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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.
Randy Dunlapa9913042005-10-23 12:57:11 -070090 SWSUSP Software suspend is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 TS Appropriate touchscreen support is enabled.
92 USB USB support is enabled.
93 USBHID USB Human Interface Device support is enabled.
94 V4L Video For Linux support is enabled.
95 VGA The VGA console has been enabled.
96 VT Virtual terminal support is enabled.
97 WDT Watchdog support is enabled.
98 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -070099 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 X86-64 X86-64 architecture is enabled.
101 More X86-64 boot options can be found in
102 Documentation/x86_64/boot-options.txt .
103
104In addition, the following text indicates that the option:
105
106 BUGS= Relates to possible processor bugs on the said processor.
107 KNL Is a kernel start-up parameter.
108 BOOT Is a boot loader parameter.
109
110Parameters denoted with BOOT are actually interpreted by the boot
111loader, and have no meaning to the kernel directly.
112Do not modify the syntax of boot loader parameters without extreme
113need or coordination with <Documentation/i386/boot.txt>.
114
Karsten Weiss55588702007-02-13 13:26:21 +0100115There are also arch-specific kernel-parameters not documented here.
116See for example <Documentation/x86_64/boot-options.txt>.
117
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
119a trailing = on the name of any parameter states that that parameter will
120be entered as an environment variable, whereas its absence indicates that
121it will appear as a kernel argument readable via /proc/cmdline by programs
122running once the system is up.
123
jens m. noedler9c4751f2006-09-29 02:00:27 -0700124The number of kernel parameters is not limited, but the length of the
125complete command line (parameters including spaces etc.) is limited to
126a fixed number of characters. This limit depends on the architecture
127and is between 256 and 4096 characters. It is defined in the file
128./include/asm/setup.h as COMMAND_LINE_SIZE.
129
130
Bernhard Walle03d926f2007-03-06 02:29:44 -0800131 acpi= [HW,ACPI,X86-64,i386]
132 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700133 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 force -- enable ACPI if default was off
135 off -- disable ACPI if default was on
136 noirq -- do not use ACPI for IRQ routing
137 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700138 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 strictly ACPI specification compliant.
140
Randy Dunlap53471122008-03-12 18:10:51 -0400141 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Len Browna1fdcc02007-03-11 03:26:14 -0400143 acpi_apic_instance= [ACPI, IOAPIC]
144 Format: <int>
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400147 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400148
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 acpi_sleep= [HW,ACPI] Sleep options
Pavel Machek23b168d2008-02-05 19:27:12 +0100150 Format: { s3_bios, s3_mode, s3_beep }
151 See Documentation/power/video.txt for s3_bios and s3_mode.
152 s3_beep is for debugging; it makes the PC's speaker beep
153 as soon as the kernel's real-mode entry point is called.
Randy Dunlapa9913042005-10-23 12:57:11 -0700154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700156 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Randy Dunlapa9913042005-10-23 12:57:11 -0700158 acpi_irq_balance [HW,ACPI]
159 ACPI will balance active IRQs
160 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Randy Dunlapa9913042005-10-23 12:57:11 -0700162 acpi_irq_nobalance [HW,ACPI]
163 ACPI will not move active IRQs (default)
164 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Randy Dunlapa9913042005-10-23 12:57:11 -0700166 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
167 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 Format: <irq>,<irq>...
169
Randy Dunlapa9913042005-10-23 12:57:11 -0700170 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 Format: <irq>,<irq>...
172
Len Brown67effe82007-07-26 00:50:06 -0400173 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
174
Len Browna1f9e652006-01-25 23:47:36 -0500175 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
176 Format: To spoof as Windows 98: ="Microsoft Windows"
177
Len Brownae00d812007-05-29 18:43:33 -0400178 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
179 acpi_osi="string1" # add string1 -- only one string
180 acpi_osi="!string2" # remove built-in string2
181 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
183 acpi_serialize [HW,ACPI] force serialization of AML methods
184
185 acpi_skip_timer_override [HW,ACPI]
186 Recognize and ignore IRQ0/pin2 Interrupt Override.
187 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100188 acpi_use_timer_override [HW,ACPI}
189 Use timer override. For some broken Nvidia NF5 boards
190 that require a timer override, but don't have
191 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Zhang Ruif9891062007-04-24 13:53:22 +0800193 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700195 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 1: enable, 0: disable. It is useful for boot time
197 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800198 via /sys/module/acpi/parameters/debug_layer.
199 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
200 Available bits (add the numbers together) to enable debug output
201 for specific parts of the ACPI subsystem:
202 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
203 0x10 namespace 0x20 parser 0x40 dispatcher
204 0x80 executer 0x100 resources 0x200 acpica debugger
205 0x400 os services 0x800 acpica disassembler.
206 The number can be in decimal or prefixed with 0x in hex.
207 Warning: Many of these options can produce a lot of
208 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
Zhang Ruif9891062007-04-24 13:53:22 +0800210 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700212 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 1: enable, 0: disable. It is useful for boot time
214 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800215 via /sys/module/acpi/parameters/debug_level.
216 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
217 Available bits (add the numbers together) to enable different
218 debug output levels of the ACPI subsystem:
219 0x01 error 0x02 warn 0x04 init 0x08 debug object
220 0x10 info 0x20 init names 0x40 parse 0x80 load
221 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
222 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
223 0x10000 resources 0x20000 user requests 0x40000 package.
224 The number can be in decimal or prefixed with 0x in hex.
225 Warning: Many of these options can produce a lot of
226 output and make your system unusable. Be very careful.
227
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700228 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700229 Override the pmtimer bug detection: force the kernel
230 to assume that this machine's pmtimer latches its value
231 and always returns good values.
232
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000233 agp= [AGP]
234 { off | try_unsupported }
235 off: disable AGP support
236 try_unsupported: try to drive unsupported chipsets
237 (may crash computer or cause data corruption)
238
Chuck Ebbert66759a02005-09-12 18:49:25 +0200239 enable_timer_pin_1 [i386,x86-64]
240 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700241 Can be useful to work around chipset bugs
242 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200243 The kernel tries to set a reasonable default.
244
245 disable_timer_pin_1 [i386,x86-64]
246 Disable PIN 1 of APIC timer
247 Can be useful to work around chipset bugs.
248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 ad1848= [HW,OSS]
250 Format: <io>,<irq>,<dma>,<dma2>,<type>
251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 advansys= [HW,SCSI]
253 See header of drivers/scsi/advansys.c.
254
255 advwdt= [HW,WDT] Advantech WDT
256 Format: <iostart>,<iostop>
257
258 aedsp16= [HW,OSS] Audio Excel DSP 16
259 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
260 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 aha152x= [HW,SCSI]
263 See Documentation/scsi/aha152x.txt.
264
265 aha1542= [HW,SCSI]
266 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
267
268 aic7xxx= [HW,SCSI]
269 See Documentation/scsi/aic7xxx.txt.
270
271 aic79xx= [HW,SCSI]
272 See Documentation/scsi/aic79xx.txt.
273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 amijoy.map= [HW,JOY] Amiga joystick support
275 Map of devices attached to JOY0DAT and JOY1DAT
276 Format: <a>,<b>
277 See also Documentation/kernel/input/joystick.txt
278
279 analog.map= [HW,JOY] Analog joystick and gamepad support
280 Specifies type or capabilities of an analog joystick
281 connected to one of 16 gameports
282 Format: <type1>,<type2>,..<type16>
283
Randy Dunlapa9913042005-10-23 12:57:11 -0700284 apc= [HW,SPARC]
285 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 Format: noidle
287 Disable APC CPU standby support. SPARCstation-Fox does
288 not play well with APC CPU idle - disable it if you have
289 APC and your system crashes randomly.
290
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700291 apic= [APIC,i386] Advanced Programmable Interrupt Controller
292 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 Format: { quiet (default) | verbose | debug }
294 Change the amount of debugging information output
295 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 apm= [APM] Advanced Power Management
298 See header of arch/i386/kernel/apm.c.
299
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
301 Format: <io>,<irq>,<nodeID>
302
303 ataflop= [HW,M68k]
304
305 atarimouse= [HW,MOUSE] Atari Mouse
306
307 atascsi= [HW,SCSI] Atari SCSI
308
309 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
310 EzKey and similar keyboards
311
312 atkbd.reset= [HW] Reset keyboard during initialization
313
Randy Dunlapa9913042005-10-23 12:57:11 -0700314 atkbd.set= [HW] Select keyboard code set
315 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
317 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
318 keyboards
319
320 atkbd.softraw= [HW] Choose between synthetic and real raw mode
321 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700322
323 atkbd.softrepeat= [HW]
324 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
326 autotest [IA64]
327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 baycom_epp= [HW,AX25]
329 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700330
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
332 Format: <io>,<mode>
333 See header of drivers/net/hamradio/baycom_par.c.
334
Randy Dunlapa9913042005-10-23 12:57:11 -0700335 baycom_ser_fdx= [HW,AX25]
336 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 Format: <io>,<irq>,<mode>[,<baud>]
338 See header of drivers/net/hamradio/baycom_ser_fdx.c.
339
Randy Dunlapa9913042005-10-23 12:57:11 -0700340 baycom_ser_hdx= [HW,AX25]
341 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 Format: <io>,<irq>,<mode>
343 See header of drivers/net/hamradio/baycom_ser_hdx.c.
344
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700345 boot_delay= Milliseconds to delay each printk during boot.
346 Values larger than 10 seconds (10000) are changed to
347 no delay (0).
348 Format: integer
349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700351 bttv.radio= Most important insmod options are available as
352 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
354 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
355
356 BusLogic= [HW,SCSI]
357 See drivers/scsi/BusLogic.c, comment before function
358 BusLogic_ParseDriverOptions().
359
360 c101= [NET] Moxa C101 synchronous serial card
361
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700362 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 Sometimes CPU hardware bugs make them report the cache
364 size incorrectly. The kernel will attempt work arounds
365 to fix known problems, but for some CPUs it is not
366 possible to determine what the correct size should be.
367 This option provides an override for these situations.
368
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200369 security= [SECURITY] Choose a security module to enable at boot.
370 If this boot parameter is not specified, only the first
371 security module asking for security registration will be
372 loaded. An invalid security module name will be treated
373 as if no module has been chosen.
374
James Morris20510f22007-10-16 23:31:32 -0700375 capability.disable=
376 [SECURITY] Disable capabilities. This would normally
377 be used only if an alternative security model is to be
378 configured. Potentially dangerous and should only be
379 used if you are entirely sure of the consequences.
380
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100381 ccw_timeout_log [S390]
382 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383
Paul Menage8bab8dd2008-04-04 14:29:57 -0700384 cgroup_disable= [KNL] Disable a particular controller
385 Format: {name of the controller(s) to disable}
386 {Currently supported controllers - "memory"}
387
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 checkreqprot [SELINUX] Set initial checkreqprot flag value.
389 Format: { "0" | "1" }
390 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700391 0 -- check protection applied by kernel (includes
392 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 1 -- check protection requested by application.
394 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700395 Value can be changed at runtime via
396 /selinux/checkreqprot.
397
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100398 cio_ignore= [S390]
399 See Documentation/s390/CommonIO for details.
400
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700401 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700402 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200403 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700404 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200405 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 Format: { pit | tsc | cyclone | pmtmr }
407
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700408 clocksource= [GENERIC_TIME] Override the default clocksource
409 Format: <string>
410 Override the default clocksource and use the clocksource
411 with the name specified.
412 Some clocksource names to choose from, depending on
413 the platform:
414 [all] jiffies (this is the base, fallback clocksource)
415 [ACPI] acpi_pm
416 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
417 pxa_timer,timer3,32k_counter,timer0_1
418 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700419 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700420 scx200_hrt on Geode; cyclone on IBM x440
421 [MIPS] MIPS
422 [PARISC] cr16
423 [S390] tod
424 [SH] SuperH
425 [SPARC64] tick
426 [X86-64] hpet,tsc
427
Andi Kleenac72e782008-01-30 13:33:21 +0100428 clearcpuid=BITNUM [X86]
429 Disable CPUID feature X for the kernel. See
430 include/asm-x86/cpufeature.h for the valid bit numbers.
431 Note the Linux specific bits are not necessarily
432 stable over kernel options, but the vendor specific
433 ones should be.
434 Also note that user programs calling CPUID directly
435 or using the feature without checking anything
436 will still see it. This just prevents it from
437 being used by the kernel or shown in /proc/cpuinfo.
438 Also note the kernel might malfunction if you disable
439 some critical bits.
440
Arjan van de Vena25bd942008-01-30 13:33:08 +0100441 code_bytes [IA32/X86_64] How many bytes of object code to print
442 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100443 Range: 0 - 8192
444 Default: 64
445
Andi Kleenf9262c12006-03-08 17:57:25 -0800446 disable_8254_timer
447 enable_8254_timer
448 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
449 over the 8254 in addition to over the IO-APIC. The
450 kernel tries to set a sensible default.
451
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200452 hpet= [X86-32,HPET] option to control HPET usage
453 Format: { enable (default) | disable | force }
454 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100455 force: allow force enabled of undocumented chips (ICH4,
456 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700459 Format:
460 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
462 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
463 Format: <io>[,<irq>]
464
Randy Dunlapa9913042005-10-23 12:57:11 -0700465 com90xx= [HW,NET]
466 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 Format: <io>[,<irq>[,<memstart>]]
468
469 condev= [HW,S390] console device
470 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700471
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 console= [KNL] Output console device and options.
473
474 tty<n> Use the virtual console device <n>.
475
476 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800477 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800479 the form "bbbbpnf", where "bbbb" is the baud rate,
480 "p" is parity ("n", "o", or "e"), "n" is number of
481 bits, and "f" is flow control ("r" for RTS or
482 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800484 See Documentation/serial-console.txt for more
485 information. See
486 Documentation/networking/netconsole.txt for an
487 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700489 uart[8250],io,<addr>[,options]
490 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 Start an early, polled-mode console on the 8250/16550
492 UART at the specified I/O port or MMIO address,
493 switching to the matching ttyS device later. The
494 options are the same as for ttyS, above.
495
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700496 If the device connected to the port is not a TTY but a braille
497 device, prepend "brl," before the device type, for instance
498 console=brl,ttyS0
499 For now, only VisioBraille is supported.
500
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700501 earlycon= [KNL] Output early console device and options.
502 uart[8250],io,<addr>[,options]
503 uart[8250],mmio,<addr>[,options]
504 Start an early, polled-mode console on the 8250/16550
505 UART at the specified I/O port or MMIO address.
506 The options are the same as for ttyS, above.
507
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700508 no_console_suspend
509 [HW] Never suspend the console
510 Disable suspending of consoles during suspend and
511 hibernate operations. Once disabled, debugging
512 messages can reach various consoles while the rest
513 of the system is being put to sleep (ie, while
514 debugging driver suspend/resume hooks). This may
515 not work reliably with all consoles, but is known
516 to work with serial and VGA consoles.
517
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700519 Format:
520 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700522 crashkernel=nn[KMG]@ss[KMG]
523 [KNL] Reserve a chunk of physical memory to
524 hold a kernel to switch to with kexec on panic.
525
Bernhard Wallefb391592007-10-18 23:41:02 -0700526 crashkernel=range1:size1[,range2:size2,...][@offset]
527 [KNL] Same as above, but depends on the memory
528 in the running system. The syntax of range is
529 start-[end] where start and end are both
530 a memory unit (amount[KMG]). See also
531 Documentation/kdump/kdump.txt for a example.
532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 cs4232= [HW,OSS]
534 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
535
536 cs89x0_dma= [HW,NET]
537 Format: <dma>
538
539 cs89x0_media= [HW,NET]
540 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700541
Randy Dunlapa9913042005-10-23 12:57:11 -0700542 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 See header of drivers/s390/block/dasd_devmap.c.
544
545 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
546 (one device per port)
547 Format: <port#>,<type>
548 See also Documentation/input/joystick-parport.txt
549
550 debug [KNL] Enable kernel debugging (events log level).
551
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700552 debug_locks_verbose=
553 [KNL] verbose self-tests
554 Format=<0|1>
555 Print debugging info while doing the locking API
556 self-tests.
557 We default to 0 (no extra messages), setting it to
558 1 will print _a lot_ more information - normally
559 only useful to kernel developers.
560
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700561 debug_objects [KNL] Enable object debugging
562
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200563 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 Format: <area>[,<node>]
565 See also Documentation/networking/decnet.txt.
566
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000567 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700568 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
569 Change the default blue palette of the console.
570 This is a 16-member array composed of values
571 ranging from 0-255.
572
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000573 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700574 Format: <green0>,<green1>,<green2>,...,<green15>
575 Change the default green palette of the console.
576 This is a 16-member array composed of values
577 ranging from 0-255.
578
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000579 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700580 Format: <red0>,<red1>,<red2>,...,<red15>
581 Change the default red palette of the console.
582 This is a 16-member array composed of values
583 ranging from 0-255.
584
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000585 vt.default_utf8=
586 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700587 Format=<0|1>
588 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000589 Default is 1, i.e. UTF-8 mode is enabled for all
590 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700591
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 dhash_entries= [KNL]
593 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 digi= [HW,SERIAL]
596 IO parameters + enable/disable command.
597
598 digiepca= [HW,SERIAL]
599 See drivers/char/README.epca and
600 Documentation/digiepca.txt.
601
Yinghai Lu093af8d2008-01-30 13:33:32 +0100602 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100603 By default the kernel will trim any uncacheable
604 memory out of your available memory pool based on
605 MTRR settings. This parameter disables that behavior,
606 possibly causing your machine to run very slowly.
607
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 dmasound= [HW,OSS] Sound subsystem buffers
609
610 dscc4.setup= [NET]
611
612 dtc3181e= [HW,SCSI]
613
Robin Getz0ae53642007-10-09 17:24:49 +0800614 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 earlyprintk=vga
616 earlyprintk=serial[,ttySn[,baudrate]]
617
Randy Dunlapa9913042005-10-23 12:57:11 -0700618 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 takes over.
620
621 Only vga or serial at a time, not both.
622
623 Currently only ttyS0 and ttyS1 are supported.
624
625 Interaction with the standard serial driver is not
626 very good.
627
628 The VGA output is eventually overwritten by the real
629 console.
630
631 eata= [HW,SCSI]
632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700634 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 eisa_irq_edge= [PARISC,HW]
637 See header of drivers/parisc/eisa.c.
638
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700639 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 See comment before function elanfreq_setup() in
641 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
642
643 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800644 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700645 See Documentation/block/as-iosched.txt and
646 Documentation/block/deadline-iosched.txt for details.
647
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700648 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700649 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800650 image elf header. Generally kexec loader will
651 pass this option to capture kernel.
652 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653
654 enforcing [SELINUX] Set initial enforcing status.
655 Format: {"0" | "1"}
656 See security/selinux/Kconfig help text.
657 0 -- permissive (log only, no denials).
658 1 -- enforcing (deny and log).
659 Default value is 0.
660 Value can be changed at runtime via /selinux/enforce.
661
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 es1371= [HW,OSS]
663 Format: <spdif>,[<nomix>,[<amplifier>]]
664 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 ether= [HW,NET] Ethernet cards parameters
667 This option is obsoleted by the "netdev=" option, which
668 has equivalent usage. See its documentation for details.
669
670 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
671 Format: <io>[,<irq>]
672
Akinobu Mitade1ba092006-12-08 02:39:42 -0800673 failslab=
674 fail_page_alloc=
675 fail_make_request=[KNL]
676 General fault injection mechanism.
677 Format: <interval>,<probability>,<space>,<times>
678 See also /Documentation/fault-injection/.
679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 fd_mcs= [HW,SCSI]
681 See header of drivers/scsi/fd_mcs.c.
682
683 fdomain= [HW,SCSI]
684 See header of drivers/scsi/fdomain.c.
685
686 floppy= [HW]
687 See Documentation/floppy.txt.
688
Alex Chiangf13ae302008-05-08 14:03:23 -0600689 force_pal_cache_flush
690 [IA-64] Avoid check_sal_cache_flush which may hang on
691 buggy SAL_CACHE_FLUSH implementations. Using this
692 parameter will force ia64_sal_cache_flush to call
693 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
694
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 gamecon.map[2|3]=
696 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
697 support via parallel port (up to 5 devices per port)
698 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
699 See also Documentation/input/joystick-parport.txt
700
701 gamma= [HW,DRM]
702
Yinghai Luaaf23042008-01-30 13:33:09 +0100703 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
704 Format: off | on
705 default: on
706
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 gdth= [HW,SCSI]
708 See header of drivers/scsi/gdth.c.
709
710 gpt [EFI] Forces disk with valid GPT signature but
711 invalid Protective MBR to be treated as GPT.
712
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 gvp11= [HW,SCSI]
714
715 hashdist= [KNL,NUMA] Large hashes allocated during boot
716 are distributed across NUMA nodes. Defaults on
717 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700718 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719
720 hcl= [IA-64] SGI's Hardware Graph compatibility layer
721
722 hd= [EIDE] (E)IDE hard drive subsystem geometry
723 Format: <cyl>,<head>,<sect>
724
725 hd?= [HW] (E)IDE subsystem
Randy Dunlap1c10e932008-03-07 21:53:50 +0100726 hd?lun= See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727
728 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
729 size of <nn>. This works even on boxes that have no
730 highmem otherwise. This also works to reduce highmem
731 size on bigger boxes.
732
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800733 highres= [KNL] Enable/disable high resolution timer mode.
734 Valid parameters: "on", "off"
735 Default: "on"
736
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 hisax= [HW,ISDN]
738 See Documentation/isdn/README.HiSax.
739
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700740 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
Jon Tollefson4ec161c2008-01-04 09:59:50 +1100741 hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200744 i8042.dumbkbd [HW] Pretend that controller can only read data from
745 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 (Don't attempt to blink the leds)
747 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500748 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400749 i8042.noloop [HW] Disable the AUX Loopback command while probing
750 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 i8042.nomux [HW] Don't check presence of an active multiplexing
752 controller
753 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
754 controllers
755 i8042.panicblink=
756 [HW] Frequency with which keyboard LEDs should blink
757 when kernel panics (default is 0.5 sec)
758 i8042.reset [HW] Reset the controller during init and cleanup
759 i8042.unlock [HW] Unlock (ignore) the keylock
760
761 i810= [HW,DRM]
762
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700763 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
764 indicates that the driver is running on unsupported
765 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
767 does not match list of supported models.
768 i8k.power_status
769 [HW] Report power status in /proc/i8k
770 (disabled by default)
771 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
772 capability is set.
773
774 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
775 See Documentation/mca.txt.
776
777 icn= [HW,ISDN]
778 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
779
780 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200781 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100782 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100785 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786
Andi Kleenf039b752007-05-02 19:27:12 +0200787 idle= [X86]
788 Format: idle=poll or idle=mwait
789 Poll forces a polling idle loop that can slightly improves the performance
790 of waking up a idle CPU, but will use a lot of power and make the system
791 run hot. Not recommended.
792 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
793 to not use it because it doesn't save as much power as a normal idle
794 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
795 as idle=poll.
Randy Dunlapa9913042005-10-23 12:57:11 -0700796
Denis Cheng594765a2008-02-06 02:57:49 +0100797 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
798 Claim all unknown PCI IDE storage controllers.
799
Ingo Molnar792908222006-12-06 20:40:51 -0800800 ignore_loglevel [KNL]
801 Ignore loglevel setting - this will print /all/
802 kernel messages to the console. Useful for debugging.
803
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 ihash_entries= [KNL]
805 Set number of hash buckets for inode cache.
806
807 in2000= [HW,SCSI]
808 See header of drivers/scsi/in2000.c.
809
810 init= [KNL]
811 Format: <full_path>
812 Run specified binary instead of /sbin/init as init
813 process.
814
815 initcall_debug [KNL] Trace initcalls as they are executed. Useful
816 for working out where the kernel is dying during
817 startup.
818
819 initrd= [BOOT] Specify the location of the initial ramdisk
820
821 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
822 Format: <irq>
823
824 inttest= [IA64]
825
Pavel Machekb552da82008-03-19 15:58:11 +0100826 iommu= [x86]
827 off
828 force
829 noforce
830 biomerge
831 panic
832 nopanic
833 merge
834 nomerge
835 forcesac
836 soft
837
838
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700839 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
840 off
841 Disable intel iommu driver.
842 igfx_off [Default Off]
843 By default, gfx is mapped as normal device. If a gfx
844 device has a dedicated DMAR unit, the DMAR unit is
845 bypassed by not enabling DMAR with this option. In
846 this case, gfx device will use physical address for
847 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700848 forcedac [x86_64]
849 With this option iommu will not optimize to look
850 for io virtual address below 32 bit forcing dual
851 address cycle on pci bus for cards supporting greater
852 than 32 bit addressing. The default is to look
853 for translation below 32 bit and if not available
854 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800855 strict [Default Off]
856 With this option on every unmap_single operation will
857 result in a hardware IOTLB flush operation as opposed
858 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700859
Rene Hermanb02aae92008-01-30 13:30:05 +0100860 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100861 0x80
862 Standard port 0x80 based delay
863 0xed
864 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100865 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100866 Simple two microseconds delay
867 none
868 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100869
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 io7= [HW] IO7 for Marvel based alpha systems
871 See comment before marvel_specify_io7 in
872 arch/alpha/kernel/core_marvel.c.
873
874 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400875 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876
877 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700878 See comment before ip2_setup() in
879 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880
881 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
882 See header of drivers/scsi/ips.c.
883
Simon Horman72c4a132006-09-13 19:57:18 -0700884 ports= [IP_VS_FTP] IPVS ftp helper module
885 Default is 21.
886 Up to 8 (IP_VS_APP_MAX_PORTS) ports
887 may be specified.
888 Format: <port>,<port>....
889
Alan Cox200803d2005-06-28 20:45:18 -0700890 irqfixup [HW]
891 When an interrupt is not handled search all handlers
892 for it. Intended to get systems with badly broken
893 firmware running.
894
895 irqpoll [HW]
896 When an interrupt is not handled search all handlers
897 for it. Also check all handlers each timer
898 interrupt. Intended to get systems with badly broken
899 firmware running.
900
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700902 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
904 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800905 Format:
906 <cpu number>,...,<cpu number>
907 or
908 <cpu number>-<cpu number> (must be a positive range in ascending order)
909 or a mixture
910 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 This option can be used to specify one or more CPUs
912 to isolate from the general SMP balancing and scheduling
913 algorithms. The only way to move a process onto or off
914 an "isolated" CPU is via the CPU affinity syscalls.
915 <cpu number> begins at 0 and the maximum value is
916 "number of CPUs in system - 1".
917
918 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700919 alternative -- manually setting the CPU mask of all
920 tasks in the system -- can cause problems and
921 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922
Randy Dunlapa9913042005-10-23 12:57:11 -0700923 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
925 js= [HW,JOY] Analog joystick
926 See Documentation/input/joystick.txt.
927
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700928 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700929 specifies the amount of memory usable by the kernel
930 for non-movable allocations. The requested amount is
931 spread evenly throughout all nodes in the system. The
932 remaining memory in each node is used for Movable
933 pages. In the event, a node is too small to have both
934 kernelcore and Movable pages, kernelcore pages will
935 take priority and other nodes will have a larger number
936 of kernelcore pages. The Movable zone is used for the
937 allocation of pages that may be reclaimed or moved
938 by the page migration subsystem. This means that
939 HugeTLB pages may not be allocated from this zone.
940 Note that allocations like PTEs-from-HighMem still
941 use the HighMem zone if it exists, and the Normal
942 zone if it does not.
943
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700944 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -0700945 is similar to kernelcore except it specifies the
946 amount of memory used for migratable allocations.
947 If both kernelcore and movablecore is specified,
948 then kernelcore will be at *least* the specified
949 value but may be more. If movablecore on its own
950 is specified, the administrator must be careful
951 that the amount of memory usable for all allocations
952 is not too small.
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 keepinitrd [HW,ARM]
955
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700956 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 in oops dumps.
958
Jason Wessel6cdf6e02008-04-17 20:05:38 +0200959 kgdboc= [HW] kgdb over consoles.
960 Requires a tty driver that supports console polling.
961 (only serial suported for now)
962 Format: <serial_device>[,baud]
963
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 l2cr= [PPC]
965
Robert Brosea78bfbf2008-03-29 07:20:23 +1100966 l3cr= [PPC]
967
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700968 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -0700969 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700971 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +0100972 C2 power state.
973
FD Camifcb71f62008-01-06 19:08:56 +0100974 libata.dma= [LIBATA] DMA control
975 libata.dma=0 Disable all PATA and SATA DMA
976 libata.dma=1 PATA and SATA Disk DMA only
977 libata.dma=2 ATAPI (CDROM) DMA only
978 libata.dma=4 Compact Flash DMA only
979 Combinations also work, so libata.dma=3 enables DMA
980 for disks and CDROMs, but not CFs.
981
Dave Jones78e70c22007-09-27 11:50:13 -0400982 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
983 when set.
984 Format: <int>
985
Tejun Heo33267322008-02-13 09:15:09 +0900986 libata.force= [LIBATA] Force configurations. The format is comma
987 separated list of "[ID:]VAL" where ID is
988 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
989 matching port, link or device. Basically, it matches
990 the ATA ID string printed on console by libata. If
991 the whole ID part is omitted, the last PORT and DEVICE
992 values are used. If ID hasn't been specified yet, the
993 configuration applies to all ports, links and devices.
994
995 If only DEVICE is omitted, the parameter applies to
996 the port and all links and devices behind it. DEVICE
997 number of 0 either selects the first device or the
998 first fan-out link behind PMP device. It does not
999 select the host link. DEVICE number of 15 selects the
1000 host link and device attached to it.
1001
1002 The VAL specifies the configuration to force. As long
1003 as there's no ambiguity shortcut notation is allowed.
1004 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1005 The following configurations can be forced.
1006
1007 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1008 Any ID with matching PORT is used.
1009
1010 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1011
1012 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1013 udma[/][16,25,33,44,66,100,133] notation is also
1014 allowed.
1015
1016 * [no]ncq: Turn on or off NCQ.
1017
1018 If there are multiple matching configurations changing
1019 the same attribute, the last one is used.
1020
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 load_ramdisk= [RAM] List of ramdisks to load from floppy
1022 See Documentation/ramdisk.txt.
1023
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001024 lockd.nlm_grace_period=P [NFS] Assign grace period.
1025 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001027 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1028 Format: <integer>
1029
1030 lockd.nlm_timeout=T [NFS] Assign timeout value.
1031 Format: <integer>
1032
1033 lockd.nlm_udpport=M [NFS] Assign UDP port.
1034 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035
1036 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1037 Format: <irq>
1038
1039 loglevel= All Kernel Messages with a loglevel smaller than the
1040 console loglevel will be printed to the console. It can
1041 also be changed with klogd or other programs. The
1042 loglevels are defined as follows:
1043
1044 0 (KERN_EMERG) system is unusable
1045 1 (KERN_ALERT) action must be taken immediately
1046 2 (KERN_CRIT) critical conditions
1047 3 (KERN_ERR) error conditions
1048 4 (KERN_WARNING) warning conditions
1049 5 (KERN_NOTICE) normal but significant condition
1050 6 (KERN_INFO) informational
1051 7 (KERN_DEBUG) debug-level messages
1052
1053 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001054 Format: { n | nk | nM }
1055 n must be a power of two. The default size
1056 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057
Randy Dunlapaccaa242007-10-16 01:29:37 -07001058 logo.nologo [FB] Disables display of the built-in Linux logo.
1059 This may be used to provide more screen space for
1060 kernel log messages and is useful when debugging
1061 kernel boot problems.
1062
Linus Torvalds1da177e2005-04-16 15:20:36 -07001063 lp=0 [LP] Specify parallel ports to use, e.g,
1064 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1065 lp=reset first parallel port). 'lp=0' disables the
1066 lp=auto printer driver. 'lp=reset' (which can be
1067 specified in addition to the ports) causes
1068 attached printers to be reset. Using
1069 lp=port1,port2,... specifies the parallel ports
1070 to associate lp devices with, starting with
1071 lp0. A port specification may be 'none' to skip
1072 that lp device, or a parport name such as
1073 'parport0'. Specifying 'lp=auto' instead of a
1074 port specification list means that device IDs
1075 from each port should be examined, to see if
1076 an IEEE 1284-compliant printer is attached; if
1077 so, the driver will manage that printer.
1078 See also header of drivers/char/lp.c.
1079
1080 lpj=n [KNL]
1081 Sets loops_per_jiffy to given constant, thus avoiding
1082 time-consuming boot-time autodetection (up to 250 ms per
1083 CPU). 0 enables autodetection (default). To determine
1084 the correct value for your kernel, boot with normal
1085 autodetection and see what value is printed. Note that
1086 on SMP systems the preset will be applied to all CPUs,
1087 which is likely to cause problems if your CPUs need
1088 significantly divergent settings. An incorrect value
1089 will cause delays in the kernel to be wrong, leading to
1090 unpredictable I/O errors and other breakage. Although
1091 unlikely, in the extreme case this might damage your
1092 hardware.
1093
1094 ltpc= [NET]
1095 Format: <io>,<irq>,<dma>
1096
Randy Dunlapa9913042005-10-23 12:57:11 -07001097 mac5380= [HW,SCSI] Format:
1098 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099
Randy Dunlapa9913042005-10-23 12:57:11 -07001100 machvec= [IA64] Force the use of a particular machine-vector
1101 (machvec) in a generic kernel.
1102 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103
Randy Dunlapa9913042005-10-23 12:57:11 -07001104 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 be mounted
1106 Format: <1-256>
1107
1108 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001109 should make use of. maxcpus=n : n >= 0 limits the
1110 kernel to using 'n' processors. n=0 is a special case,
1111 it is equivalent to "nosmp", which also disables
1112 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113
Bob Picco2b2c3752005-06-29 18:00:00 -07001114 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1115 equal to this physical address is ignored.
1116
Randy Dunlapa9913042005-10-23 12:57:11 -07001117 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 Should be between 1 and 2^32-1.
1119
1120 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001121 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 Should be between 1 and 16384.
1123
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124 mcatest= [IA-64]
1125
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001126 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127
Andi Kleen909dd322007-10-17 18:04:38 +02001128 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1129
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 md= [HW] RAID subsystems devices and level
1131 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001132
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 mdacon= [MDA]
1134 Format: <first>,<last>
1135 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001136
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1138 Amount of memory to be used when the kernel is not able
1139 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001140 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 address space collisions. Without memmap= PCI devices
1142 could be placed at addresses belonging to unused RAM.
1143
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001144 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 memory.
1146
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001147 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 E820 memory map, as specified by the user.
1149 Such memmap=exactmap lines can be constructed based on
1150 BIOS output or other requirements. See the memmap=nn@ss
1151 option description.
1152
1153 memmap=nn[KMG]@ss[KMG]
1154 [KNL] Force usage of a specific region of memory
1155 Region of memory to be used, from ss to ss+nn.
1156
1157 memmap=nn[KMG]#ss[KMG]
1158 [KNL,ACPI] Mark specific memory as ACPI data.
1159 Region of memory to be used, from ss to ss+nn.
1160
1161 memmap=nn[KMG]$ss[KMG]
1162 [KNL,ACPI] Mark specific memory as reserved.
1163 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001164 Example: Exclude memory from 0x18690000-0x1869ffff
1165 memmap=64K$0x18690000
1166 or
1167 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168
Yinghai Luc64df702008-03-21 18:56:19 -07001169 memtest= [KNL,X86_64] Enable memtest
1170 Format: <integer>
1171 range: 0,4 : pattern number
1172 default : 0 <disable>
1173
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 meye.*= [HW] Set MotionEye Camera parameters
1175 See Documentation/video4linux/meye.txt.
1176
Andres Salomon8f368812007-10-12 23:04:06 +02001177 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1178 Multi-Function General Purpose Timers on AMD Geode
1179 platforms.
1180
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001181 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1182 the BIOS has incorrectly applied a workaround. TinyBIOS
1183 version 0.98 is known to be affected, 0.99 fixes the
1184 problem by letting the user disable the workaround.
1185
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186 mga= [HW,DRM]
1187
1188 mousedev.tap_time=
1189 [MOUSE] Maximum time between finger touching and
1190 leaving touchpad surface for touch to be considered
1191 a tap and be reported as a left button click (for
1192 touchpads working in absolute mode only).
1193 Format: <msecs>
1194 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1195 reporting absolute coordinates, such as tablets
1196 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1197 reporting absolute coordinates, such as tablets
1198
1199 mpu401= [HW,OSS]
1200 Format: <io>,<irq>
1201
1202 MTD_Partition= [MTD]
1203 Format: <name>,<region-number>,<size>,<offset>
1204
Randy Dunlapa9913042005-10-23 12:57:11 -07001205 MTD_Region= [MTD] Format:
1206 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207
1208 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001209 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210
1211 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001212 [HW] Make the MicroTouch USB driver use raw coordinates
1213 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214
1215 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1216
1217 NCR_D700= [HW,SCSI]
1218 See header of drivers/scsi/NCR_D700.c.
1219
1220 ncr5380= [HW,SCSI]
1221
1222 ncr53c400= [HW,SCSI]
1223
1224 ncr53c400a= [HW,SCSI]
1225
1226 ncr53c406a= [HW,SCSI]
1227
1228 ncr53c8xx= [HW,SCSI]
1229
1230 netdev= [NET] Network devices parameters
1231 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1232 Note that mem_start is often overloaded to mean
1233 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001234 This usage is only documented in each driver source
1235 file if at all.
1236
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001238 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239
1240 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001241 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242
Trond Myklebusta72b4422006-01-03 09:55:41 +01001243 nfs.callback_tcpport=
1244 [NFS] set the TCP port on which the NFSv4 callback
1245 channel should listen.
1246
Trond Myklebust58df0952006-01-03 09:55:57 +01001247 nfs.idmap_cache_timeout=
1248 [NFS] set the maximum lifetime for idmapper cache
1249 entries.
1250
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001251 nfs.enable_ino64=
1252 [NFS] enable 64-bit inode numbers.
1253 If zero, the NFS client will fake up a 32-bit inode
1254 number for the readdir() and stat() syscalls instead
1255 of returning the full 64-bit number.
1256 The default is to return 64-bit inode numbers.
1257
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001258 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1259 when a NMI is triggered.
1260 Format: [state][,regs][,debounce][,die]
1261
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001262 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001264 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 emulation library even if a 387 maths coprocessor
1266 is present.
1267
Christoph Lameterc1aee212007-05-31 00:40:47 -07001268 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1269 caches in the slab allocator. Saves per-node memory,
1270 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001271
Randy Dunlapa9913042005-10-23 12:57:11 -07001272 noalign [KNL,ARM]
1273
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 noapic [SMP,APIC] Tells the kernel to not make use of any
1275 IOAPICs that may be present in the system.
1276
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 nobats [PPC] Do not use BATs for mapping kernel lowmem
1278 on "Classic" PPC cores.
1279
1280 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001281
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001282 nodelayacct [KNL] Disable per-task delay accounting
1283
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1285
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001286 noefi [X86-32,X86-64] Disable EFI runtime services support.
1287
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 noexec [IA-64]
1289
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001290 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001291 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001293 noexec=off: disable non-executable mappings
1294
1295 noexec32 [X86-64]
1296 This affects only 32-bit executables.
1297 noexec32=on: enable non-executable mappings (default)
1298 read doesn't imply executable mappings
1299 noexec32=off: disable non-executable mappings
1300 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001302 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001303 register save and restore. The kernel will only save
1304 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305
Andi Kleen191679f2008-01-30 13:33:21 +01001306 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1307
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001309
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001310 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 instruction doesn't work correctly and not to
1312 use it.
1313
1314 nohalt [IA-64] Tells the kernel not to use the power saving
1315 function PAL_HALT_LIGHT when idle. This increases
1316 power-consumption. On the positive side, it reduces
1317 interrupt wake-up latency, which may improve performance
1318 in certain environments such as networked servers or
1319 real-time systems.
1320
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001321 nohz= [KNL] Boottime enable/disable dynamic ticks
1322 Valid arguments: on, off
1323 Default: on
1324
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001325 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001326
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001327 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 disable unhandled interrupt sources.
1329
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001330 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001331 broken timer IRQ sources.
1332
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 noisapnp [ISAPNP] Disables ISA PnP code.
1334
1335 noinitrd [RAM] Tells the kernel not to load any configured
1336 initial RAM disk.
1337
1338 nointroute [IA-64]
1339
Tony Luck0aa366f2007-07-20 11:22:30 -07001340 nojitter [IA64] Disables jitter checking for ITC timers.
1341
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001342 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001344 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001345
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 noltlbs [PPC] Do not use large page/tlb entries for kernel
1347 lowmem mapping on PPC40x.
1348
Horms312f1f02006-02-22 09:57:55 +09001349 nomca [IA-64] Disable machine check abort handling
1350
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001351 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001352
Andres Salomon83d73842007-10-12 23:04:06 +02001353 nomfgpt [X86-32] Disable Multi-Function General Purpose
1354 Timer usage (for AMD Geode machines).
1355
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001356 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001357
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001358 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001359 with UP alternatives
1360
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 noresidual [PPC] Don't use residual data on PReP machines.
1362
Randy Dunlapa9913042005-10-23 12:57:11 -07001363 noresume [SWSUSP] Disables resume and restores original swap
1364 space.
1365
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 no-scroll [VGA] Disables scrollback.
1367 This is required for the Braillex ib80-piezo Braille
1368 reader made by F.H. Papenmeier (Germany).
1369
1370 nosbagart [IA-64]
1371
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001372 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001373
Len Brown61ec7562007-08-16 03:34:22 -04001374 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1375 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376
Dave Jones97842212007-07-15 23:41:05 -07001377 nosoftlockup [KNL] Disable the soft-lockup detector.
1378
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379 nosync [HW,M68K] Disables sync negotiation for all devices.
1380
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001381 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382
1383 nousb [USB] Disable the USB subsystem
1384
1385 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001386
Fenghua Yua6c75b862008-03-14 13:57:08 -07001387 nptcg= [IA64] Override max number of concurrent global TLB
1388 purges which is reported from either PAL_VM_SUMMARY or
1389 SAL PALO.
1390
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001391 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1392 one of ['zone', 'node', 'default'] can be specified
1393 This can be set from sysctl after boot.
1394 See Documentation/sysctl/vm.txt for details.
1395
Dave Jonesa61c2d72006-01-07 23:18:19 +00001396 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1397
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001398 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1399 Rather than timing out after 20 ms if an EC
1400 command is not properly ACKed, override the length
1401 of the timeout. We have interrupts disabled while
1402 waiting for the ACK, so if this is set too high
1403 interrupts *may* be lost!
1404
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 opl3= [HW,OSS]
1406 Format: <io>
1407
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 oprofile.timer= [HW]
1409 Use timer interrupt instead of performance counters
1410
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 osst= [HW,SCSI] SCSI Tape Driver
1412 Format: <buffer_size>,<write_threshold>
1413 See also Documentation/scsi/st.txt.
1414
1415 panic= [KNL] Kernel behaviour on panic
1416 Format: <timeout>
1417
1418 parkbd.port= [HW] Parallel port number the keyboard adapter is
1419 connected to, default is 0.
1420 Format: <parport#>
1421 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1422 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001423 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424
Randy Dunlapa9913042005-10-23 12:57:11 -07001425 parport= [HW,PPT] Specify parallel ports. 0 disables.
1426 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1427 Use 'auto' to force the driver to use any
1428 IRQ/DMA settings detected (the default is to
1429 ignore detected IRQ/DMA settings because of
1430 possible conflicts). You can specify the base
1431 address, IRQ, and DMA settings; IRQ and DMA
1432 should be numbers, or 'auto' (for using detected
1433 settings on that particular port), or 'nofifo'
1434 (to avoid using a FIFO even if it is detected).
1435 Parallel ports are assigned in the order they
1436 are specified on the command line, starting
1437 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438
Randy Dunlapa9913042005-10-23 12:57:11 -07001439 parport_init_mode= [HW,PPT]
1440 Configure VIA parallel port to operate in
1441 a specific mode. This is necessary on Pegasos
1442 computer where firmware has no options for setting
1443 up parallel port mode and sets it to spp.
1444 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445 Format: [spp|ps2|epp|ecp|ecpepp]
1446
Randy Dunlapa9913042005-10-23 12:57:11 -07001447 pas2= [HW,OSS] Format:
1448 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1449
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450 pas16= [HW,SCSI]
1451 See header of drivers/scsi/pas16.c.
1452
Andrew Mortondd287792006-03-23 03:00:57 -08001453 pause_on_oops=
1454 Halt all CPUs after the first oops has been printed for
1455 the specified number of seconds. This is to be used if
1456 your oopses keep scrolling off the screen.
1457
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 pcbit= [HW,ISDN]
1459
1460 pcd. [PARIDE]
1461 See header of drivers/block/paride/pcd.c.
1462 See also Documentation/paride.txt.
1463
Randy Dunlapa9913042005-10-23 12:57:11 -07001464 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001465 off [X86-32] don't probe for the PCI bus
1466 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001467 the hardware directly. Use this if your machine
1468 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001469 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001470 hardware access methods are allowed. Use this
1471 if you experience crashes upon bootup and you
1472 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001473 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001474 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001475 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001476 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001477 noaer [PCIE] If the PCIEAER kernel config parameter is
1478 enabled, this kernel boot option can be used to
1479 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001480 nodomains [PCI] Disable support for multiple PCI
1481 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001482 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001483 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001484 nomsi [MSI] If the PCI_MSI kernel config parameter is
1485 enabled, this kernel boot option can be used to
1486 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001487 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001488 routing table. These calls are known to be buggy
1489 on several machines and they hang the machine
1490 when used, but on other computers it's the only
1491 way to get the interrupt routing table. Try
1492 this option if the kernel is unable to allocate
1493 IRQs or discover secondary PCI buses on your
1494 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001495 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001496 Use with caution as certain devices share
1497 address decoders between ROMs and other
1498 resources.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001499 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001500 assigned automatically to PCI devices. You can
1501 make the kernel exclude IRQs of your ISA cards
1502 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001503 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001504 of the PIRQ table (normally generated
1505 by the BIOS) if it is outside the
1506 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001507 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001508 useful if the kernel is unable to find your
1509 secondary buses and you want to tell it
1510 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001511 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001512 numbers ourselves, overriding
1513 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001514 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001515 in the BIOS $PIR table. This is needed on
1516 some systems with broken BIOSes, notably
1517 some HP Pavilion N5400 and Omnibook XE3
1518 notebooks. This will have no effect if ACPI
1519 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001520 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001521 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001522 use_crs [X86-32] Use _CRS for PCI resource
1523 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001524 routeirq Do IRQ routing for all PCI devices.
1525 This is normally done in pci_enable_device(),
1526 so this option is a temporary workaround
1527 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001528 skip_isa_align [X86] do not align io start addr, so can
1529 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001530 firmware [ARM] Do not re-enumerate the bus but instead
1531 just use the configuration from the
1532 bootloader. This is currently used on
1533 IXP2000 systems where the bus has to be
1534 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001535 noearly [X86] Don't do any early type 1 scanning.
1536 This might help on some broken boards which
1537 machine check when some devices' config space
1538 is read. But various workarounds are disabled
1539 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001540 bfsort Sort PCI devices into breadth-first order.
1541 This sorting is done to get a device
1542 order compatible with older (<= 2.4) kernels.
1543 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001544 cbiosize=nn[KMG] The fixed amount of bus space which is
1545 reserved for the CardBus bridge's IO window.
1546 The default value is 256 bytes.
1547 cbmemsize=nn[KMG] The fixed amount of bus space which is
1548 reserved for the CardBus bridge's memory
1549 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001550
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 pcmv= [HW,PCMCIA] BadgePAD 4
1552
1553 pd. [PARIDE]
1554 See Documentation/paride.txt.
1555
1556 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1557 boot time.
1558 Format: { 0 | 1 }
1559 See arch/parisc/kernel/pdc_chassis.c
1560
1561 pf. [PARIDE]
1562 See Documentation/paride.txt.
1563
1564 pg. [PARIDE]
1565 See Documentation/paride.txt.
1566
1567 pirq= [SMP,APIC] Manual mp-table setup
1568 See Documentation/i386/IO-APIC.txt.
1569
1570 plip= [PPT,NET] Parallel port network link
1571 Format: { parport<nr> | timid | 0 }
1572 See also Documentation/parport.txt.
1573
1574 pnpacpi= [ACPI]
1575 { off }
1576
1577 pnpbios= [ISAPNP]
1578 { on | off | curr | res | no-curr | no-res }
1579
1580 pnp_reserve_irq=
1581 [ISAPNP] Exclude IRQs for the autoconfiguration
1582
1583 pnp_reserve_dma=
1584 [ISAPNP] Exclude DMAs for the autoconfiguration
1585
1586 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001587 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588
1589 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001590 [ISAPNP] Exclude memory regions for the
1591 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001592 Ranges are in pairs (memory base and size).
1593
Ingo Molnar45807a12007-07-15 23:40:10 -07001594 print-fatal-signals=
1595 [KNL] debug: print fatal signals
1596 print-fatal-signals=1: print segfault info to
1597 the kernel console.
1598 default: off.
1599
Randy Dunlape84845c2007-07-15 23:40:25 -07001600 printk.time= Show timing data prefixed to each printk message line
1601 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1602
Linus Torvalds1da177e2005-04-16 15:20:36 -07001603 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001604 Format: [schedule,]<number>
1605 Param: "schedule" - profile schedule points.
1606 Param: <number> - step/bucket size as a power of 2 for
1607 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001608 Param: "sleep" - profile D-state sleeping (millisecs).
1609 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001610 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611
Randy Dunlapa9913042005-10-23 12:57:11 -07001612 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613 Limit processor to maximum C-state
1614 max_cstate=9 overrides any DMI blacklist limit.
1615
Len Brown41c0d862005-12-28 12:43:51 -05001616 processor.nocst [HW,ACPI]
1617 Ignore the _CST method to determine C-states,
1618 instead using the legacy FADT method
1619
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1621 before loading.
1622 See Documentation/ramdisk.txt.
1623
Randy Dunlapa9913042005-10-23 12:57:11 -07001624 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1625 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1627 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001628 psmouse.resetafter= [HW,MOUSE]
1629 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630 (0 = never).
1631 psmouse.resolution=
1632 [HW,MOUSE] Set desired mouse resolution, in dpi.
1633 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001634 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001635 0 = disabled, 1 = enabled (default).
1636
1637 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001638 Format:
1639 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640
1641 pt. [PARIDE]
1642 See Documentation/paride.txt.
1643
Kay Sieversdc8c8582007-08-15 12:25:38 +02001644 pty.legacy_count=
1645 [KNL] Number of legacy pty's. Overwrites compiled-in
1646 default number.
1647
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001648 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001649
Linus Torvalds1da177e2005-04-16 15:20:36 -07001650 r128= [HW,DRM]
1651
1652 raid= [HW,RAID]
1653 See Documentation/md.txt.
1654
Randy Dunlapa9913042005-10-23 12:57:11 -07001655 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001657
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 See Documentation/ramdisk.txt.
1660
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001661 rcupdate.blimit= [KNL,BOOT]
1662 Set maximum number of finished RCU callbacks to process
1663 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001664
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001665 rcupdate.qhimark= [KNL,BOOT]
1666 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001667 RCU callbacks over which batch limiting is disabled.
1668
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001669 rcupdate.qlowmark= [KNL,BOOT]
1670 Set threshold of queued RCU callbacks below which
1671 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001672
Olof Johanssonffdfc402005-09-06 15:17:19 -07001673 rdinit= [KNL]
1674 Format: <full_path>
1675 Run specified binary instead of /init from the ramdisk,
1676 used for early userspace startup. See initrd.
1677
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001678 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001680 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681
1682 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1683
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001684 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001685 Format: nn[KMG]
1686 Reserves a hole at the top of the kernel virtual
1687 address space.
1688
Vivek Goyal7e962872006-09-27 01:50:44 -07001689 reset_devices [KNL] Force drivers to reset the underlying device
1690 during initialization.
1691
Randy Dunlapa9913042005-10-23 12:57:11 -07001692 resume= [SWSUSP]
1693 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001695 resume_offset= [SWSUSP]
1696 Specify the offset from the beginning of the partition
1697 given by "resume=" at which the swap header is located,
1698 in <PAGE_SIZE> units (needed only for swap files).
1699 See Documentation/power/swsusp-and-swap-files.txt
1700
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001701 retain_initrd [RAM] Keep initrd memory after extraction
1702
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 rhash_entries= [KNL,NET]
1704 Set number of hash buckets for route cache
1705
1706 riscom8= [HW,SERIAL]
1707 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1708
1709 ro [KNL] Mount root device read-only on boot
1710
1711 root= [KNL] Root filesystem
1712
1713 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1714 mount the root filesystem
1715
1716 rootflags= [KNL] Set root filesystem mount option string
1717
1718 rootfstype= [KNL] Set root filesystem type
1719
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001720 rootwait [KNL] Wait (indefinitely) for root device to show up.
1721 Useful for devices that are detected asynchronously
1722 (e.g. USB and MMC devices).
1723
James Morris20510f22007-10-16 23:31:32 -07001724 root_plug.vendor_id=
1725 [ROOTPLUG] Override the default vendor ID
1726
1727 root_plug.product_id=
1728 [ROOTPLUG] Override the default product ID
1729
1730 root_plug.debug=
1731 [ROOTPLUG] Enable debugging output
1732
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 rw [KNL] Mount root device read-write on boot
1734
1735 S [KNL] Run init in single mode
1736
1737 sa1100ir [NET]
1738 See drivers/net/irda/sa1100_ir.c.
1739
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001741
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1743 Format: <io>[,<timeout>[,<isapnp>]]
1744
1745 scsi_debug_*= [SCSI]
1746 See drivers/scsi/scsi_debug.c.
1747
1748 scsi_default_dev_flags=
1749 [SCSI] SCSI default device flags
1750 Format: <integer>
1751
1752 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1753 Format: <vendor>:<model>:<flags>
1754 (flags are integer value)
1755
Randy Dunlap6af66322007-11-14 16:52:25 -08001756 scsi_logging_level= [SCSI] a bit mask of logging levels
1757 See drivers/scsi/scsi_logging.h for bits. Also
1758 settable via sysctl at dev.scsi.logging_level
1759 (/proc/sys/dev/scsi/logging_level).
1760 There is also a nice 'scsi_logging_level' script in the
1761 S390-tools package, available for download at
1762 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001764 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1765 discovered. async scans them in kernel threads,
1766 allowing boot to proceed. none ignores them, expecting
1767 user space to do the scan.
1768
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 selinux [SELINUX] Disable or enable SELinux at boot time.
1770 Format: { "0" | "1" }
1771 See security/selinux/Kconfig help text.
1772 0 -- disable.
1773 1 -- enable.
1774 Default value is set via kernel config option.
1775 If enabled at boot time, /selinux/disable can be used
1776 later to disable prior to initial policy load.
1777
James Morris4e5ab4c2006-06-09 00:33:33 -07001778 selinux_compat_net =
1779 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001780 Format: { "0" | "1" }
1781 0 -- use new secmark-based packet controls
1782 1 -- use legacy packet controls
1783 Default value is 0 (preferred).
1784 Value can be changed at runtime via
1785 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001786
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001787 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 shapers= [NET]
1790 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001791
Linus Torvalds1da177e2005-04-16 15:20:36 -07001792 sim710= [SCSI,HW]
1793 See header of drivers/scsi/sim710.c.
1794
1795 simeth= [IA-64]
1796 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001797
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798 slram= [HW,MTD]
1799
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001800 slub_debug[=options[,slabs]] [MM, SLUB]
1801 Enabling slub_debug allows one to determine the
1802 culprit if slab objects become corrupted. Enabling
1803 slub_debug can create guard zones around objects and
1804 may poison objects when not in use. Also tracks the
1805 last alloc / free. For more information see
1806 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001807
1808 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001809 Determines the maximum allowed order for slabs.
1810 A high setting may cause OOMs due to memory
1811 fragmentation. For more information see
1812 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001813
1814 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001815 The minimum number of objects per slab. SLUB will
1816 increase the slab order up to slub_max_order to
1817 generate a sufficiently large slab able to contain
1818 the number of objects indicated. The higher the number
1819 of objects the smaller the overhead of tracking slabs
1820 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001821 For more information see Documentation/vm/slub.txt.
1822
1823 slub_min_order= [MM, SLUB]
1824 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001825 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001826 For more information see Documentation/vm/slub.txt.
1827
1828 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001829 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001830 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001831 allocs to different slabs. Debug options disable
1832 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001833 For more information see Documentation/vm/slub.txt.
1834
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835 smart2= [HW]
1836 Format: <io1>[,<io2>[,...,<io8>]]
1837
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001838 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001839 attempt to substitute SMP alternatives once at boot.
1840
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001841 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1842 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1843 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1844 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1845 smsc-ircc2.ircc_irq= [HW] IRQ line
1846 smsc-ircc2.ircc_dma= [HW] DMA channel
1847 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1848 0: Toshiba Satellite 1800 (GP data pin select)
1849 1: Fast pin select (default)
1850 2: ATC IRMode
1851
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852 snd-ad1816a= [HW,ALSA]
1853
1854 snd-ad1848= [HW,ALSA]
1855
1856 snd-ali5451= [HW,ALSA]
1857
1858 snd-als100= [HW,ALSA]
1859
1860 snd-als4000= [HW,ALSA]
1861
1862 snd-azt2320= [HW,ALSA]
1863
1864 snd-cmi8330= [HW,ALSA]
1865
1866 snd-cmipci= [HW,ALSA]
1867
1868 snd-cs4231= [HW,ALSA]
1869
1870 snd-cs4232= [HW,ALSA]
1871
1872 snd-cs4236= [HW,ALSA]
1873
1874 snd-cs4281= [HW,ALSA]
1875
1876 snd-cs46xx= [HW,ALSA]
1877
1878 snd-dt019x= [HW,ALSA]
1879
1880 snd-dummy= [HW,ALSA]
1881
1882 snd-emu10k1= [HW,ALSA]
1883
1884 snd-ens1370= [HW,ALSA]
1885
1886 snd-ens1371= [HW,ALSA]
1887
1888 snd-es968= [HW,ALSA]
1889
1890 snd-es1688= [HW,ALSA]
1891
1892 snd-es18xx= [HW,ALSA]
1893
1894 snd-es1938= [HW,ALSA]
1895
1896 snd-es1968= [HW,ALSA]
1897
1898 snd-fm801= [HW,ALSA]
1899
1900 snd-gusclassic= [HW,ALSA]
1901
1902 snd-gusextreme= [HW,ALSA]
1903
1904 snd-gusmax= [HW,ALSA]
1905
1906 snd-hdsp= [HW,ALSA]
1907
1908 snd-ice1712= [HW,ALSA]
1909
1910 snd-intel8x0= [HW,ALSA]
1911
1912 snd-interwave= [HW,ALSA]
1913
1914 snd-interwave-stb=
1915 [HW,ALSA]
1916
1917 snd-korg1212= [HW,ALSA]
1918
1919 snd-maestro3= [HW,ALSA]
1920
1921 snd-mpu401= [HW,ALSA]
1922
1923 snd-mtpav= [HW,ALSA]
1924
1925 snd-nm256= [HW,ALSA]
1926
1927 snd-opl3sa2= [HW,ALSA]
1928
1929 snd-opti92x-ad1848=
1930 [HW,ALSA]
1931
1932 snd-opti92x-cs4231=
1933 [HW,ALSA]
1934
1935 snd-opti93x= [HW,ALSA]
1936
1937 snd-pmac= [HW,ALSA]
1938
1939 snd-rme32= [HW,ALSA]
1940
1941 snd-rme96= [HW,ALSA]
1942
1943 snd-rme9652= [HW,ALSA]
1944
1945 snd-sb8= [HW,ALSA]
1946
1947 snd-sb16= [HW,ALSA]
1948
1949 snd-sbawe= [HW,ALSA]
1950
1951 snd-serial= [HW,ALSA]
1952
1953 snd-sgalaxy= [HW,ALSA]
1954
1955 snd-sonicvibes= [HW,ALSA]
1956
1957 snd-sun-amd7930=
1958 [HW,ALSA]
1959
1960 snd-sun-cs4231= [HW,ALSA]
1961
1962 snd-trident= [HW,ALSA]
1963
1964 snd-usb-audio= [HW,ALSA,USB]
1965
1966 snd-via82xx= [HW,ALSA]
1967
1968 snd-virmidi= [HW,ALSA]
1969
1970 snd-wavefront= [HW,ALSA]
1971
1972 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001973
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1975 See Documentation/sonypi.txt
1976
1977 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1978 See Documentation/specialix.txt.
1979
1980 spia_io_base= [HW,MTD]
1981 spia_fio_base=
1982 spia_pedr=
1983 spia_peddr=
1984
1985 sscape= [HW,OSS]
1986 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07001987
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1989 See Documentation/scsi/st.txt.
1990
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991 sti= [PARISC,HW]
1992 Format: <num>
1993 Set the STI (builtin display/keyboard on the HP-PARISC
1994 machines) console (graphic card) which should be used
1995 as the initial boot-console.
1996 See also comment in drivers/video/console/sticore.c.
1997
1998 sti_font= [HW]
1999 See comment in drivers/video/console/sticore.c.
2000
2001 stifb= [HW]
2002 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2003
Greg Banks42a7fc42007-03-06 01:42:23 -08002004 sunrpc.pool_mode=
2005 [NFS]
2006 Control how the NFS server code allocates CPUs to
2007 service thread pools. Depending on how many NICs
2008 you have and where their interrupts are bound, this
2009 option will affect which CPUs will do NFS serving.
2010 Note: this parameter cannot be changed while the
2011 NFS server is running.
2012
2013 auto the server chooses an appropriate mode
2014 automatically using heuristics
2015 global a single global pool contains all CPUs
2016 percpu one pool for each CPU
2017 pernode one pool for each NUMA node (equivalent
2018 to global on non-NUMA machines)
2019
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002021
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022 switches= [HW,M68k]
2023
2024 sym53c416= [HW,SCSI]
2025 See header of drivers/scsi/sym53c416.c.
2026
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002027 sysrq_always_enabled
2028 [KNL]
2029 Ignore sysrq setting - this boot parameter will
2030 neutralize any effect of /proc/sys/kernel/sysrq.
2031 Useful for debugging.
2032
Linus Torvalds1da177e2005-04-16 15:20:36 -07002033 t128= [HW,SCSI]
2034 See header of drivers/scsi/t128.c.
2035
2036 tdfx= [HW,DRM]
2037
2038 thash_entries= [KNL,NET]
2039 Set number of hash buckets for TCP connection
2040
Len Brownf8707ec2007-08-12 00:12:54 -04002041 thermal.act= [HW,ACPI]
2042 -1: disable all active trip points in all thermal zones
2043 <degrees C>: override all lowest active trip points
2044
Len Brownc52a7412007-08-14 15:49:32 -04002045 thermal.crt= [HW,ACPI]
2046 -1: disable all critical trip points in all thermal zones
2047 <degrees C>: lower all critical trip points
2048
Len Brownf5487142007-08-12 00:12:44 -04002049 thermal.nocrt= [HW,ACPI]
2050 Set to disable actions on ACPI thermal zone
2051 critical and hot trip points.
2052
Len Brown72b33ef2007-08-12 00:12:17 -04002053 thermal.off= [HW,ACPI]
2054 1: disable ACPI thermal control
2055
Len Browna70cdc52007-08-12 00:12:35 -04002056 thermal.psv= [HW,ACPI]
2057 -1: disable all passive trip points
2058 <degrees C>: override all passive trip points to this value
2059
Len Brown730ff342007-08-12 00:12:26 -04002060 thermal.tzp= [HW,ACPI]
2061 Specify global default ACPI thermal zone polling rate
2062 <deci-seconds>: poll all this frequency
2063 0: no polling (default)
2064
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 tipar.timeout= [HW,PPT]
2066 Set communications timeout in tenths of a second
2067 (default 15).
2068
2069 tipar.delay= [HW,PPT]
2070 Set inter-bit delay in microseconds (default 10).
2071
Linus Torvalds1da177e2005-04-16 15:20:36 -07002072 tmscsim= [HW,SCSI]
2073 See comment before function dc390_setup() in
2074 drivers/scsi/tmscsim.c.
2075
2076 tp720= [HW,PS2]
2077
2078 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002079 Format:
2080 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2081
Randy Dunlapa9913042005-10-23 12:57:11 -07002082 turbografx.map[2|3]= [HW,JOY]
2083 TurboGraFX parallel port interface
2084 Format:
2085 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002086 See also Documentation/input/joystick-parport.txt
2087
2088 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2089 See header of drivers/scsi/u14-34f.c.
2090
2091 uart401= [HW,OSS]
2092 Format: <io>,<irq>
2093
2094 uart6850= [HW,OSS]
2095 Format: <io>,<irq>
2096
Alan Stern5f8364b2006-12-05 16:29:55 -05002097 uhci-hcd.ignore_oc=
2098 [USB] Ignore overcurrent events (default N).
2099 Some badly-designed motherboards generate lots of
2100 bogus events, for ports that aren't wired to
2101 anything. Set this parameter to avoid log spamming.
2102 Note that genuine overcurrent events won't be
2103 reported either.
2104
Alan Sternb5e795f2007-02-20 15:00:53 -05002105 usbcore.autosuspend=
2106 [USB] The autosuspend time delay (in seconds) used
2107 for newly-detected USB devices (default 2). This
2108 is the time required before an idle device will be
2109 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002110 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002111
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112 usbhid.mousepoll=
2113 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002114
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002115 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002116 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002117 vdso=1: enable VDSO (default)
2118 vdso=0: disable VDSO mapping
2119
Roland McGrathaf65d642008-01-30 13:30:43 +01002120 vdso32= [X86-32,X86-64]
2121 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2122 vdso32=1: enable 32-bit VDSO (default)
2123 vdso32=0: disable 32-bit VDSO mapping
2124
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002125 vector= [IA-64,SMP]
2126 vector=percpu: enable percpu vector domain
2127
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128 video= [FB] Frame buffer configuration
2129 See Documentation/fb/modedb.txt.
2130
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002131 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002132 See Documentation/i386/boot.txt and
2133 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 Use vga=ask for menu.
2135 This is actually a boot loader parameter; the value is
2136 passed to the kernel using a special protocol.
2137
Randy Dunlapa9913042005-10-23 12:57:11 -07002138 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139 size of <nn>. This can be used to increase the
2140 minimum size (128MB on x86). It can also be used to
2141 decrease the size and leave more room for directly
2142 mapped kernel RAM.
2143
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002144 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2145 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002146
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002147 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2148 Format: <command>
2149
2150 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2151 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002152
Linus Torvalds1da177e2005-04-16 15:20:36 -07002153 waveartist= [HW,OSS]
2154 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002155
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 wd33c93= [HW,SCSI]
2157 See header of drivers/scsi/wd33c93.c.
2158
2159 wd7000= [HW,SCSI]
2160 See header of drivers/scsi/wd7000.c.
2161
2162 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002163 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164
2165 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2166 xd_geo= See header of drivers/block/xd.c.
2167
2168 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002169 Format:
2170 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171
Andi Kleena62eaf12006-02-16 23:41:58 +01002172 norandmaps Don't use address space randomization
2173 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2174
Randy Dunlapa9913042005-10-23 12:57:11 -07002175______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002176
2177TODO:
2178
2179 Add documentation for ALSA options.
2180 Add more DRM drivers.