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Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
Linus Torvalds1da177e2005-04-16 15:20:36 -07003
4The following is a consolidated list of the kernel parameters as implemented
5(mostly) by the __setup() macro and sorted into English Dictionary order
6(defined as ignoring all punctuation and sorting digits before letters in a
7case insensitive manner), and with descriptions where known.
8
9Module parameters for loadable modules are specified only as the
10parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14Module parameters for modules that are built into the kernel image
15are specified on the kernel command line with the module name plus
16'.' plus parameter name, with '=' and value if appropriate, such as:
17
18 usbcore.blinkenlights=1
19
Stefan Richtera901ebb2006-04-01 01:43:18 +020020This document may not be entirely up to date and comprehensive. The command
21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22module. Loadable modules, after being loaded into the running kernel, also
23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24parameters may be changed at runtime by the command
25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
Stefan Richter6585fa82006-04-01 01:44:30 +020027The parameters listed below are only valid if certain kernel build options were
28enabled and if respective hardware is present. The text in square brackets at
29the beginning of each description states the restrictions within which a
30parameter is applicable:
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32 ACPI ACPI support is enabled.
Chuck Ebbertc99c1082007-07-27 10:46:20 +100033 AGP AGP (Accelerated Graphics Port) is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +020037 AVR32 AVR32 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 AX25 Appropriate AX.25 support is enabled.
Robin Getz0ae53642007-10-09 17:24:49 +080039 BLACKFIN Blackfin architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070040 DRM Direct Rendering Management support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070048 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
Kristen Carlson Accardi11ef6972006-09-28 11:29:01 -070052 LIBATA Libata driver is enabled
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070061 MSI Message Signaled Interrupts (PCI).
Randy Dunlapc8facbb2007-07-31 00:37:40 -070062 MTD MTD (Memory Technology Device) support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070065 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
Randy Dunlapc8facbb2007-07-31 00:37:40 -070068 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
Randy Dunlap7f785762007-10-05 13:17:58 -070072 PCIE PCI Express support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
James Morris20510f22007-10-16 23:31:32 -070079 ROOTPLUG The example Root Plug LSM is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
83 Documentation/scsi/.
James Morris20510f22007-10-16 23:31:32 -070084 SECURITY Different security models are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
Paul Mundte523d932007-02-28 18:30:01 +090087 SH SuperH architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
David Brownell77437fd2008-07-23 21:28:33 -070090 SWSUSP Software suspend (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700100 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
104
105In addition, the following text indicates that the option:
106
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
110
111Parameters denoted with BOOT are actually interpreted by the boot
112loader, and have no meaning to the kernel directly.
113Do not modify the syntax of boot loader parameters without extreme
114need or coordination with <Documentation/i386/boot.txt>.
115
Karsten Weiss55588702007-02-13 13:26:21 +0100116There are also arch-specific kernel-parameters not documented here.
117See for example <Documentation/x86_64/boot-options.txt>.
118
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120a trailing = on the name of any parameter states that that parameter will
121be entered as an environment variable, whereas its absence indicates that
122it will appear as a kernel argument readable via /proc/cmdline by programs
123running once the system is up.
124
jens m. noedler9c4751f2006-09-29 02:00:27 -0700125The number of kernel parameters is not limited, but the length of the
126complete command line (parameters including spaces etc.) is limited to
127a fixed number of characters. This limit depends on the architecture
128and is between 256 and 4096 characters. It is defined in the file
129./include/asm/setup.h as COMMAND_LINE_SIZE.
130
131
Bernhard Walle03d926f2007-03-06 02:29:44 -0800132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700134 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700139 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 strictly ACPI specification compliant.
141
Randy Dunlap53471122008-03-12 18:10:51 -0400142 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Len Browna1fdcc02007-03-11 03:26:14 -0400144 acpi_apic_instance= [ACPI, IOAPIC]
145 Format: <int>
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400148 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400149
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 acpi_sleep= [HW,ACPI] Sleep options
Shaohua Libdfe6b72008-07-23 21:28:41 -0700151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
Pavel Machek23b168d2008-02-05 19:27:12 +0100152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
Shaohua Libdfe6b72008-07-23 21:28:41 -0700155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
160 used by default).
Randy Dunlapa9913042005-10-23 12:57:11 -0700161
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700163 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
Randy Dunlapa9913042005-10-23 12:57:11 -0700165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
167 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
Randy Dunlapa9913042005-10-23 12:57:11 -0700169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
171 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
Randy Dunlapa9913042005-10-23 12:57:11 -0700173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
174 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 Format: <irq>,<irq>...
176
Randy Dunlapa9913042005-10-23 12:57:11 -0700177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 Format: <irq>,<irq>...
179
Len Brown67effe82007-07-26 00:50:06 -0400180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
181
Len Browna1f9e652006-01-25 23:47:36 -0500182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
184
Len Brownae00d812007-05-29 18:43:33 -0400185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190 acpi_serialize [HW,ACPI] force serialization of AML methods
191
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
198 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
Zhang Ruif9891062007-04-24 13:53:22 +0800200 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700202 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Zhang Ruif9891062007-04-24 13:53:22 +0800217 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700219 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 1: enable, 0: disable. It is useful for boot time
221 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800222 via /sys/module/acpi/parameters/debug_level.
223 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
224 Available bits (add the numbers together) to enable different
225 debug output levels of the ACPI subsystem:
226 0x01 error 0x02 warn 0x04 init 0x08 debug object
227 0x10 info 0x20 init names 0x40 parse 0x80 load
228 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
229 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
230 0x10000 resources 0x20000 user requests 0x40000 package.
231 The number can be in decimal or prefixed with 0x in hex.
232 Warning: Many of these options can produce a lot of
233 output and make your system unusable. Be very careful.
234
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700235 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700236 Override the pmtimer bug detection: force the kernel
237 to assume that this machine's pmtimer latches its value
238 and always returns good values.
239
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000240 agp= [AGP]
241 { off | try_unsupported }
242 off: disable AGP support
243 try_unsupported: try to drive unsupported chipsets
244 (may crash computer or cause data corruption)
245
Chuck Ebbert66759a02005-09-12 18:49:25 +0200246 enable_timer_pin_1 [i386,x86-64]
247 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700248 Can be useful to work around chipset bugs
249 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200250 The kernel tries to set a reasonable default.
251
252 disable_timer_pin_1 [i386,x86-64]
253 Disable PIN 1 of APIC timer
254 Can be useful to work around chipset bugs.
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 ad1848= [HW,OSS]
257 Format: <io>,<irq>,<dma>,<dma2>,<type>
258
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 advansys= [HW,SCSI]
260 See header of drivers/scsi/advansys.c.
261
262 advwdt= [HW,WDT] Advantech WDT
263 Format: <iostart>,<iostop>
264
265 aedsp16= [HW,OSS] Audio Excel DSP 16
266 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
267 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 aha152x= [HW,SCSI]
270 See Documentation/scsi/aha152x.txt.
271
272 aha1542= [HW,SCSI]
273 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
274
275 aic7xxx= [HW,SCSI]
276 See Documentation/scsi/aic7xxx.txt.
277
278 aic79xx= [HW,SCSI]
279 See Documentation/scsi/aic79xx.txt.
280
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200281 amd_iommu= [HW,X86-84]
282 Pass parameters to the AMD IOMMU driver in the system.
283 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200284 isolate - enable device isolation (each device, as far
285 as possible, will get its own protection
286 domain)
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900287 fullflush - enable flushing of IO/TLB entries when
288 they are unmapped. Otherwise they are
289 flushed before they will be reused, which
290 is a lot of faster
291
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200292 amd_iommu_size= [HW,X86-64]
293 Define the size of the aperture for the AMD IOMMU
294 driver. Possible values are:
295 '32M', '64M' (default), '128M', '256M', '512M', '1G'
296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 amijoy.map= [HW,JOY] Amiga joystick support
298 Map of devices attached to JOY0DAT and JOY1DAT
299 Format: <a>,<b>
300 See also Documentation/kernel/input/joystick.txt
301
302 analog.map= [HW,JOY] Analog joystick and gamepad support
303 Specifies type or capabilities of an analog joystick
304 connected to one of 16 gameports
305 Format: <type1>,<type2>,..<type16>
306
Randy Dunlapa9913042005-10-23 12:57:11 -0700307 apc= [HW,SPARC]
308 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 Format: noidle
310 Disable APC CPU standby support. SPARCstation-Fox does
311 not play well with APC CPU idle - disable it if you have
312 APC and your system crashes randomly.
313
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700314 apic= [APIC,i386] Advanced Programmable Interrupt Controller
315 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 Format: { quiet (default) | verbose | debug }
317 Change the amount of debugging information output
318 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700319
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700321 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
324 Format: <io>,<irq>,<nodeID>
325
326 ataflop= [HW,M68k]
327
328 atarimouse= [HW,MOUSE] Atari Mouse
329
330 atascsi= [HW,SCSI] Atari SCSI
331
332 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
333 EzKey and similar keyboards
334
335 atkbd.reset= [HW] Reset keyboard during initialization
336
Randy Dunlapa9913042005-10-23 12:57:11 -0700337 atkbd.set= [HW] Select keyboard code set
338 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
340 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
341 keyboards
342
343 atkbd.softraw= [HW] Choose between synthetic and real raw mode
344 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700345
346 atkbd.softrepeat= [HW]
347 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
349 autotest [IA64]
350
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 baycom_epp= [HW,AX25]
352 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700353
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
355 Format: <io>,<mode>
356 See header of drivers/net/hamradio/baycom_par.c.
357
Randy Dunlapa9913042005-10-23 12:57:11 -0700358 baycom_ser_fdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 Format: <io>,<irq>,<mode>[,<baud>]
361 See header of drivers/net/hamradio/baycom_ser_fdx.c.
362
Randy Dunlapa9913042005-10-23 12:57:11 -0700363 baycom_ser_hdx= [HW,AX25]
364 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 Format: <io>,<irq>,<mode>
366 See header of drivers/net/hamradio/baycom_ser_hdx.c.
367
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700368 boot_delay= Milliseconds to delay each printk during boot.
369 Values larger than 10 seconds (10000) are changed to
370 no delay (0).
371 Format: integer
372
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700373 bootmem_debug [KNL] Enable bootmem allocator debug messages.
374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700376 bttv.radio= Most important insmod options are available as
377 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
379 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
380
381 BusLogic= [HW,SCSI]
382 See drivers/scsi/BusLogic.c, comment before function
383 BusLogic_ParseDriverOptions().
384
385 c101= [NET] Moxa C101 synchronous serial card
386
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700387 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 Sometimes CPU hardware bugs make them report the cache
389 size incorrectly. The kernel will attempt work arounds
390 to fix known problems, but for some CPUs it is not
391 possible to determine what the correct size should be.
392 This option provides an override for these situations.
393
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200394 security= [SECURITY] Choose a security module to enable at boot.
395 If this boot parameter is not specified, only the first
396 security module asking for security registration will be
397 loaded. An invalid security module name will be treated
398 as if no module has been chosen.
399
James Morris20510f22007-10-16 23:31:32 -0700400 capability.disable=
401 [SECURITY] Disable capabilities. This would normally
402 be used only if an alternative security model is to be
403 configured. Potentially dangerous and should only be
404 used if you are entirely sure of the consequences.
405
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100406 ccw_timeout_log [S390]
407 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
Paul Menage8bab8dd2008-04-04 14:29:57 -0700409 cgroup_disable= [KNL] Disable a particular controller
410 Format: {name of the controller(s) to disable}
411 {Currently supported controllers - "memory"}
412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 checkreqprot [SELINUX] Set initial checkreqprot flag value.
414 Format: { "0" | "1" }
415 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700416 0 -- check protection applied by kernel (includes
417 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 1 -- check protection requested by application.
419 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700420 Value can be changed at runtime via
421 /selinux/checkreqprot.
422
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100423 cio_ignore= [S390]
424 See Documentation/s390/CommonIO for details.
425
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700426 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700427 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200428 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700429 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200430 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 Format: { pit | tsc | cyclone | pmtmr }
432
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700433 clocksource= [GENERIC_TIME] Override the default clocksource
434 Format: <string>
435 Override the default clocksource and use the clocksource
436 with the name specified.
437 Some clocksource names to choose from, depending on
438 the platform:
439 [all] jiffies (this is the base, fallback clocksource)
440 [ACPI] acpi_pm
441 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
442 pxa_timer,timer3,32k_counter,timer0_1
443 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700444 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700445 scx200_hrt on Geode; cyclone on IBM x440
446 [MIPS] MIPS
447 [PARISC] cr16
448 [S390] tod
449 [SH] SuperH
450 [SPARC64] tick
451 [X86-64] hpet,tsc
452
Andi Kleenac72e782008-01-30 13:33:21 +0100453 clearcpuid=BITNUM [X86]
454 Disable CPUID feature X for the kernel. See
455 include/asm-x86/cpufeature.h for the valid bit numbers.
456 Note the Linux specific bits are not necessarily
457 stable over kernel options, but the vendor specific
458 ones should be.
459 Also note that user programs calling CPUID directly
460 or using the feature without checking anything
461 will still see it. This just prevents it from
462 being used by the kernel or shown in /proc/cpuinfo.
463 Also note the kernel might malfunction if you disable
464 some critical bits.
465
Arjan van de Vena25bd942008-01-30 13:33:08 +0100466 code_bytes [IA32/X86_64] How many bytes of object code to print
467 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100468 Range: 0 - 8192
469 Default: 64
470
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200471 hpet= [X86-32,HPET] option to control HPET usage
472 Format: { enable (default) | disable | force }
473 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100474 force: allow force enabled of undocumented chips (ICH4,
475 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700478 Format:
479 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480
481 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
482 Format: <io>[,<irq>]
483
Randy Dunlapa9913042005-10-23 12:57:11 -0700484 com90xx= [HW,NET]
485 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 Format: <io>[,<irq>[,<memstart>]]
487
488 condev= [HW,S390] console device
489 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700490
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 console= [KNL] Output console device and options.
492
493 tty<n> Use the virtual console device <n>.
494
495 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800496 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800498 the form "bbbbpnf", where "bbbb" is the baud rate,
499 "p" is parity ("n", "o", or "e"), "n" is number of
500 bits, and "f" is flow control ("r" for RTS or
501 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800503 See Documentation/serial-console.txt for more
504 information. See
505 Documentation/networking/netconsole.txt for an
506 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700508 uart[8250],io,<addr>[,options]
509 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 Start an early, polled-mode console on the 8250/16550
511 UART at the specified I/O port or MMIO address,
512 switching to the matching ttyS device later. The
513 options are the same as for ttyS, above.
514
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700515 If the device connected to the port is not a TTY but a braille
516 device, prepend "brl," before the device type, for instance
517 console=brl,ttyS0
518 For now, only VisioBraille is supported.
519
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700520 earlycon= [KNL] Output early console device and options.
521 uart[8250],io,<addr>[,options]
522 uart[8250],mmio,<addr>[,options]
523 Start an early, polled-mode console on the 8250/16550
524 UART at the specified I/O port or MMIO address.
525 The options are the same as for ttyS, above.
526
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700527 no_console_suspend
528 [HW] Never suspend the console
529 Disable suspending of consoles during suspend and
530 hibernate operations. Once disabled, debugging
531 messages can reach various consoles while the rest
532 of the system is being put to sleep (ie, while
533 debugging driver suspend/resume hooks). This may
534 not work reliably with all consoles, but is known
535 to work with serial and VGA consoles.
536
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700538 Format:
539 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700541 crashkernel=nn[KMG]@ss[KMG]
542 [KNL] Reserve a chunk of physical memory to
543 hold a kernel to switch to with kexec on panic.
544
Bernhard Wallefb391592007-10-18 23:41:02 -0700545 crashkernel=range1:size1[,range2:size2,...][@offset]
546 [KNL] Same as above, but depends on the memory
547 in the running system. The syntax of range is
548 start-[end] where start and end are both
549 a memory unit (amount[KMG]). See also
550 Documentation/kdump/kdump.txt for a example.
551
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 cs4232= [HW,OSS]
553 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
554
555 cs89x0_dma= [HW,NET]
556 Format: <dma>
557
558 cs89x0_media= [HW,NET]
559 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700560
Randy Dunlapa9913042005-10-23 12:57:11 -0700561 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 See header of drivers/s390/block/dasd_devmap.c.
563
564 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
565 (one device per port)
566 Format: <port#>,<type>
567 See also Documentation/input/joystick-parport.txt
568
569 debug [KNL] Enable kernel debugging (events log level).
570
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700571 debug_locks_verbose=
572 [KNL] verbose self-tests
573 Format=<0|1>
574 Print debugging info while doing the locking API
575 self-tests.
576 We default to 0 (no extra messages), setting it to
577 1 will print _a lot_ more information - normally
578 only useful to kernel developers.
579
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700580 debug_objects [KNL] Enable object debugging
581
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200582 debugpat [X86] Enable PAT debugging
583
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200584 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 Format: <area>[,<node>]
586 See also Documentation/networking/decnet.txt.
587
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000588 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700589 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
590 Change the default blue palette of the console.
591 This is a 16-member array composed of values
592 ranging from 0-255.
593
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000594 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700595 Format: <green0>,<green1>,<green2>,...,<green15>
596 Change the default green palette of the console.
597 This is a 16-member array composed of values
598 ranging from 0-255.
599
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000600 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700601 Format: <red0>,<red1>,<red2>,...,<red15>
602 Change the default red palette of the console.
603 This is a 16-member array composed of values
604 ranging from 0-255.
605
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000606 vt.default_utf8=
607 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700608 Format=<0|1>
609 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000610 Default is 1, i.e. UTF-8 mode is enabled for all
611 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 dhash_entries= [KNL]
614 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700615
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 digi= [HW,SERIAL]
617 IO parameters + enable/disable command.
618
619 digiepca= [HW,SERIAL]
620 See drivers/char/README.epca and
621 Documentation/digiepca.txt.
622
Yinghai Lu95ffa242008-04-29 03:52:33 -0700623 disable_mtrr_cleanup [X86]
624 enable_mtrr_cleanup [X86]
625 The kernel tries to adjust MTRR layout from continuous
626 to discrete, to make X server driver able to add WB
627 entry later. This parameter enables/disables that.
628
629 mtrr_chunk_size=nn[KMG] [X86]
630 used for mtrr cleanup. It is largest continous chunk
631 that could hold holes aka. UC entries.
632
633 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700634 Used for mtrr cleanup. It is granularity of mtrr block.
635 Default is 1.
636 Large value could prevent small alignment from
637 using up MTRRs.
638
639 mtrr_spare_reg_nr=n [X86]
640 Format: <integer>
641 Range: 0,7 : spare reg number
642 Default : 1
643 Used for mtrr cleanup. It is spare mtrr entries number.
644 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700645
Yinghai Lu093af8d2008-01-30 13:33:32 +0100646 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100647 By default the kernel will trim any uncacheable
648 memory out of your available memory pool based on
649 MTRR settings. This parameter disables that behavior,
650 possibly causing your machine to run very slowly.
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 dmasound= [HW,OSS] Sound subsystem buffers
653
654 dscc4.setup= [NET]
655
656 dtc3181e= [HW,SCSI]
657
Robin Getz0ae53642007-10-09 17:24:49 +0800658 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 earlyprintk=vga
660 earlyprintk=serial[,ttySn[,baudrate]]
661
Randy Dunlapa9913042005-10-23 12:57:11 -0700662 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 takes over.
664
665 Only vga or serial at a time, not both.
666
667 Currently only ttyS0 and ttyS1 are supported.
668
669 Interaction with the standard serial driver is not
670 very good.
671
672 The VGA output is eventually overwritten by the real
673 console.
674
675 eata= [HW,SCSI]
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700678 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 eisa_irq_edge= [PARISC,HW]
681 See header of drivers/parisc/eisa.c.
682
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700683 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700685 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686
687 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800688 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700689 See Documentation/block/as-iosched.txt and
690 Documentation/block/deadline-iosched.txt for details.
691
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700692 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700693 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800694 image elf header. Generally kexec loader will
695 pass this option to capture kernel.
696 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
698 enforcing [SELINUX] Set initial enforcing status.
699 Format: {"0" | "1"}
700 See security/selinux/Kconfig help text.
701 0 -- permissive (log only, no denials).
702 1 -- enforcing (deny and log).
703 Default value is 0.
704 Value can be changed at runtime via /selinux/enforce.
705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 es1371= [HW,OSS]
707 Format: <spdif>,[<nomix>,[<amplifier>]]
708 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700709
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 ether= [HW,NET] Ethernet cards parameters
711 This option is obsoleted by the "netdev=" option, which
712 has equivalent usage. See its documentation for details.
713
714 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
715 Format: <io>[,<irq>]
716
Akinobu Mitade1ba092006-12-08 02:39:42 -0800717 failslab=
718 fail_page_alloc=
719 fail_make_request=[KNL]
720 General fault injection mechanism.
721 Format: <interval>,<probability>,<space>,<times>
722 See also /Documentation/fault-injection/.
723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 fd_mcs= [HW,SCSI]
725 See header of drivers/scsi/fd_mcs.c.
726
727 fdomain= [HW,SCSI]
728 See header of drivers/scsi/fdomain.c.
729
730 floppy= [HW]
731 See Documentation/floppy.txt.
732
Alex Chiangf13ae302008-05-08 14:03:23 -0600733 force_pal_cache_flush
734 [IA-64] Avoid check_sal_cache_flush which may hang on
735 buggy SAL_CACHE_FLUSH implementations. Using this
736 parameter will force ia64_sal_cache_flush to call
737 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
738
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 gamecon.map[2|3]=
740 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
741 support via parallel port (up to 5 devices per port)
742 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
743 See also Documentation/input/joystick-parport.txt
744
745 gamma= [HW,DRM]
746
Yinghai Luaaf23042008-01-30 13:33:09 +0100747 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
748 Format: off | on
749 default: on
750
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 gdth= [HW,SCSI]
752 See header of drivers/scsi/gdth.c.
753
754 gpt [EFI] Forces disk with valid GPT signature but
755 invalid Protective MBR to be treated as GPT.
756
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 gvp11= [HW,SCSI]
758
759 hashdist= [KNL,NUMA] Large hashes allocated during boot
760 are distributed across NUMA nodes. Defaults on
761 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700762 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763
764 hcl= [IA-64] SGI's Hardware Graph compatibility layer
765
766 hd= [EIDE] (E)IDE hard drive subsystem geometry
767 Format: <cyl>,<head>,<sect>
768
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
770 size of <nn>. This works even on boxes that have no
771 highmem otherwise. This also works to reduce highmem
772 size on bigger boxes.
773
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800774 highres= [KNL] Enable/disable high resolution timer mode.
775 Valid parameters: "on", "off"
776 Default: "on"
777
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 hisax= [HW,ISDN]
779 See Documentation/isdn/README.HiSax.
780
Andi Kleenb4718e62008-07-23 21:27:51 -0700781 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
782 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700783 On x86-64 and powerpc, this option can be specified
784 multiple times interleaved with hugepages= to reserve
785 huge pages of different sizes. Valid pages sizes on
786 x86-64 are 2M (when the CPU supports "pse") and 1G
787 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700788 Note that 1GB pages can only be allocated at boot time
789 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700790 default_hugepagesz=
791 [same as hugepagesz=] The size of the default
792 HugeTLB page size. This is the size represented by
793 the legacy /proc/ hugepages APIs, used for SHM, and
794 default size when mounting hugetlbfs filesystems.
795 Defaults to the default architecture's huge page size
796 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200799 i8042.dumbkbd [HW] Pretend that controller can only read data from
800 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 (Don't attempt to blink the leds)
802 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500803 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400804 i8042.noloop [HW] Disable the AUX Loopback command while probing
805 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 i8042.nomux [HW] Don't check presence of an active multiplexing
807 controller
808 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
809 controllers
810 i8042.panicblink=
811 [HW] Frequency with which keyboard LEDs should blink
812 when kernel panics (default is 0.5 sec)
813 i8042.reset [HW] Reset the controller during init and cleanup
814 i8042.unlock [HW] Unlock (ignore) the keylock
815
816 i810= [HW,DRM]
817
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700818 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
819 indicates that the driver is running on unsupported
820 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
822 does not match list of supported models.
823 i8k.power_status
824 [HW] Report power status in /proc/i8k
825 (disabled by default)
826 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
827 capability is set.
828
829 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
830 See Documentation/mca.txt.
831
832 icn= [HW,ISDN]
833 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
834
835 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200836 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100837 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100840 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841
Andi Kleenf039b752007-05-02 19:27:12 +0200842 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800843 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200844 Poll forces a polling idle loop that can slightly improves the performance
845 of waking up a idle CPU, but will use a lot of power and make the system
846 run hot. Not recommended.
847 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
848 to not use it because it doesn't save as much power as a normal idle
849 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
850 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800851 idle=halt. Halt is forced to be used for CPU idle.
852 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800853 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700854
Denis Cheng594765a2008-02-06 02:57:49 +0100855 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
856 Claim all unknown PCI IDE storage controllers.
857
Ingo Molnar792908222006-12-06 20:40:51 -0800858 ignore_loglevel [KNL]
859 Ignore loglevel setting - this will print /all/
860 kernel messages to the console. Useful for debugging.
861
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 ihash_entries= [KNL]
863 Set number of hash buckets for inode cache.
864
865 in2000= [HW,SCSI]
866 See header of drivers/scsi/in2000.c.
867
868 init= [KNL]
869 Format: <full_path>
870 Run specified binary instead of /sbin/init as init
871 process.
872
873 initcall_debug [KNL] Trace initcalls as they are executed. Useful
874 for working out where the kernel is dying during
875 startup.
876
877 initrd= [BOOT] Specify the location of the initial ramdisk
878
879 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
880 Format: <irq>
881
882 inttest= [IA64]
883
Pavel Machekb552da82008-03-19 15:58:11 +0100884 iommu= [x86]
885 off
886 force
887 noforce
888 biomerge
889 panic
890 nopanic
891 merge
892 nomerge
893 forcesac
894 soft
895
896
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700897 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
898 off
899 Disable intel iommu driver.
900 igfx_off [Default Off]
901 By default, gfx is mapped as normal device. If a gfx
902 device has a dedicated DMAR unit, the DMAR unit is
903 bypassed by not enabling DMAR with this option. In
904 this case, gfx device will use physical address for
905 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700906 forcedac [x86_64]
907 With this option iommu will not optimize to look
908 for io virtual address below 32 bit forcing dual
909 address cycle on pci bus for cards supporting greater
910 than 32 bit addressing. The default is to look
911 for translation below 32 bit and if not available
912 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800913 strict [Default Off]
914 With this option on every unmap_single operation will
915 result in a hardware IOTLB flush operation as opposed
916 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700917
Rene Hermanb02aae92008-01-30 13:30:05 +0100918 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100919 0x80
920 Standard port 0x80 based delay
921 0xed
922 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100923 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100924 Simple two microseconds delay
925 none
926 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100927
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 io7= [HW] IO7 for Marvel based alpha systems
929 See comment before marvel_specify_io7 in
930 arch/alpha/kernel/core_marvel.c.
931
932 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400933 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934
935 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700936 See comment before ip2_setup() in
937 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938
939 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
940 See header of drivers/scsi/ips.c.
941
Simon Horman72c4a132006-09-13 19:57:18 -0700942 ports= [IP_VS_FTP] IPVS ftp helper module
943 Default is 21.
944 Up to 8 (IP_VS_APP_MAX_PORTS) ports
945 may be specified.
946 Format: <port>,<port>....
947
Alan Cox200803d2005-06-28 20:45:18 -0700948 irqfixup [HW]
949 When an interrupt is not handled search all handlers
950 for it. Intended to get systems with badly broken
951 firmware running.
952
953 irqpoll [HW]
954 When an interrupt is not handled search all handlers
955 for it. Also check all handlers each timer
956 interrupt. Intended to get systems with badly broken
957 firmware running.
958
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700960 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961
962 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800963 Format:
964 <cpu number>,...,<cpu number>
965 or
966 <cpu number>-<cpu number> (must be a positive range in ascending order)
967 or a mixture
968 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 This option can be used to specify one or more CPUs
970 to isolate from the general SMP balancing and scheduling
971 algorithms. The only way to move a process onto or off
972 an "isolated" CPU is via the CPU affinity syscalls.
973 <cpu number> begins at 0 and the maximum value is
974 "number of CPUs in system - 1".
975
976 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700977 alternative -- manually setting the CPU mask of all
978 tasks in the system -- can cause problems and
979 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980
Randy Dunlapa9913042005-10-23 12:57:11 -0700981 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
983 js= [HW,JOY] Analog joystick
984 See Documentation/input/joystick.txt.
985
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700986 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700987 specifies the amount of memory usable by the kernel
988 for non-movable allocations. The requested amount is
989 spread evenly throughout all nodes in the system. The
990 remaining memory in each node is used for Movable
991 pages. In the event, a node is too small to have both
992 kernelcore and Movable pages, kernelcore pages will
993 take priority and other nodes will have a larger number
994 of kernelcore pages. The Movable zone is used for the
995 allocation of pages that may be reclaimed or moved
996 by the page migration subsystem. This means that
997 HugeTLB pages may not be allocated from this zone.
998 Note that allocations like PTEs-from-HighMem still
999 use the HighMem zone if it exists, and the Normal
1000 zone if it does not.
1001
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001002 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001003 is similar to kernelcore except it specifies the
1004 amount of memory used for migratable allocations.
1005 If both kernelcore and movablecore is specified,
1006 then kernelcore will be at *least* the specified
1007 value but may be more. If movablecore on its own
1008 is specified, the administrator must be careful
1009 that the amount of memory usable for all allocations
1010 is not too small.
1011
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 keepinitrd [HW,ARM]
1013
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001014 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 in oops dumps.
1016
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001017 kgdboc= [HW] kgdb over consoles.
1018 Requires a tty driver that supports console polling.
1019 (only serial suported for now)
1020 Format: <serial_device>[,baud]
1021
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001022 kmac= [MIPS] korina ethernet MAC address.
1023 Configure the RouterBoard 532 series on-chip
1024 Ethernet adapter MAC address.
1025
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 l2cr= [PPC]
1027
Robert Brosea78bfbf2008-03-29 07:20:23 +11001028 l3cr= [PPC]
1029
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001030 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001031 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001033 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001034 C2 power state.
1035
FD Camifcb71f62008-01-06 19:08:56 +01001036 libata.dma= [LIBATA] DMA control
1037 libata.dma=0 Disable all PATA and SATA DMA
1038 libata.dma=1 PATA and SATA Disk DMA only
1039 libata.dma=2 ATAPI (CDROM) DMA only
1040 libata.dma=4 Compact Flash DMA only
1041 Combinations also work, so libata.dma=3 enables DMA
1042 for disks and CDROMs, but not CFs.
1043
Dave Jones78e70c22007-09-27 11:50:13 -04001044 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1045 when set.
1046 Format: <int>
1047
Tejun Heo33267322008-02-13 09:15:09 +09001048 libata.force= [LIBATA] Force configurations. The format is comma
1049 separated list of "[ID:]VAL" where ID is
1050 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1051 matching port, link or device. Basically, it matches
1052 the ATA ID string printed on console by libata. If
1053 the whole ID part is omitted, the last PORT and DEVICE
1054 values are used. If ID hasn't been specified yet, the
1055 configuration applies to all ports, links and devices.
1056
1057 If only DEVICE is omitted, the parameter applies to
1058 the port and all links and devices behind it. DEVICE
1059 number of 0 either selects the first device or the
1060 first fan-out link behind PMP device. It does not
1061 select the host link. DEVICE number of 15 selects the
1062 host link and device attached to it.
1063
1064 The VAL specifies the configuration to force. As long
1065 as there's no ambiguity shortcut notation is allowed.
1066 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1067 The following configurations can be forced.
1068
1069 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1070 Any ID with matching PORT is used.
1071
1072 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1073
1074 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1075 udma[/][16,25,33,44,66,100,133] notation is also
1076 allowed.
1077
1078 * [no]ncq: Turn on or off NCQ.
1079
Tejun Heo05944bd2008-08-13 20:19:09 +09001080 * nohrst, nosrst, norst: suppress hard, soft
1081 and both resets.
1082
Tejun Heo33267322008-02-13 09:15:09 +09001083 If there are multiple matching configurations changing
1084 the same attribute, the last one is used.
1085
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 load_ramdisk= [RAM] List of ramdisks to load from floppy
1087 See Documentation/ramdisk.txt.
1088
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001089 lockd.nlm_grace_period=P [NFS] Assign grace period.
1090 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001092 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1093 Format: <integer>
1094
1095 lockd.nlm_timeout=T [NFS] Assign timeout value.
1096 Format: <integer>
1097
1098 lockd.nlm_udpport=M [NFS] Assign UDP port.
1099 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100
1101 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1102 Format: <irq>
1103
1104 loglevel= All Kernel Messages with a loglevel smaller than the
1105 console loglevel will be printed to the console. It can
1106 also be changed with klogd or other programs. The
1107 loglevels are defined as follows:
1108
1109 0 (KERN_EMERG) system is unusable
1110 1 (KERN_ALERT) action must be taken immediately
1111 2 (KERN_CRIT) critical conditions
1112 3 (KERN_ERR) error conditions
1113 4 (KERN_WARNING) warning conditions
1114 5 (KERN_NOTICE) normal but significant condition
1115 6 (KERN_INFO) informational
1116 7 (KERN_DEBUG) debug-level messages
1117
1118 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001119 Format: { n | nk | nM }
1120 n must be a power of two. The default size
1121 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122
Randy Dunlapaccaa242007-10-16 01:29:37 -07001123 logo.nologo [FB] Disables display of the built-in Linux logo.
1124 This may be used to provide more screen space for
1125 kernel log messages and is useful when debugging
1126 kernel boot problems.
1127
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 lp=0 [LP] Specify parallel ports to use, e.g,
1129 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1130 lp=reset first parallel port). 'lp=0' disables the
1131 lp=auto printer driver. 'lp=reset' (which can be
1132 specified in addition to the ports) causes
1133 attached printers to be reset. Using
1134 lp=port1,port2,... specifies the parallel ports
1135 to associate lp devices with, starting with
1136 lp0. A port specification may be 'none' to skip
1137 that lp device, or a parport name such as
1138 'parport0'. Specifying 'lp=auto' instead of a
1139 port specification list means that device IDs
1140 from each port should be examined, to see if
1141 an IEEE 1284-compliant printer is attached; if
1142 so, the driver will manage that printer.
1143 See also header of drivers/char/lp.c.
1144
1145 lpj=n [KNL]
1146 Sets loops_per_jiffy to given constant, thus avoiding
1147 time-consuming boot-time autodetection (up to 250 ms per
1148 CPU). 0 enables autodetection (default). To determine
1149 the correct value for your kernel, boot with normal
1150 autodetection and see what value is printed. Note that
1151 on SMP systems the preset will be applied to all CPUs,
1152 which is likely to cause problems if your CPUs need
1153 significantly divergent settings. An incorrect value
1154 will cause delays in the kernel to be wrong, leading to
1155 unpredictable I/O errors and other breakage. Although
1156 unlikely, in the extreme case this might damage your
1157 hardware.
1158
1159 ltpc= [NET]
1160 Format: <io>,<irq>,<dma>
1161
Randy Dunlapa9913042005-10-23 12:57:11 -07001162 mac5380= [HW,SCSI] Format:
1163 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164
Randy Dunlapa9913042005-10-23 12:57:11 -07001165 machvec= [IA64] Force the use of a particular machine-vector
1166 (machvec) in a generic kernel.
1167 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168
Randy Dunlapa9913042005-10-23 12:57:11 -07001169 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 be mounted
1171 Format: <1-256>
1172
1173 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001174 should make use of. maxcpus=n : n >= 0 limits the
1175 kernel to using 'n' processors. n=0 is a special case,
1176 it is equivalent to "nosmp", which also disables
1177 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178
Bob Picco2b2c3752005-06-29 18:00:00 -07001179 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1180 equal to this physical address is ignored.
1181
Randy Dunlapa9913042005-10-23 12:57:11 -07001182 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183 Should be between 1 and 2^32-1.
1184
1185 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001186 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 Should be between 1 and 16384.
1188
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 mcatest= [IA-64]
1190
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001191 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192
Andi Kleen909dd322007-10-17 18:04:38 +02001193 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1194
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 md= [HW] RAID subsystems devices and level
1196 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001197
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 mdacon= [MDA]
1199 Format: <first>,<last>
1200 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001201
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1203 Amount of memory to be used when the kernel is not able
1204 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001205 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 address space collisions. Without memmap= PCI devices
1207 could be placed at addresses belonging to unused RAM.
1208
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001209 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 memory.
1211
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001212 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 E820 memory map, as specified by the user.
1214 Such memmap=exactmap lines can be constructed based on
1215 BIOS output or other requirements. See the memmap=nn@ss
1216 option description.
1217
1218 memmap=nn[KMG]@ss[KMG]
1219 [KNL] Force usage of a specific region of memory
1220 Region of memory to be used, from ss to ss+nn.
1221
1222 memmap=nn[KMG]#ss[KMG]
1223 [KNL,ACPI] Mark specific memory as ACPI data.
1224 Region of memory to be used, from ss to ss+nn.
1225
1226 memmap=nn[KMG]$ss[KMG]
1227 [KNL,ACPI] Mark specific memory as reserved.
1228 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001229 Example: Exclude memory from 0x18690000-0x1869ffff
1230 memmap=64K$0x18690000
1231 or
1232 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001234 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001235 Format: <integer>
1236 range: 0,4 : pattern number
1237 default : 0 <disable>
1238
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239 meye.*= [HW] Set MotionEye Camera parameters
1240 See Documentation/video4linux/meye.txt.
1241
Andres Salomon8f368812007-10-12 23:04:06 +02001242 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1243 Multi-Function General Purpose Timers on AMD Geode
1244 platforms.
1245
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001246 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1247 the BIOS has incorrectly applied a workaround. TinyBIOS
1248 version 0.98 is known to be affected, 0.99 fixes the
1249 problem by letting the user disable the workaround.
1250
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 mga= [HW,DRM]
1252
Mel Gorman6b74ab92008-07-23 21:26:49 -07001253 mminit_loglevel=
1254 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1255 parameter allows control of the logging verbosity for
1256 the additional memory initialisation checks. A value
1257 of 0 disables mminit logging and a level of 4 will
1258 log everything. Information is printed at KERN_DEBUG
1259 so loglevel=8 may also need to be specified.
1260
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 mousedev.tap_time=
1262 [MOUSE] Maximum time between finger touching and
1263 leaving touchpad surface for touch to be considered
1264 a tap and be reported as a left button click (for
1265 touchpads working in absolute mode only).
1266 Format: <msecs>
1267 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1268 reporting absolute coordinates, such as tablets
1269 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1270 reporting absolute coordinates, such as tablets
1271
1272 mpu401= [HW,OSS]
1273 Format: <io>,<irq>
1274
1275 MTD_Partition= [MTD]
1276 Format: <name>,<region-number>,<size>,<offset>
1277
Randy Dunlapa9913042005-10-23 12:57:11 -07001278 MTD_Region= [MTD] Format:
1279 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280
1281 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001282 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283
Ben Dooks9db829f2008-07-03 11:24:29 +01001284 mtdset= [ARM]
1285 ARM/S3C2412 JIVE boot control
1286
1287 See arch/arm/mach-s3c2412/mach-jive.c
1288
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001290 [HW] Make the MicroTouch USB driver use raw coordinates
1291 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292
1293 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1294
1295 NCR_D700= [HW,SCSI]
1296 See header of drivers/scsi/NCR_D700.c.
1297
1298 ncr5380= [HW,SCSI]
1299
1300 ncr53c400= [HW,SCSI]
1301
1302 ncr53c400a= [HW,SCSI]
1303
1304 ncr53c406a= [HW,SCSI]
1305
1306 ncr53c8xx= [HW,SCSI]
1307
1308 netdev= [NET] Network devices parameters
1309 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1310 Note that mem_start is often overloaded to mean
1311 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001312 This usage is only documented in each driver source
1313 file if at all.
1314
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001315 nf_conntrack.acct=
1316 [NETFILTER] Enable connection tracking flow accounting
1317 0 to disable accounting
1318 1 to enable accounting
1319 Default value depends on CONFIG_NF_CT_ACCT that is
1320 going to be removed in 2.6.29.
1321
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001323 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324
1325 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001326 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327
Trond Myklebusta72b4422006-01-03 09:55:41 +01001328 nfs.callback_tcpport=
1329 [NFS] set the TCP port on which the NFSv4 callback
1330 channel should listen.
1331
Trond Myklebust58df0952006-01-03 09:55:57 +01001332 nfs.idmap_cache_timeout=
1333 [NFS] set the maximum lifetime for idmapper cache
1334 entries.
1335
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001336 nfs.enable_ino64=
1337 [NFS] enable 64-bit inode numbers.
1338 If zero, the NFS client will fake up a 32-bit inode
1339 number for the readdir() and stat() syscalls instead
1340 of returning the full 64-bit number.
1341 The default is to return 64-bit inode numbers.
1342
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001343 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1344 when a NMI is triggered.
1345 Format: [state][,regs][,debounce][,die]
1346
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001347 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001349 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 emulation library even if a 387 maths coprocessor
1351 is present.
1352
Christoph Lameterc1aee212007-05-31 00:40:47 -07001353 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1354 caches in the slab allocator. Saves per-node memory,
1355 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001356
Randy Dunlapa9913042005-10-23 12:57:11 -07001357 noalign [KNL,ARM]
1358
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 noapic [SMP,APIC] Tells the kernel to not make use of any
1360 IOAPICs that may be present in the system.
1361
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 nobats [PPC] Do not use BATs for mapping kernel lowmem
1363 on "Classic" PPC cores.
1364
1365 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001366
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001367 nodelayacct [KNL] Disable per-task delay accounting
1368
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1370
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001371 noefi [X86-32,X86-64] Disable EFI runtime services support.
1372
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373 noexec [IA-64]
1374
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001375 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001376 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001378 noexec=off: disable non-executable mappings
1379
1380 noexec32 [X86-64]
1381 This affects only 32-bit executables.
1382 noexec32=on: enable non-executable mappings (default)
1383 read doesn't imply executable mappings
1384 noexec32=off: disable non-executable mappings
1385 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001387 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001388 register save and restore. The kernel will only save
1389 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390
Andi Kleen191679f2008-01-30 13:33:21 +01001391 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1392
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001394
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001395 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396 instruction doesn't work correctly and not to
1397 use it.
1398
1399 nohalt [IA-64] Tells the kernel not to use the power saving
1400 function PAL_HALT_LIGHT when idle. This increases
1401 power-consumption. On the positive side, it reduces
1402 interrupt wake-up latency, which may improve performance
1403 in certain environments such as networked servers or
1404 real-time systems.
1405
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001406 nohz= [KNL] Boottime enable/disable dynamic ticks
1407 Valid arguments: on, off
1408 Default: on
1409
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001410 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001411
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001412 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413 disable unhandled interrupt sources.
1414
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001415 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001416 broken timer IRQ sources.
1417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 noisapnp [ISAPNP] Disables ISA PnP code.
1419
1420 noinitrd [RAM] Tells the kernel not to load any configured
1421 initial RAM disk.
1422
1423 nointroute [IA-64]
1424
Tony Luck0aa366f2007-07-20 11:22:30 -07001425 nojitter [IA64] Disables jitter checking for ITC timers.
1426
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001427 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001429 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001430
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 noltlbs [PPC] Do not use large page/tlb entries for kernel
1432 lowmem mapping on PPC40x.
1433
Horms312f1f02006-02-22 09:57:55 +09001434 nomca [IA-64] Disable machine check abort handling
1435
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001436 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001437
Andres Salomon83d73842007-10-12 23:04:06 +02001438 nomfgpt [X86-32] Disable Multi-Function General Purpose
1439 Timer usage (for AMD Geode machines).
1440
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001441 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001442
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001443 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001444 with UP alternatives
1445
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 noresidual [PPC] Don't use residual data on PReP machines.
1447
Randy Dunlapa9913042005-10-23 12:57:11 -07001448 noresume [SWSUSP] Disables resume and restores original swap
1449 space.
1450
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451 no-scroll [VGA] Disables scrollback.
1452 This is required for the Braillex ib80-piezo Braille
1453 reader made by F.H. Papenmeier (Germany).
1454
1455 nosbagart [IA-64]
1456
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001457 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001458
Len Brown61ec7562007-08-16 03:34:22 -04001459 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1460 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461
Dave Jones97842212007-07-15 23:41:05 -07001462 nosoftlockup [KNL] Disable the soft-lockup detector.
1463
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 nosync [HW,M68K] Disables sync negotiation for all devices.
1465
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001466 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467
1468 nousb [USB] Disable the USB subsystem
1469
1470 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001471
Fenghua Yua6c75b862008-03-14 13:57:08 -07001472 nptcg= [IA64] Override max number of concurrent global TLB
1473 purges which is reported from either PAL_VM_SUMMARY or
1474 SAL PALO.
1475
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001476 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1477 one of ['zone', 'node', 'default'] can be specified
1478 This can be set from sysctl after boot.
1479 See Documentation/sysctl/vm.txt for details.
1480
Dave Jonesa61c2d72006-01-07 23:18:19 +00001481 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1482
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001483 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1484 Rather than timing out after 20 ms if an EC
1485 command is not properly ACKed, override the length
1486 of the timeout. We have interrupts disabled while
1487 waiting for the ACK, so if this is set too high
1488 interrupts *may* be lost!
1489
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 opl3= [HW,OSS]
1491 Format: <io>
1492
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 oprofile.timer= [HW]
1494 Use timer interrupt instead of performance counters
1495
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 osst= [HW,SCSI] SCSI Tape Driver
1497 Format: <buffer_size>,<write_threshold>
1498 See also Documentation/scsi/st.txt.
1499
1500 panic= [KNL] Kernel behaviour on panic
1501 Format: <timeout>
1502
1503 parkbd.port= [HW] Parallel port number the keyboard adapter is
1504 connected to, default is 0.
1505 Format: <parport#>
1506 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1507 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001508 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001509
Randy Dunlapa9913042005-10-23 12:57:11 -07001510 parport= [HW,PPT] Specify parallel ports. 0 disables.
1511 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1512 Use 'auto' to force the driver to use any
1513 IRQ/DMA settings detected (the default is to
1514 ignore detected IRQ/DMA settings because of
1515 possible conflicts). You can specify the base
1516 address, IRQ, and DMA settings; IRQ and DMA
1517 should be numbers, or 'auto' (for using detected
1518 settings on that particular port), or 'nofifo'
1519 (to avoid using a FIFO even if it is detected).
1520 Parallel ports are assigned in the order they
1521 are specified on the command line, starting
1522 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523
Randy Dunlapa9913042005-10-23 12:57:11 -07001524 parport_init_mode= [HW,PPT]
1525 Configure VIA parallel port to operate in
1526 a specific mode. This is necessary on Pegasos
1527 computer where firmware has no options for setting
1528 up parallel port mode and sets it to spp.
1529 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 Format: [spp|ps2|epp|ecp|ecpepp]
1531
Randy Dunlapa9913042005-10-23 12:57:11 -07001532 pas2= [HW,OSS] Format:
1533 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1534
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535 pas16= [HW,SCSI]
1536 See header of drivers/scsi/pas16.c.
1537
Andrew Mortondd287792006-03-23 03:00:57 -08001538 pause_on_oops=
1539 Halt all CPUs after the first oops has been printed for
1540 the specified number of seconds. This is to be used if
1541 your oopses keep scrolling off the screen.
1542
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543 pcbit= [HW,ISDN]
1544
1545 pcd. [PARIDE]
1546 See header of drivers/block/paride/pcd.c.
1547 See also Documentation/paride.txt.
1548
Randy Dunlapa9913042005-10-23 12:57:11 -07001549 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001550 off [X86-32] don't probe for the PCI bus
1551 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001552 the hardware directly. Use this if your machine
1553 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001554 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001555 hardware access methods are allowed. Use this
1556 if you experience crashes upon bootup and you
1557 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001558 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001559 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001560 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001561 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001562 noaer [PCIE] If the PCIEAER kernel config parameter is
1563 enabled, this kernel boot option can be used to
1564 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001565 nodomains [PCI] Disable support for multiple PCI
1566 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001567 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001568 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001569 nomsi [MSI] If the PCI_MSI kernel config parameter is
1570 enabled, this kernel boot option can be used to
1571 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001572 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001573 routing table. These calls are known to be buggy
1574 on several machines and they hang the machine
1575 when used, but on other computers it's the only
1576 way to get the interrupt routing table. Try
1577 this option if the kernel is unable to allocate
1578 IRQs or discover secondary PCI buses on your
1579 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001580 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001581 Use with caution as certain devices share
1582 address decoders between ROMs and other
1583 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001584 norom [X86-32,X86_64] Do not assign address space to
1585 expansion ROMs that do not already have
1586 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001587 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001588 assigned automatically to PCI devices. You can
1589 make the kernel exclude IRQs of your ISA cards
1590 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001591 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001592 of the PIRQ table (normally generated
1593 by the BIOS) if it is outside the
1594 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001595 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001596 useful if the kernel is unable to find your
1597 secondary buses and you want to tell it
1598 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001599 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001600 numbers ourselves, overriding
1601 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001602 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001603 in the BIOS $PIR table. This is needed on
1604 some systems with broken BIOSes, notably
1605 some HP Pavilion N5400 and Omnibook XE3
1606 notebooks. This will have no effect if ACPI
1607 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001608 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001609 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001610 use_crs [X86-32] Use _CRS for PCI resource
1611 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001612 routeirq Do IRQ routing for all PCI devices.
1613 This is normally done in pci_enable_device(),
1614 so this option is a temporary workaround
1615 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001616 skip_isa_align [X86] do not align io start addr, so can
1617 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001618 firmware [ARM] Do not re-enumerate the bus but instead
1619 just use the configuration from the
1620 bootloader. This is currently used on
1621 IXP2000 systems where the bus has to be
1622 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001623 noearly [X86] Don't do any early type 1 scanning.
1624 This might help on some broken boards which
1625 machine check when some devices' config space
1626 is read. But various workarounds are disabled
1627 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001628 bfsort Sort PCI devices into breadth-first order.
1629 This sorting is done to get a device
1630 order compatible with older (<= 2.4) kernels.
1631 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001632 cbiosize=nn[KMG] The fixed amount of bus space which is
1633 reserved for the CardBus bridge's IO window.
1634 The default value is 256 bytes.
1635 cbmemsize=nn[KMG] The fixed amount of bus space which is
1636 reserved for the CardBus bridge's memory
1637 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001638
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639 pcmv= [HW,PCMCIA] BadgePAD 4
1640
1641 pd. [PARIDE]
1642 See Documentation/paride.txt.
1643
1644 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1645 boot time.
1646 Format: { 0 | 1 }
1647 See arch/parisc/kernel/pdc_chassis.c
1648
1649 pf. [PARIDE]
1650 See Documentation/paride.txt.
1651
1652 pg. [PARIDE]
1653 See Documentation/paride.txt.
1654
1655 pirq= [SMP,APIC] Manual mp-table setup
1656 See Documentation/i386/IO-APIC.txt.
1657
1658 plip= [PPT,NET] Parallel port network link
1659 Format: { parport<nr> | timid | 0 }
1660 See also Documentation/parport.txt.
1661
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001662 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1663 Override pmtimer IOPort with a hex value.
1664 e.g. pmtmr=0x508
1665
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 pnpacpi= [ACPI]
1667 { off }
1668
1669 pnpbios= [ISAPNP]
1670 { on | off | curr | res | no-curr | no-res }
1671
1672 pnp_reserve_irq=
1673 [ISAPNP] Exclude IRQs for the autoconfiguration
1674
1675 pnp_reserve_dma=
1676 [ISAPNP] Exclude DMAs for the autoconfiguration
1677
1678 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001679 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680
1681 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001682 [ISAPNP] Exclude memory regions for the
1683 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684 Ranges are in pairs (memory base and size).
1685
Ingo Molnar45807a12007-07-15 23:40:10 -07001686 print-fatal-signals=
1687 [KNL] debug: print fatal signals
1688 print-fatal-signals=1: print segfault info to
1689 the kernel console.
1690 default: off.
1691
Randy Dunlape84845c2007-07-15 23:40:25 -07001692 printk.time= Show timing data prefixed to each printk message line
1693 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1694
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001696 Format: [schedule,]<number>
1697 Param: "schedule" - profile schedule points.
1698 Param: <number> - step/bucket size as a power of 2 for
1699 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001700 Param: "sleep" - profile D-state sleeping (millisecs).
1701 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001702 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703
Randy Dunlapa9913042005-10-23 12:57:11 -07001704 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705 Limit processor to maximum C-state
1706 max_cstate=9 overrides any DMI blacklist limit.
1707
Len Brown41c0d862005-12-28 12:43:51 -05001708 processor.nocst [HW,ACPI]
1709 Ignore the _CST method to determine C-states,
1710 instead using the legacy FADT method
1711
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1713 before loading.
1714 See Documentation/ramdisk.txt.
1715
Randy Dunlapa9913042005-10-23 12:57:11 -07001716 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1717 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1719 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001720 psmouse.resetafter= [HW,MOUSE]
1721 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 (0 = never).
1723 psmouse.resolution=
1724 [HW,MOUSE] Set desired mouse resolution, in dpi.
1725 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001726 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727 0 = disabled, 1 = enabled (default).
1728
1729 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001730 Format:
1731 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732
1733 pt. [PARIDE]
1734 See Documentation/paride.txt.
1735
Kay Sieversdc8c8582007-08-15 12:25:38 +02001736 pty.legacy_count=
1737 [KNL] Number of legacy pty's. Overwrites compiled-in
1738 default number.
1739
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001740 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001741
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 r128= [HW,DRM]
1743
1744 raid= [HW,RAID]
1745 See Documentation/md.txt.
1746
Randy Dunlapa9913042005-10-23 12:57:11 -07001747 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001749
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 See Documentation/ramdisk.txt.
1752
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001753 rcupdate.blimit= [KNL,BOOT]
1754 Set maximum number of finished RCU callbacks to process
1755 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001756
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001757 rcupdate.qhimark= [KNL,BOOT]
1758 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001759 RCU callbacks over which batch limiting is disabled.
1760
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001761 rcupdate.qlowmark= [KNL,BOOT]
1762 Set threshold of queued RCU callbacks below which
1763 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001764
Olof Johanssonffdfc402005-09-06 15:17:19 -07001765 rdinit= [KNL]
1766 Format: <full_path>
1767 Run specified binary instead of /init from the ramdisk,
1768 used for early userspace startup. See initrd.
1769
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001770 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001772 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773
Paul Jackson46b6d942008-07-04 10:00:09 -07001774 relax_domain_level=
1775 [KNL, SMP] Set scheduler's default relax_domain_level.
1776 See Documentation/cpusets.txt.
1777
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1779
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001780 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001781 Format: nn[KMG]
1782 Reserves a hole at the top of the kernel virtual
1783 address space.
1784
Vivek Goyal7e962872006-09-27 01:50:44 -07001785 reset_devices [KNL] Force drivers to reset the underlying device
1786 during initialization.
1787
Randy Dunlapa9913042005-10-23 12:57:11 -07001788 resume= [SWSUSP]
1789 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001790
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001791 resume_offset= [SWSUSP]
1792 Specify the offset from the beginning of the partition
1793 given by "resume=" at which the swap header is located,
1794 in <PAGE_SIZE> units (needed only for swap files).
1795 See Documentation/power/swsusp-and-swap-files.txt
1796
Michael Neuling0a7b35c2007-02-10 01:44:33 -08001797 retain_initrd [RAM] Keep initrd memory after extraction
1798
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 rhash_entries= [KNL,NET]
1800 Set number of hash buckets for route cache
1801
1802 riscom8= [HW,SERIAL]
1803 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1804
1805 ro [KNL] Mount root device read-only on boot
1806
1807 root= [KNL] Root filesystem
1808
1809 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1810 mount the root filesystem
1811
1812 rootflags= [KNL] Set root filesystem mount option string
1813
1814 rootfstype= [KNL] Set root filesystem type
1815
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001816 rootwait [KNL] Wait (indefinitely) for root device to show up.
1817 Useful for devices that are detected asynchronously
1818 (e.g. USB and MMC devices).
1819
James Morris20510f22007-10-16 23:31:32 -07001820 root_plug.vendor_id=
1821 [ROOTPLUG] Override the default vendor ID
1822
1823 root_plug.product_id=
1824 [ROOTPLUG] Override the default product ID
1825
1826 root_plug.debug=
1827 [ROOTPLUG] Enable debugging output
1828
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 rw [KNL] Mount root device read-write on boot
1830
1831 S [KNL] Run init in single mode
1832
1833 sa1100ir [NET]
1834 See drivers/net/irda/sa1100_ir.c.
1835
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001837
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1839 Format: <io>[,<timeout>[,<isapnp>]]
1840
1841 scsi_debug_*= [SCSI]
1842 See drivers/scsi/scsi_debug.c.
1843
1844 scsi_default_dev_flags=
1845 [SCSI] SCSI default device flags
1846 Format: <integer>
1847
1848 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1849 Format: <vendor>:<model>:<flags>
1850 (flags are integer value)
1851
Randy Dunlap6af66322007-11-14 16:52:25 -08001852 scsi_logging_level= [SCSI] a bit mask of logging levels
1853 See drivers/scsi/scsi_logging.h for bits. Also
1854 settable via sysctl at dev.scsi.logging_level
1855 (/proc/sys/dev/scsi/logging_level).
1856 There is also a nice 'scsi_logging_level' script in the
1857 S390-tools package, available for download at
1858 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001860 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1861 discovered. async scans them in kernel threads,
1862 allowing boot to proceed. none ignores them, expecting
1863 user space to do the scan.
1864
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 selinux [SELINUX] Disable or enable SELinux at boot time.
1866 Format: { "0" | "1" }
1867 See security/selinux/Kconfig help text.
1868 0 -- disable.
1869 1 -- enable.
1870 Default value is set via kernel config option.
1871 If enabled at boot time, /selinux/disable can be used
1872 later to disable prior to initial policy load.
1873
James Morris4e5ab4c2006-06-09 00:33:33 -07001874 selinux_compat_net =
1875 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001876 Format: { "0" | "1" }
1877 0 -- use new secmark-based packet controls
1878 1 -- use legacy packet controls
1879 Default value is 0 (preferred).
1880 Value can be changed at runtime via
1881 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001882
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001883 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 shapers= [NET]
1886 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001887
Yinghai Lub05f78f2008-08-22 01:32:50 -07001888 show_msr= [x86] show boot-time MSR settings
1889 Format: { <integer> }
1890 Show boot-time (BIOS-initialized) MSR settings.
1891 The parameter means the number of CPUs to show,
1892 for example 1 means boot CPU only.
1893
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894 sim710= [SCSI,HW]
1895 See header of drivers/scsi/sim710.c.
1896
1897 simeth= [IA-64]
1898 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001899
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 slram= [HW,MTD]
1901
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001902 slub_debug[=options[,slabs]] [MM, SLUB]
1903 Enabling slub_debug allows one to determine the
1904 culprit if slab objects become corrupted. Enabling
1905 slub_debug can create guard zones around objects and
1906 may poison objects when not in use. Also tracks the
1907 last alloc / free. For more information see
1908 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001909
1910 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001911 Determines the maximum allowed order for slabs.
1912 A high setting may cause OOMs due to memory
1913 fragmentation. For more information see
1914 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001915
1916 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001917 The minimum number of objects per slab. SLUB will
1918 increase the slab order up to slub_max_order to
1919 generate a sufficiently large slab able to contain
1920 the number of objects indicated. The higher the number
1921 of objects the smaller the overhead of tracking slabs
1922 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001923 For more information see Documentation/vm/slub.txt.
1924
1925 slub_min_order= [MM, SLUB]
1926 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001927 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001928 For more information see Documentation/vm/slub.txt.
1929
1930 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001931 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001932 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001933 allocs to different slabs. Debug options disable
1934 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001935 For more information see Documentation/vm/slub.txt.
1936
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 smart2= [HW]
1938 Format: <io1>[,<io2>[,...,<io8>]]
1939
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001940 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001941 attempt to substitute SMP alternatives once at boot.
1942
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001943 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1944 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1945 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1946 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1947 smsc-ircc2.ircc_irq= [HW] IRQ line
1948 smsc-ircc2.ircc_dma= [HW] DMA channel
1949 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1950 0: Toshiba Satellite 1800 (GP data pin select)
1951 1: Fast pin select (default)
1952 2: ATC IRMode
1953
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 snd-ad1816a= [HW,ALSA]
1955
1956 snd-ad1848= [HW,ALSA]
1957
1958 snd-ali5451= [HW,ALSA]
1959
1960 snd-als100= [HW,ALSA]
1961
1962 snd-als4000= [HW,ALSA]
1963
1964 snd-azt2320= [HW,ALSA]
1965
1966 snd-cmi8330= [HW,ALSA]
1967
1968 snd-cmipci= [HW,ALSA]
1969
1970 snd-cs4231= [HW,ALSA]
1971
1972 snd-cs4232= [HW,ALSA]
1973
1974 snd-cs4236= [HW,ALSA]
1975
1976 snd-cs4281= [HW,ALSA]
1977
1978 snd-cs46xx= [HW,ALSA]
1979
1980 snd-dt019x= [HW,ALSA]
1981
1982 snd-dummy= [HW,ALSA]
1983
1984 snd-emu10k1= [HW,ALSA]
1985
1986 snd-ens1370= [HW,ALSA]
1987
1988 snd-ens1371= [HW,ALSA]
1989
1990 snd-es968= [HW,ALSA]
1991
1992 snd-es1688= [HW,ALSA]
1993
1994 snd-es18xx= [HW,ALSA]
1995
1996 snd-es1938= [HW,ALSA]
1997
1998 snd-es1968= [HW,ALSA]
1999
2000 snd-fm801= [HW,ALSA]
2001
2002 snd-gusclassic= [HW,ALSA]
2003
2004 snd-gusextreme= [HW,ALSA]
2005
2006 snd-gusmax= [HW,ALSA]
2007
2008 snd-hdsp= [HW,ALSA]
2009
2010 snd-ice1712= [HW,ALSA]
2011
2012 snd-intel8x0= [HW,ALSA]
2013
2014 snd-interwave= [HW,ALSA]
2015
2016 snd-interwave-stb=
2017 [HW,ALSA]
2018
2019 snd-korg1212= [HW,ALSA]
2020
2021 snd-maestro3= [HW,ALSA]
2022
2023 snd-mpu401= [HW,ALSA]
2024
2025 snd-mtpav= [HW,ALSA]
2026
2027 snd-nm256= [HW,ALSA]
2028
2029 snd-opl3sa2= [HW,ALSA]
2030
2031 snd-opti92x-ad1848=
2032 [HW,ALSA]
2033
2034 snd-opti92x-cs4231=
2035 [HW,ALSA]
2036
2037 snd-opti93x= [HW,ALSA]
2038
2039 snd-pmac= [HW,ALSA]
2040
2041 snd-rme32= [HW,ALSA]
2042
2043 snd-rme96= [HW,ALSA]
2044
2045 snd-rme9652= [HW,ALSA]
2046
2047 snd-sb8= [HW,ALSA]
2048
2049 snd-sb16= [HW,ALSA]
2050
2051 snd-sbawe= [HW,ALSA]
2052
2053 snd-serial= [HW,ALSA]
2054
2055 snd-sgalaxy= [HW,ALSA]
2056
2057 snd-sonicvibes= [HW,ALSA]
2058
2059 snd-sun-amd7930=
2060 [HW,ALSA]
2061
2062 snd-sun-cs4231= [HW,ALSA]
2063
2064 snd-trident= [HW,ALSA]
2065
2066 snd-usb-audio= [HW,ALSA,USB]
2067
2068 snd-via82xx= [HW,ALSA]
2069
2070 snd-virmidi= [HW,ALSA]
2071
2072 snd-wavefront= [HW,ALSA]
2073
2074 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002075
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002076 softlockup_panic=
2077 [KNL] Should the soft-lockup detector generate panics.
2078
Linus Torvalds1da177e2005-04-16 15:20:36 -07002079 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2080 See Documentation/sonypi.txt
2081
2082 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2083 See Documentation/specialix.txt.
2084
2085 spia_io_base= [HW,MTD]
2086 spia_fio_base=
2087 spia_pedr=
2088 spia_peddr=
2089
2090 sscape= [HW,OSS]
2091 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002092
Linus Torvalds1da177e2005-04-16 15:20:36 -07002093 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2094 See Documentation/scsi/st.txt.
2095
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 sti= [PARISC,HW]
2097 Format: <num>
2098 Set the STI (builtin display/keyboard on the HP-PARISC
2099 machines) console (graphic card) which should be used
2100 as the initial boot-console.
2101 See also comment in drivers/video/console/sticore.c.
2102
2103 sti_font= [HW]
2104 See comment in drivers/video/console/sticore.c.
2105
2106 stifb= [HW]
2107 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2108
Greg Banks42a7fc42007-03-06 01:42:23 -08002109 sunrpc.pool_mode=
2110 [NFS]
2111 Control how the NFS server code allocates CPUs to
2112 service thread pools. Depending on how many NICs
2113 you have and where their interrupts are bound, this
2114 option will affect which CPUs will do NFS serving.
2115 Note: this parameter cannot be changed while the
2116 NFS server is running.
2117
2118 auto the server chooses an appropriate mode
2119 automatically using heuristics
2120 global a single global pool contains all CPUs
2121 percpu one pool for each CPU
2122 pernode one pool for each NUMA node (equivalent
2123 to global on non-NUMA machines)
2124
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002126
Linus Torvalds1da177e2005-04-16 15:20:36 -07002127 switches= [HW,M68k]
2128
2129 sym53c416= [HW,SCSI]
2130 See header of drivers/scsi/sym53c416.c.
2131
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002132 sysrq_always_enabled
2133 [KNL]
2134 Ignore sysrq setting - this boot parameter will
2135 neutralize any effect of /proc/sys/kernel/sysrq.
2136 Useful for debugging.
2137
Linus Torvalds1da177e2005-04-16 15:20:36 -07002138 t128= [HW,SCSI]
2139 See header of drivers/scsi/t128.c.
2140
2141 tdfx= [HW,DRM]
2142
David Brownell77437fd2008-07-23 21:28:33 -07002143 test_suspend= [SUSPEND]
2144 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2145 standby suspend) as the system sleep state to briefly
2146 enter during system startup. The system is woken from
2147 this state using a wakeup-capable RTC alarm.
2148
Linus Torvalds1da177e2005-04-16 15:20:36 -07002149 thash_entries= [KNL,NET]
2150 Set number of hash buckets for TCP connection
2151
Len Brownf8707ec2007-08-12 00:12:54 -04002152 thermal.act= [HW,ACPI]
2153 -1: disable all active trip points in all thermal zones
2154 <degrees C>: override all lowest active trip points
2155
Len Brownc52a7412007-08-14 15:49:32 -04002156 thermal.crt= [HW,ACPI]
2157 -1: disable all critical trip points in all thermal zones
2158 <degrees C>: lower all critical trip points
2159
Len Brownf5487142007-08-12 00:12:44 -04002160 thermal.nocrt= [HW,ACPI]
2161 Set to disable actions on ACPI thermal zone
2162 critical and hot trip points.
2163
Len Brown72b33ef2007-08-12 00:12:17 -04002164 thermal.off= [HW,ACPI]
2165 1: disable ACPI thermal control
2166
Len Browna70cdc52007-08-12 00:12:35 -04002167 thermal.psv= [HW,ACPI]
2168 -1: disable all passive trip points
2169 <degrees C>: override all passive trip points to this value
2170
Len Brown730ff342007-08-12 00:12:26 -04002171 thermal.tzp= [HW,ACPI]
2172 Specify global default ACPI thermal zone polling rate
2173 <deci-seconds>: poll all this frequency
2174 0: no polling (default)
2175
Linus Torvalds1da177e2005-04-16 15:20:36 -07002176 tmscsim= [HW,SCSI]
2177 See comment before function dc390_setup() in
2178 drivers/scsi/tmscsim.c.
2179
2180 tp720= [HW,PS2]
2181
2182 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002183 Format:
2184 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2185
Randy Dunlapa9913042005-10-23 12:57:11 -07002186 turbografx.map[2|3]= [HW,JOY]
2187 TurboGraFX parallel port interface
2188 Format:
2189 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 See also Documentation/input/joystick-parport.txt
2191
2192 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2193 See header of drivers/scsi/u14-34f.c.
2194
2195 uart401= [HW,OSS]
2196 Format: <io>,<irq>
2197
2198 uart6850= [HW,OSS]
2199 Format: <io>,<irq>
2200
Alan Stern5f8364b2006-12-05 16:29:55 -05002201 uhci-hcd.ignore_oc=
2202 [USB] Ignore overcurrent events (default N).
2203 Some badly-designed motherboards generate lots of
2204 bogus events, for ports that aren't wired to
2205 anything. Set this parameter to avoid log spamming.
2206 Note that genuine overcurrent events won't be
2207 reported either.
2208
Simon Arlotte3a61b02008-07-19 23:32:54 +01002209 unknown_nmi_panic
2210 [X86-32,X86-64]
2211 Set unknown_nmi_panic=1 early on boot.
2212
Alan Sternb5e795f2007-02-20 15:00:53 -05002213 usbcore.autosuspend=
2214 [USB] The autosuspend time delay (in seconds) used
2215 for newly-detected USB devices (default 2). This
2216 is the time required before an idle device will be
2217 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002218 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002219
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220 usbhid.mousepoll=
2221 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002222
Paul Jackson200001e2008-06-25 05:44:46 -07002223 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2224 kernel's map of available physical RAM.
2225
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002226 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002227 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002228 vdso=1: enable VDSO (default)
2229 vdso=0: disable VDSO mapping
2230
Roland McGrathaf65d642008-01-30 13:30:43 +01002231 vdso32= [X86-32,X86-64]
2232 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2233 vdso32=1: enable 32-bit VDSO (default)
2234 vdso32=0: disable 32-bit VDSO mapping
2235
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002236 vector= [IA-64,SMP]
2237 vector=percpu: enable percpu vector domain
2238
Linus Torvalds1da177e2005-04-16 15:20:36 -07002239 video= [FB] Frame buffer configuration
2240 See Documentation/fb/modedb.txt.
2241
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002242 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002243 See Documentation/i386/boot.txt and
2244 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245 Use vga=ask for menu.
2246 This is actually a boot loader parameter; the value is
2247 passed to the kernel using a special protocol.
2248
Randy Dunlapa9913042005-10-23 12:57:11 -07002249 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 size of <nn>. This can be used to increase the
2251 minimum size (128MB on x86). It can also be used to
2252 decrease the size and leave more room for directly
2253 mapped kernel RAM.
2254
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002255 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2256 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002258 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2259 Format: <command>
2260
2261 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2262 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002263
Linus Torvalds1da177e2005-04-16 15:20:36 -07002264 waveartist= [HW,OSS]
2265 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002266
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267 wd33c93= [HW,SCSI]
2268 See header of drivers/scsi/wd33c93.c.
2269
2270 wd7000= [HW,SCSI]
2271 See header of drivers/scsi/wd7000.c.
2272
2273 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002274 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275
2276 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2277 xd_geo= See header of drivers/block/xd.c.
2278
2279 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002280 Format:
2281 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282
Andi Kleena62eaf12006-02-16 23:41:58 +01002283 norandmaps Don't use address space randomization
2284 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2285
Randy Dunlapa9913042005-10-23 12:57:11 -07002286______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002287
2288TODO:
2289
2290 Add documentation for ALSA options.
2291 Add more DRM drivers.