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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.
37 AX25 Appropriate AX.25 support is enabled.
Robin Getz0ae53642007-10-09 17:24:49 +080038 BLACKFIN Blackfin architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070039 DRM Direct Rendering Management support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070047 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
Kristen Carlson Accardi11ef6972006-09-28 11:29:01 -070051 LIBATA Libata driver is enabled
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070060 MSI Message Signaled Interrupts (PCI).
Randy Dunlapc8facbb2007-07-31 00:37:40 -070061 MTD MTD (Memory Technology Device) support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070064 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
Randy Dunlapc8facbb2007-07-31 00:37:40 -070067 PV_OPS A paravirtualized kernel is enabled.
68 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 PARISC The PA-RISC architecture is enabled.
70 PCI PCI bus support is enabled.
Randy Dunlap7f785762007-10-05 13:17:58 -070071 PCIE PCI Express support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 PCMCIA The PCMCIA subsystem is enabled.
73 PNP Plug & Play support is enabled.
74 PPC PowerPC architecture is enabled.
75 PPT Parallel port support is enabled.
76 PS2 Appropriate PS/2 support is enabled.
77 RAM RAM disk support is enabled.
James Morris20510f22007-10-16 23:31:32 -070078 ROOTPLUG The example Root Plug LSM is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 S390 S390 architecture is enabled.
80 SCSI Appropriate SCSI support is enabled.
81 A lot of drivers has their options described inside of
82 Documentation/scsi/.
James Morris20510f22007-10-16 23:31:32 -070083 SECURITY Different security models are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 SELINUX SELinux support is enabled.
85 SERIAL Serial support is enabled.
Paul Mundte523d932007-02-28 18:30:01 +090086 SH SuperH architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 SMP The kernel is an SMP kernel.
88 SPARC Sparc architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070089 SWSUSP Software suspend is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 TS Appropriate touchscreen support is enabled.
91 USB USB support is enabled.
92 USBHID USB Human Interface Device support is enabled.
93 V4L Video For Linux support is enabled.
94 VGA The VGA console has been enabled.
95 VT Virtual terminal support is enabled.
96 WDT Watchdog support is enabled.
97 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -070098 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 X86-64 X86-64 architecture is enabled.
100 More X86-64 boot options can be found in
101 Documentation/x86_64/boot-options.txt .
102
103In addition, the following text indicates that the option:
104
105 BUGS= Relates to possible processor bugs on the said processor.
106 KNL Is a kernel start-up parameter.
107 BOOT Is a boot loader parameter.
108
109Parameters denoted with BOOT are actually interpreted by the boot
110loader, and have no meaning to the kernel directly.
111Do not modify the syntax of boot loader parameters without extreme
112need or coordination with <Documentation/i386/boot.txt>.
113
Karsten Weiss55588702007-02-13 13:26:21 +0100114There are also arch-specific kernel-parameters not documented here.
115See for example <Documentation/x86_64/boot-options.txt>.
116
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
118a trailing = on the name of any parameter states that that parameter will
119be entered as an environment variable, whereas its absence indicates that
120it will appear as a kernel argument readable via /proc/cmdline by programs
121running once the system is up.
122
jens m. noedler9c4751f2006-09-29 02:00:27 -0700123The number of kernel parameters is not limited, but the length of the
124complete command line (parameters including spaces etc.) is limited to
125a fixed number of characters. This limit depends on the architecture
126and is between 256 and 4096 characters. It is defined in the file
127./include/asm/setup.h as COMMAND_LINE_SIZE.
128
129
Bernhard Walle03d926f2007-03-06 02:29:44 -0800130 acpi= [HW,ACPI,X86-64,i386]
131 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700132 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 force -- enable ACPI if default was off
134 off -- disable ACPI if default was on
135 noirq -- do not use ACPI for IRQ routing
136 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700137 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 strictly ACPI specification compliant.
139
140 See also Documentation/pm.txt, pci=noacpi
141
Len Browna1fdcc02007-03-11 03:26:14 -0400142 acpi_apic_instance= [ACPI, IOAPIC]
143 Format: <int>
144 2: use 2nd APIC table, if available
145 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400146 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400147
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 acpi_sleep= [HW,ACPI] Sleep options
149 Format: { s3_bios, s3_mode }
150 See Documentation/power/video.txt
Randy Dunlapa9913042005-10-23 12:57:11 -0700151
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700153 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
Randy Dunlapa9913042005-10-23 12:57:11 -0700155 acpi_irq_balance [HW,ACPI]
156 ACPI will balance active IRQs
157 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Randy Dunlapa9913042005-10-23 12:57:11 -0700159 acpi_irq_nobalance [HW,ACPI]
160 ACPI will not move active IRQs (default)
161 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Randy Dunlapa9913042005-10-23 12:57:11 -0700163 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
164 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 Format: <irq>,<irq>...
166
Randy Dunlapa9913042005-10-23 12:57:11 -0700167 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 Format: <irq>,<irq>...
169
Len Brown67effe82007-07-26 00:50:06 -0400170 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
171
Len Browna1f9e652006-01-25 23:47:36 -0500172 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
173 Format: To spoof as Windows 98: ="Microsoft Windows"
174
Len Brownae00d812007-05-29 18:43:33 -0400175 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
176 acpi_osi="string1" # add string1 -- only one string
177 acpi_osi="!string2" # remove built-in string2
178 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
180 acpi_serialize [HW,ACPI] force serialization of AML methods
181
182 acpi_skip_timer_override [HW,ACPI]
183 Recognize and ignore IRQ0/pin2 Interrupt Override.
184 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100185 acpi_use_timer_override [HW,ACPI}
186 Use timer override. For some broken Nvidia NF5 boards
187 that require a timer override, but don't have
188 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
Zhang Ruif9891062007-04-24 13:53:22 +0800190 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700192 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 1: enable, 0: disable. It is useful for boot time
194 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800195 via /sys/module/acpi/parameters/debug_layer.
196 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
197 Available bits (add the numbers together) to enable debug output
198 for specific parts of the ACPI subsystem:
199 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
200 0x10 namespace 0x20 parser 0x40 dispatcher
201 0x80 executer 0x100 resources 0x200 acpica debugger
202 0x400 os services 0x800 acpica disassembler.
203 The number can be in decimal or prefixed with 0x in hex.
204 Warning: Many of these options can produce a lot of
205 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Zhang Ruif9891062007-04-24 13:53:22 +0800207 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700209 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 1: enable, 0: disable. It is useful for boot time
211 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800212 via /sys/module/acpi/parameters/debug_level.
213 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
214 Available bits (add the numbers together) to enable different
215 debug output levels of the ACPI subsystem:
216 0x01 error 0x02 warn 0x04 init 0x08 debug object
217 0x10 info 0x20 init names 0x40 parse 0x80 load
218 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
219 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
220 0x10000 resources 0x20000 user requests 0x40000 package.
221 The number can be in decimal or prefixed with 0x in hex.
222 Warning: Many of these options can produce a lot of
223 output and make your system unusable. Be very careful.
224
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700225 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700226 Override the pmtimer bug detection: force the kernel
227 to assume that this machine's pmtimer latches its value
228 and always returns good values.
229
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000230 agp= [AGP]
231 { off | try_unsupported }
232 off: disable AGP support
233 try_unsupported: try to drive unsupported chipsets
234 (may crash computer or cause data corruption)
235
Chuck Ebbert66759a02005-09-12 18:49:25 +0200236 enable_timer_pin_1 [i386,x86-64]
237 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700238 Can be useful to work around chipset bugs
239 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200240 The kernel tries to set a reasonable default.
241
242 disable_timer_pin_1 [i386,x86-64]
243 Disable PIN 1 of APIC timer
244 Can be useful to work around chipset bugs.
245
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 ad1848= [HW,OSS]
247 Format: <io>,<irq>,<dma>,<dma2>,<type>
248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 advansys= [HW,SCSI]
250 See header of drivers/scsi/advansys.c.
251
252 advwdt= [HW,WDT] Advantech WDT
253 Format: <iostart>,<iostop>
254
255 aedsp16= [HW,OSS] Audio Excel DSP 16
256 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
257 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700258
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 aha152x= [HW,SCSI]
260 See Documentation/scsi/aha152x.txt.
261
262 aha1542= [HW,SCSI]
263 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
264
265 aic7xxx= [HW,SCSI]
266 See Documentation/scsi/aic7xxx.txt.
267
268 aic79xx= [HW,SCSI]
269 See Documentation/scsi/aic79xx.txt.
270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 amijoy.map= [HW,JOY] Amiga joystick support
272 Map of devices attached to JOY0DAT and JOY1DAT
273 Format: <a>,<b>
274 See also Documentation/kernel/input/joystick.txt
275
276 analog.map= [HW,JOY] Analog joystick and gamepad support
277 Specifies type or capabilities of an analog joystick
278 connected to one of 16 gameports
279 Format: <type1>,<type2>,..<type16>
280
Randy Dunlapa9913042005-10-23 12:57:11 -0700281 apc= [HW,SPARC]
282 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 Format: noidle
284 Disable APC CPU standby support. SPARCstation-Fox does
285 not play well with APC CPU idle - disable it if you have
286 APC and your system crashes randomly.
287
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700288 apic= [APIC,i386] Advanced Programmable Interrupt Controller
289 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 Format: { quiet (default) | verbose | debug }
291 Change the amount of debugging information output
292 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 apm= [APM] Advanced Power Management
295 See header of arch/i386/kernel/apm.c.
296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
298 Format: <io>,<irq>,<nodeID>
299
300 ataflop= [HW,M68k]
301
302 atarimouse= [HW,MOUSE] Atari Mouse
303
304 atascsi= [HW,SCSI] Atari SCSI
305
306 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
307 EzKey and similar keyboards
308
309 atkbd.reset= [HW] Reset keyboard during initialization
310
Randy Dunlapa9913042005-10-23 12:57:11 -0700311 atkbd.set= [HW] Select keyboard code set
312 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
314 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
315 keyboards
316
317 atkbd.softraw= [HW] Choose between synthetic and real raw mode
318 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700319
320 atkbd.softrepeat= [HW]
321 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
323 autotest [IA64]
324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 baycom_epp= [HW,AX25]
326 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
329 Format: <io>,<mode>
330 See header of drivers/net/hamradio/baycom_par.c.
331
Randy Dunlapa9913042005-10-23 12:57:11 -0700332 baycom_ser_fdx= [HW,AX25]
333 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 Format: <io>,<irq>,<mode>[,<baud>]
335 See header of drivers/net/hamradio/baycom_ser_fdx.c.
336
Randy Dunlapa9913042005-10-23 12:57:11 -0700337 baycom_ser_hdx= [HW,AX25]
338 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 Format: <io>,<irq>,<mode>
340 See header of drivers/net/hamradio/baycom_ser_hdx.c.
341
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700342 boot_delay= Milliseconds to delay each printk during boot.
343 Values larger than 10 seconds (10000) are changed to
344 no delay (0).
345 Format: integer
346
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700348 bttv.radio= Most important insmod options are available as
349 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
351 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
352
353 BusLogic= [HW,SCSI]
354 See drivers/scsi/BusLogic.c, comment before function
355 BusLogic_ParseDriverOptions().
356
357 c101= [NET] Moxa C101 synchronous serial card
358
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700359 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 Sometimes CPU hardware bugs make them report the cache
361 size incorrectly. The kernel will attempt work arounds
362 to fix known problems, but for some CPUs it is not
363 possible to determine what the correct size should be.
364 This option provides an override for these situations.
365
James Morris20510f22007-10-16 23:31:32 -0700366 capability.disable=
367 [SECURITY] Disable capabilities. This would normally
368 be used only if an alternative security model is to be
369 configured. Potentially dangerous and should only be
370 used if you are entirely sure of the consequences.
371
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 chandev= [HW,NET] Generic channel device initialisation
373
374 checkreqprot [SELINUX] Set initial checkreqprot flag value.
375 Format: { "0" | "1" }
376 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700377 0 -- check protection applied by kernel (includes
378 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 1 -- check protection requested by application.
380 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700381 Value can be changed at runtime via
382 /selinux/checkreqprot.
383
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700384 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700385 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200386 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700387 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200388 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 Format: { pit | tsc | cyclone | pmtmr }
390
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700391 clocksource= [GENERIC_TIME] Override the default clocksource
392 Format: <string>
393 Override the default clocksource and use the clocksource
394 with the name specified.
395 Some clocksource names to choose from, depending on
396 the platform:
397 [all] jiffies (this is the base, fallback clocksource)
398 [ACPI] acpi_pm
399 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
400 pxa_timer,timer3,32k_counter,timer0_1
401 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700402 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700403 scx200_hrt on Geode; cyclone on IBM x440
404 [MIPS] MIPS
405 [PARISC] cr16
406 [S390] tod
407 [SH] SuperH
408 [SPARC64] tick
409 [X86-64] hpet,tsc
410
Chuck Ebbert86c41832007-02-13 13:26:25 +0100411 code_bytes [IA32] How many bytes of object code to print in an
412 oops report.
413 Range: 0 - 8192
414 Default: 64
415
Andi Kleenf9262c12006-03-08 17:57:25 -0800416 disable_8254_timer
417 enable_8254_timer
418 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
419 over the 8254 in addition to over the IO-APIC. The
420 kernel tries to set a sensible default.
421
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200422 hpet= [X86-32,HPET] option to control HPET usage
423 Format: { enable (default) | disable | force }
424 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100425 force: allow force enabled of undocumented chips (ICH4,
426 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700429 Format:
430 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
432 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
433 Format: <io>[,<irq>]
434
Randy Dunlapa9913042005-10-23 12:57:11 -0700435 com90xx= [HW,NET]
436 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 Format: <io>[,<irq>[,<memstart>]]
438
439 condev= [HW,S390] console device
440 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700441
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 console= [KNL] Output console device and options.
443
444 tty<n> Use the virtual console device <n>.
445
446 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800447 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800449 the form "bbbbpnf", where "bbbb" is the baud rate,
450 "p" is parity ("n", "o", or "e"), "n" is number of
451 bits, and "f" is flow control ("r" for RTS or
452 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800454 See Documentation/serial-console.txt for more
455 information. See
456 Documentation/networking/netconsole.txt for an
457 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700459 uart[8250],io,<addr>[,options]
460 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 Start an early, polled-mode console on the 8250/16550
462 UART at the specified I/O port or MMIO address,
463 switching to the matching ttyS device later. The
464 options are the same as for ttyS, above.
465
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700466 earlycon= [KNL] Output early console device and options.
467 uart[8250],io,<addr>[,options]
468 uart[8250],mmio,<addr>[,options]
469 Start an early, polled-mode console on the 8250/16550
470 UART at the specified I/O port or MMIO address.
471 The options are the same as for ttyS, above.
472
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700473 no_console_suspend
474 [HW] Never suspend the console
475 Disable suspending of consoles during suspend and
476 hibernate operations. Once disabled, debugging
477 messages can reach various consoles while the rest
478 of the system is being put to sleep (ie, while
479 debugging driver suspend/resume hooks). This may
480 not work reliably with all consoles, but is known
481 to work with serial and VGA consoles.
482
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700484 Format:
485 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700487 crashkernel=nn[KMG]@ss[KMG]
488 [KNL] Reserve a chunk of physical memory to
489 hold a kernel to switch to with kexec on panic.
490
Bernhard Wallefb391592007-10-18 23:41:02 -0700491 crashkernel=range1:size1[,range2:size2,...][@offset]
492 [KNL] Same as above, but depends on the memory
493 in the running system. The syntax of range is
494 start-[end] where start and end are both
495 a memory unit (amount[KMG]). See also
496 Documentation/kdump/kdump.txt for a example.
497
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 cs4232= [HW,OSS]
499 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
500
501 cs89x0_dma= [HW,NET]
502 Format: <dma>
503
504 cs89x0_media= [HW,NET]
505 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700506
Randy Dunlapa9913042005-10-23 12:57:11 -0700507 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 See header of drivers/s390/block/dasd_devmap.c.
509
510 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
511 (one device per port)
512 Format: <port#>,<type>
513 See also Documentation/input/joystick-parport.txt
514
515 debug [KNL] Enable kernel debugging (events log level).
516
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700517 debug_locks_verbose=
518 [KNL] verbose self-tests
519 Format=<0|1>
520 Print debugging info while doing the locking API
521 self-tests.
522 We default to 0 (no extra messages), setting it to
523 1 will print _a lot_ more information - normally
524 only useful to kernel developers.
525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 decnet= [HW,NET]
527 Format: <area>[,<node>]
528 See also Documentation/networking/decnet.txt.
529
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700530 default_blu= [VT]
531 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
532 Change the default blue palette of the console.
533 This is a 16-member array composed of values
534 ranging from 0-255.
535
536 default_grn= [VT]
537 Format: <green0>,<green1>,<green2>,...,<green15>
538 Change the default green palette of the console.
539 This is a 16-member array composed of values
540 ranging from 0-255.
541
542 default_red= [VT]
543 Format: <red0>,<red1>,<red2>,...,<red15>
544 Change the default red palette of the console.
545 This is a 16-member array composed of values
546 ranging from 0-255.
547
548 default_utf8= [VT]
549 Format=<0|1>
550 Set system-wide default UTF-8 mode for all tty's.
551 Default is 0 and by setting to 1, it enables UTF-8
552 mode for all newly opened or allocated terminals.
553
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 dhash_entries= [KNL]
555 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700556
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 digi= [HW,SERIAL]
558 IO parameters + enable/disable command.
559
560 digiepca= [HW,SERIAL]
561 See drivers/char/README.epca and
562 Documentation/digiepca.txt.
563
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 dmasound= [HW,OSS] Sound subsystem buffers
565
566 dscc4.setup= [NET]
567
568 dtc3181e= [HW,SCSI]
569
Robin Getz0ae53642007-10-09 17:24:49 +0800570 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 earlyprintk=vga
572 earlyprintk=serial[,ttySn[,baudrate]]
573
Randy Dunlapa9913042005-10-23 12:57:11 -0700574 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 takes over.
576
577 Only vga or serial at a time, not both.
578
579 Currently only ttyS0 and ttyS1 are supported.
580
581 Interaction with the standard serial driver is not
582 very good.
583
584 The VGA output is eventually overwritten by the real
585 console.
586
587 eata= [HW,SCSI]
588
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 edd= [EDD]
590 Format: {"of[f]" | "sk[ipmbr]"}
591 See comment in arch/i386/boot/edd.S
592
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 eisa_irq_edge= [PARISC,HW]
594 See header of drivers/parisc/eisa.c.
595
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700596 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 See comment before function elanfreq_setup() in
598 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
599
600 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800601 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700602 See Documentation/block/as-iosched.txt and
603 Documentation/block/deadline-iosched.txt for details.
604
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700605 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700606 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800607 image elf header. Generally kexec loader will
608 pass this option to capture kernel.
609 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
611 enforcing [SELINUX] Set initial enforcing status.
612 Format: {"0" | "1"}
613 See security/selinux/Kconfig help text.
614 0 -- permissive (log only, no denials).
615 1 -- enforcing (deny and log).
616 Default value is 0.
617 Value can be changed at runtime via /selinux/enforce.
618
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 es1371= [HW,OSS]
620 Format: <spdif>,[<nomix>,[<amplifier>]]
621 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700622
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 ether= [HW,NET] Ethernet cards parameters
624 This option is obsoleted by the "netdev=" option, which
625 has equivalent usage. See its documentation for details.
626
627 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
628 Format: <io>[,<irq>]
629
Akinobu Mitade1ba092006-12-08 02:39:42 -0800630 failslab=
631 fail_page_alloc=
632 fail_make_request=[KNL]
633 General fault injection mechanism.
634 Format: <interval>,<probability>,<space>,<times>
635 See also /Documentation/fault-injection/.
636
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 fd_mcs= [HW,SCSI]
638 See header of drivers/scsi/fd_mcs.c.
639
640 fdomain= [HW,SCSI]
641 See header of drivers/scsi/fdomain.c.
642
643 floppy= [HW]
644 See Documentation/floppy.txt.
645
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 gamecon.map[2|3]=
647 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
648 support via parallel port (up to 5 devices per port)
649 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
650 See also Documentation/input/joystick-parport.txt
651
652 gamma= [HW,DRM]
653
654 gdth= [HW,SCSI]
655 See header of drivers/scsi/gdth.c.
656
657 gpt [EFI] Forces disk with valid GPT signature but
658 invalid Protective MBR to be treated as GPT.
659
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 gvp11= [HW,SCSI]
661
662 hashdist= [KNL,NUMA] Large hashes allocated during boot
663 are distributed across NUMA nodes. Defaults on
664 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700665 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666
667 hcl= [IA-64] SGI's Hardware Graph compatibility layer
668
669 hd= [EIDE] (E)IDE hard drive subsystem geometry
670 Format: <cyl>,<head>,<sect>
671
672 hd?= [HW] (E)IDE subsystem
673 hd?lun= See Documentation/ide.txt.
674
675 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
676 size of <nn>. This works even on boxes that have no
677 highmem otherwise. This also works to reduce highmem
678 size on bigger boxes.
679
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800680 highres= [KNL] Enable/disable high resolution timer mode.
681 Valid parameters: "on", "off"
682 Default: "on"
683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 hisax= [HW,ISDN]
685 See Documentation/isdn/README.HiSax.
686
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700687 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200690 i8042.dumbkbd [HW] Pretend that controller can only read data from
691 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 (Don't attempt to blink the leds)
693 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500694 i8042.nokbd [HW] Don't check/create keyboard port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 i8042.nomux [HW] Don't check presence of an active multiplexing
696 controller
697 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
698 controllers
699 i8042.panicblink=
700 [HW] Frequency with which keyboard LEDs should blink
701 when kernel panics (default is 0.5 sec)
702 i8042.reset [HW] Reset the controller during init and cleanup
703 i8042.unlock [HW] Unlock (ignore) the keylock
704
705 i810= [HW,DRM]
706
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700707 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
708 indicates that the driver is running on unsupported
709 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
711 does not match list of supported models.
712 i8k.power_status
713 [HW] Report power status in /proc/i8k
714 (disabled by default)
715 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
716 capability is set.
717
718 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
719 See Documentation/mca.txt.
720
721 icn= [HW,ISDN]
722 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
723
724 ide= [HW] (E)IDE subsystem
725 Format: ide=nodma or ide=doubler or ide=reverse
726 See Documentation/ide.txt.
727
728 ide?= [HW] (E)IDE subsystem
729 Format: ide?=noprobe or chipset specific parameters.
730 See Documentation/ide.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -0700731
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
733 See Documentation/ide.txt.
734
Andi Kleenf039b752007-05-02 19:27:12 +0200735 idle= [X86]
736 Format: idle=poll or idle=mwait
737 Poll forces a polling idle loop that can slightly improves the performance
738 of waking up a idle CPU, but will use a lot of power and make the system
739 run hot. Not recommended.
740 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
741 to not use it because it doesn't save as much power as a normal idle
742 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
743 as idle=poll.
Randy Dunlapa9913042005-10-23 12:57:11 -0700744
Ingo Molnar792908222006-12-06 20:40:51 -0800745 ignore_loglevel [KNL]
746 Ignore loglevel setting - this will print /all/
747 kernel messages to the console. Useful for debugging.
748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 ihash_entries= [KNL]
750 Set number of hash buckets for inode cache.
751
752 in2000= [HW,SCSI]
753 See header of drivers/scsi/in2000.c.
754
755 init= [KNL]
756 Format: <full_path>
757 Run specified binary instead of /sbin/init as init
758 process.
759
760 initcall_debug [KNL] Trace initcalls as they are executed. Useful
761 for working out where the kernel is dying during
762 startup.
763
764 initrd= [BOOT] Specify the location of the initial ramdisk
765
766 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
767 Format: <irq>
768
769 inttest= [IA64]
770
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700771 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
772 off
773 Disable intel iommu driver.
774 igfx_off [Default Off]
775 By default, gfx is mapped as normal device. If a gfx
776 device has a dedicated DMAR unit, the DMAR unit is
777 bypassed by not enabling DMAR with this option. In
778 this case, gfx device will use physical address for
779 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700780 forcedac [x86_64]
781 With this option iommu will not optimize to look
782 for io virtual address below 32 bit forcing dual
783 address cycle on pci bus for cards supporting greater
784 than 32 bit addressing. The default is to look
785 for translation below 32 bit and if not available
786 then look in the higher range.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700787
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 io7= [HW] IO7 for Marvel based alpha systems
789 See comment before marvel_specify_io7 in
790 arch/alpha/kernel/core_marvel.c.
791
792 ip= [IP_PNP]
793 See Documentation/nfsroot.txt.
794
795 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700796 See comment before ip2_setup() in
797 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798
799 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
800 See header of drivers/scsi/ips.c.
801
Simon Horman72c4a132006-09-13 19:57:18 -0700802 ports= [IP_VS_FTP] IPVS ftp helper module
803 Default is 21.
804 Up to 8 (IP_VS_APP_MAX_PORTS) ports
805 may be specified.
806 Format: <port>,<port>....
807
Alan Cox200803d2005-06-28 20:45:18 -0700808 irqfixup [HW]
809 When an interrupt is not handled search all handlers
810 for it. Intended to get systems with badly broken
811 firmware running.
812
813 irqpoll [HW]
814 When an interrupt is not handled search all handlers
815 for it. Also check all handlers each timer
816 interrupt. Intended to get systems with badly broken
817 firmware running.
818
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700820 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821
822 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800823 Format:
824 <cpu number>,...,<cpu number>
825 or
826 <cpu number>-<cpu number> (must be a positive range in ascending order)
827 or a mixture
828 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 This option can be used to specify one or more CPUs
830 to isolate from the general SMP balancing and scheduling
831 algorithms. The only way to move a process onto or off
832 an "isolated" CPU is via the CPU affinity syscalls.
833 <cpu number> begins at 0 and the maximum value is
834 "number of CPUs in system - 1".
835
836 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700837 alternative -- manually setting the CPU mask of all
838 tasks in the system -- can cause problems and
839 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Randy Dunlapa9913042005-10-23 12:57:11 -0700841 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842
843 js= [HW,JOY] Analog joystick
844 See Documentation/input/joystick.txt.
845
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700846 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700847 specifies the amount of memory usable by the kernel
848 for non-movable allocations. The requested amount is
849 spread evenly throughout all nodes in the system. The
850 remaining memory in each node is used for Movable
851 pages. In the event, a node is too small to have both
852 kernelcore and Movable pages, kernelcore pages will
853 take priority and other nodes will have a larger number
854 of kernelcore pages. The Movable zone is used for the
855 allocation of pages that may be reclaimed or moved
856 by the page migration subsystem. This means that
857 HugeTLB pages may not be allocated from this zone.
858 Note that allocations like PTEs-from-HighMem still
859 use the HighMem zone if it exists, and the Normal
860 zone if it does not.
861
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700862 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -0700863 is similar to kernelcore except it specifies the
864 amount of memory used for migratable allocations.
865 If both kernelcore and movablecore is specified,
866 then kernelcore will be at *least* the specified
867 value but may be more. If movablecore on its own
868 is specified, the administrator must be careful
869 that the amount of memory usable for all allocations
870 is not too small.
871
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 keepinitrd [HW,ARM]
873
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700874 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 in oops dumps.
876
877 l2cr= [PPC]
878
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700879 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -0700880 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700882 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +0100883 C2 power state.
884
Dave Jones78e70c22007-09-27 11:50:13 -0400885 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
886 when set.
887 Format: <int>
888
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 load_ramdisk= [RAM] List of ramdisks to load from floppy
890 See Documentation/ramdisk.txt.
891
Randy Dunlapa6b25b62006-01-14 13:21:19 -0800892 lockd.nlm_grace_period=P [NFS] Assign grace period.
893 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894
Randy Dunlapa6b25b62006-01-14 13:21:19 -0800895 lockd.nlm_tcpport=N [NFS] Assign TCP port.
896 Format: <integer>
897
898 lockd.nlm_timeout=T [NFS] Assign timeout value.
899 Format: <integer>
900
901 lockd.nlm_udpport=M [NFS] Assign UDP port.
902 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
904 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
905 Format: <irq>
906
907 loglevel= All Kernel Messages with a loglevel smaller than the
908 console loglevel will be printed to the console. It can
909 also be changed with klogd or other programs. The
910 loglevels are defined as follows:
911
912 0 (KERN_EMERG) system is unusable
913 1 (KERN_ALERT) action must be taken immediately
914 2 (KERN_CRIT) critical conditions
915 3 (KERN_ERR) error conditions
916 4 (KERN_WARNING) warning conditions
917 5 (KERN_NOTICE) normal but significant condition
918 6 (KERN_INFO) informational
919 7 (KERN_DEBUG) debug-level messages
920
921 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -0700922 Format: { n | nk | nM }
923 n must be a power of two. The default size
924 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925
Randy Dunlapaccaa242007-10-16 01:29:37 -0700926 logo.nologo [FB] Disables display of the built-in Linux logo.
927 This may be used to provide more screen space for
928 kernel log messages and is useful when debugging
929 kernel boot problems.
930
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 lp=0 [LP] Specify parallel ports to use, e.g,
932 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
933 lp=reset first parallel port). 'lp=0' disables the
934 lp=auto printer driver. 'lp=reset' (which can be
935 specified in addition to the ports) causes
936 attached printers to be reset. Using
937 lp=port1,port2,... specifies the parallel ports
938 to associate lp devices with, starting with
939 lp0. A port specification may be 'none' to skip
940 that lp device, or a parport name such as
941 'parport0'. Specifying 'lp=auto' instead of a
942 port specification list means that device IDs
943 from each port should be examined, to see if
944 an IEEE 1284-compliant printer is attached; if
945 so, the driver will manage that printer.
946 See also header of drivers/char/lp.c.
947
948 lpj=n [KNL]
949 Sets loops_per_jiffy to given constant, thus avoiding
950 time-consuming boot-time autodetection (up to 250 ms per
951 CPU). 0 enables autodetection (default). To determine
952 the correct value for your kernel, boot with normal
953 autodetection and see what value is printed. Note that
954 on SMP systems the preset will be applied to all CPUs,
955 which is likely to cause problems if your CPUs need
956 significantly divergent settings. An incorrect value
957 will cause delays in the kernel to be wrong, leading to
958 unpredictable I/O errors and other breakage. Although
959 unlikely, in the extreme case this might damage your
960 hardware.
961
962 ltpc= [NET]
963 Format: <io>,<irq>,<dma>
964
Randy Dunlapa9913042005-10-23 12:57:11 -0700965 mac5380= [HW,SCSI] Format:
966 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
Randy Dunlapa9913042005-10-23 12:57:11 -0700968 mac53c9x= [HW,SCSI] Format:
969 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970
Randy Dunlapa9913042005-10-23 12:57:11 -0700971 machvec= [IA64] Force the use of a particular machine-vector
972 (machvec) in a generic kernel.
973 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974
Randy Dunlapa9913042005-10-23 12:57:11 -0700975 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 be mounted
977 Format: <1-256>
978
979 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -0400980 should make use of. maxcpus=n : n >= 0 limits the
981 kernel to using 'n' processors. n=0 is a special case,
982 it is equivalent to "nosmp", which also disables
983 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984
Bob Picco2b2c3752005-06-29 18:00:00 -0700985 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
986 equal to this physical address is ignored.
987
Randy Dunlapa9913042005-10-23 12:57:11 -0700988 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 Should be between 1 and 2^32-1.
990
991 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -0700992 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 Should be between 1 and 16384.
994
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700995 mca-pentium [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996
997 mcatest= [IA-64]
998
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700999 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000
Andi Kleen909dd322007-10-17 18:04:38 +02001001 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1002
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 md= [HW] RAID subsystems devices and level
1004 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001005
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 mdacon= [MDA]
1007 Format: <first>,<last>
1008 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001009
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1011 Amount of memory to be used when the kernel is not able
1012 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001013 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 address space collisions. Without memmap= PCI devices
1015 could be placed at addresses belonging to unused RAM.
1016
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001017 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 memory.
1019
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001020 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 E820 memory map, as specified by the user.
1022 Such memmap=exactmap lines can be constructed based on
1023 BIOS output or other requirements. See the memmap=nn@ss
1024 option description.
1025
1026 memmap=nn[KMG]@ss[KMG]
1027 [KNL] Force usage of a specific region of memory
1028 Region of memory to be used, from ss to ss+nn.
1029
1030 memmap=nn[KMG]#ss[KMG]
1031 [KNL,ACPI] Mark specific memory as ACPI data.
1032 Region of memory to be used, from ss to ss+nn.
1033
1034 memmap=nn[KMG]$ss[KMG]
1035 [KNL,ACPI] Mark specific memory as reserved.
1036 Region of memory to be used, from ss to ss+nn.
1037
1038 meye.*= [HW] Set MotionEye Camera parameters
1039 See Documentation/video4linux/meye.txt.
1040
Andres Salomon8f368812007-10-12 23:04:06 +02001041 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1042 Multi-Function General Purpose Timers on AMD Geode
1043 platforms.
1044
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 mga= [HW,DRM]
1046
1047 mousedev.tap_time=
1048 [MOUSE] Maximum time between finger touching and
1049 leaving touchpad surface for touch to be considered
1050 a tap and be reported as a left button click (for
1051 touchpads working in absolute mode only).
1052 Format: <msecs>
1053 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1054 reporting absolute coordinates, such as tablets
1055 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1056 reporting absolute coordinates, such as tablets
1057
1058 mpu401= [HW,OSS]
1059 Format: <io>,<irq>
1060
1061 MTD_Partition= [MTD]
1062 Format: <name>,<region-number>,<size>,<offset>
1063
Randy Dunlapa9913042005-10-23 12:57:11 -07001064 MTD_Region= [MTD] Format:
1065 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066
1067 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001068 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069
1070 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001071 [HW] Make the MicroTouch USB driver use raw coordinates
1072 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073
1074 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1075
1076 NCR_D700= [HW,SCSI]
1077 See header of drivers/scsi/NCR_D700.c.
1078
1079 ncr5380= [HW,SCSI]
1080
1081 ncr53c400= [HW,SCSI]
1082
1083 ncr53c400a= [HW,SCSI]
1084
1085 ncr53c406a= [HW,SCSI]
1086
1087 ncr53c8xx= [HW,SCSI]
1088
1089 netdev= [NET] Network devices parameters
1090 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1091 Note that mem_start is often overloaded to mean
1092 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001093 This usage is only documented in each driver source
1094 file if at all.
1095
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 nfsaddrs= [NFS]
1097 See Documentation/nfsroot.txt.
1098
1099 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1100 See Documentation/nfsroot.txt.
1101
Trond Myklebusta72b4422006-01-03 09:55:41 +01001102 nfs.callback_tcpport=
1103 [NFS] set the TCP port on which the NFSv4 callback
1104 channel should listen.
1105
Trond Myklebust58df0952006-01-03 09:55:57 +01001106 nfs.idmap_cache_timeout=
1107 [NFS] set the maximum lifetime for idmapper cache
1108 entries.
1109
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001110 nfs.enable_ino64=
1111 [NFS] enable 64-bit inode numbers.
1112 If zero, the NFS client will fake up a 32-bit inode
1113 number for the readdir() and stat() syscalls instead
1114 of returning the full 64-bit number.
1115 The default is to return 64-bit inode numbers.
1116
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001117 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001119 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 emulation library even if a 387 maths coprocessor
1121 is present.
1122
Christoph Lameterc1aee212007-05-31 00:40:47 -07001123 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1124 caches in the slab allocator. Saves per-node memory,
1125 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001126
Randy Dunlapa9913042005-10-23 12:57:11 -07001127 noalign [KNL,ARM]
1128
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129 noapic [SMP,APIC] Tells the kernel to not make use of any
1130 IOAPICs that may be present in the system.
1131
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 nobats [PPC] Do not use BATs for mapping kernel lowmem
1133 on "Classic" PPC cores.
1134
1135 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001136
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001137 nodelayacct [KNL] Disable per-task delay accounting
1138
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1140
1141 noexec [IA-64]
1142
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001143 noexec [X86-32,X86-64]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 noexec=on: enable non-executable mappings (default)
1145 noexec=off: disable nn-executable mappings
1146
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001147 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001148 register save and restore. The kernel will only save
1149 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150
1151 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001152
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001153 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 instruction doesn't work correctly and not to
1155 use it.
1156
1157 nohalt [IA-64] Tells the kernel not to use the power saving
1158 function PAL_HALT_LIGHT when idle. This increases
1159 power-consumption. On the positive side, it reduces
1160 interrupt wake-up latency, which may improve performance
1161 in certain environments such as networked servers or
1162 real-time systems.
1163
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001164 nohz= [KNL] Boottime enable/disable dynamic ticks
1165 Valid arguments: on, off
1166 Default: on
1167
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001168 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001169
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001170 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 disable unhandled interrupt sources.
1172
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001173 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001174 broken timer IRQ sources.
1175
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 noisapnp [ISAPNP] Disables ISA PnP code.
1177
1178 noinitrd [RAM] Tells the kernel not to load any configured
1179 initial RAM disk.
1180
1181 nointroute [IA-64]
1182
Tony Luck0aa366f2007-07-20 11:22:30 -07001183 nojitter [IA64] Disables jitter checking for ITC timers.
1184
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001185 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001187 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001188
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 noltlbs [PPC] Do not use large page/tlb entries for kernel
1190 lowmem mapping on PPC40x.
1191
Horms312f1f02006-02-22 09:57:55 +09001192 nomca [IA-64] Disable machine check abort handling
1193
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001194 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001195
Andres Salomon83d73842007-10-12 23:04:06 +02001196 nomfgpt [X86-32] Disable Multi-Function General Purpose
1197 Timer usage (for AMD Geode machines).
1198
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001199 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001200
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001201 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001202 with UP alternatives
1203
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 noresidual [PPC] Don't use residual data on PReP machines.
1205
Randy Dunlapa9913042005-10-23 12:57:11 -07001206 noresume [SWSUSP] Disables resume and restores original swap
1207 space.
1208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 no-scroll [VGA] Disables scrollback.
1210 This is required for the Braillex ib80-piezo Braille
1211 reader made by F.H. Papenmeier (Germany).
1212
1213 nosbagart [IA-64]
1214
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001215 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001216
Len Brown61ec7562007-08-16 03:34:22 -04001217 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1218 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219
Dave Jones97842212007-07-15 23:41:05 -07001220 nosoftlockup [KNL] Disable the soft-lockup detector.
1221
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 nosync [HW,M68K] Disables sync negotiation for all devices.
1223
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001224 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
1226 nousb [USB] Disable the USB subsystem
1227
1228 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001229
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001230 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1231 one of ['zone', 'node', 'default'] can be specified
1232 This can be set from sysctl after boot.
1233 See Documentation/sysctl/vm.txt for details.
1234
Dave Jonesa61c2d72006-01-07 23:18:19 +00001235 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1236
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 opl3= [HW,OSS]
1238 Format: <io>
1239
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 oprofile.timer= [HW]
1241 Use timer interrupt instead of performance counters
1242
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 osst= [HW,SCSI] SCSI Tape Driver
1244 Format: <buffer_size>,<write_threshold>
1245 See also Documentation/scsi/st.txt.
1246
1247 panic= [KNL] Kernel behaviour on panic
1248 Format: <timeout>
1249
1250 parkbd.port= [HW] Parallel port number the keyboard adapter is
1251 connected to, default is 0.
1252 Format: <parport#>
1253 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1254 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001255 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256
Randy Dunlapa9913042005-10-23 12:57:11 -07001257 parport= [HW,PPT] Specify parallel ports. 0 disables.
1258 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1259 Use 'auto' to force the driver to use any
1260 IRQ/DMA settings detected (the default is to
1261 ignore detected IRQ/DMA settings because of
1262 possible conflicts). You can specify the base
1263 address, IRQ, and DMA settings; IRQ and DMA
1264 should be numbers, or 'auto' (for using detected
1265 settings on that particular port), or 'nofifo'
1266 (to avoid using a FIFO even if it is detected).
1267 Parallel ports are assigned in the order they
1268 are specified on the command line, starting
1269 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270
Randy Dunlapa9913042005-10-23 12:57:11 -07001271 parport_init_mode= [HW,PPT]
1272 Configure VIA parallel port to operate in
1273 a specific mode. This is necessary on Pegasos
1274 computer where firmware has no options for setting
1275 up parallel port mode and sets it to spp.
1276 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 Format: [spp|ps2|epp|ecp|ecpepp]
1278
Randy Dunlapa9913042005-10-23 12:57:11 -07001279 pas2= [HW,OSS] Format:
1280 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 pas16= [HW,SCSI]
1283 See header of drivers/scsi/pas16.c.
1284
Andrew Mortondd287792006-03-23 03:00:57 -08001285 pause_on_oops=
1286 Halt all CPUs after the first oops has been printed for
1287 the specified number of seconds. This is to be used if
1288 your oopses keep scrolling off the screen.
1289
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 pcbit= [HW,ISDN]
1291
1292 pcd. [PARIDE]
1293 See header of drivers/block/paride/pcd.c.
1294 See also Documentation/paride.txt.
1295
Randy Dunlapa9913042005-10-23 12:57:11 -07001296 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001297 off [X86-32] don't probe for the PCI bus
1298 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001299 the hardware directly. Use this if your machine
1300 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001301 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001302 hardware access methods are allowed. Use this
1303 if you experience crashes upon bootup and you
1304 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001305 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001306 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001307 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001308 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001309 noaer [PCIE] If the PCIEAER kernel config parameter is
1310 enabled, this kernel boot option can be used to
1311 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001312 nodomains [PCI] Disable support for multiple PCI
1313 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001314 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001315 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001316 nomsi [MSI] If the PCI_MSI kernel config parameter is
1317 enabled, this kernel boot option can be used to
1318 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001319 nosort [X86-32] Don't sort PCI devices according to
Randy Dunlapa9913042005-10-23 12:57:11 -07001320 order given by the PCI BIOS. This sorting is
1321 done to get a device order compatible with
1322 older kernels.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001323 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001324 routing table. These calls are known to be buggy
1325 on several machines and they hang the machine
1326 when used, but on other computers it's the only
1327 way to get the interrupt routing table. Try
1328 this option if the kernel is unable to allocate
1329 IRQs or discover secondary PCI buses on your
1330 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001331 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001332 Use with caution as certain devices share
1333 address decoders between ROMs and other
1334 resources.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001335 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001336 assigned automatically to PCI devices. You can
1337 make the kernel exclude IRQs of your ISA cards
1338 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001339 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001340 of the PIRQ table (normally generated
1341 by the BIOS) if it is outside the
1342 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001343 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001344 useful if the kernel is unable to find your
1345 secondary buses and you want to tell it
1346 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001347 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001348 numbers ourselves, overriding
1349 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001350 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001351 in the BIOS $PIR table. This is needed on
1352 some systems with broken BIOSes, notably
1353 some HP Pavilion N5400 and Omnibook XE3
1354 notebooks. This will have no effect if ACPI
1355 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001356 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001357 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001358 use_crs [X86-32] Use _CRS for PCI resource
1359 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001360 routeirq Do IRQ routing for all PCI devices.
1361 This is normally done in pci_enable_device(),
1362 so this option is a temporary workaround
1363 for broken drivers that don't call it.
1364 firmware [ARM] Do not re-enumerate the bus but instead
1365 just use the configuration from the
1366 bootloader. This is currently used on
1367 IXP2000 systems where the bus has to be
1368 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001369 noearly [X86] Don't do any early type 1 scanning.
1370 This might help on some broken boards which
1371 machine check when some devices' config space
1372 is read. But various workarounds are disabled
1373 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001374 bfsort Sort PCI devices into breadth-first order.
1375 This sorting is done to get a device
1376 order compatible with older (<= 2.4) kernels.
1377 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001378 cbiosize=nn[KMG] The fixed amount of bus space which is
1379 reserved for the CardBus bridge's IO window.
1380 The default value is 256 bytes.
1381 cbmemsize=nn[KMG] The fixed amount of bus space which is
1382 reserved for the CardBus bridge's memory
1383 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001384
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385 pcmv= [HW,PCMCIA] BadgePAD 4
1386
1387 pd. [PARIDE]
1388 See Documentation/paride.txt.
1389
1390 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1391 boot time.
1392 Format: { 0 | 1 }
1393 See arch/parisc/kernel/pdc_chassis.c
1394
1395 pf. [PARIDE]
1396 See Documentation/paride.txt.
1397
1398 pg. [PARIDE]
1399 See Documentation/paride.txt.
1400
1401 pirq= [SMP,APIC] Manual mp-table setup
1402 See Documentation/i386/IO-APIC.txt.
1403
1404 plip= [PPT,NET] Parallel port network link
1405 Format: { parport<nr> | timid | 0 }
1406 See also Documentation/parport.txt.
1407
1408 pnpacpi= [ACPI]
1409 { off }
1410
1411 pnpbios= [ISAPNP]
1412 { on | off | curr | res | no-curr | no-res }
1413
1414 pnp_reserve_irq=
1415 [ISAPNP] Exclude IRQs for the autoconfiguration
1416
1417 pnp_reserve_dma=
1418 [ISAPNP] Exclude DMAs for the autoconfiguration
1419
1420 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001421 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422
1423 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001424 [ISAPNP] Exclude memory regions for the
1425 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 Ranges are in pairs (memory base and size).
1427
Ingo Molnar45807a12007-07-15 23:40:10 -07001428 print-fatal-signals=
1429 [KNL] debug: print fatal signals
1430 print-fatal-signals=1: print segfault info to
1431 the kernel console.
1432 default: off.
1433
Randy Dunlape84845c2007-07-15 23:40:25 -07001434 printk.time= Show timing data prefixed to each printk message line
1435 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1436
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001438 Format: [schedule,]<number>
1439 Param: "schedule" - profile schedule points.
1440 Param: <number> - step/bucket size as a power of 2 for
1441 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001442 Param: "sleep" - profile D-state sleeping (millisecs).
1443 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001444 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445
Randy Dunlapa9913042005-10-23 12:57:11 -07001446 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 Limit processor to maximum C-state
1448 max_cstate=9 overrides any DMI blacklist limit.
1449
Len Brown41c0d862005-12-28 12:43:51 -05001450 processor.nocst [HW,ACPI]
1451 Ignore the _CST method to determine C-states,
1452 instead using the legacy FADT method
1453
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1455 before loading.
1456 See Documentation/ramdisk.txt.
1457
Randy Dunlapa9913042005-10-23 12:57:11 -07001458 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1459 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1461 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001462 psmouse.resetafter= [HW,MOUSE]
1463 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 (0 = never).
1465 psmouse.resolution=
1466 [HW,MOUSE] Set desired mouse resolution, in dpi.
1467 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001468 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 0 = disabled, 1 = enabled (default).
1470
1471 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001472 Format:
1473 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474
1475 pt. [PARIDE]
1476 See Documentation/paride.txt.
1477
Kay Sieversdc8c8582007-08-15 12:25:38 +02001478 pty.legacy_count=
1479 [KNL] Number of legacy pty's. Overwrites compiled-in
1480 default number.
1481
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001482 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001483
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 r128= [HW,DRM]
1485
1486 raid= [HW,RAID]
1487 See Documentation/md.txt.
1488
Randy Dunlapa9913042005-10-23 12:57:11 -07001489 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001491
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 See Documentation/ramdisk.txt.
1494
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001495 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1496 RCU callbacks to process in one batch.
1497
1498 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1499 RCU callbacks over which batch limiting is disabled.
1500
1501 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1502 RCU callbacks below which batch limiting is re-enabled.
1503
Olof Johanssonffdfc402005-09-06 15:17:19 -07001504 rdinit= [KNL]
1505 Format: <full_path>
1506 Run specified binary instead of /init from the ramdisk,
1507 used for early userspace startup. See initrd.
1508
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001509 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001511 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512
1513 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1514
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001515 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001516 Format: nn[KMG]
1517 Reserves a hole at the top of the kernel virtual
1518 address space.
1519
Vivek Goyal7e962872006-09-27 01:50:44 -07001520 reset_devices [KNL] Force drivers to reset the underlying device
1521 during initialization.
1522
Randy Dunlapa9913042005-10-23 12:57:11 -07001523 resume= [SWSUSP]
1524 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001526 resume_offset= [SWSUSP]
1527 Specify the offset from the beginning of the partition
1528 given by "resume=" at which the swap header is located,
1529 in <PAGE_SIZE> units (needed only for swap files).
1530 See Documentation/power/swsusp-and-swap-files.txt
1531
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001532 retain_initrd [RAM] Keep initrd memory after extraction
1533
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534 rhash_entries= [KNL,NET]
1535 Set number of hash buckets for route cache
1536
1537 riscom8= [HW,SERIAL]
1538 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1539
1540 ro [KNL] Mount root device read-only on boot
1541
1542 root= [KNL] Root filesystem
1543
1544 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1545 mount the root filesystem
1546
1547 rootflags= [KNL] Set root filesystem mount option string
1548
1549 rootfstype= [KNL] Set root filesystem type
1550
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001551 rootwait [KNL] Wait (indefinitely) for root device to show up.
1552 Useful for devices that are detected asynchronously
1553 (e.g. USB and MMC devices).
1554
James Morris20510f22007-10-16 23:31:32 -07001555 root_plug.vendor_id=
1556 [ROOTPLUG] Override the default vendor ID
1557
1558 root_plug.product_id=
1559 [ROOTPLUG] Override the default product ID
1560
1561 root_plug.debug=
1562 [ROOTPLUG] Enable debugging output
1563
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564 rw [KNL] Mount root device read-write on boot
1565
1566 S [KNL] Run init in single mode
1567
1568 sa1100ir [NET]
1569 See drivers/net/irda/sa1100_ir.c.
1570
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001572
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1574 Format: <io>[,<timeout>[,<isapnp>]]
1575
1576 scsi_debug_*= [SCSI]
1577 See drivers/scsi/scsi_debug.c.
1578
1579 scsi_default_dev_flags=
1580 [SCSI] SCSI default device flags
1581 Format: <integer>
1582
1583 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1584 Format: <vendor>:<model>:<flags>
1585 (flags are integer value)
1586
1587 scsi_logging= [SCSI]
1588
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001589 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1590 discovered. async scans them in kernel threads,
1591 allowing boot to proceed. none ignores them, expecting
1592 user space to do the scan.
1593
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594 selinux [SELINUX] Disable or enable SELinux at boot time.
1595 Format: { "0" | "1" }
1596 See security/selinux/Kconfig help text.
1597 0 -- disable.
1598 1 -- enable.
1599 Default value is set via kernel config option.
1600 If enabled at boot time, /selinux/disable can be used
1601 later to disable prior to initial policy load.
1602
James Morris4e5ab4c2006-06-09 00:33:33 -07001603 selinux_compat_net =
1604 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001605 Format: { "0" | "1" }
1606 0 -- use new secmark-based packet controls
1607 1 -- use legacy packet controls
1608 Default value is 0 (preferred).
1609 Value can be changed at runtime via
1610 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001611
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001612 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614 shapers= [NET]
1615 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001616
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 sim710= [SCSI,HW]
1618 See header of drivers/scsi/sim710.c.
1619
1620 simeth= [IA-64]
1621 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001622
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623 slram= [HW,MTD]
1624
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001625 slub_debug[=options[,slabs]] [MM, SLUB]
1626 Enabling slub_debug allows one to determine the
1627 culprit if slab objects become corrupted. Enabling
1628 slub_debug can create guard zones around objects and
1629 may poison objects when not in use. Also tracks the
1630 last alloc / free. For more information see
1631 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001632
1633 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001634 Determines the maximum allowed order for slabs.
1635 A high setting may cause OOMs due to memory
1636 fragmentation. For more information see
1637 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001638
1639 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001640 The minimum number of objects per slab. SLUB will
1641 increase the slab order up to slub_max_order to
1642 generate a sufficiently large slab able to contain
1643 the number of objects indicated. The higher the number
1644 of objects the smaller the overhead of tracking slabs
1645 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001646 For more information see Documentation/vm/slub.txt.
1647
1648 slub_min_order= [MM, SLUB]
1649 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001650 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001651 For more information see Documentation/vm/slub.txt.
1652
1653 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001654 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001655 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001656 allocs to different slabs. Debug options disable
1657 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001658 For more information see Documentation/vm/slub.txt.
1659
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660 smart2= [HW]
1661 Format: <io1>[,<io2>[,...,<io8>]]
1662
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001663 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001664 attempt to substitute SMP alternatives once at boot.
1665
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001666 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1667 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1668 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1669 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1670 smsc-ircc2.ircc_irq= [HW] IRQ line
1671 smsc-ircc2.ircc_dma= [HW] DMA channel
1672 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1673 0: Toshiba Satellite 1800 (GP data pin select)
1674 1: Fast pin select (default)
1675 2: ATC IRMode
1676
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677 snd-ad1816a= [HW,ALSA]
1678
1679 snd-ad1848= [HW,ALSA]
1680
1681 snd-ali5451= [HW,ALSA]
1682
1683 snd-als100= [HW,ALSA]
1684
1685 snd-als4000= [HW,ALSA]
1686
1687 snd-azt2320= [HW,ALSA]
1688
1689 snd-cmi8330= [HW,ALSA]
1690
1691 snd-cmipci= [HW,ALSA]
1692
1693 snd-cs4231= [HW,ALSA]
1694
1695 snd-cs4232= [HW,ALSA]
1696
1697 snd-cs4236= [HW,ALSA]
1698
1699 snd-cs4281= [HW,ALSA]
1700
1701 snd-cs46xx= [HW,ALSA]
1702
1703 snd-dt019x= [HW,ALSA]
1704
1705 snd-dummy= [HW,ALSA]
1706
1707 snd-emu10k1= [HW,ALSA]
1708
1709 snd-ens1370= [HW,ALSA]
1710
1711 snd-ens1371= [HW,ALSA]
1712
1713 snd-es968= [HW,ALSA]
1714
1715 snd-es1688= [HW,ALSA]
1716
1717 snd-es18xx= [HW,ALSA]
1718
1719 snd-es1938= [HW,ALSA]
1720
1721 snd-es1968= [HW,ALSA]
1722
1723 snd-fm801= [HW,ALSA]
1724
1725 snd-gusclassic= [HW,ALSA]
1726
1727 snd-gusextreme= [HW,ALSA]
1728
1729 snd-gusmax= [HW,ALSA]
1730
1731 snd-hdsp= [HW,ALSA]
1732
1733 snd-ice1712= [HW,ALSA]
1734
1735 snd-intel8x0= [HW,ALSA]
1736
1737 snd-interwave= [HW,ALSA]
1738
1739 snd-interwave-stb=
1740 [HW,ALSA]
1741
1742 snd-korg1212= [HW,ALSA]
1743
1744 snd-maestro3= [HW,ALSA]
1745
1746 snd-mpu401= [HW,ALSA]
1747
1748 snd-mtpav= [HW,ALSA]
1749
1750 snd-nm256= [HW,ALSA]
1751
1752 snd-opl3sa2= [HW,ALSA]
1753
1754 snd-opti92x-ad1848=
1755 [HW,ALSA]
1756
1757 snd-opti92x-cs4231=
1758 [HW,ALSA]
1759
1760 snd-opti93x= [HW,ALSA]
1761
1762 snd-pmac= [HW,ALSA]
1763
1764 snd-rme32= [HW,ALSA]
1765
1766 snd-rme96= [HW,ALSA]
1767
1768 snd-rme9652= [HW,ALSA]
1769
1770 snd-sb8= [HW,ALSA]
1771
1772 snd-sb16= [HW,ALSA]
1773
1774 snd-sbawe= [HW,ALSA]
1775
1776 snd-serial= [HW,ALSA]
1777
1778 snd-sgalaxy= [HW,ALSA]
1779
1780 snd-sonicvibes= [HW,ALSA]
1781
1782 snd-sun-amd7930=
1783 [HW,ALSA]
1784
1785 snd-sun-cs4231= [HW,ALSA]
1786
1787 snd-trident= [HW,ALSA]
1788
1789 snd-usb-audio= [HW,ALSA,USB]
1790
1791 snd-via82xx= [HW,ALSA]
1792
1793 snd-virmidi= [HW,ALSA]
1794
1795 snd-wavefront= [HW,ALSA]
1796
1797 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001798
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1800 See Documentation/sonypi.txt
1801
1802 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1803 See Documentation/specialix.txt.
1804
1805 spia_io_base= [HW,MTD]
1806 spia_fio_base=
1807 spia_pedr=
1808 spia_peddr=
1809
1810 sscape= [HW,OSS]
1811 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07001812
Linus Torvalds1da177e2005-04-16 15:20:36 -07001813 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1814 See Documentation/scsi/st.txt.
1815
1816 st0x= [HW,SCSI]
1817 See header of drivers/scsi/seagate.c.
1818
1819 sti= [PARISC,HW]
1820 Format: <num>
1821 Set the STI (builtin display/keyboard on the HP-PARISC
1822 machines) console (graphic card) which should be used
1823 as the initial boot-console.
1824 See also comment in drivers/video/console/sticore.c.
1825
1826 sti_font= [HW]
1827 See comment in drivers/video/console/sticore.c.
1828
1829 stifb= [HW]
1830 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1831
Greg Banks42a7fc42007-03-06 01:42:23 -08001832 sunrpc.pool_mode=
1833 [NFS]
1834 Control how the NFS server code allocates CPUs to
1835 service thread pools. Depending on how many NICs
1836 you have and where their interrupts are bound, this
1837 option will affect which CPUs will do NFS serving.
1838 Note: this parameter cannot be changed while the
1839 NFS server is running.
1840
1841 auto the server chooses an appropriate mode
1842 automatically using heuristics
1843 global a single global pool contains all CPUs
1844 percpu one pool for each CPU
1845 pernode one pool for each NUMA node (equivalent
1846 to global on non-NUMA machines)
1847
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07001849
Linus Torvalds1da177e2005-04-16 15:20:36 -07001850 switches= [HW,M68k]
1851
1852 sym53c416= [HW,SCSI]
1853 See header of drivers/scsi/sym53c416.c.
1854
Ingo Molnar5d6f6472006-12-13 00:34:36 -08001855 sysrq_always_enabled
1856 [KNL]
1857 Ignore sysrq setting - this boot parameter will
1858 neutralize any effect of /proc/sys/kernel/sysrq.
1859 Useful for debugging.
1860
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 t128= [HW,SCSI]
1862 See header of drivers/scsi/t128.c.
1863
1864 tdfx= [HW,DRM]
1865
1866 thash_entries= [KNL,NET]
1867 Set number of hash buckets for TCP connection
1868
Len Brownf8707ec2007-08-12 00:12:54 -04001869 thermal.act= [HW,ACPI]
1870 -1: disable all active trip points in all thermal zones
1871 <degrees C>: override all lowest active trip points
1872
Len Brownc52a7412007-08-14 15:49:32 -04001873 thermal.crt= [HW,ACPI]
1874 -1: disable all critical trip points in all thermal zones
1875 <degrees C>: lower all critical trip points
1876
Len Brownf5487142007-08-12 00:12:44 -04001877 thermal.nocrt= [HW,ACPI]
1878 Set to disable actions on ACPI thermal zone
1879 critical and hot trip points.
1880
Len Brown72b33ef2007-08-12 00:12:17 -04001881 thermal.off= [HW,ACPI]
1882 1: disable ACPI thermal control
1883
Len Browna70cdc52007-08-12 00:12:35 -04001884 thermal.psv= [HW,ACPI]
1885 -1: disable all passive trip points
1886 <degrees C>: override all passive trip points to this value
1887
Len Brown730ff342007-08-12 00:12:26 -04001888 thermal.tzp= [HW,ACPI]
1889 Specify global default ACPI thermal zone polling rate
1890 <deci-seconds>: poll all this frequency
1891 0: no polling (default)
1892
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 time Show timing data prefixed to each printk message line
Randy Dunlape84845c2007-07-15 23:40:25 -07001894 [deprecated, see 'printk.time']
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895
1896 tipar.timeout= [HW,PPT]
1897 Set communications timeout in tenths of a second
1898 (default 15).
1899
1900 tipar.delay= [HW,PPT]
1901 Set inter-bit delay in microseconds (default 10).
1902
1903 tmc8xx= [HW,SCSI]
1904 See header of drivers/scsi/seagate.c.
1905
1906 tmscsim= [HW,SCSI]
1907 See comment before function dc390_setup() in
1908 drivers/scsi/tmscsim.c.
1909
1910 tp720= [HW,PS2]
1911
1912 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07001913 Format:
1914 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1915
Randy Dunlapa9913042005-10-23 12:57:11 -07001916 turbografx.map[2|3]= [HW,JOY]
1917 TurboGraFX parallel port interface
1918 Format:
1919 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 See also Documentation/input/joystick-parport.txt
1921
1922 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1923 See header of drivers/scsi/u14-34f.c.
1924
1925 uart401= [HW,OSS]
1926 Format: <io>,<irq>
1927
1928 uart6850= [HW,OSS]
1929 Format: <io>,<irq>
1930
Alan Stern5f8364b2006-12-05 16:29:55 -05001931 uhci-hcd.ignore_oc=
1932 [USB] Ignore overcurrent events (default N).
1933 Some badly-designed motherboards generate lots of
1934 bogus events, for ports that aren't wired to
1935 anything. Set this parameter to avoid log spamming.
1936 Note that genuine overcurrent events won't be
1937 reported either.
1938
Alan Sternb5e795f2007-02-20 15:00:53 -05001939 usbcore.autosuspend=
1940 [USB] The autosuspend time delay (in seconds) used
1941 for newly-detected USB devices (default 2). This
1942 is the time required before an idle device will be
1943 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04001944 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05001945
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 usbhid.mousepoll=
1947 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07001948
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001949 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02001950 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07001951 vdso=1: enable VDSO (default)
1952 vdso=0: disable VDSO mapping
1953
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09001954 vector= [IA-64,SMP]
1955 vector=percpu: enable percpu vector domain
1956
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957 video= [FB] Frame buffer configuration
1958 See Documentation/fb/modedb.txt.
1959
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001960 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07001961 See Documentation/i386/boot.txt and
1962 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963 Use vga=ask for menu.
1964 This is actually a boot loader parameter; the value is
1965 passed to the kernel using a special protocol.
1966
Randy Dunlapa9913042005-10-23 12:57:11 -07001967 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001968 size of <nn>. This can be used to increase the
1969 minimum size (128MB on x86). It can also be used to
1970 decrease the size and leave more room for directly
1971 mapped kernel RAM.
1972
Peter Oberparleiter585c3042006-06-29 15:08:25 +02001973 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1974 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975
Peter Oberparleiter585c3042006-06-29 15:08:25 +02001976 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1977 Format: <command>
1978
1979 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1980 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07001981
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982 waveartist= [HW,OSS]
1983 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07001984
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 wd33c93= [HW,SCSI]
1986 See header of drivers/scsi/wd33c93.c.
1987
1988 wd7000= [HW,SCSI]
1989 See header of drivers/scsi/wd7000.c.
1990
1991 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07001992 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001993
1994 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1995 xd_geo= See header of drivers/block/xd.c.
1996
1997 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001998 Format:
1999 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000
Andi Kleena62eaf12006-02-16 23:41:58 +01002001 norandmaps Don't use address space randomization
2002 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2003
Randy Dunlapa9913042005-10-23 12:57:11 -07002004______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005
2006TODO:
2007
2008 Add documentation for ALSA options.
2009 Add more DRM drivers.