSA]
2144
2145 snd-serial= [HW,ALSA]
2146
2147 snd-sgalaxy= [HW,ALSA]
2148
2149 snd-sonicvibes= [HW,ALSA]
2150
2151 snd-sun-amd7930=
2152 [HW,ALSA]
2153
2154 snd-sun-cs4231= [HW,ALSA]
2155
2156 snd-trident= [HW,ALSA]
2157
2158 snd-usb-audio= [HW,ALSA,USB]
2159
2160 snd-via82xx= [HW,ALSA]
2161
2162 snd-virmidi= [HW,ALSA]
2163
2164 snd-wavefront= [HW,ALSA]
2165
2166 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002167
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002168 softlockup_panic=
2169 [KNL] Should the soft-lockup detector generate panics.
2170
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2172 See Documentation/sonypi.txt
2173
2174 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2175 See Documentation/specialix.txt.
2176
2177 spia_io_base= [HW,MTD]
2178 spia_fio_base=
2179 spia_pedr=
2180 spia_peddr=
2181
2182 sscape= [HW,OSS]
2183 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002184
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2186 See Documentation/scsi/st.txt.
2187
Linus Torvalds1da177e2005-04-16 15:20:36 -07002188 sti= [PARISC,HW]
2189 Format: <num>
2190 Set the STI (builtin display/keyboard on the HP-PARISC
2191 machines) console (graphic card) which should be used
2192 as the initial boot-console.
2193 See also comment in drivers/video/console/sticore.c.
2194
2195 sti_font= [HW]
2196 See comment in drivers/video/console/sticore.c.
2197
2198 stifb= [HW]
2199 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2200
Greg Banks42a7fc42007-03-06 01:42:23 -08002201 sunrpc.pool_mode=
2202 [NFS]
2203 Control how the NFS server code allocates CPUs to
2204 service thread pools. Depending on how many NICs
2205 you have and where their interrupts are bound, this
2206 option will affect which CPUs will do NFS serving.
2207 Note: this parameter cannot be changed while the
2208 NFS server is running.
2209
2210 auto the server chooses an appropriate mode
2211 automatically using heuristics
2212 global a single global pool contains all CPUs
2213 percpu one pool for each CPU
2214 pernode one pool for each NUMA node (equivalent
2215 to global on non-NUMA machines)
2216
Linus Torvalds1da177e2005-04-16 15:20:36 -07002217 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002218
Linus Torvalds1da177e2005-04-16 15:20:36 -07002219 switches= [HW,M68k]
2220
2221 sym53c416= [HW,SCSI]
2222 See header of drivers/scsi/sym53c416.c.
2223
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002224 sysrq_always_enabled
2225 [KNL]
2226 Ignore sysrq setting - this boot parameter will
2227 neutralize any effect of /proc/sys/kernel/sysrq.
2228 Useful for debugging.
2229
Linus Torvalds1da177e2005-04-16 15:20:36 -07002230 t128= [HW,SCSI]
2231 See header of drivers/scsi/t128.c.
2232
2233 tdfx= [HW,DRM]
2234
David Brownell77437fd2008-07-23 21:28:33 -07002235 test_suspend= [SUSPEND]
2236 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2237 standby suspend) as the system sleep state to briefly
2238 enter during system startup. The system is woken from
2239 this state using a wakeup-capable RTC alarm.
2240
Linus Torvalds1da177e2005-04-16 15:20:36 -07002241 thash_entries= [KNL,NET]
2242 Set number of hash buckets for TCP connection
2243
Len Brownf8707ec2007-08-12 00:12:54 -04002244 thermal.act= [HW,ACPI]
2245 -1: disable all active trip points in all thermal zones
2246 <degrees C>: override all lowest active trip points
2247
Len Brownc52a7412007-08-14 15:49:32 -04002248 thermal.crt= [HW,ACPI]
2249 -1: disable all critical trip points in all thermal zones
Zhang Rui22a94d72008-10-17 02:41:20 -04002250 <degrees C>: override all critical trip points
Len Brownc52a7412007-08-14 15:49:32 -04002251
Len Brownf5487142007-08-12 00:12:44 -04002252 thermal.nocrt= [HW,ACPI]
2253 Set to disable actions on ACPI thermal zone
2254 critical and hot trip points.
2255
Len Brown72b33ef2007-08-12 00:12:17 -04002256 thermal.off= [HW,ACPI]
2257 1: disable ACPI thermal control
2258
Len Browna70cdc52007-08-12 00:12:35 -04002259 thermal.psv= [HW,ACPI]
2260 -1: disable all passive trip points
2261 <degrees C>: override all passive trip points to this value
2262
Len Brown730ff342007-08-12 00:12:26 -04002263 thermal.tzp= [HW,ACPI]
2264 Specify global default ACPI thermal zone polling rate
2265 <deci-seconds>: poll all this frequency
2266 0: no polling (default)
2267
Linus Torvalds1da177e2005-04-16 15:20:36 -07002268 tmscsim= [HW,SCSI]
2269 See comment before function dc390_setup() in
2270 drivers/scsi/tmscsim.c.
2271
2272 tp720= [HW,PS2]
2273
2274 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002275 Format:
2276 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2277
Randy Dunlapa9913042005-10-23 12:57:11 -07002278 turbografx.map[2|3]= [HW,JOY]
2279 TurboGraFX parallel port interface
2280 Format:
2281 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282 See also Documentation/input/joystick-parport.txt
2283
2284 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2285 See header of drivers/scsi/u14-34f.c.
2286
2287 uart401= [HW,OSS]
2288 Format: <io>,<irq>
2289
2290 uart6850= [HW,OSS]
2291 Format: <io>,<irq>
2292
Alan Stern5f8364b2006-12-05 16:29:55 -05002293 uhci-hcd.ignore_oc=
2294 [USB] Ignore overcurrent events (default N).
2295 Some badly-designed motherboards generate lots of
2296 bogus events, for ports that aren't wired to
2297 anything. Set this parameter to avoid log spamming.
2298 Note that genuine overcurrent events won't be
2299 reported either.
2300
Simon Arlotte3a61b02008-07-19 23:32:54 +01002301 unknown_nmi_panic
2302 [X86-32,X86-64]
2303 Set unknown_nmi_panic=1 early on boot.
2304
Alan Sternb5e795f2007-02-20 15:00:53 -05002305 usbcore.autosuspend=
2306 [USB] The autosuspend time delay (in seconds) used
2307 for newly-detected USB devices (default 2). This
2308 is the time required before an idle device will be
2309 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002310 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002311
Jaroslav Kyselafd7c5192008-10-10 16:24:45 +02002312 usbcore.usbfs_snoop=
2313 [USB] Set to log all usbfs traffic (default 0 = off).
2314
2315 usbcore.blinkenlights=
2316 [USB] Set to cycle leds on hubs (default 0 = off).
2317
2318 usbcore.old_scheme_first=
2319 [USB] Start with the old device initialization
2320 scheme (default 0 = off).
2321
2322 usbcore.use_both_schemes=
2323 [USB] Try the other device initialization scheme
2324 if the first one fails (default 1 = enabled).
2325
2326 usbcore.initial_descriptor_timeout=
2327 [USB] Specifies timeout for the initial 64-byte
2328 USB_REQ_GET_DESCRIPTOR request in milliseconds
2329 (default 5000 = 5.0 seconds).
2330
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331 usbhid.mousepoll=
2332 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002333
Paul Jackson200001e2008-06-25 05:44:46 -07002334 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2335 kernel's map of available physical RAM.
2336
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002337 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002338 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002339 vdso=1: enable VDSO (default)
2340 vdso=0: disable VDSO mapping
2341
Roland McGrathaf65d642008-01-30 13:30:43 +01002342 vdso32= [X86-32,X86-64]
2343 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2344 vdso32=1: enable 32-bit VDSO (default)
2345 vdso32=0: disable 32-bit VDSO mapping
2346
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002347 vector= [IA-64,SMP]
2348 vector=percpu: enable percpu vector domain
2349
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350 video= [FB] Frame buffer configuration
2351 See Documentation/fb/modedb.txt.
2352
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002353 vga= [BOOT,X86-32] Select a particular video mode
Uwe Hermann71cced62008-10-20 09:32:21 -07002354 See Documentation/x86/i386/boot.txt and
Randy Dunlapa9913042005-10-23 12:57:11 -07002355 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356 Use vga=ask for menu.
2357 This is actually a boot loader parameter; the value is
2358 passed to the kernel using a special protocol.
2359
Randy Dunlapa9913042005-10-23 12:57:11 -07002360 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 size of <nn>. This can be used to increase the
2362 minimum size (128MB on x86). It can also be used to
2363 decrease the size and leave more room for directly
2364 mapped kernel RAM.
2365
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002366 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2367 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002368
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002369 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2370 Format: <command>
2371
2372 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2373 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002374
Linus Torvalds1da177e2005-04-16 15:20:36 -07002375 waveartist= [HW,OSS]
2376 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002377
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378 wd33c93= [HW,SCSI]
2379 See header of drivers/scsi/wd33c93.c.
2380
2381 wd7000= [HW,SCSI]
2382 See header of drivers/scsi/wd7000.c.
2383
2384 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002385 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002386
2387 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2388 xd_geo= See header of drivers/block/xd.c.
2389
2390 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002391 Format:
2392 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393
Andi Kleena62eaf12006-02-16 23:41:58 +01002394 norandmaps Don't use address space randomization
2395 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2396
Randy Dunlapa9913042005-10-23 12:57:11 -07002397______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002398
2399TODO:
2400
2401 Add documentation for ALSA options.
2402 Add more DRM drivers.