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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
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200150 Format: { s3_bios, s3_mode, s3_beep, old_ordering }
Pavel Machek23b168d2008-02-05 19:27:12 +0100151 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.
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200154 old_ordering causes the ACPI 1.0 ordering of the _PTS
155 control method, wrt putting devices into low power
156 states, to be enforced (the ACPI 2.0 ordering of _PTS is
157 used by default).
Randy Dunlapa9913042005-10-23 12:57:11 -0700158
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700160 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Randy Dunlapa9913042005-10-23 12:57:11 -0700162 acpi_irq_balance [HW,ACPI]
163 ACPI will balance active IRQs
164 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Randy Dunlapa9913042005-10-23 12:57:11 -0700166 acpi_irq_nobalance [HW,ACPI]
167 ACPI will not move active IRQs (default)
168 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
Randy Dunlapa9913042005-10-23 12:57:11 -0700170 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
171 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 Format: <irq>,<irq>...
173
Randy Dunlapa9913042005-10-23 12:57:11 -0700174 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 Format: <irq>,<irq>...
176
Len Brown67effe82007-07-26 00:50:06 -0400177 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
178
Len Browna1f9e652006-01-25 23:47:36 -0500179 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
180 Format: To spoof as Windows 98: ="Microsoft Windows"
181
Len Brownae00d812007-05-29 18:43:33 -0400182 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
183 acpi_osi="string1" # add string1 -- only one string
184 acpi_osi="!string2" # remove built-in string2
185 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
187 acpi_serialize [HW,ACPI] force serialization of AML methods
188
189 acpi_skip_timer_override [HW,ACPI]
190 Recognize and ignore IRQ0/pin2 Interrupt Override.
191 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100192 acpi_use_timer_override [HW,ACPI}
193 Use timer override. For some broken Nvidia NF5 boards
194 that require a timer override, but don't have
195 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
Zhang Ruif9891062007-04-24 13:53:22 +0800197 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700199 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 1: enable, 0: disable. It is useful for boot time
201 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800202 via /sys/module/acpi/parameters/debug_layer.
203 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
204 Available bits (add the numbers together) to enable debug output
205 for specific parts of the ACPI subsystem:
206 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
207 0x10 namespace 0x20 parser 0x40 dispatcher
208 0x80 executer 0x100 resources 0x200 acpica debugger
209 0x400 os services 0x800 acpica disassembler.
210 The number can be in decimal or prefixed with 0x in hex.
211 Warning: Many of these options can produce a lot of
212 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Zhang Ruif9891062007-04-24 13:53:22 +0800214 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700216 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 1: enable, 0: disable. It is useful for boot time
218 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800219 via /sys/module/acpi/parameters/debug_level.
220 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
221 Available bits (add the numbers together) to enable different
222 debug output levels of the ACPI subsystem:
223 0x01 error 0x02 warn 0x04 init 0x08 debug object
224 0x10 info 0x20 init names 0x40 parse 0x80 load
225 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
226 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
227 0x10000 resources 0x20000 user requests 0x40000 package.
228 The number can be in decimal or prefixed with 0x in hex.
229 Warning: Many of these options can produce a lot of
230 output and make your system unusable. Be very careful.
231
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700232 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700233 Override the pmtimer bug detection: force the kernel
234 to assume that this machine's pmtimer latches its value
235 and always returns good values.
236
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000237 agp= [AGP]
238 { off | try_unsupported }
239 off: disable AGP support
240 try_unsupported: try to drive unsupported chipsets
241 (may crash computer or cause data corruption)
242
Chuck Ebbert66759a02005-09-12 18:49:25 +0200243 enable_timer_pin_1 [i386,x86-64]
244 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700245 Can be useful to work around chipset bugs
246 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200247 The kernel tries to set a reasonable default.
248
249 disable_timer_pin_1 [i386,x86-64]
250 Disable PIN 1 of APIC timer
251 Can be useful to work around chipset bugs.
252
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 ad1848= [HW,OSS]
254 Format: <io>,<irq>,<dma>,<dma2>,<type>
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 advansys= [HW,SCSI]
257 See header of drivers/scsi/advansys.c.
258
259 advwdt= [HW,WDT] Advantech WDT
260 Format: <iostart>,<iostop>
261
262 aedsp16= [HW,OSS] Audio Excel DSP 16
263 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
264 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700265
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 aha152x= [HW,SCSI]
267 See Documentation/scsi/aha152x.txt.
268
269 aha1542= [HW,SCSI]
270 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
271
272 aic7xxx= [HW,SCSI]
273 See Documentation/scsi/aic7xxx.txt.
274
275 aic79xx= [HW,SCSI]
276 See Documentation/scsi/aic79xx.txt.
277
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200278 amd_iommu= [HW,X86-84]
279 Pass parameters to the AMD IOMMU driver in the system.
280 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200281 isolate - enable device isolation (each device, as far
282 as possible, will get its own protection
283 domain)
284 amd_iommu_size= [HW,X86-64]
285 Define the size of the aperture for the AMD IOMMU
286 driver. Possible values are:
287 '32M', '64M' (default), '128M', '256M', '512M', '1G'
288
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 amijoy.map= [HW,JOY] Amiga joystick support
290 Map of devices attached to JOY0DAT and JOY1DAT
291 Format: <a>,<b>
292 See also Documentation/kernel/input/joystick.txt
293
294 analog.map= [HW,JOY] Analog joystick and gamepad support
295 Specifies type or capabilities of an analog joystick
296 connected to one of 16 gameports
297 Format: <type1>,<type2>,..<type16>
298
Randy Dunlapa9913042005-10-23 12:57:11 -0700299 apc= [HW,SPARC]
300 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 Format: noidle
302 Disable APC CPU standby support. SPARCstation-Fox does
303 not play well with APC CPU idle - disable it if you have
304 APC and your system crashes randomly.
305
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700306 apic= [APIC,i386] Advanced Programmable Interrupt Controller
307 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 Format: { quiet (default) | verbose | debug }
309 Change the amount of debugging information output
310 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700311
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700313 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
316 Format: <io>,<irq>,<nodeID>
317
318 ataflop= [HW,M68k]
319
320 atarimouse= [HW,MOUSE] Atari Mouse
321
322 atascsi= [HW,SCSI] Atari SCSI
323
324 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
325 EzKey and similar keyboards
326
327 atkbd.reset= [HW] Reset keyboard during initialization
328
Randy Dunlapa9913042005-10-23 12:57:11 -0700329 atkbd.set= [HW] Select keyboard code set
330 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331
332 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
333 keyboards
334
335 atkbd.softraw= [HW] Choose between synthetic and real raw mode
336 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700337
338 atkbd.softrepeat= [HW]
339 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340
341 autotest [IA64]
342
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 baycom_epp= [HW,AX25]
344 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700345
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
347 Format: <io>,<mode>
348 See header of drivers/net/hamradio/baycom_par.c.
349
Randy Dunlapa9913042005-10-23 12:57:11 -0700350 baycom_ser_fdx= [HW,AX25]
351 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 Format: <io>,<irq>,<mode>[,<baud>]
353 See header of drivers/net/hamradio/baycom_ser_fdx.c.
354
Randy Dunlapa9913042005-10-23 12:57:11 -0700355 baycom_ser_hdx= [HW,AX25]
356 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 Format: <io>,<irq>,<mode>
358 See header of drivers/net/hamradio/baycom_ser_hdx.c.
359
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700360 boot_delay= Milliseconds to delay each printk during boot.
361 Values larger than 10 seconds (10000) are changed to
362 no delay (0).
363 Format: integer
364
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700366 bttv.radio= Most important insmod options are available as
367 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
369 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
370
371 BusLogic= [HW,SCSI]
372 See drivers/scsi/BusLogic.c, comment before function
373 BusLogic_ParseDriverOptions().
374
375 c101= [NET] Moxa C101 synchronous serial card
376
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700377 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 Sometimes CPU hardware bugs make them report the cache
379 size incorrectly. The kernel will attempt work arounds
380 to fix known problems, but for some CPUs it is not
381 possible to determine what the correct size should be.
382 This option provides an override for these situations.
383
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200384 security= [SECURITY] Choose a security module to enable at boot.
385 If this boot parameter is not specified, only the first
386 security module asking for security registration will be
387 loaded. An invalid security module name will be treated
388 as if no module has been chosen.
389
James Morris20510f22007-10-16 23:31:32 -0700390 capability.disable=
391 [SECURITY] Disable capabilities. This would normally
392 be used only if an alternative security model is to be
393 configured. Potentially dangerous and should only be
394 used if you are entirely sure of the consequences.
395
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100396 ccw_timeout_log [S390]
397 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398
Paul Menage8bab8dd2008-04-04 14:29:57 -0700399 cgroup_disable= [KNL] Disable a particular controller
400 Format: {name of the controller(s) to disable}
401 {Currently supported controllers - "memory"}
402
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 checkreqprot [SELINUX] Set initial checkreqprot flag value.
404 Format: { "0" | "1" }
405 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700406 0 -- check protection applied by kernel (includes
407 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 1 -- check protection requested by application.
409 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700410 Value can be changed at runtime via
411 /selinux/checkreqprot.
412
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100413 cio_ignore= [S390]
414 See Documentation/s390/CommonIO for details.
415
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700416 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700417 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200418 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700419 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200420 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 Format: { pit | tsc | cyclone | pmtmr }
422
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700423 clocksource= [GENERIC_TIME] Override the default clocksource
424 Format: <string>
425 Override the default clocksource and use the clocksource
426 with the name specified.
427 Some clocksource names to choose from, depending on
428 the platform:
429 [all] jiffies (this is the base, fallback clocksource)
430 [ACPI] acpi_pm
431 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
432 pxa_timer,timer3,32k_counter,timer0_1
433 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700434 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700435 scx200_hrt on Geode; cyclone on IBM x440
436 [MIPS] MIPS
437 [PARISC] cr16
438 [S390] tod
439 [SH] SuperH
440 [SPARC64] tick
441 [X86-64] hpet,tsc
442
Andi Kleenac72e782008-01-30 13:33:21 +0100443 clearcpuid=BITNUM [X86]
444 Disable CPUID feature X for the kernel. See
445 include/asm-x86/cpufeature.h for the valid bit numbers.
446 Note the Linux specific bits are not necessarily
447 stable over kernel options, but the vendor specific
448 ones should be.
449 Also note that user programs calling CPUID directly
450 or using the feature without checking anything
451 will still see it. This just prevents it from
452 being used by the kernel or shown in /proc/cpuinfo.
453 Also note the kernel might malfunction if you disable
454 some critical bits.
455
Arjan van de Vena25bd942008-01-30 13:33:08 +0100456 code_bytes [IA32/X86_64] How many bytes of object code to print
457 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100458 Range: 0 - 8192
459 Default: 64
460
Andi Kleenf9262c12006-03-08 17:57:25 -0800461 disable_8254_timer
462 enable_8254_timer
463 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
464 over the 8254 in addition to over the IO-APIC. The
465 kernel tries to set a sensible default.
466
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200467 hpet= [X86-32,HPET] option to control HPET usage
468 Format: { enable (default) | disable | force }
469 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100470 force: allow force enabled of undocumented chips (ICH4,
471 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700474 Format:
475 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
477 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
478 Format: <io>[,<irq>]
479
Randy Dunlapa9913042005-10-23 12:57:11 -0700480 com90xx= [HW,NET]
481 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 Format: <io>[,<irq>[,<memstart>]]
483
484 condev= [HW,S390] console device
485 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700486
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 console= [KNL] Output console device and options.
488
489 tty<n> Use the virtual console device <n>.
490
491 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800492 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800494 the form "bbbbpnf", where "bbbb" is the baud rate,
495 "p" is parity ("n", "o", or "e"), "n" is number of
496 bits, and "f" is flow control ("r" for RTS or
497 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800499 See Documentation/serial-console.txt for more
500 information. See
501 Documentation/networking/netconsole.txt for an
502 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700504 uart[8250],io,<addr>[,options]
505 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 Start an early, polled-mode console on the 8250/16550
507 UART at the specified I/O port or MMIO address,
508 switching to the matching ttyS device later. The
509 options are the same as for ttyS, above.
510
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700511 If the device connected to the port is not a TTY but a braille
512 device, prepend "brl," before the device type, for instance
513 console=brl,ttyS0
514 For now, only VisioBraille is supported.
515
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700516 earlycon= [KNL] Output early console device and options.
517 uart[8250],io,<addr>[,options]
518 uart[8250],mmio,<addr>[,options]
519 Start an early, polled-mode console on the 8250/16550
520 UART at the specified I/O port or MMIO address.
521 The options are the same as for ttyS, above.
522
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700523 no_console_suspend
524 [HW] Never suspend the console
525 Disable suspending of consoles during suspend and
526 hibernate operations. Once disabled, debugging
527 messages can reach various consoles while the rest
528 of the system is being put to sleep (ie, while
529 debugging driver suspend/resume hooks). This may
530 not work reliably with all consoles, but is known
531 to work with serial and VGA consoles.
532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700534 Format:
535 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700537 crashkernel=nn[KMG]@ss[KMG]
538 [KNL] Reserve a chunk of physical memory to
539 hold a kernel to switch to with kexec on panic.
540
Bernhard Wallefb391592007-10-18 23:41:02 -0700541 crashkernel=range1:size1[,range2:size2,...][@offset]
542 [KNL] Same as above, but depends on the memory
543 in the running system. The syntax of range is
544 start-[end] where start and end are both
545 a memory unit (amount[KMG]). See also
546 Documentation/kdump/kdump.txt for a example.
547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 cs4232= [HW,OSS]
549 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
550
551 cs89x0_dma= [HW,NET]
552 Format: <dma>
553
554 cs89x0_media= [HW,NET]
555 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700556
Randy Dunlapa9913042005-10-23 12:57:11 -0700557 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 See header of drivers/s390/block/dasd_devmap.c.
559
560 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
561 (one device per port)
562 Format: <port#>,<type>
563 See also Documentation/input/joystick-parport.txt
564
565 debug [KNL] Enable kernel debugging (events log level).
566
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700567 debug_locks_verbose=
568 [KNL] verbose self-tests
569 Format=<0|1>
570 Print debugging info while doing the locking API
571 self-tests.
572 We default to 0 (no extra messages), setting it to
573 1 will print _a lot_ more information - normally
574 only useful to kernel developers.
575
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700576 debug_objects [KNL] Enable object debugging
577
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200578 debugpat [X86] Enable PAT debugging
579
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200580 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 Format: <area>[,<node>]
582 See also Documentation/networking/decnet.txt.
583
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000584 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700585 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
586 Change the default blue palette of the console.
587 This is a 16-member array composed of values
588 ranging from 0-255.
589
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000590 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700591 Format: <green0>,<green1>,<green2>,...,<green15>
592 Change the default green palette of the console.
593 This is a 16-member array composed of values
594 ranging from 0-255.
595
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000596 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700597 Format: <red0>,<red1>,<red2>,...,<red15>
598 Change the default red palette of the console.
599 This is a 16-member array composed of values
600 ranging from 0-255.
601
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000602 vt.default_utf8=
603 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700604 Format=<0|1>
605 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000606 Default is 1, i.e. UTF-8 mode is enabled for all
607 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700608
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 dhash_entries= [KNL]
610 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700611
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 digi= [HW,SERIAL]
613 IO parameters + enable/disable command.
614
615 digiepca= [HW,SERIAL]
616 See drivers/char/README.epca and
617 Documentation/digiepca.txt.
618
Yinghai Lu95ffa242008-04-29 03:52:33 -0700619 disable_mtrr_cleanup [X86]
620 enable_mtrr_cleanup [X86]
621 The kernel tries to adjust MTRR layout from continuous
622 to discrete, to make X server driver able to add WB
623 entry later. This parameter enables/disables that.
624
625 mtrr_chunk_size=nn[KMG] [X86]
626 used for mtrr cleanup. It is largest continous chunk
627 that could hold holes aka. UC entries.
628
629 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700630 Used for mtrr cleanup. It is granularity of mtrr block.
631 Default is 1.
632 Large value could prevent small alignment from
633 using up MTRRs.
634
635 mtrr_spare_reg_nr=n [X86]
636 Format: <integer>
637 Range: 0,7 : spare reg number
638 Default : 1
639 Used for mtrr cleanup. It is spare mtrr entries number.
640 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700641
Yinghai Lu093af8d2008-01-30 13:33:32 +0100642 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100643 By default the kernel will trim any uncacheable
644 memory out of your available memory pool based on
645 MTRR settings. This parameter disables that behavior,
646 possibly causing your machine to run very slowly.
647
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 dmasound= [HW,OSS] Sound subsystem buffers
649
650 dscc4.setup= [NET]
651
652 dtc3181e= [HW,SCSI]
653
Robin Getz0ae53642007-10-09 17:24:49 +0800654 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 earlyprintk=vga
656 earlyprintk=serial[,ttySn[,baudrate]]
657
Randy Dunlapa9913042005-10-23 12:57:11 -0700658 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 takes over.
660
661 Only vga or serial at a time, not both.
662
663 Currently only ttyS0 and ttyS1 are supported.
664
665 Interaction with the standard serial driver is not
666 very good.
667
668 The VGA output is eventually overwritten by the real
669 console.
670
671 eata= [HW,SCSI]
672
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700674 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 eisa_irq_edge= [PARISC,HW]
677 See header of drivers/parisc/eisa.c.
678
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700679 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700681 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682
683 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800684 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700685 See Documentation/block/as-iosched.txt and
686 Documentation/block/deadline-iosched.txt for details.
687
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700688 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700689 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800690 image elf header. Generally kexec loader will
691 pass this option to capture kernel.
692 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693
694 enforcing [SELINUX] Set initial enforcing status.
695 Format: {"0" | "1"}
696 See security/selinux/Kconfig help text.
697 0 -- permissive (log only, no denials).
698 1 -- enforcing (deny and log).
699 Default value is 0.
700 Value can be changed at runtime via /selinux/enforce.
701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 es1371= [HW,OSS]
703 Format: <spdif>,[<nomix>,[<amplifier>]]
704 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 ether= [HW,NET] Ethernet cards parameters
707 This option is obsoleted by the "netdev=" option, which
708 has equivalent usage. See its documentation for details.
709
710 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
711 Format: <io>[,<irq>]
712
Akinobu Mitade1ba092006-12-08 02:39:42 -0800713 failslab=
714 fail_page_alloc=
715 fail_make_request=[KNL]
716 General fault injection mechanism.
717 Format: <interval>,<probability>,<space>,<times>
718 See also /Documentation/fault-injection/.
719
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 fd_mcs= [HW,SCSI]
721 See header of drivers/scsi/fd_mcs.c.
722
723 fdomain= [HW,SCSI]
724 See header of drivers/scsi/fdomain.c.
725
726 floppy= [HW]
727 See Documentation/floppy.txt.
728
Alex Chiangf13ae302008-05-08 14:03:23 -0600729 force_pal_cache_flush
730 [IA-64] Avoid check_sal_cache_flush which may hang on
731 buggy SAL_CACHE_FLUSH implementations. Using this
732 parameter will force ia64_sal_cache_flush to call
733 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
734
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 gamecon.map[2|3]=
736 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
737 support via parallel port (up to 5 devices per port)
738 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
739 See also Documentation/input/joystick-parport.txt
740
741 gamma= [HW,DRM]
742
Yinghai Luaaf23042008-01-30 13:33:09 +0100743 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
744 Format: off | on
745 default: on
746
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 gdth= [HW,SCSI]
748 See header of drivers/scsi/gdth.c.
749
750 gpt [EFI] Forces disk with valid GPT signature but
751 invalid Protective MBR to be treated as GPT.
752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 gvp11= [HW,SCSI]
754
755 hashdist= [KNL,NUMA] Large hashes allocated during boot
756 are distributed across NUMA nodes. Defaults on
757 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700758 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759
760 hcl= [IA-64] SGI's Hardware Graph compatibility layer
761
762 hd= [EIDE] (E)IDE hard drive subsystem geometry
763 Format: <cyl>,<head>,<sect>
764
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
766 size of <nn>. This works even on boxes that have no
767 highmem otherwise. This also works to reduce highmem
768 size on bigger boxes.
769
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800770 highres= [KNL] Enable/disable high resolution timer mode.
771 Valid parameters: "on", "off"
772 Default: "on"
773
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 hisax= [HW,ISDN]
775 See Documentation/isdn/README.HiSax.
776
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700777 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
Jon Tollefson4ec161c2008-01-04 09:59:50 +1100778 hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200781 i8042.dumbkbd [HW] Pretend that controller can only read data from
782 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 (Don't attempt to blink the leds)
784 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500785 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400786 i8042.noloop [HW] Disable the AUX Loopback command while probing
787 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 i8042.nomux [HW] Don't check presence of an active multiplexing
789 controller
790 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
791 controllers
792 i8042.panicblink=
793 [HW] Frequency with which keyboard LEDs should blink
794 when kernel panics (default is 0.5 sec)
795 i8042.reset [HW] Reset the controller during init and cleanup
796 i8042.unlock [HW] Unlock (ignore) the keylock
797
798 i810= [HW,DRM]
799
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700800 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
801 indicates that the driver is running on unsupported
802 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
804 does not match list of supported models.
805 i8k.power_status
806 [HW] Report power status in /proc/i8k
807 (disabled by default)
808 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
809 capability is set.
810
811 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
812 See Documentation/mca.txt.
813
814 icn= [HW,ISDN]
815 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
816
817 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200818 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100819 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100822 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823
Andi Kleenf039b752007-05-02 19:27:12 +0200824 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800825 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200826 Poll forces a polling idle loop that can slightly improves the performance
827 of waking up a idle CPU, but will use a lot of power and make the system
828 run hot. Not recommended.
829 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
830 to not use it because it doesn't save as much power as a normal idle
831 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
832 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800833 idle=halt. Halt is forced to be used for CPU idle.
834 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800835 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700836
Denis Cheng594765a2008-02-06 02:57:49 +0100837 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
838 Claim all unknown PCI IDE storage controllers.
839
Ingo Molnar792908222006-12-06 20:40:51 -0800840 ignore_loglevel [KNL]
841 Ignore loglevel setting - this will print /all/
842 kernel messages to the console. Useful for debugging.
843
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 ihash_entries= [KNL]
845 Set number of hash buckets for inode cache.
846
847 in2000= [HW,SCSI]
848 See header of drivers/scsi/in2000.c.
849
850 init= [KNL]
851 Format: <full_path>
852 Run specified binary instead of /sbin/init as init
853 process.
854
855 initcall_debug [KNL] Trace initcalls as they are executed. Useful
856 for working out where the kernel is dying during
857 startup.
858
859 initrd= [BOOT] Specify the location of the initial ramdisk
860
861 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
862 Format: <irq>
863
864 inttest= [IA64]
865
Pavel Machekb552da82008-03-19 15:58:11 +0100866 iommu= [x86]
867 off
868 force
869 noforce
870 biomerge
871 panic
872 nopanic
873 merge
874 nomerge
875 forcesac
876 soft
877
878
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700879 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
880 off
881 Disable intel iommu driver.
882 igfx_off [Default Off]
883 By default, gfx is mapped as normal device. If a gfx
884 device has a dedicated DMAR unit, the DMAR unit is
885 bypassed by not enabling DMAR with this option. In
886 this case, gfx device will use physical address for
887 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700888 forcedac [x86_64]
889 With this option iommu will not optimize to look
890 for io virtual address below 32 bit forcing dual
891 address cycle on pci bus for cards supporting greater
892 than 32 bit addressing. The default is to look
893 for translation below 32 bit and if not available
894 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800895 strict [Default Off]
896 With this option on every unmap_single operation will
897 result in a hardware IOTLB flush operation as opposed
898 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700899
Rene Hermanb02aae92008-01-30 13:30:05 +0100900 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100901 0x80
902 Standard port 0x80 based delay
903 0xed
904 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100905 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100906 Simple two microseconds delay
907 none
908 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100909
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 io7= [HW] IO7 for Marvel based alpha systems
911 See comment before marvel_specify_io7 in
912 arch/alpha/kernel/core_marvel.c.
913
914 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400915 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916
917 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700918 See comment before ip2_setup() in
919 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920
921 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
922 See header of drivers/scsi/ips.c.
923
Simon Horman72c4a132006-09-13 19:57:18 -0700924 ports= [IP_VS_FTP] IPVS ftp helper module
925 Default is 21.
926 Up to 8 (IP_VS_APP_MAX_PORTS) ports
927 may be specified.
928 Format: <port>,<port>....
929
Alan Cox200803d2005-06-28 20:45:18 -0700930 irqfixup [HW]
931 When an interrupt is not handled search all handlers
932 for it. Intended to get systems with badly broken
933 firmware running.
934
935 irqpoll [HW]
936 When an interrupt is not handled search all handlers
937 for it. Also check all handlers each timer
938 interrupt. Intended to get systems with badly broken
939 firmware running.
940
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700942 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943
944 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800945 Format:
946 <cpu number>,...,<cpu number>
947 or
948 <cpu number>-<cpu number> (must be a positive range in ascending order)
949 or a mixture
950 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 This option can be used to specify one or more CPUs
952 to isolate from the general SMP balancing and scheduling
953 algorithms. The only way to move a process onto or off
954 an "isolated" CPU is via the CPU affinity syscalls.
955 <cpu number> begins at 0 and the maximum value is
956 "number of CPUs in system - 1".
957
958 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700959 alternative -- manually setting the CPU mask of all
960 tasks in the system -- can cause problems and
961 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962
Randy Dunlapa9913042005-10-23 12:57:11 -0700963 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964
965 js= [HW,JOY] Analog joystick
966 See Documentation/input/joystick.txt.
967
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700968 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700969 specifies the amount of memory usable by the kernel
970 for non-movable allocations. The requested amount is
971 spread evenly throughout all nodes in the system. The
972 remaining memory in each node is used for Movable
973 pages. In the event, a node is too small to have both
974 kernelcore and Movable pages, kernelcore pages will
975 take priority and other nodes will have a larger number
976 of kernelcore pages. The Movable zone is used for the
977 allocation of pages that may be reclaimed or moved
978 by the page migration subsystem. This means that
979 HugeTLB pages may not be allocated from this zone.
980 Note that allocations like PTEs-from-HighMem still
981 use the HighMem zone if it exists, and the Normal
982 zone if it does not.
983
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700984 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -0700985 is similar to kernelcore except it specifies the
986 amount of memory used for migratable allocations.
987 If both kernelcore and movablecore is specified,
988 then kernelcore will be at *least* the specified
989 value but may be more. If movablecore on its own
990 is specified, the administrator must be careful
991 that the amount of memory usable for all allocations
992 is not too small.
993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 keepinitrd [HW,ARM]
995
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700996 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 in oops dumps.
998
Jason Wessel6cdf6e02008-04-17 20:05:38 +0200999 kgdboc= [HW] kgdb over consoles.
1000 Requires a tty driver that supports console polling.
1001 (only serial suported for now)
1002 Format: <serial_device>[,baud]
1003
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 l2cr= [PPC]
1005
Robert Brosea78bfbf2008-03-29 07:20:23 +11001006 l3cr= [PPC]
1007
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001008 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001009 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001011 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001012 C2 power state.
1013
FD Camifcb71f62008-01-06 19:08:56 +01001014 libata.dma= [LIBATA] DMA control
1015 libata.dma=0 Disable all PATA and SATA DMA
1016 libata.dma=1 PATA and SATA Disk DMA only
1017 libata.dma=2 ATAPI (CDROM) DMA only
1018 libata.dma=4 Compact Flash DMA only
1019 Combinations also work, so libata.dma=3 enables DMA
1020 for disks and CDROMs, but not CFs.
1021
Dave Jones78e70c22007-09-27 11:50:13 -04001022 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1023 when set.
1024 Format: <int>
1025
Tejun Heo33267322008-02-13 09:15:09 +09001026 libata.force= [LIBATA] Force configurations. The format is comma
1027 separated list of "[ID:]VAL" where ID is
1028 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1029 matching port, link or device. Basically, it matches
1030 the ATA ID string printed on console by libata. If
1031 the whole ID part is omitted, the last PORT and DEVICE
1032 values are used. If ID hasn't been specified yet, the
1033 configuration applies to all ports, links and devices.
1034
1035 If only DEVICE is omitted, the parameter applies to
1036 the port and all links and devices behind it. DEVICE
1037 number of 0 either selects the first device or the
1038 first fan-out link behind PMP device. It does not
1039 select the host link. DEVICE number of 15 selects the
1040 host link and device attached to it.
1041
1042 The VAL specifies the configuration to force. As long
1043 as there's no ambiguity shortcut notation is allowed.
1044 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1045 The following configurations can be forced.
1046
1047 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1048 Any ID with matching PORT is used.
1049
1050 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1051
1052 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1053 udma[/][16,25,33,44,66,100,133] notation is also
1054 allowed.
1055
1056 * [no]ncq: Turn on or off NCQ.
1057
1058 If there are multiple matching configurations changing
1059 the same attribute, the last one is used.
1060
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 load_ramdisk= [RAM] List of ramdisks to load from floppy
1062 See Documentation/ramdisk.txt.
1063
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001064 lockd.nlm_grace_period=P [NFS] Assign grace period.
1065 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001067 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1068 Format: <integer>
1069
1070 lockd.nlm_timeout=T [NFS] Assign timeout value.
1071 Format: <integer>
1072
1073 lockd.nlm_udpport=M [NFS] Assign UDP port.
1074 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075
1076 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1077 Format: <irq>
1078
1079 loglevel= All Kernel Messages with a loglevel smaller than the
1080 console loglevel will be printed to the console. It can
1081 also be changed with klogd or other programs. The
1082 loglevels are defined as follows:
1083
1084 0 (KERN_EMERG) system is unusable
1085 1 (KERN_ALERT) action must be taken immediately
1086 2 (KERN_CRIT) critical conditions
1087 3 (KERN_ERR) error conditions
1088 4 (KERN_WARNING) warning conditions
1089 5 (KERN_NOTICE) normal but significant condition
1090 6 (KERN_INFO) informational
1091 7 (KERN_DEBUG) debug-level messages
1092
1093 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001094 Format: { n | nk | nM }
1095 n must be a power of two. The default size
1096 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097
Randy Dunlapaccaa242007-10-16 01:29:37 -07001098 logo.nologo [FB] Disables display of the built-in Linux logo.
1099 This may be used to provide more screen space for
1100 kernel log messages and is useful when debugging
1101 kernel boot problems.
1102
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 lp=0 [LP] Specify parallel ports to use, e.g,
1104 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1105 lp=reset first parallel port). 'lp=0' disables the
1106 lp=auto printer driver. 'lp=reset' (which can be
1107 specified in addition to the ports) causes
1108 attached printers to be reset. Using
1109 lp=port1,port2,... specifies the parallel ports
1110 to associate lp devices with, starting with
1111 lp0. A port specification may be 'none' to skip
1112 that lp device, or a parport name such as
1113 'parport0'. Specifying 'lp=auto' instead of a
1114 port specification list means that device IDs
1115 from each port should be examined, to see if
1116 an IEEE 1284-compliant printer is attached; if
1117 so, the driver will manage that printer.
1118 See also header of drivers/char/lp.c.
1119
1120 lpj=n [KNL]
1121 Sets loops_per_jiffy to given constant, thus avoiding
1122 time-consuming boot-time autodetection (up to 250 ms per
1123 CPU). 0 enables autodetection (default). To determine
1124 the correct value for your kernel, boot with normal
1125 autodetection and see what value is printed. Note that
1126 on SMP systems the preset will be applied to all CPUs,
1127 which is likely to cause problems if your CPUs need
1128 significantly divergent settings. An incorrect value
1129 will cause delays in the kernel to be wrong, leading to
1130 unpredictable I/O errors and other breakage. Although
1131 unlikely, in the extreme case this might damage your
1132 hardware.
1133
1134 ltpc= [NET]
1135 Format: <io>,<irq>,<dma>
1136
Randy Dunlapa9913042005-10-23 12:57:11 -07001137 mac5380= [HW,SCSI] Format:
1138 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139
Randy Dunlapa9913042005-10-23 12:57:11 -07001140 machvec= [IA64] Force the use of a particular machine-vector
1141 (machvec) in a generic kernel.
1142 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143
Randy Dunlapa9913042005-10-23 12:57:11 -07001144 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 be mounted
1146 Format: <1-256>
1147
1148 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001149 should make use of. maxcpus=n : n >= 0 limits the
1150 kernel to using 'n' processors. n=0 is a special case,
1151 it is equivalent to "nosmp", which also disables
1152 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153
Bob Picco2b2c3752005-06-29 18:00:00 -07001154 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1155 equal to this physical address is ignored.
1156
Randy Dunlapa9913042005-10-23 12:57:11 -07001157 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 Should be between 1 and 2^32-1.
1159
1160 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001161 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 Should be between 1 and 16384.
1163
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 mcatest= [IA-64]
1165
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001166 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167
Andi Kleen909dd322007-10-17 18:04:38 +02001168 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1169
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 md= [HW] RAID subsystems devices and level
1171 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001172
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 mdacon= [MDA]
1174 Format: <first>,<last>
1175 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001176
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1178 Amount of memory to be used when the kernel is not able
1179 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001180 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 address space collisions. Without memmap= PCI devices
1182 could be placed at addresses belonging to unused RAM.
1183
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001184 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185 memory.
1186
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001187 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 E820 memory map, as specified by the user.
1189 Such memmap=exactmap lines can be constructed based on
1190 BIOS output or other requirements. See the memmap=nn@ss
1191 option description.
1192
1193 memmap=nn[KMG]@ss[KMG]
1194 [KNL] Force usage of a specific region of memory
1195 Region of memory to be used, from ss to ss+nn.
1196
1197 memmap=nn[KMG]#ss[KMG]
1198 [KNL,ACPI] Mark specific memory as ACPI data.
1199 Region of memory to be used, from ss to ss+nn.
1200
1201 memmap=nn[KMG]$ss[KMG]
1202 [KNL,ACPI] Mark specific memory as reserved.
1203 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001204 Example: Exclude memory from 0x18690000-0x1869ffff
1205 memmap=64K$0x18690000
1206 or
1207 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208
Yinghai Luc64df702008-03-21 18:56:19 -07001209 memtest= [KNL,X86_64] Enable memtest
1210 Format: <integer>
1211 range: 0,4 : pattern number
1212 default : 0 <disable>
1213
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 meye.*= [HW] Set MotionEye Camera parameters
1215 See Documentation/video4linux/meye.txt.
1216
Andres Salomon8f368812007-10-12 23:04:06 +02001217 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1218 Multi-Function General Purpose Timers on AMD Geode
1219 platforms.
1220
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001221 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1222 the BIOS has incorrectly applied a workaround. TinyBIOS
1223 version 0.98 is known to be affected, 0.99 fixes the
1224 problem by letting the user disable the workaround.
1225
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 mga= [HW,DRM]
1227
1228 mousedev.tap_time=
1229 [MOUSE] Maximum time between finger touching and
1230 leaving touchpad surface for touch to be considered
1231 a tap and be reported as a left button click (for
1232 touchpads working in absolute mode only).
1233 Format: <msecs>
1234 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1235 reporting absolute coordinates, such as tablets
1236 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1237 reporting absolute coordinates, such as tablets
1238
1239 mpu401= [HW,OSS]
1240 Format: <io>,<irq>
1241
1242 MTD_Partition= [MTD]
1243 Format: <name>,<region-number>,<size>,<offset>
1244
Randy Dunlapa9913042005-10-23 12:57:11 -07001245 MTD_Region= [MTD] Format:
1246 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247
1248 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001249 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250
Ben Dooks9db829f2008-07-03 11:24:29 +01001251 mtdset= [ARM]
1252 ARM/S3C2412 JIVE boot control
1253
1254 See arch/arm/mach-s3c2412/mach-jive.c
1255
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001257 [HW] Make the MicroTouch USB driver use raw coordinates
1258 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259
1260 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1261
1262 NCR_D700= [HW,SCSI]
1263 See header of drivers/scsi/NCR_D700.c.
1264
1265 ncr5380= [HW,SCSI]
1266
1267 ncr53c400= [HW,SCSI]
1268
1269 ncr53c400a= [HW,SCSI]
1270
1271 ncr53c406a= [HW,SCSI]
1272
1273 ncr53c8xx= [HW,SCSI]
1274
1275 netdev= [NET] Network devices parameters
1276 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1277 Note that mem_start is often overloaded to mean
1278 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001279 This usage is only documented in each driver source
1280 file if at all.
1281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001283 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284
1285 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001286 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287
Trond Myklebusta72b4422006-01-03 09:55:41 +01001288 nfs.callback_tcpport=
1289 [NFS] set the TCP port on which the NFSv4 callback
1290 channel should listen.
1291
Trond Myklebust58df0952006-01-03 09:55:57 +01001292 nfs.idmap_cache_timeout=
1293 [NFS] set the maximum lifetime for idmapper cache
1294 entries.
1295
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001296 nfs.enable_ino64=
1297 [NFS] enable 64-bit inode numbers.
1298 If zero, the NFS client will fake up a 32-bit inode
1299 number for the readdir() and stat() syscalls instead
1300 of returning the full 64-bit number.
1301 The default is to return 64-bit inode numbers.
1302
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001303 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1304 when a NMI is triggered.
1305 Format: [state][,regs][,debounce][,die]
1306
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001307 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001309 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310 emulation library even if a 387 maths coprocessor
1311 is present.
1312
Christoph Lameterc1aee212007-05-31 00:40:47 -07001313 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1314 caches in the slab allocator. Saves per-node memory,
1315 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001316
Randy Dunlapa9913042005-10-23 12:57:11 -07001317 noalign [KNL,ARM]
1318
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 noapic [SMP,APIC] Tells the kernel to not make use of any
1320 IOAPICs that may be present in the system.
1321
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 nobats [PPC] Do not use BATs for mapping kernel lowmem
1323 on "Classic" PPC cores.
1324
1325 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001326
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001327 nodelayacct [KNL] Disable per-task delay accounting
1328
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1330
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001331 noefi [X86-32,X86-64] Disable EFI runtime services support.
1332
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 noexec [IA-64]
1334
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001335 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001336 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001338 noexec=off: disable non-executable mappings
1339
1340 noexec32 [X86-64]
1341 This affects only 32-bit executables.
1342 noexec32=on: enable non-executable mappings (default)
1343 read doesn't imply executable mappings
1344 noexec32=off: disable non-executable mappings
1345 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001347 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001348 register save and restore. The kernel will only save
1349 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350
Andi Kleen191679f2008-01-30 13:33:21 +01001351 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1352
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001354
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001355 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 instruction doesn't work correctly and not to
1357 use it.
1358
1359 nohalt [IA-64] Tells the kernel not to use the power saving
1360 function PAL_HALT_LIGHT when idle. This increases
1361 power-consumption. On the positive side, it reduces
1362 interrupt wake-up latency, which may improve performance
1363 in certain environments such as networked servers or
1364 real-time systems.
1365
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001366 nohz= [KNL] Boottime enable/disable dynamic ticks
1367 Valid arguments: on, off
1368 Default: on
1369
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001370 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001371
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001372 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373 disable unhandled interrupt sources.
1374
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001375 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001376 broken timer IRQ sources.
1377
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378 noisapnp [ISAPNP] Disables ISA PnP code.
1379
1380 noinitrd [RAM] Tells the kernel not to load any configured
1381 initial RAM disk.
1382
1383 nointroute [IA-64]
1384
Tony Luck0aa366f2007-07-20 11:22:30 -07001385 nojitter [IA64] Disables jitter checking for ITC timers.
1386
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001387 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001389 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001390
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 noltlbs [PPC] Do not use large page/tlb entries for kernel
1392 lowmem mapping on PPC40x.
1393
Horms312f1f02006-02-22 09:57:55 +09001394 nomca [IA-64] Disable machine check abort handling
1395
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001396 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001397
Andres Salomon83d73842007-10-12 23:04:06 +02001398 nomfgpt [X86-32] Disable Multi-Function General Purpose
1399 Timer usage (for AMD Geode machines).
1400
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001401 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001402
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001403 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001404 with UP alternatives
1405
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406 noresidual [PPC] Don't use residual data on PReP machines.
1407
Randy Dunlapa9913042005-10-23 12:57:11 -07001408 noresume [SWSUSP] Disables resume and restores original swap
1409 space.
1410
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 no-scroll [VGA] Disables scrollback.
1412 This is required for the Braillex ib80-piezo Braille
1413 reader made by F.H. Papenmeier (Germany).
1414
1415 nosbagart [IA-64]
1416
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001417 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001418
Len Brown61ec7562007-08-16 03:34:22 -04001419 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1420 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421
Dave Jones97842212007-07-15 23:41:05 -07001422 nosoftlockup [KNL] Disable the soft-lockup detector.
1423
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 nosync [HW,M68K] Disables sync negotiation for all devices.
1425
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001426 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427
1428 nousb [USB] Disable the USB subsystem
1429
1430 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001431
Fenghua Yua6c75b862008-03-14 13:57:08 -07001432 nptcg= [IA64] Override max number of concurrent global TLB
1433 purges which is reported from either PAL_VM_SUMMARY or
1434 SAL PALO.
1435
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001436 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1437 one of ['zone', 'node', 'default'] can be specified
1438 This can be set from sysctl after boot.
1439 See Documentation/sysctl/vm.txt for details.
1440
Dave Jonesa61c2d72006-01-07 23:18:19 +00001441 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1442
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001443 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1444 Rather than timing out after 20 ms if an EC
1445 command is not properly ACKed, override the length
1446 of the timeout. We have interrupts disabled while
1447 waiting for the ACK, so if this is set too high
1448 interrupts *may* be lost!
1449
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450 opl3= [HW,OSS]
1451 Format: <io>
1452
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 oprofile.timer= [HW]
1454 Use timer interrupt instead of performance counters
1455
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 osst= [HW,SCSI] SCSI Tape Driver
1457 Format: <buffer_size>,<write_threshold>
1458 See also Documentation/scsi/st.txt.
1459
1460 panic= [KNL] Kernel behaviour on panic
1461 Format: <timeout>
1462
1463 parkbd.port= [HW] Parallel port number the keyboard adapter is
1464 connected to, default is 0.
1465 Format: <parport#>
1466 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1467 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001468 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469
Randy Dunlapa9913042005-10-23 12:57:11 -07001470 parport= [HW,PPT] Specify parallel ports. 0 disables.
1471 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1472 Use 'auto' to force the driver to use any
1473 IRQ/DMA settings detected (the default is to
1474 ignore detected IRQ/DMA settings because of
1475 possible conflicts). You can specify the base
1476 address, IRQ, and DMA settings; IRQ and DMA
1477 should be numbers, or 'auto' (for using detected
1478 settings on that particular port), or 'nofifo'
1479 (to avoid using a FIFO even if it is detected).
1480 Parallel ports are assigned in the order they
1481 are specified on the command line, starting
1482 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483
Randy Dunlapa9913042005-10-23 12:57:11 -07001484 parport_init_mode= [HW,PPT]
1485 Configure VIA parallel port to operate in
1486 a specific mode. This is necessary on Pegasos
1487 computer where firmware has no options for setting
1488 up parallel port mode and sets it to spp.
1489 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 Format: [spp|ps2|epp|ecp|ecpepp]
1491
Randy Dunlapa9913042005-10-23 12:57:11 -07001492 pas2= [HW,OSS] Format:
1493 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1494
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 pas16= [HW,SCSI]
1496 See header of drivers/scsi/pas16.c.
1497
Andrew Mortondd287792006-03-23 03:00:57 -08001498 pause_on_oops=
1499 Halt all CPUs after the first oops has been printed for
1500 the specified number of seconds. This is to be used if
1501 your oopses keep scrolling off the screen.
1502
Linus Torvalds1da177e2005-04-16 15:20:36 -07001503 pcbit= [HW,ISDN]
1504
1505 pcd. [PARIDE]
1506 See header of drivers/block/paride/pcd.c.
1507 See also Documentation/paride.txt.
1508
Randy Dunlapa9913042005-10-23 12:57:11 -07001509 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001510 off [X86-32] don't probe for the PCI bus
1511 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001512 the hardware directly. Use this if your machine
1513 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001514 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001515 hardware access methods are allowed. Use this
1516 if you experience crashes upon bootup and you
1517 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001518 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001519 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001520 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001521 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001522 noaer [PCIE] If the PCIEAER kernel config parameter is
1523 enabled, this kernel boot option can be used to
1524 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001525 nodomains [PCI] Disable support for multiple PCI
1526 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001527 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001528 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001529 nomsi [MSI] If the PCI_MSI kernel config parameter is
1530 enabled, this kernel boot option can be used to
1531 disable the use of MSI interrupts system-wide.
Stefan Assmanna9322f62008-06-11 16:35:14 +02001532 noioapicquirk [APIC] Disable all boot interrupt quirks.
1533 Safety option to keep boot IRQs enabled. This
1534 should never be necessary.
Stefan Assmann91979792008-06-11 16:35:15 +02001535 ioapicreroute [APIC] Enable rerouting of boot IRQs to the
1536 primary IO-APIC for bridges that cannot disable
1537 boot IRQs. This fixes a source of spurious IRQs
1538 when the system masks IRQs.
Stefan Assmann41b9eb22008-07-15 13:48:55 +02001539 noioapicreroute [APIC] Disable workaround that uses the
1540 boot IRQ equivalent of an IRQ that connects to
1541 a chipset where boot IRQs cannot be disabled.
1542 The opposite of ioapicreroute.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001543 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001544 routing table. These calls are known to be buggy
1545 on several machines and they hang the machine
1546 when used, but on other computers it's the only
1547 way to get the interrupt routing table. Try
1548 this option if the kernel is unable to allocate
1549 IRQs or discover secondary PCI buses on your
1550 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001551 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001552 Use with caution as certain devices share
1553 address decoders between ROMs and other
1554 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001555 norom [X86-32,X86_64] Do not assign address space to
1556 expansion ROMs that do not already have
1557 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001558 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001559 assigned automatically to PCI devices. You can
1560 make the kernel exclude IRQs of your ISA cards
1561 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001562 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001563 of the PIRQ table (normally generated
1564 by the BIOS) if it is outside the
1565 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001566 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001567 useful if the kernel is unable to find your
1568 secondary buses and you want to tell it
1569 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001570 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001571 numbers ourselves, overriding
1572 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001573 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001574 in the BIOS $PIR table. This is needed on
1575 some systems with broken BIOSes, notably
1576 some HP Pavilion N5400 and Omnibook XE3
1577 notebooks. This will have no effect if ACPI
1578 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001579 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001580 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001581 use_crs [X86-32] Use _CRS for PCI resource
1582 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001583 routeirq Do IRQ routing for all PCI devices.
1584 This is normally done in pci_enable_device(),
1585 so this option is a temporary workaround
1586 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001587 skip_isa_align [X86] do not align io start addr, so can
1588 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001589 firmware [ARM] Do not re-enumerate the bus but instead
1590 just use the configuration from the
1591 bootloader. This is currently used on
1592 IXP2000 systems where the bus has to be
1593 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001594 noearly [X86] Don't do any early type 1 scanning.
1595 This might help on some broken boards which
1596 machine check when some devices' config space
1597 is read. But various workarounds are disabled
1598 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001599 bfsort Sort PCI devices into breadth-first order.
1600 This sorting is done to get a device
1601 order compatible with older (<= 2.4) kernels.
1602 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001603 cbiosize=nn[KMG] The fixed amount of bus space which is
1604 reserved for the CardBus bridge's IO window.
1605 The default value is 256 bytes.
1606 cbmemsize=nn[KMG] The fixed amount of bus space which is
1607 reserved for the CardBus bridge's memory
1608 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001609
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 pcmv= [HW,PCMCIA] BadgePAD 4
1611
1612 pd. [PARIDE]
1613 See Documentation/paride.txt.
1614
1615 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1616 boot time.
1617 Format: { 0 | 1 }
1618 See arch/parisc/kernel/pdc_chassis.c
1619
1620 pf. [PARIDE]
1621 See Documentation/paride.txt.
1622
1623 pg. [PARIDE]
1624 See Documentation/paride.txt.
1625
1626 pirq= [SMP,APIC] Manual mp-table setup
1627 See Documentation/i386/IO-APIC.txt.
1628
1629 plip= [PPT,NET] Parallel port network link
1630 Format: { parport<nr> | timid | 0 }
1631 See also Documentation/parport.txt.
1632
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001633 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1634 Override pmtimer IOPort with a hex value.
1635 e.g. pmtmr=0x508
1636
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637 pnpacpi= [ACPI]
1638 { off }
1639
1640 pnpbios= [ISAPNP]
1641 { on | off | curr | res | no-curr | no-res }
1642
1643 pnp_reserve_irq=
1644 [ISAPNP] Exclude IRQs for the autoconfiguration
1645
1646 pnp_reserve_dma=
1647 [ISAPNP] Exclude DMAs for the autoconfiguration
1648
1649 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001650 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651
1652 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001653 [ISAPNP] Exclude memory regions for the
1654 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001655 Ranges are in pairs (memory base and size).
1656
Ingo Molnar45807a12007-07-15 23:40:10 -07001657 print-fatal-signals=
1658 [KNL] debug: print fatal signals
1659 print-fatal-signals=1: print segfault info to
1660 the kernel console.
1661 default: off.
1662
Randy Dunlape84845c2007-07-15 23:40:25 -07001663 printk.time= Show timing data prefixed to each printk message line
1664 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1665
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001667 Format: [schedule,]<number>
1668 Param: "schedule" - profile schedule points.
1669 Param: <number> - step/bucket size as a power of 2 for
1670 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001671 Param: "sleep" - profile D-state sleeping (millisecs).
1672 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001673 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674
Randy Dunlapa9913042005-10-23 12:57:11 -07001675 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001676 Limit processor to maximum C-state
1677 max_cstate=9 overrides any DMI blacklist limit.
1678
Len Brown41c0d862005-12-28 12:43:51 -05001679 processor.nocst [HW,ACPI]
1680 Ignore the _CST method to determine C-states,
1681 instead using the legacy FADT method
1682
Linus Torvalds1da177e2005-04-16 15:20:36 -07001683 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1684 before loading.
1685 See Documentation/ramdisk.txt.
1686
Randy Dunlapa9913042005-10-23 12:57:11 -07001687 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1688 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1690 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001691 psmouse.resetafter= [HW,MOUSE]
1692 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001693 (0 = never).
1694 psmouse.resolution=
1695 [HW,MOUSE] Set desired mouse resolution, in dpi.
1696 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001697 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698 0 = disabled, 1 = enabled (default).
1699
1700 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001701 Format:
1702 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703
1704 pt. [PARIDE]
1705 See Documentation/paride.txt.
1706
Kay Sieversdc8c8582007-08-15 12:25:38 +02001707 pty.legacy_count=
1708 [KNL] Number of legacy pty's. Overwrites compiled-in
1709 default number.
1710
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001711 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001712
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 r128= [HW,DRM]
1714
1715 raid= [HW,RAID]
1716 See Documentation/md.txt.
1717
Randy Dunlapa9913042005-10-23 12:57:11 -07001718 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001720
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 See Documentation/ramdisk.txt.
1723
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001724 rcupdate.blimit= [KNL,BOOT]
1725 Set maximum number of finished RCU callbacks to process
1726 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001727
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001728 rcupdate.qhimark= [KNL,BOOT]
1729 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001730 RCU callbacks over which batch limiting is disabled.
1731
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001732 rcupdate.qlowmark= [KNL,BOOT]
1733 Set threshold of queued RCU callbacks below which
1734 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001735
Olof Johanssonffdfc402005-09-06 15:17:19 -07001736 rdinit= [KNL]
1737 Format: <full_path>
1738 Run specified binary instead of /init from the ramdisk,
1739 used for early userspace startup. See initrd.
1740
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001741 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001743 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744
Paul Jackson46b6d942008-07-04 10:00:09 -07001745 relax_domain_level=
1746 [KNL, SMP] Set scheduler's default relax_domain_level.
1747 See Documentation/cpusets.txt.
1748
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1750
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001751 reservetop= [X86-32]
Zachary Amsden461a9aff2006-09-25 23:32:25 -07001752 Format: nn[KMG]
1753 Reserves a hole at the top of the kernel virtual
1754 address space.
1755
Vivek Goyal7e962872006-09-27 01:50:44 -07001756 reset_devices [KNL] Force drivers to reset the underlying device
1757 during initialization.
1758
Randy Dunlapa9913042005-10-23 12:57:11 -07001759 resume= [SWSUSP]
1760 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001762 resume_offset= [SWSUSP]
1763 Specify the offset from the beginning of the partition
1764 given by "resume=" at which the swap header is located,
1765 in <PAGE_SIZE> units (needed only for swap files).
1766 See Documentation/power/swsusp-and-swap-files.txt
1767
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001768 retain_initrd [RAM] Keep initrd memory after extraction
1769
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 rhash_entries= [KNL,NET]
1771 Set number of hash buckets for route cache
1772
1773 riscom8= [HW,SERIAL]
1774 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1775
1776 ro [KNL] Mount root device read-only on boot
1777
1778 root= [KNL] Root filesystem
1779
1780 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1781 mount the root filesystem
1782
1783 rootflags= [KNL] Set root filesystem mount option string
1784
1785 rootfstype= [KNL] Set root filesystem type
1786
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001787 rootwait [KNL] Wait (indefinitely) for root device to show up.
1788 Useful for devices that are detected asynchronously
1789 (e.g. USB and MMC devices).
1790
James Morris20510f22007-10-16 23:31:32 -07001791 root_plug.vendor_id=
1792 [ROOTPLUG] Override the default vendor ID
1793
1794 root_plug.product_id=
1795 [ROOTPLUG] Override the default product ID
1796
1797 root_plug.debug=
1798 [ROOTPLUG] Enable debugging output
1799
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800 rw [KNL] Mount root device read-write on boot
1801
1802 S [KNL] Run init in single mode
1803
1804 sa1100ir [NET]
1805 See drivers/net/irda/sa1100_ir.c.
1806
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001808
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1810 Format: <io>[,<timeout>[,<isapnp>]]
1811
1812 scsi_debug_*= [SCSI]
1813 See drivers/scsi/scsi_debug.c.
1814
1815 scsi_default_dev_flags=
1816 [SCSI] SCSI default device flags
1817 Format: <integer>
1818
1819 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1820 Format: <vendor>:<model>:<flags>
1821 (flags are integer value)
1822
Randy Dunlap6af66322007-11-14 16:52:25 -08001823 scsi_logging_level= [SCSI] a bit mask of logging levels
1824 See drivers/scsi/scsi_logging.h for bits. Also
1825 settable via sysctl at dev.scsi.logging_level
1826 (/proc/sys/dev/scsi/logging_level).
1827 There is also a nice 'scsi_logging_level' script in the
1828 S390-tools package, available for download at
1829 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001830
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001831 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1832 discovered. async scans them in kernel threads,
1833 allowing boot to proceed. none ignores them, expecting
1834 user space to do the scan.
1835
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836 selinux [SELINUX] Disable or enable SELinux at boot time.
1837 Format: { "0" | "1" }
1838 See security/selinux/Kconfig help text.
1839 0 -- disable.
1840 1 -- enable.
1841 Default value is set via kernel config option.
1842 If enabled at boot time, /selinux/disable can be used
1843 later to disable prior to initial policy load.
1844
James Morris4e5ab4c2006-06-09 00:33:33 -07001845 selinux_compat_net =
1846 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001847 Format: { "0" | "1" }
1848 0 -- use new secmark-based packet controls
1849 1 -- use legacy packet controls
1850 Default value is 0 (preferred).
1851 Value can be changed at runtime via
1852 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001853
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001854 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856 shapers= [NET]
1857 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001858
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859 sim710= [SCSI,HW]
1860 See header of drivers/scsi/sim710.c.
1861
1862 simeth= [IA-64]
1863 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001864
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 slram= [HW,MTD]
1866
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001867 slub_debug[=options[,slabs]] [MM, SLUB]
1868 Enabling slub_debug allows one to determine the
1869 culprit if slab objects become corrupted. Enabling
1870 slub_debug can create guard zones around objects and
1871 may poison objects when not in use. Also tracks the
1872 last alloc / free. For more information see
1873 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001874
1875 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001876 Determines the maximum allowed order for slabs.
1877 A high setting may cause OOMs due to memory
1878 fragmentation. For more information see
1879 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001880
1881 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001882 The minimum number of objects per slab. SLUB will
1883 increase the slab order up to slub_max_order to
1884 generate a sufficiently large slab able to contain
1885 the number of objects indicated. The higher the number
1886 of objects the smaller the overhead of tracking slabs
1887 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001888 For more information see Documentation/vm/slub.txt.
1889
1890 slub_min_order= [MM, SLUB]
1891 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001892 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001893 For more information see Documentation/vm/slub.txt.
1894
1895 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001896 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001897 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001898 allocs to different slabs. Debug options disable
1899 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001900 For more information see Documentation/vm/slub.txt.
1901
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 smart2= [HW]
1903 Format: <io1>[,<io2>[,...,<io8>]]
1904
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001905 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001906 attempt to substitute SMP alternatives once at boot.
1907
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001908 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1909 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1910 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1911 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1912 smsc-ircc2.ircc_irq= [HW] IRQ line
1913 smsc-ircc2.ircc_dma= [HW] DMA channel
1914 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1915 0: Toshiba Satellite 1800 (GP data pin select)
1916 1: Fast pin select (default)
1917 2: ATC IRMode
1918
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919 snd-ad1816a= [HW,ALSA]
1920
1921 snd-ad1848= [HW,ALSA]
1922
1923 snd-ali5451= [HW,ALSA]
1924
1925 snd-als100= [HW,ALSA]
1926
1927 snd-als4000= [HW,ALSA]
1928
1929 snd-azt2320= [HW,ALSA]
1930
1931 snd-cmi8330= [HW,ALSA]
1932
1933 snd-cmipci= [HW,ALSA]
1934
1935 snd-cs4231= [HW,ALSA]
1936
1937 snd-cs4232= [HW,ALSA]
1938
1939 snd-cs4236= [HW,ALSA]
1940
1941 snd-cs4281= [HW,ALSA]
1942
1943 snd-cs46xx= [HW,ALSA]
1944
1945 snd-dt019x= [HW,ALSA]
1946
1947 snd-dummy= [HW,ALSA]
1948
1949 snd-emu10k1= [HW,ALSA]
1950
1951 snd-ens1370= [HW,ALSA]
1952
1953 snd-ens1371= [HW,ALSA]
1954
1955 snd-es968= [HW,ALSA]
1956
1957 snd-es1688= [HW,ALSA]
1958
1959 snd-es18xx= [HW,ALSA]
1960
1961 snd-es1938= [HW,ALSA]
1962
1963 snd-es1968= [HW,ALSA]
1964
1965 snd-fm801= [HW,ALSA]
1966
1967 snd-gusclassic= [HW,ALSA]
1968
1969 snd-gusextreme= [HW,ALSA]
1970
1971 snd-gusmax= [HW,ALSA]
1972
1973 snd-hdsp= [HW,ALSA]
1974
1975 snd-ice1712= [HW,ALSA]
1976
1977 snd-intel8x0= [HW,ALSA]
1978
1979 snd-interwave= [HW,ALSA]
1980
1981 snd-interwave-stb=
1982 [HW,ALSA]
1983
1984 snd-korg1212= [HW,ALSA]
1985
1986 snd-maestro3= [HW,ALSA]
1987
1988 snd-mpu401= [HW,ALSA]
1989
1990 snd-mtpav= [HW,ALSA]
1991
1992 snd-nm256= [HW,ALSA]
1993
1994 snd-opl3sa2= [HW,ALSA]
1995
1996 snd-opti92x-ad1848=
1997 [HW,ALSA]
1998
1999 snd-opti92x-cs4231=
2000 [HW,ALSA]
2001
2002 snd-opti93x= [HW,ALSA]
2003
2004 snd-pmac= [HW,ALSA]
2005
2006 snd-rme32= [HW,ALSA]
2007
2008 snd-rme96= [HW,ALSA]
2009
2010 snd-rme9652= [HW,ALSA]
2011
2012 snd-sb8= [HW,ALSA]
2013
2014 snd-sb16= [HW,ALSA]
2015
2016 snd-sbawe= [HW,ALSA]
2017
2018 snd-serial= [HW,ALSA]
2019
2020 snd-sgalaxy= [HW,ALSA]
2021
2022 snd-sonicvibes= [HW,ALSA]
2023
2024 snd-sun-amd7930=
2025 [HW,ALSA]
2026
2027 snd-sun-cs4231= [HW,ALSA]
2028
2029 snd-trident= [HW,ALSA]
2030
2031 snd-usb-audio= [HW,ALSA,USB]
2032
2033 snd-via82xx= [HW,ALSA]
2034
2035 snd-virmidi= [HW,ALSA]
2036
2037 snd-wavefront= [HW,ALSA]
2038
2039 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002040
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2042 See Documentation/sonypi.txt
2043
2044 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2045 See Documentation/specialix.txt.
2046
2047 spia_io_base= [HW,MTD]
2048 spia_fio_base=
2049 spia_pedr=
2050 spia_peddr=
2051
2052 sscape= [HW,OSS]
2053 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002054
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2056 See Documentation/scsi/st.txt.
2057
Linus Torvalds1da177e2005-04-16 15:20:36 -07002058 sti= [PARISC,HW]
2059 Format: <num>
2060 Set the STI (builtin display/keyboard on the HP-PARISC
2061 machines) console (graphic card) which should be used
2062 as the initial boot-console.
2063 See also comment in drivers/video/console/sticore.c.
2064
2065 sti_font= [HW]
2066 See comment in drivers/video/console/sticore.c.
2067
2068 stifb= [HW]
2069 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2070
Greg Banks42a7fc42007-03-06 01:42:23 -08002071 sunrpc.pool_mode=
2072 [NFS]
2073 Control how the NFS server code allocates CPUs to
2074 service thread pools. Depending on how many NICs
2075 you have and where their interrupts are bound, this
2076 option will affect which CPUs will do NFS serving.
2077 Note: this parameter cannot be changed while the
2078 NFS server is running.
2079
2080 auto the server chooses an appropriate mode
2081 automatically using heuristics
2082 global a single global pool contains all CPUs
2083 percpu one pool for each CPU
2084 pernode one pool for each NUMA node (equivalent
2085 to global on non-NUMA machines)
2086
Linus Torvalds1da177e2005-04-16 15:20:36 -07002087 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002088
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089 switches= [HW,M68k]
2090
2091 sym53c416= [HW,SCSI]
2092 See header of drivers/scsi/sym53c416.c.
2093
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002094 sysrq_always_enabled
2095 [KNL]
2096 Ignore sysrq setting - this boot parameter will
2097 neutralize any effect of /proc/sys/kernel/sysrq.
2098 Useful for debugging.
2099
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100 t128= [HW,SCSI]
2101 See header of drivers/scsi/t128.c.
2102
2103 tdfx= [HW,DRM]
2104
2105 thash_entries= [KNL,NET]
2106 Set number of hash buckets for TCP connection
2107
Len Brownf8707ec2007-08-12 00:12:54 -04002108 thermal.act= [HW,ACPI]
2109 -1: disable all active trip points in all thermal zones
2110 <degrees C>: override all lowest active trip points
2111
Len Brownc52a7412007-08-14 15:49:32 -04002112 thermal.crt= [HW,ACPI]
2113 -1: disable all critical trip points in all thermal zones
2114 <degrees C>: lower all critical trip points
2115
Len Brownf5487142007-08-12 00:12:44 -04002116 thermal.nocrt= [HW,ACPI]
2117 Set to disable actions on ACPI thermal zone
2118 critical and hot trip points.
2119
Len Brown72b33ef2007-08-12 00:12:17 -04002120 thermal.off= [HW,ACPI]
2121 1: disable ACPI thermal control
2122
Len Browna70cdc52007-08-12 00:12:35 -04002123 thermal.psv= [HW,ACPI]
2124 -1: disable all passive trip points
2125 <degrees C>: override all passive trip points to this value
2126
Len Brown730ff342007-08-12 00:12:26 -04002127 thermal.tzp= [HW,ACPI]
2128 Specify global default ACPI thermal zone polling rate
2129 <deci-seconds>: poll all this frequency
2130 0: no polling (default)
2131
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132 tipar.timeout= [HW,PPT]
2133 Set communications timeout in tenths of a second
2134 (default 15).
2135
2136 tipar.delay= [HW,PPT]
2137 Set inter-bit delay in microseconds (default 10).
2138
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139 tmscsim= [HW,SCSI]
2140 See comment before function dc390_setup() in
2141 drivers/scsi/tmscsim.c.
2142
2143 tp720= [HW,PS2]
2144
2145 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002146 Format:
2147 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2148
Randy Dunlapa9913042005-10-23 12:57:11 -07002149 turbografx.map[2|3]= [HW,JOY]
2150 TurboGraFX parallel port interface
2151 Format:
2152 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002153 See also Documentation/input/joystick-parport.txt
2154
2155 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2156 See header of drivers/scsi/u14-34f.c.
2157
2158 uart401= [HW,OSS]
2159 Format: <io>,<irq>
2160
2161 uart6850= [HW,OSS]
2162 Format: <io>,<irq>
2163
Alan Stern5f8364b2006-12-05 16:29:55 -05002164 uhci-hcd.ignore_oc=
2165 [USB] Ignore overcurrent events (default N).
2166 Some badly-designed motherboards generate lots of
2167 bogus events, for ports that aren't wired to
2168 anything. Set this parameter to avoid log spamming.
2169 Note that genuine overcurrent events won't be
2170 reported either.
2171
Alan Sternb5e795f2007-02-20 15:00:53 -05002172 usbcore.autosuspend=
2173 [USB] The autosuspend time delay (in seconds) used
2174 for newly-detected USB devices (default 2). This
2175 is the time required before an idle device will be
2176 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002177 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002178
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 usbhid.mousepoll=
2180 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002181
Paul Jackson200001e2008-06-25 05:44:46 -07002182 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2183 kernel's map of available physical RAM.
2184
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002185 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002186 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002187 vdso=1: enable VDSO (default)
2188 vdso=0: disable VDSO mapping
2189
Roland McGrathaf65d642008-01-30 13:30:43 +01002190 vdso32= [X86-32,X86-64]
2191 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2192 vdso32=1: enable 32-bit VDSO (default)
2193 vdso32=0: disable 32-bit VDSO mapping
2194
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002195 vector= [IA-64,SMP]
2196 vector=percpu: enable percpu vector domain
2197
Linus Torvalds1da177e2005-04-16 15:20:36 -07002198 video= [FB] Frame buffer configuration
2199 See Documentation/fb/modedb.txt.
2200
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002201 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002202 See Documentation/i386/boot.txt and
2203 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002204 Use vga=ask for menu.
2205 This is actually a boot loader parameter; the value is
2206 passed to the kernel using a special protocol.
2207
Randy Dunlapa9913042005-10-23 12:57:11 -07002208 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002209 size of <nn>. This can be used to increase the
2210 minimum size (128MB on x86). It can also be used to
2211 decrease the size and leave more room for directly
2212 mapped kernel RAM.
2213
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002214 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2215 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002217 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2218 Format: <command>
2219
2220 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2221 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002222
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223 waveartist= [HW,OSS]
2224 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002225
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 wd33c93= [HW,SCSI]
2227 See header of drivers/scsi/wd33c93.c.
2228
2229 wd7000= [HW,SCSI]
2230 See header of drivers/scsi/wd7000.c.
2231
2232 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002233 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234
2235 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2236 xd_geo= See header of drivers/block/xd.c.
2237
2238 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002239 Format:
2240 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002241
Andi Kleena62eaf12006-02-16 23:41:58 +01002242 norandmaps Don't use address space randomization
2243 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2244
Randy Dunlapa9913042005-10-23 12:57:11 -07002245______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002246
2247TODO:
2248
2249 Add documentation for ALSA options.
2250 Add more DRM drivers.