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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)
287 amd_iommu_size= [HW,X86-64]
288 Define the size of the aperture for the AMD IOMMU
289 driver. Possible values are:
290 '32M', '64M' (default), '128M', '256M', '512M', '1G'
291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 amijoy.map= [HW,JOY] Amiga joystick support
293 Map of devices attached to JOY0DAT and JOY1DAT
294 Format: <a>,<b>
295 See also Documentation/kernel/input/joystick.txt
296
297 analog.map= [HW,JOY] Analog joystick and gamepad support
298 Specifies type or capabilities of an analog joystick
299 connected to one of 16 gameports
300 Format: <type1>,<type2>,..<type16>
301
Randy Dunlapa9913042005-10-23 12:57:11 -0700302 apc= [HW,SPARC]
303 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 Format: noidle
305 Disable APC CPU standby support. SPARCstation-Fox does
306 not play well with APC CPU idle - disable it if you have
307 APC and your system crashes randomly.
308
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700309 apic= [APIC,i386] Advanced Programmable Interrupt Controller
310 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 Format: { quiet (default) | verbose | debug }
312 Change the amount of debugging information output
313 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700316 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
319 Format: <io>,<irq>,<nodeID>
320
321 ataflop= [HW,M68k]
322
323 atarimouse= [HW,MOUSE] Atari Mouse
324
325 atascsi= [HW,SCSI] Atari SCSI
326
327 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
328 EzKey and similar keyboards
329
330 atkbd.reset= [HW] Reset keyboard during initialization
331
Randy Dunlapa9913042005-10-23 12:57:11 -0700332 atkbd.set= [HW] Select keyboard code set
333 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
335 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
336 keyboards
337
338 atkbd.softraw= [HW] Choose between synthetic and real raw mode
339 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700340
341 atkbd.softrepeat= [HW]
342 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
344 autotest [IA64]
345
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 baycom_epp= [HW,AX25]
347 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
350 Format: <io>,<mode>
351 See header of drivers/net/hamradio/baycom_par.c.
352
Randy Dunlapa9913042005-10-23 12:57:11 -0700353 baycom_ser_fdx= [HW,AX25]
354 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 Format: <io>,<irq>,<mode>[,<baud>]
356 See header of drivers/net/hamradio/baycom_ser_fdx.c.
357
Randy Dunlapa9913042005-10-23 12:57:11 -0700358 baycom_ser_hdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 Format: <io>,<irq>,<mode>
361 See header of drivers/net/hamradio/baycom_ser_hdx.c.
362
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700363 boot_delay= Milliseconds to delay each printk during boot.
364 Values larger than 10 seconds (10000) are changed to
365 no delay (0).
366 Format: integer
367
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700368 bootmem_debug [KNL] Enable bootmem allocator debug messages.
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700371 bttv.radio= Most important insmod options are available as
372 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
374 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
375
376 BusLogic= [HW,SCSI]
377 See drivers/scsi/BusLogic.c, comment before function
378 BusLogic_ParseDriverOptions().
379
380 c101= [NET] Moxa C101 synchronous serial card
381
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700382 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 Sometimes CPU hardware bugs make them report the cache
384 size incorrectly. The kernel will attempt work arounds
385 to fix known problems, but for some CPUs it is not
386 possible to determine what the correct size should be.
387 This option provides an override for these situations.
388
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200389 security= [SECURITY] Choose a security module to enable at boot.
390 If this boot parameter is not specified, only the first
391 security module asking for security registration will be
392 loaded. An invalid security module name will be treated
393 as if no module has been chosen.
394
James Morris20510f22007-10-16 23:31:32 -0700395 capability.disable=
396 [SECURITY] Disable capabilities. This would normally
397 be used only if an alternative security model is to be
398 configured. Potentially dangerous and should only be
399 used if you are entirely sure of the consequences.
400
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100401 ccw_timeout_log [S390]
402 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
Paul Menage8bab8dd2008-04-04 14:29:57 -0700404 cgroup_disable= [KNL] Disable a particular controller
405 Format: {name of the controller(s) to disable}
406 {Currently supported controllers - "memory"}
407
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 checkreqprot [SELINUX] Set initial checkreqprot flag value.
409 Format: { "0" | "1" }
410 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700411 0 -- check protection applied by kernel (includes
412 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 1 -- check protection requested by application.
414 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700415 Value can be changed at runtime via
416 /selinux/checkreqprot.
417
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100418 cio_ignore= [S390]
419 See Documentation/s390/CommonIO for details.
420
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700421 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700422 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200423 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700424 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200425 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 Format: { pit | tsc | cyclone | pmtmr }
427
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700428 clocksource= [GENERIC_TIME] Override the default clocksource
429 Format: <string>
430 Override the default clocksource and use the clocksource
431 with the name specified.
432 Some clocksource names to choose from, depending on
433 the platform:
434 [all] jiffies (this is the base, fallback clocksource)
435 [ACPI] acpi_pm
436 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
437 pxa_timer,timer3,32k_counter,timer0_1
438 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700439 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700440 scx200_hrt on Geode; cyclone on IBM x440
441 [MIPS] MIPS
442 [PARISC] cr16
443 [S390] tod
444 [SH] SuperH
445 [SPARC64] tick
446 [X86-64] hpet,tsc
447
Andi Kleenac72e782008-01-30 13:33:21 +0100448 clearcpuid=BITNUM [X86]
449 Disable CPUID feature X for the kernel. See
450 include/asm-x86/cpufeature.h for the valid bit numbers.
451 Note the Linux specific bits are not necessarily
452 stable over kernel options, but the vendor specific
453 ones should be.
454 Also note that user programs calling CPUID directly
455 or using the feature without checking anything
456 will still see it. This just prevents it from
457 being used by the kernel or shown in /proc/cpuinfo.
458 Also note the kernel might malfunction if you disable
459 some critical bits.
460
Arjan van de Vena25bd942008-01-30 13:33:08 +0100461 code_bytes [IA32/X86_64] How many bytes of object code to print
462 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100463 Range: 0 - 8192
464 Default: 64
465
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200466 hpet= [X86-32,HPET] option to control HPET usage
467 Format: { enable (default) | disable | force }
468 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100469 force: allow force enabled of undocumented chips (ICH4,
470 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700473 Format:
474 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
476 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
477 Format: <io>[,<irq>]
478
Randy Dunlapa9913042005-10-23 12:57:11 -0700479 com90xx= [HW,NET]
480 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 Format: <io>[,<irq>[,<memstart>]]
482
483 condev= [HW,S390] console device
484 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700485
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 console= [KNL] Output console device and options.
487
488 tty<n> Use the virtual console device <n>.
489
490 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800491 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800493 the form "bbbbpnf", where "bbbb" is the baud rate,
494 "p" is parity ("n", "o", or "e"), "n" is number of
495 bits, and "f" is flow control ("r" for RTS or
496 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800498 See Documentation/serial-console.txt for more
499 information. See
500 Documentation/networking/netconsole.txt for an
501 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700503 uart[8250],io,<addr>[,options]
504 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 Start an early, polled-mode console on the 8250/16550
506 UART at the specified I/O port or MMIO address,
507 switching to the matching ttyS device later. The
508 options are the same as for ttyS, above.
509
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700510 If the device connected to the port is not a TTY but a braille
511 device, prepend "brl," before the device type, for instance
512 console=brl,ttyS0
513 For now, only VisioBraille is supported.
514
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700515 earlycon= [KNL] Output early console device and options.
516 uart[8250],io,<addr>[,options]
517 uart[8250],mmio,<addr>[,options]
518 Start an early, polled-mode console on the 8250/16550
519 UART at the specified I/O port or MMIO address.
520 The options are the same as for ttyS, above.
521
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700522 no_console_suspend
523 [HW] Never suspend the console
524 Disable suspending of consoles during suspend and
525 hibernate operations. Once disabled, debugging
526 messages can reach various consoles while the rest
527 of the system is being put to sleep (ie, while
528 debugging driver suspend/resume hooks). This may
529 not work reliably with all consoles, but is known
530 to work with serial and VGA consoles.
531
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700533 Format:
534 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700536 crashkernel=nn[KMG]@ss[KMG]
537 [KNL] Reserve a chunk of physical memory to
538 hold a kernel to switch to with kexec on panic.
539
Bernhard Wallefb391592007-10-18 23:41:02 -0700540 crashkernel=range1:size1[,range2:size2,...][@offset]
541 [KNL] Same as above, but depends on the memory
542 in the running system. The syntax of range is
543 start-[end] where start and end are both
544 a memory unit (amount[KMG]). See also
545 Documentation/kdump/kdump.txt for a example.
546
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 cs4232= [HW,OSS]
548 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
549
550 cs89x0_dma= [HW,NET]
551 Format: <dma>
552
553 cs89x0_media= [HW,NET]
554 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700555
Randy Dunlapa9913042005-10-23 12:57:11 -0700556 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 See header of drivers/s390/block/dasd_devmap.c.
558
559 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
560 (one device per port)
561 Format: <port#>,<type>
562 See also Documentation/input/joystick-parport.txt
563
564 debug [KNL] Enable kernel debugging (events log level).
565
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700566 debug_locks_verbose=
567 [KNL] verbose self-tests
568 Format=<0|1>
569 Print debugging info while doing the locking API
570 self-tests.
571 We default to 0 (no extra messages), setting it to
572 1 will print _a lot_ more information - normally
573 only useful to kernel developers.
574
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700575 debug_objects [KNL] Enable object debugging
576
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200577 debugpat [X86] Enable PAT debugging
578
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200579 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 Format: <area>[,<node>]
581 See also Documentation/networking/decnet.txt.
582
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000583 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700584 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
585 Change the default blue palette of the console.
586 This is a 16-member array composed of values
587 ranging from 0-255.
588
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000589 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700590 Format: <green0>,<green1>,<green2>,...,<green15>
591 Change the default green palette of the console.
592 This is a 16-member array composed of values
593 ranging from 0-255.
594
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000595 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700596 Format: <red0>,<red1>,<red2>,...,<red15>
597 Change the default red palette of the console.
598 This is a 16-member array composed of values
599 ranging from 0-255.
600
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000601 vt.default_utf8=
602 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700603 Format=<0|1>
604 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000605 Default is 1, i.e. UTF-8 mode is enabled for all
606 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700607
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 dhash_entries= [KNL]
609 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700610
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 digi= [HW,SERIAL]
612 IO parameters + enable/disable command.
613
614 digiepca= [HW,SERIAL]
615 See drivers/char/README.epca and
616 Documentation/digiepca.txt.
617
Yinghai Lu95ffa242008-04-29 03:52:33 -0700618 disable_mtrr_cleanup [X86]
619 enable_mtrr_cleanup [X86]
620 The kernel tries to adjust MTRR layout from continuous
621 to discrete, to make X server driver able to add WB
622 entry later. This parameter enables/disables that.
623
624 mtrr_chunk_size=nn[KMG] [X86]
625 used for mtrr cleanup. It is largest continous chunk
626 that could hold holes aka. UC entries.
627
628 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700629 Used for mtrr cleanup. It is granularity of mtrr block.
630 Default is 1.
631 Large value could prevent small alignment from
632 using up MTRRs.
633
634 mtrr_spare_reg_nr=n [X86]
635 Format: <integer>
636 Range: 0,7 : spare reg number
637 Default : 1
638 Used for mtrr cleanup. It is spare mtrr entries number.
639 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700640
Yinghai Lu093af8d2008-01-30 13:33:32 +0100641 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100642 By default the kernel will trim any uncacheable
643 memory out of your available memory pool based on
644 MTRR settings. This parameter disables that behavior,
645 possibly causing your machine to run very slowly.
646
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 dmasound= [HW,OSS] Sound subsystem buffers
648
649 dscc4.setup= [NET]
650
651 dtc3181e= [HW,SCSI]
652
Robin Getz0ae53642007-10-09 17:24:49 +0800653 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 earlyprintk=vga
655 earlyprintk=serial[,ttySn[,baudrate]]
656
Randy Dunlapa9913042005-10-23 12:57:11 -0700657 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 takes over.
659
660 Only vga or serial at a time, not both.
661
662 Currently only ttyS0 and ttyS1 are supported.
663
664 Interaction with the standard serial driver is not
665 very good.
666
667 The VGA output is eventually overwritten by the real
668 console.
669
670 eata= [HW,SCSI]
671
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700673 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 eisa_irq_edge= [PARISC,HW]
676 See header of drivers/parisc/eisa.c.
677
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700678 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700680 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
682 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800683 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700684 See Documentation/block/as-iosched.txt and
685 Documentation/block/deadline-iosched.txt for details.
686
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700687 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700688 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800689 image elf header. Generally kexec loader will
690 pass this option to capture kernel.
691 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692
693 enforcing [SELINUX] Set initial enforcing status.
694 Format: {"0" | "1"}
695 See security/selinux/Kconfig help text.
696 0 -- permissive (log only, no denials).
697 1 -- enforcing (deny and log).
698 Default value is 0.
699 Value can be changed at runtime via /selinux/enforce.
700
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 es1371= [HW,OSS]
702 Format: <spdif>,[<nomix>,[<amplifier>]]
703 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700704
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 ether= [HW,NET] Ethernet cards parameters
706 This option is obsoleted by the "netdev=" option, which
707 has equivalent usage. See its documentation for details.
708
709 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
710 Format: <io>[,<irq>]
711
Akinobu Mitade1ba092006-12-08 02:39:42 -0800712 failslab=
713 fail_page_alloc=
714 fail_make_request=[KNL]
715 General fault injection mechanism.
716 Format: <interval>,<probability>,<space>,<times>
717 See also /Documentation/fault-injection/.
718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 fd_mcs= [HW,SCSI]
720 See header of drivers/scsi/fd_mcs.c.
721
722 fdomain= [HW,SCSI]
723 See header of drivers/scsi/fdomain.c.
724
725 floppy= [HW]
726 See Documentation/floppy.txt.
727
Alex Chiangf13ae302008-05-08 14:03:23 -0600728 force_pal_cache_flush
729 [IA-64] Avoid check_sal_cache_flush which may hang on
730 buggy SAL_CACHE_FLUSH implementations. Using this
731 parameter will force ia64_sal_cache_flush to call
732 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
733
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 gamecon.map[2|3]=
735 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
736 support via parallel port (up to 5 devices per port)
737 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
738 See also Documentation/input/joystick-parport.txt
739
740 gamma= [HW,DRM]
741
Yinghai Luaaf23042008-01-30 13:33:09 +0100742 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
743 Format: off | on
744 default: on
745
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 gdth= [HW,SCSI]
747 See header of drivers/scsi/gdth.c.
748
749 gpt [EFI] Forces disk with valid GPT signature but
750 invalid Protective MBR to be treated as GPT.
751
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 gvp11= [HW,SCSI]
753
754 hashdist= [KNL,NUMA] Large hashes allocated during boot
755 are distributed across NUMA nodes. Defaults on
756 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700757 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758
759 hcl= [IA-64] SGI's Hardware Graph compatibility layer
760
761 hd= [EIDE] (E)IDE hard drive subsystem geometry
762 Format: <cyl>,<head>,<sect>
763
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
765 size of <nn>. This works even on boxes that have no
766 highmem otherwise. This also works to reduce highmem
767 size on bigger boxes.
768
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800769 highres= [KNL] Enable/disable high resolution timer mode.
770 Valid parameters: "on", "off"
771 Default: "on"
772
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 hisax= [HW,ISDN]
774 See Documentation/isdn/README.HiSax.
775
Andi Kleenb4718e62008-07-23 21:27:51 -0700776 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
777 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700778 On x86-64 and powerpc, this option can be specified
779 multiple times interleaved with hugepages= to reserve
780 huge pages of different sizes. Valid pages sizes on
781 x86-64 are 2M (when the CPU supports "pse") and 1G
782 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700783 Note that 1GB pages can only be allocated at boot time
784 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700785 default_hugepagesz=
786 [same as hugepagesz=] The size of the default
787 HugeTLB page size. This is the size represented by
788 the legacy /proc/ hugepages APIs, used for SHM, and
789 default size when mounting hugetlbfs filesystems.
790 Defaults to the default architecture's huge page size
791 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200794 i8042.dumbkbd [HW] Pretend that controller can only read data from
795 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 (Don't attempt to blink the leds)
797 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500798 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400799 i8042.noloop [HW] Disable the AUX Loopback command while probing
800 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 i8042.nomux [HW] Don't check presence of an active multiplexing
802 controller
803 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
804 controllers
805 i8042.panicblink=
806 [HW] Frequency with which keyboard LEDs should blink
807 when kernel panics (default is 0.5 sec)
808 i8042.reset [HW] Reset the controller during init and cleanup
809 i8042.unlock [HW] Unlock (ignore) the keylock
810
811 i810= [HW,DRM]
812
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700813 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
814 indicates that the driver is running on unsupported
815 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
817 does not match list of supported models.
818 i8k.power_status
819 [HW] Report power status in /proc/i8k
820 (disabled by default)
821 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
822 capability is set.
823
824 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
825 See Documentation/mca.txt.
826
827 icn= [HW,ISDN]
828 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
829
830 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200831 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100832 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100835 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836
Andi Kleenf039b752007-05-02 19:27:12 +0200837 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800838 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200839 Poll forces a polling idle loop that can slightly improves the performance
840 of waking up a idle CPU, but will use a lot of power and make the system
841 run hot. Not recommended.
842 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
843 to not use it because it doesn't save as much power as a normal idle
844 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
845 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800846 idle=halt. Halt is forced to be used for CPU idle.
847 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800848 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700849
Denis Cheng594765a2008-02-06 02:57:49 +0100850 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
851 Claim all unknown PCI IDE storage controllers.
852
Ingo Molnar792908222006-12-06 20:40:51 -0800853 ignore_loglevel [KNL]
854 Ignore loglevel setting - this will print /all/
855 kernel messages to the console. Useful for debugging.
856
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 ihash_entries= [KNL]
858 Set number of hash buckets for inode cache.
859
860 in2000= [HW,SCSI]
861 See header of drivers/scsi/in2000.c.
862
863 init= [KNL]
864 Format: <full_path>
865 Run specified binary instead of /sbin/init as init
866 process.
867
868 initcall_debug [KNL] Trace initcalls as they are executed. Useful
869 for working out where the kernel is dying during
870 startup.
871
872 initrd= [BOOT] Specify the location of the initial ramdisk
873
874 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
875 Format: <irq>
876
877 inttest= [IA64]
878
Pavel Machekb552da82008-03-19 15:58:11 +0100879 iommu= [x86]
880 off
881 force
882 noforce
883 biomerge
884 panic
885 nopanic
886 merge
887 nomerge
888 forcesac
889 soft
890
891
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700892 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
893 off
894 Disable intel iommu driver.
895 igfx_off [Default Off]
896 By default, gfx is mapped as normal device. If a gfx
897 device has a dedicated DMAR unit, the DMAR unit is
898 bypassed by not enabling DMAR with this option. In
899 this case, gfx device will use physical address for
900 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700901 forcedac [x86_64]
902 With this option iommu will not optimize to look
903 for io virtual address below 32 bit forcing dual
904 address cycle on pci bus for cards supporting greater
905 than 32 bit addressing. The default is to look
906 for translation below 32 bit and if not available
907 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800908 strict [Default Off]
909 With this option on every unmap_single operation will
910 result in a hardware IOTLB flush operation as opposed
911 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700912
Rene Hermanb02aae92008-01-30 13:30:05 +0100913 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100914 0x80
915 Standard port 0x80 based delay
916 0xed
917 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100918 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100919 Simple two microseconds delay
920 none
921 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100922
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 io7= [HW] IO7 for Marvel based alpha systems
924 See comment before marvel_specify_io7 in
925 arch/alpha/kernel/core_marvel.c.
926
927 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400928 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929
930 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700931 See comment before ip2_setup() in
932 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
934 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
935 See header of drivers/scsi/ips.c.
936
Simon Horman72c4a132006-09-13 19:57:18 -0700937 ports= [IP_VS_FTP] IPVS ftp helper module
938 Default is 21.
939 Up to 8 (IP_VS_APP_MAX_PORTS) ports
940 may be specified.
941 Format: <port>,<port>....
942
Alan Cox200803d2005-06-28 20:45:18 -0700943 irqfixup [HW]
944 When an interrupt is not handled search all handlers
945 for it. Intended to get systems with badly broken
946 firmware running.
947
948 irqpoll [HW]
949 When an interrupt is not handled search all handlers
950 for it. Also check all handlers each timer
951 interrupt. Intended to get systems with badly broken
952 firmware running.
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700955 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956
957 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800958 Format:
959 <cpu number>,...,<cpu number>
960 or
961 <cpu number>-<cpu number> (must be a positive range in ascending order)
962 or a mixture
963 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 This option can be used to specify one or more CPUs
965 to isolate from the general SMP balancing and scheduling
966 algorithms. The only way to move a process onto or off
967 an "isolated" CPU is via the CPU affinity syscalls.
968 <cpu number> begins at 0 and the maximum value is
969 "number of CPUs in system - 1".
970
971 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700972 alternative -- manually setting the CPU mask of all
973 tasks in the system -- can cause problems and
974 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975
Randy Dunlapa9913042005-10-23 12:57:11 -0700976 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977
978 js= [HW,JOY] Analog joystick
979 See Documentation/input/joystick.txt.
980
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700981 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700982 specifies the amount of memory usable by the kernel
983 for non-movable allocations. The requested amount is
984 spread evenly throughout all nodes in the system. The
985 remaining memory in each node is used for Movable
986 pages. In the event, a node is too small to have both
987 kernelcore and Movable pages, kernelcore pages will
988 take priority and other nodes will have a larger number
989 of kernelcore pages. The Movable zone is used for the
990 allocation of pages that may be reclaimed or moved
991 by the page migration subsystem. This means that
992 HugeTLB pages may not be allocated from this zone.
993 Note that allocations like PTEs-from-HighMem still
994 use the HighMem zone if it exists, and the Normal
995 zone if it does not.
996
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700997 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efef2007-07-17 04:03:15 -0700998 is similar to kernelcore except it specifies the
999 amount of memory used for migratable allocations.
1000 If both kernelcore and movablecore is specified,
1001 then kernelcore will be at *least* the specified
1002 value but may be more. If movablecore on its own
1003 is specified, the administrator must be careful
1004 that the amount of memory usable for all allocations
1005 is not too small.
1006
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 keepinitrd [HW,ARM]
1008
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001009 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 in oops dumps.
1011
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001012 kgdboc= [HW] kgdb over consoles.
1013 Requires a tty driver that supports console polling.
1014 (only serial suported for now)
1015 Format: <serial_device>[,baud]
1016
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001017 kmac= [MIPS] korina ethernet MAC address.
1018 Configure the RouterBoard 532 series on-chip
1019 Ethernet adapter MAC address.
1020
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 l2cr= [PPC]
1022
Robert Brosea78bfbf2008-03-29 07:20:23 +11001023 l3cr= [PPC]
1024
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001025 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001026 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001028 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001029 C2 power state.
1030
FD Camifcb71f62008-01-06 19:08:56 +01001031 libata.dma= [LIBATA] DMA control
1032 libata.dma=0 Disable all PATA and SATA DMA
1033 libata.dma=1 PATA and SATA Disk DMA only
1034 libata.dma=2 ATAPI (CDROM) DMA only
1035 libata.dma=4 Compact Flash DMA only
1036 Combinations also work, so libata.dma=3 enables DMA
1037 for disks and CDROMs, but not CFs.
1038
Dave Jones78e70c22007-09-27 11:50:13 -04001039 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1040 when set.
1041 Format: <int>
1042
Tejun Heo33267322008-02-13 09:15:09 +09001043 libata.force= [LIBATA] Force configurations. The format is comma
1044 separated list of "[ID:]VAL" where ID is
1045 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1046 matching port, link or device. Basically, it matches
1047 the ATA ID string printed on console by libata. If
1048 the whole ID part is omitted, the last PORT and DEVICE
1049 values are used. If ID hasn't been specified yet, the
1050 configuration applies to all ports, links and devices.
1051
1052 If only DEVICE is omitted, the parameter applies to
1053 the port and all links and devices behind it. DEVICE
1054 number of 0 either selects the first device or the
1055 first fan-out link behind PMP device. It does not
1056 select the host link. DEVICE number of 15 selects the
1057 host link and device attached to it.
1058
1059 The VAL specifies the configuration to force. As long
1060 as there's no ambiguity shortcut notation is allowed.
1061 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1062 The following configurations can be forced.
1063
1064 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1065 Any ID with matching PORT is used.
1066
1067 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1068
1069 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1070 udma[/][16,25,33,44,66,100,133] notation is also
1071 allowed.
1072
1073 * [no]ncq: Turn on or off NCQ.
1074
Tejun Heo05944bd2008-08-13 20:19:09 +09001075 * nohrst, nosrst, norst: suppress hard, soft
1076 and both resets.
1077
Tejun Heo33267322008-02-13 09:15:09 +09001078 If there are multiple matching configurations changing
1079 the same attribute, the last one is used.
1080
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 load_ramdisk= [RAM] List of ramdisks to load from floppy
1082 See Documentation/ramdisk.txt.
1083
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001084 lockd.nlm_grace_period=P [NFS] Assign grace period.
1085 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001087 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1088 Format: <integer>
1089
1090 lockd.nlm_timeout=T [NFS] Assign timeout value.
1091 Format: <integer>
1092
1093 lockd.nlm_udpport=M [NFS] Assign UDP port.
1094 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095
1096 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1097 Format: <irq>
1098
1099 loglevel= All Kernel Messages with a loglevel smaller than the
1100 console loglevel will be printed to the console. It can
1101 also be changed with klogd or other programs. The
1102 loglevels are defined as follows:
1103
1104 0 (KERN_EMERG) system is unusable
1105 1 (KERN_ALERT) action must be taken immediately
1106 2 (KERN_CRIT) critical conditions
1107 3 (KERN_ERR) error conditions
1108 4 (KERN_WARNING) warning conditions
1109 5 (KERN_NOTICE) normal but significant condition
1110 6 (KERN_INFO) informational
1111 7 (KERN_DEBUG) debug-level messages
1112
1113 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001114 Format: { n | nk | nM }
1115 n must be a power of two. The default size
1116 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117
Randy Dunlapaccaa242007-10-16 01:29:37 -07001118 logo.nologo [FB] Disables display of the built-in Linux logo.
1119 This may be used to provide more screen space for
1120 kernel log messages and is useful when debugging
1121 kernel boot problems.
1122
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 lp=0 [LP] Specify parallel ports to use, e.g,
1124 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1125 lp=reset first parallel port). 'lp=0' disables the
1126 lp=auto printer driver. 'lp=reset' (which can be
1127 specified in addition to the ports) causes
1128 attached printers to be reset. Using
1129 lp=port1,port2,... specifies the parallel ports
1130 to associate lp devices with, starting with
1131 lp0. A port specification may be 'none' to skip
1132 that lp device, or a parport name such as
1133 'parport0'. Specifying 'lp=auto' instead of a
1134 port specification list means that device IDs
1135 from each port should be examined, to see if
1136 an IEEE 1284-compliant printer is attached; if
1137 so, the driver will manage that printer.
1138 See also header of drivers/char/lp.c.
1139
1140 lpj=n [KNL]
1141 Sets loops_per_jiffy to given constant, thus avoiding
1142 time-consuming boot-time autodetection (up to 250 ms per
1143 CPU). 0 enables autodetection (default). To determine
1144 the correct value for your kernel, boot with normal
1145 autodetection and see what value is printed. Note that
1146 on SMP systems the preset will be applied to all CPUs,
1147 which is likely to cause problems if your CPUs need
1148 significantly divergent settings. An incorrect value
1149 will cause delays in the kernel to be wrong, leading to
1150 unpredictable I/O errors and other breakage. Although
1151 unlikely, in the extreme case this might damage your
1152 hardware.
1153
1154 ltpc= [NET]
1155 Format: <io>,<irq>,<dma>
1156
Randy Dunlapa9913042005-10-23 12:57:11 -07001157 mac5380= [HW,SCSI] Format:
1158 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159
Randy Dunlapa9913042005-10-23 12:57:11 -07001160 machvec= [IA64] Force the use of a particular machine-vector
1161 (machvec) in a generic kernel.
1162 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163
Randy Dunlapa9913042005-10-23 12:57:11 -07001164 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 be mounted
1166 Format: <1-256>
1167
1168 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001169 should make use of. maxcpus=n : n >= 0 limits the
1170 kernel to using 'n' processors. n=0 is a special case,
1171 it is equivalent to "nosmp", which also disables
1172 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173
Bob Picco2b2c3752005-06-29 18:00:00 -07001174 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1175 equal to this physical address is ignored.
1176
Randy Dunlapa9913042005-10-23 12:57:11 -07001177 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 Should be between 1 and 2^32-1.
1179
1180 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001181 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 Should be between 1 and 16384.
1183
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 mcatest= [IA-64]
1185
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001186 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187
Andi Kleen909dd322007-10-17 18:04:38 +02001188 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1189
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 md= [HW] RAID subsystems devices and level
1191 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001192
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193 mdacon= [MDA]
1194 Format: <first>,<last>
1195 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001196
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1198 Amount of memory to be used when the kernel is not able
1199 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001200 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 address space collisions. Without memmap= PCI devices
1202 could be placed at addresses belonging to unused RAM.
1203
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001204 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 memory.
1206
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001207 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208 E820 memory map, as specified by the user.
1209 Such memmap=exactmap lines can be constructed based on
1210 BIOS output or other requirements. See the memmap=nn@ss
1211 option description.
1212
1213 memmap=nn[KMG]@ss[KMG]
1214 [KNL] Force usage of a specific region of memory
1215 Region of memory to be used, from ss to ss+nn.
1216
1217 memmap=nn[KMG]#ss[KMG]
1218 [KNL,ACPI] Mark specific memory as ACPI data.
1219 Region of memory to be used, from ss to ss+nn.
1220
1221 memmap=nn[KMG]$ss[KMG]
1222 [KNL,ACPI] Mark specific memory as reserved.
1223 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001224 Example: Exclude memory from 0x18690000-0x1869ffff
1225 memmap=64K$0x18690000
1226 or
1227 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001229 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001230 Format: <integer>
1231 range: 0,4 : pattern number
1232 default : 0 <disable>
1233
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234 meye.*= [HW] Set MotionEye Camera parameters
1235 See Documentation/video4linux/meye.txt.
1236
Andres Salomon8f368812007-10-12 23:04:06 +02001237 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1238 Multi-Function General Purpose Timers on AMD Geode
1239 platforms.
1240
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001241 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1242 the BIOS has incorrectly applied a workaround. TinyBIOS
1243 version 0.98 is known to be affected, 0.99 fixes the
1244 problem by letting the user disable the workaround.
1245
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 mga= [HW,DRM]
1247
Mel Gorman6b74ab92008-07-23 21:26:49 -07001248 mminit_loglevel=
1249 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1250 parameter allows control of the logging verbosity for
1251 the additional memory initialisation checks. A value
1252 of 0 disables mminit logging and a level of 4 will
1253 log everything. Information is printed at KERN_DEBUG
1254 so loglevel=8 may also need to be specified.
1255
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 mousedev.tap_time=
1257 [MOUSE] Maximum time between finger touching and
1258 leaving touchpad surface for touch to be considered
1259 a tap and be reported as a left button click (for
1260 touchpads working in absolute mode only).
1261 Format: <msecs>
1262 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1263 reporting absolute coordinates, such as tablets
1264 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1265 reporting absolute coordinates, such as tablets
1266
1267 mpu401= [HW,OSS]
1268 Format: <io>,<irq>
1269
1270 MTD_Partition= [MTD]
1271 Format: <name>,<region-number>,<size>,<offset>
1272
Randy Dunlapa9913042005-10-23 12:57:11 -07001273 MTD_Region= [MTD] Format:
1274 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275
1276 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001277 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278
Ben Dooks9db829f2008-07-03 11:24:29 +01001279 mtdset= [ARM]
1280 ARM/S3C2412 JIVE boot control
1281
1282 See arch/arm/mach-s3c2412/mach-jive.c
1283
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001285 [HW] Make the MicroTouch USB driver use raw coordinates
1286 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287
1288 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1289
1290 NCR_D700= [HW,SCSI]
1291 See header of drivers/scsi/NCR_D700.c.
1292
1293 ncr5380= [HW,SCSI]
1294
1295 ncr53c400= [HW,SCSI]
1296
1297 ncr53c400a= [HW,SCSI]
1298
1299 ncr53c406a= [HW,SCSI]
1300
1301 ncr53c8xx= [HW,SCSI]
1302
1303 netdev= [NET] Network devices parameters
1304 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1305 Note that mem_start is often overloaded to mean
1306 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001307 This usage is only documented in each driver source
1308 file if at all.
1309
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001310 nf_conntrack.acct=
1311 [NETFILTER] Enable connection tracking flow accounting
1312 0 to disable accounting
1313 1 to enable accounting
1314 Default value depends on CONFIG_NF_CT_ACCT that is
1315 going to be removed in 2.6.29.
1316
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001318 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
1320 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001321 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322
Trond Myklebusta72b4422006-01-03 09:55:41 +01001323 nfs.callback_tcpport=
1324 [NFS] set the TCP port on which the NFSv4 callback
1325 channel should listen.
1326
Trond Myklebust58df0952006-01-03 09:55:57 +01001327 nfs.idmap_cache_timeout=
1328 [NFS] set the maximum lifetime for idmapper cache
1329 entries.
1330
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001331 nfs.enable_ino64=
1332 [NFS] enable 64-bit inode numbers.
1333 If zero, the NFS client will fake up a 32-bit inode
1334 number for the readdir() and stat() syscalls instead
1335 of returning the full 64-bit number.
1336 The default is to return 64-bit inode numbers.
1337
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001338 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1339 when a NMI is triggered.
1340 Format: [state][,regs][,debounce][,die]
1341
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001342 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001344 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345 emulation library even if a 387 maths coprocessor
1346 is present.
1347
Christoph Lameterc1aee212007-05-31 00:40:47 -07001348 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1349 caches in the slab allocator. Saves per-node memory,
1350 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001351
Randy Dunlapa9913042005-10-23 12:57:11 -07001352 noalign [KNL,ARM]
1353
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 noapic [SMP,APIC] Tells the kernel to not make use of any
1355 IOAPICs that may be present in the system.
1356
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 nobats [PPC] Do not use BATs for mapping kernel lowmem
1358 on "Classic" PPC cores.
1359
1360 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001361
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001362 nodelayacct [KNL] Disable per-task delay accounting
1363
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1365
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001366 noefi [X86-32,X86-64] Disable EFI runtime services support.
1367
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 noexec [IA-64]
1369
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001370 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001371 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001373 noexec=off: disable non-executable mappings
1374
1375 noexec32 [X86-64]
1376 This affects only 32-bit executables.
1377 noexec32=on: enable non-executable mappings (default)
1378 read doesn't imply executable mappings
1379 noexec32=off: disable non-executable mappings
1380 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001382 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001383 register save and restore. The kernel will only save
1384 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385
Andi Kleen191679f2008-01-30 13:33:21 +01001386 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1387
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001389
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001390 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 instruction doesn't work correctly and not to
1392 use it.
1393
1394 nohalt [IA-64] Tells the kernel not to use the power saving
1395 function PAL_HALT_LIGHT when idle. This increases
1396 power-consumption. On the positive side, it reduces
1397 interrupt wake-up latency, which may improve performance
1398 in certain environments such as networked servers or
1399 real-time systems.
1400
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001401 nohz= [KNL] Boottime enable/disable dynamic ticks
1402 Valid arguments: on, off
1403 Default: on
1404
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001405 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001406
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001407 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 disable unhandled interrupt sources.
1409
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001410 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001411 broken timer IRQ sources.
1412
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413 noisapnp [ISAPNP] Disables ISA PnP code.
1414
1415 noinitrd [RAM] Tells the kernel not to load any configured
1416 initial RAM disk.
1417
1418 nointroute [IA-64]
1419
Tony Luck0aa366f2007-07-20 11:22:30 -07001420 nojitter [IA64] Disables jitter checking for ITC timers.
1421
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001422 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001424 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001425
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 noltlbs [PPC] Do not use large page/tlb entries for kernel
1427 lowmem mapping on PPC40x.
1428
Horms312f1f02006-02-22 09:57:55 +09001429 nomca [IA-64] Disable machine check abort handling
1430
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001431 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001432
Andres Salomon83d73842007-10-12 23:04:06 +02001433 nomfgpt [X86-32] Disable Multi-Function General Purpose
1434 Timer usage (for AMD Geode machines).
1435
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001436 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001437
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001438 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001439 with UP alternatives
1440
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441 noresidual [PPC] Don't use residual data on PReP machines.
1442
Randy Dunlapa9913042005-10-23 12:57:11 -07001443 noresume [SWSUSP] Disables resume and restores original swap
1444 space.
1445
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 no-scroll [VGA] Disables scrollback.
1447 This is required for the Braillex ib80-piezo Braille
1448 reader made by F.H. Papenmeier (Germany).
1449
1450 nosbagart [IA-64]
1451
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001452 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001453
Len Brown61ec7562007-08-16 03:34:22 -04001454 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1455 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456
Dave Jones97842212007-07-15 23:41:05 -07001457 nosoftlockup [KNL] Disable the soft-lockup detector.
1458
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 nosync [HW,M68K] Disables sync negotiation for all devices.
1460
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001461 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
1463 nousb [USB] Disable the USB subsystem
1464
1465 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001466
Fenghua Yua6c75b862008-03-14 13:57:08 -07001467 nptcg= [IA64] Override max number of concurrent global TLB
1468 purges which is reported from either PAL_VM_SUMMARY or
1469 SAL PALO.
1470
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001471 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1472 one of ['zone', 'node', 'default'] can be specified
1473 This can be set from sysctl after boot.
1474 See Documentation/sysctl/vm.txt for details.
1475
Dave Jonesa61c2d72006-01-07 23:18:19 +00001476 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1477
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001478 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1479 Rather than timing out after 20 ms if an EC
1480 command is not properly ACKed, override the length
1481 of the timeout. We have interrupts disabled while
1482 waiting for the ACK, so if this is set too high
1483 interrupts *may* be lost!
1484
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 opl3= [HW,OSS]
1486 Format: <io>
1487
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 oprofile.timer= [HW]
1489 Use timer interrupt instead of performance counters
1490
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 osst= [HW,SCSI] SCSI Tape Driver
1492 Format: <buffer_size>,<write_threshold>
1493 See also Documentation/scsi/st.txt.
1494
1495 panic= [KNL] Kernel behaviour on panic
1496 Format: <timeout>
1497
1498 parkbd.port= [HW] Parallel port number the keyboard adapter is
1499 connected to, default is 0.
1500 Format: <parport#>
1501 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1502 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001503 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504
Randy Dunlapa9913042005-10-23 12:57:11 -07001505 parport= [HW,PPT] Specify parallel ports. 0 disables.
1506 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1507 Use 'auto' to force the driver to use any
1508 IRQ/DMA settings detected (the default is to
1509 ignore detected IRQ/DMA settings because of
1510 possible conflicts). You can specify the base
1511 address, IRQ, and DMA settings; IRQ and DMA
1512 should be numbers, or 'auto' (for using detected
1513 settings on that particular port), or 'nofifo'
1514 (to avoid using a FIFO even if it is detected).
1515 Parallel ports are assigned in the order they
1516 are specified on the command line, starting
1517 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518
Randy Dunlapa9913042005-10-23 12:57:11 -07001519 parport_init_mode= [HW,PPT]
1520 Configure VIA parallel port to operate in
1521 a specific mode. This is necessary on Pegasos
1522 computer where firmware has no options for setting
1523 up parallel port mode and sets it to spp.
1524 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525 Format: [spp|ps2|epp|ecp|ecpepp]
1526
Randy Dunlapa9913042005-10-23 12:57:11 -07001527 pas2= [HW,OSS] Format:
1528 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1529
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 pas16= [HW,SCSI]
1531 See header of drivers/scsi/pas16.c.
1532
Andrew Mortondd287792006-03-23 03:00:57 -08001533 pause_on_oops=
1534 Halt all CPUs after the first oops has been printed for
1535 the specified number of seconds. This is to be used if
1536 your oopses keep scrolling off the screen.
1537
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538 pcbit= [HW,ISDN]
1539
1540 pcd. [PARIDE]
1541 See header of drivers/block/paride/pcd.c.
1542 See also Documentation/paride.txt.
1543
Randy Dunlapa9913042005-10-23 12:57:11 -07001544 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001545 off [X86-32] don't probe for the PCI bus
1546 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001547 the hardware directly. Use this if your machine
1548 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001549 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001550 hardware access methods are allowed. Use this
1551 if you experience crashes upon bootup and you
1552 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001553 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001554 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001555 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001556 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001557 noaer [PCIE] If the PCIEAER kernel config parameter is
1558 enabled, this kernel boot option can be used to
1559 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001560 nodomains [PCI] Disable support for multiple PCI
1561 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001562 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001563 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001564 nomsi [MSI] If the PCI_MSI kernel config parameter is
1565 enabled, this kernel boot option can be used to
1566 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001567 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001568 routing table. These calls are known to be buggy
1569 on several machines and they hang the machine
1570 when used, but on other computers it's the only
1571 way to get the interrupt routing table. Try
1572 this option if the kernel is unable to allocate
1573 IRQs or discover secondary PCI buses on your
1574 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001575 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001576 Use with caution as certain devices share
1577 address decoders between ROMs and other
1578 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001579 norom [X86-32,X86_64] Do not assign address space to
1580 expansion ROMs that do not already have
1581 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001582 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001583 assigned automatically to PCI devices. You can
1584 make the kernel exclude IRQs of your ISA cards
1585 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001586 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001587 of the PIRQ table (normally generated
1588 by the BIOS) if it is outside the
1589 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001590 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001591 useful if the kernel is unable to find your
1592 secondary buses and you want to tell it
1593 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001594 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001595 numbers ourselves, overriding
1596 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001597 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001598 in the BIOS $PIR table. This is needed on
1599 some systems with broken BIOSes, notably
1600 some HP Pavilion N5400 and Omnibook XE3
1601 notebooks. This will have no effect if ACPI
1602 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001603 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001604 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001605 use_crs [X86-32] Use _CRS for PCI resource
1606 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001607 routeirq Do IRQ routing for all PCI devices.
1608 This is normally done in pci_enable_device(),
1609 so this option is a temporary workaround
1610 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001611 skip_isa_align [X86] do not align io start addr, so can
1612 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001613 firmware [ARM] Do not re-enumerate the bus but instead
1614 just use the configuration from the
1615 bootloader. This is currently used on
1616 IXP2000 systems where the bus has to be
1617 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001618 noearly [X86] Don't do any early type 1 scanning.
1619 This might help on some broken boards which
1620 machine check when some devices' config space
1621 is read. But various workarounds are disabled
1622 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001623 bfsort Sort PCI devices into breadth-first order.
1624 This sorting is done to get a device
1625 order compatible with older (<= 2.4) kernels.
1626 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001627 cbiosize=nn[KMG] The fixed amount of bus space which is
1628 reserved for the CardBus bridge's IO window.
1629 The default value is 256 bytes.
1630 cbmemsize=nn[KMG] The fixed amount of bus space which is
1631 reserved for the CardBus bridge's memory
1632 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001633
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634 pcmv= [HW,PCMCIA] BadgePAD 4
1635
1636 pd. [PARIDE]
1637 See Documentation/paride.txt.
1638
1639 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1640 boot time.
1641 Format: { 0 | 1 }
1642 See arch/parisc/kernel/pdc_chassis.c
1643
1644 pf. [PARIDE]
1645 See Documentation/paride.txt.
1646
1647 pg. [PARIDE]
1648 See Documentation/paride.txt.
1649
1650 pirq= [SMP,APIC] Manual mp-table setup
1651 See Documentation/i386/IO-APIC.txt.
1652
1653 plip= [PPT,NET] Parallel port network link
1654 Format: { parport<nr> | timid | 0 }
1655 See also Documentation/parport.txt.
1656
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001657 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1658 Override pmtimer IOPort with a hex value.
1659 e.g. pmtmr=0x508
1660
Linus Torvalds1da177e2005-04-16 15:20:36 -07001661 pnpacpi= [ACPI]
1662 { off }
1663
1664 pnpbios= [ISAPNP]
1665 { on | off | curr | res | no-curr | no-res }
1666
1667 pnp_reserve_irq=
1668 [ISAPNP] Exclude IRQs for the autoconfiguration
1669
1670 pnp_reserve_dma=
1671 [ISAPNP] Exclude DMAs for the autoconfiguration
1672
1673 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001674 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675
1676 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001677 [ISAPNP] Exclude memory regions for the
1678 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 Ranges are in pairs (memory base and size).
1680
Ingo Molnar45807a12007-07-15 23:40:10 -07001681 print-fatal-signals=
1682 [KNL] debug: print fatal signals
1683 print-fatal-signals=1: print segfault info to
1684 the kernel console.
1685 default: off.
1686
Randy Dunlape84845c2007-07-15 23:40:25 -07001687 printk.time= Show timing data prefixed to each printk message line
1688 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1689
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001691 Format: [schedule,]<number>
1692 Param: "schedule" - profile schedule points.
1693 Param: <number> - step/bucket size as a power of 2 for
1694 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001695 Param: "sleep" - profile D-state sleeping (millisecs).
1696 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001697 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698
Randy Dunlapa9913042005-10-23 12:57:11 -07001699 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700 Limit processor to maximum C-state
1701 max_cstate=9 overrides any DMI blacklist limit.
1702
Len Brown41c0d862005-12-28 12:43:51 -05001703 processor.nocst [HW,ACPI]
1704 Ignore the _CST method to determine C-states,
1705 instead using the legacy FADT method
1706
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1708 before loading.
1709 See Documentation/ramdisk.txt.
1710
Randy Dunlapa9913042005-10-23 12:57:11 -07001711 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1712 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1714 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001715 psmouse.resetafter= [HW,MOUSE]
1716 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717 (0 = never).
1718 psmouse.resolution=
1719 [HW,MOUSE] Set desired mouse resolution, in dpi.
1720 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001721 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 0 = disabled, 1 = enabled (default).
1723
1724 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001725 Format:
1726 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727
1728 pt. [PARIDE]
1729 See Documentation/paride.txt.
1730
Kay Sieversdc8c8582007-08-15 12:25:38 +02001731 pty.legacy_count=
1732 [KNL] Number of legacy pty's. Overwrites compiled-in
1733 default number.
1734
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001735 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001736
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 r128= [HW,DRM]
1738
1739 raid= [HW,RAID]
1740 See Documentation/md.txt.
1741
Randy Dunlapa9913042005-10-23 12:57:11 -07001742 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001744
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 See Documentation/ramdisk.txt.
1747
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001748 rcupdate.blimit= [KNL,BOOT]
1749 Set maximum number of finished RCU callbacks to process
1750 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001751
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001752 rcupdate.qhimark= [KNL,BOOT]
1753 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001754 RCU callbacks over which batch limiting is disabled.
1755
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001756 rcupdate.qlowmark= [KNL,BOOT]
1757 Set threshold of queued RCU callbacks below which
1758 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001759
Olof Johanssonffdfc402005-09-06 15:17:19 -07001760 rdinit= [KNL]
1761 Format: <full_path>
1762 Run specified binary instead of /init from the ramdisk,
1763 used for early userspace startup. See initrd.
1764
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001765 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001767 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001768
Paul Jackson46b6d942008-07-04 10:00:09 -07001769 relax_domain_level=
1770 [KNL, SMP] Set scheduler's default relax_domain_level.
1771 See Documentation/cpusets.txt.
1772
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1774
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001775 reservetop= [X86-32]
Zachary Amsden461a9aff2006-09-25 23:32:25 -07001776 Format: nn[KMG]
1777 Reserves a hole at the top of the kernel virtual
1778 address space.
1779
Vivek Goyal7e962872006-09-27 01:50:44 -07001780 reset_devices [KNL] Force drivers to reset the underlying device
1781 during initialization.
1782
Randy Dunlapa9913042005-10-23 12:57:11 -07001783 resume= [SWSUSP]
1784 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001786 resume_offset= [SWSUSP]
1787 Specify the offset from the beginning of the partition
1788 given by "resume=" at which the swap header is located,
1789 in <PAGE_SIZE> units (needed only for swap files).
1790 See Documentation/power/swsusp-and-swap-files.txt
1791
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001792 retain_initrd [RAM] Keep initrd memory after extraction
1793
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 rhash_entries= [KNL,NET]
1795 Set number of hash buckets for route cache
1796
1797 riscom8= [HW,SERIAL]
1798 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1799
1800 ro [KNL] Mount root device read-only on boot
1801
1802 root= [KNL] Root filesystem
1803
1804 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1805 mount the root filesystem
1806
1807 rootflags= [KNL] Set root filesystem mount option string
1808
1809 rootfstype= [KNL] Set root filesystem type
1810
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001811 rootwait [KNL] Wait (indefinitely) for root device to show up.
1812 Useful for devices that are detected asynchronously
1813 (e.g. USB and MMC devices).
1814
James Morris20510f22007-10-16 23:31:32 -07001815 root_plug.vendor_id=
1816 [ROOTPLUG] Override the default vendor ID
1817
1818 root_plug.product_id=
1819 [ROOTPLUG] Override the default product ID
1820
1821 root_plug.debug=
1822 [ROOTPLUG] Enable debugging output
1823
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 rw [KNL] Mount root device read-write on boot
1825
1826 S [KNL] Run init in single mode
1827
1828 sa1100ir [NET]
1829 See drivers/net/irda/sa1100_ir.c.
1830
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001832
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1834 Format: <io>[,<timeout>[,<isapnp>]]
1835
1836 scsi_debug_*= [SCSI]
1837 See drivers/scsi/scsi_debug.c.
1838
1839 scsi_default_dev_flags=
1840 [SCSI] SCSI default device flags
1841 Format: <integer>
1842
1843 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1844 Format: <vendor>:<model>:<flags>
1845 (flags are integer value)
1846
Randy Dunlap6af66322007-11-14 16:52:25 -08001847 scsi_logging_level= [SCSI] a bit mask of logging levels
1848 See drivers/scsi/scsi_logging.h for bits. Also
1849 settable via sysctl at dev.scsi.logging_level
1850 (/proc/sys/dev/scsi/logging_level).
1851 There is also a nice 'scsi_logging_level' script in the
1852 S390-tools package, available for download at
1853 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001855 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1856 discovered. async scans them in kernel threads,
1857 allowing boot to proceed. none ignores them, expecting
1858 user space to do the scan.
1859
Linus Torvalds1da177e2005-04-16 15:20:36 -07001860 selinux [SELINUX] Disable or enable SELinux at boot time.
1861 Format: { "0" | "1" }
1862 See security/selinux/Kconfig help text.
1863 0 -- disable.
1864 1 -- enable.
1865 Default value is set via kernel config option.
1866 If enabled at boot time, /selinux/disable can be used
1867 later to disable prior to initial policy load.
1868
James Morris4e5ab4c2006-06-09 00:33:33 -07001869 selinux_compat_net =
1870 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001871 Format: { "0" | "1" }
1872 0 -- use new secmark-based packet controls
1873 1 -- use legacy packet controls
1874 Default value is 0 (preferred).
1875 Value can be changed at runtime via
1876 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001877
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001878 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 shapers= [NET]
1881 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001882
Yinghai Lub05f78f2008-08-22 01:32:50 -07001883 show_msr= [x86] show boot-time MSR settings
1884 Format: { <integer> }
1885 Show boot-time (BIOS-initialized) MSR settings.
1886 The parameter means the number of CPUs to show,
1887 for example 1 means boot CPU only.
1888
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889 sim710= [SCSI,HW]
1890 See header of drivers/scsi/sim710.c.
1891
1892 simeth= [IA-64]
1893 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001894
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 slram= [HW,MTD]
1896
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001897 slub_debug[=options[,slabs]] [MM, SLUB]
1898 Enabling slub_debug allows one to determine the
1899 culprit if slab objects become corrupted. Enabling
1900 slub_debug can create guard zones around objects and
1901 may poison objects when not in use. Also tracks the
1902 last alloc / free. For more information see
1903 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001904
1905 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001906 Determines the maximum allowed order for slabs.
1907 A high setting may cause OOMs due to memory
1908 fragmentation. For more information see
1909 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001910
1911 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001912 The minimum number of objects per slab. SLUB will
1913 increase the slab order up to slub_max_order to
1914 generate a sufficiently large slab able to contain
1915 the number of objects indicated. The higher the number
1916 of objects the smaller the overhead of tracking slabs
1917 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001918 For more information see Documentation/vm/slub.txt.
1919
1920 slub_min_order= [MM, SLUB]
1921 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001922 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001923 For more information see Documentation/vm/slub.txt.
1924
1925 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001926 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001927 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001928 allocs to different slabs. Debug options disable
1929 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001930 For more information see Documentation/vm/slub.txt.
1931
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932 smart2= [HW]
1933 Format: <io1>[,<io2>[,...,<io8>]]
1934
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001935 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001936 attempt to substitute SMP alternatives once at boot.
1937
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001938 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1939 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1940 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1941 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1942 smsc-ircc2.ircc_irq= [HW] IRQ line
1943 smsc-ircc2.ircc_dma= [HW] DMA channel
1944 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1945 0: Toshiba Satellite 1800 (GP data pin select)
1946 1: Fast pin select (default)
1947 2: ATC IRMode
1948
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949 snd-ad1816a= [HW,ALSA]
1950
1951 snd-ad1848= [HW,ALSA]
1952
1953 snd-ali5451= [HW,ALSA]
1954
1955 snd-als100= [HW,ALSA]
1956
1957 snd-als4000= [HW,ALSA]
1958
1959 snd-azt2320= [HW,ALSA]
1960
1961 snd-cmi8330= [HW,ALSA]
1962
1963 snd-cmipci= [HW,ALSA]
1964
1965 snd-cs4231= [HW,ALSA]
1966
1967 snd-cs4232= [HW,ALSA]
1968
1969 snd-cs4236= [HW,ALSA]
1970
1971 snd-cs4281= [HW,ALSA]
1972
1973 snd-cs46xx= [HW,ALSA]
1974
1975 snd-dt019x= [HW,ALSA]
1976
1977 snd-dummy= [HW,ALSA]
1978
1979 snd-emu10k1= [HW,ALSA]
1980
1981 snd-ens1370= [HW,ALSA]
1982
1983 snd-ens1371= [HW,ALSA]
1984
1985 snd-es968= [HW,ALSA]
1986
1987 snd-es1688= [HW,ALSA]
1988
1989 snd-es18xx= [HW,ALSA]
1990
1991 snd-es1938= [HW,ALSA]
1992
1993 snd-es1968= [HW,ALSA]
1994
1995 snd-fm801= [HW,ALSA]
1996
1997 snd-gusclassic= [HW,ALSA]
1998
1999 snd-gusextreme= [HW,ALSA]
2000
2001 snd-gusmax= [HW,ALSA]
2002
2003 snd-hdsp= [HW,ALSA]
2004
2005 snd-ice1712= [HW,ALSA]
2006
2007 snd-intel8x0= [HW,ALSA]
2008
2009 snd-interwave= [HW,ALSA]
2010
2011 snd-interwave-stb=
2012 [HW,ALSA]
2013
2014 snd-korg1212= [HW,ALSA]
2015
2016 snd-maestro3= [HW,ALSA]
2017
2018 snd-mpu401= [HW,ALSA]
2019
2020 snd-mtpav= [HW,ALSA]
2021
2022 snd-nm256= [HW,ALSA]
2023
2024 snd-opl3sa2= [HW,ALSA]
2025
2026 snd-opti92x-ad1848=
2027 [HW,ALSA]
2028
2029 snd-opti92x-cs4231=
2030 [HW,ALSA]
2031
2032 snd-opti93x= [HW,ALSA]
2033
2034 snd-pmac= [HW,ALSA]
2035
2036 snd-rme32= [HW,ALSA]
2037
2038 snd-rme96= [HW,ALSA]
2039
2040 snd-rme9652= [HW,ALSA]
2041
2042 snd-sb8= [HW,ALSA]
2043
2044 snd-sb16= [HW,ALSA]
2045
2046 snd-sbawe= [HW,ALSA]
2047
2048 snd-serial= [HW,ALSA]
2049
2050 snd-sgalaxy= [HW,ALSA]
2051
2052 snd-sonicvibes= [HW,ALSA]
2053
2054 snd-sun-amd7930=
2055 [HW,ALSA]
2056
2057 snd-sun-cs4231= [HW,ALSA]
2058
2059 snd-trident= [HW,ALSA]
2060
2061 snd-usb-audio= [HW,ALSA,USB]
2062
2063 snd-via82xx= [HW,ALSA]
2064
2065 snd-virmidi= [HW,ALSA]
2066
2067 snd-wavefront= [HW,ALSA]
2068
2069 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002070
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002071 softlockup_panic=
2072 [KNL] Should the soft-lockup detector generate panics.
2073
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2075 See Documentation/sonypi.txt
2076
2077 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2078 See Documentation/specialix.txt.
2079
2080 spia_io_base= [HW,MTD]
2081 spia_fio_base=
2082 spia_pedr=
2083 spia_peddr=
2084
2085 sscape= [HW,OSS]
2086 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002087
Linus Torvalds1da177e2005-04-16 15:20:36 -07002088 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2089 See Documentation/scsi/st.txt.
2090
Linus Torvalds1da177e2005-04-16 15:20:36 -07002091 sti= [PARISC,HW]
2092 Format: <num>
2093 Set the STI (builtin display/keyboard on the HP-PARISC
2094 machines) console (graphic card) which should be used
2095 as the initial boot-console.
2096 See also comment in drivers/video/console/sticore.c.
2097
2098 sti_font= [HW]
2099 See comment in drivers/video/console/sticore.c.
2100
2101 stifb= [HW]
2102 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2103
Greg Banks42a7fc42007-03-06 01:42:23 -08002104 sunrpc.pool_mode=
2105 [NFS]
2106 Control how the NFS server code allocates CPUs to
2107 service thread pools. Depending on how many NICs
2108 you have and where their interrupts are bound, this
2109 option will affect which CPUs will do NFS serving.
2110 Note: this parameter cannot be changed while the
2111 NFS server is running.
2112
2113 auto the server chooses an appropriate mode
2114 automatically using heuristics
2115 global a single global pool contains all CPUs
2116 percpu one pool for each CPU
2117 pernode one pool for each NUMA node (equivalent
2118 to global on non-NUMA machines)
2119
Linus Torvalds1da177e2005-04-16 15:20:36 -07002120 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002121
Linus Torvalds1da177e2005-04-16 15:20:36 -07002122 switches= [HW,M68k]
2123
2124 sym53c416= [HW,SCSI]
2125 See header of drivers/scsi/sym53c416.c.
2126
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002127 sysrq_always_enabled
2128 [KNL]
2129 Ignore sysrq setting - this boot parameter will
2130 neutralize any effect of /proc/sys/kernel/sysrq.
2131 Useful for debugging.
2132
Linus Torvalds1da177e2005-04-16 15:20:36 -07002133 t128= [HW,SCSI]
2134 See header of drivers/scsi/t128.c.
2135
2136 tdfx= [HW,DRM]
2137
David Brownell77437fd2008-07-23 21:28:33 -07002138 test_suspend= [SUSPEND]
2139 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2140 standby suspend) as the system sleep state to briefly
2141 enter during system startup. The system is woken from
2142 this state using a wakeup-capable RTC alarm.
2143
Linus Torvalds1da177e2005-04-16 15:20:36 -07002144 thash_entries= [KNL,NET]
2145 Set number of hash buckets for TCP connection
2146
Len Brownf8707ec2007-08-12 00:12:54 -04002147 thermal.act= [HW,ACPI]
2148 -1: disable all active trip points in all thermal zones
2149 <degrees C>: override all lowest active trip points
2150
Len Brownc52a7412007-08-14 15:49:32 -04002151 thermal.crt= [HW,ACPI]
2152 -1: disable all critical trip points in all thermal zones
2153 <degrees C>: lower all critical trip points
2154
Len Brownf5487142007-08-12 00:12:44 -04002155 thermal.nocrt= [HW,ACPI]
2156 Set to disable actions on ACPI thermal zone
2157 critical and hot trip points.
2158
Len Brown72b33ef2007-08-12 00:12:17 -04002159 thermal.off= [HW,ACPI]
2160 1: disable ACPI thermal control
2161
Len Browna70cdc52007-08-12 00:12:35 -04002162 thermal.psv= [HW,ACPI]
2163 -1: disable all passive trip points
2164 <degrees C>: override all passive trip points to this value
2165
Len Brown730ff342007-08-12 00:12:26 -04002166 thermal.tzp= [HW,ACPI]
2167 Specify global default ACPI thermal zone polling rate
2168 <deci-seconds>: poll all this frequency
2169 0: no polling (default)
2170
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 tmscsim= [HW,SCSI]
2172 See comment before function dc390_setup() in
2173 drivers/scsi/tmscsim.c.
2174
2175 tp720= [HW,PS2]
2176
2177 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002178 Format:
2179 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2180
Randy Dunlapa9913042005-10-23 12:57:11 -07002181 turbografx.map[2|3]= [HW,JOY]
2182 TurboGraFX parallel port interface
2183 Format:
2184 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185 See also Documentation/input/joystick-parport.txt
2186
2187 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2188 See header of drivers/scsi/u14-34f.c.
2189
2190 uart401= [HW,OSS]
2191 Format: <io>,<irq>
2192
2193 uart6850= [HW,OSS]
2194 Format: <io>,<irq>
2195
Alan Stern5f8364b2006-12-05 16:29:55 -05002196 uhci-hcd.ignore_oc=
2197 [USB] Ignore overcurrent events (default N).
2198 Some badly-designed motherboards generate lots of
2199 bogus events, for ports that aren't wired to
2200 anything. Set this parameter to avoid log spamming.
2201 Note that genuine overcurrent events won't be
2202 reported either.
2203
Simon Arlotte3a61b02008-07-19 23:32:54 +01002204 unknown_nmi_panic
2205 [X86-32,X86-64]
2206 Set unknown_nmi_panic=1 early on boot.
2207
Alan Sternb5e795f2007-02-20 15:00:53 -05002208 usbcore.autosuspend=
2209 [USB] The autosuspend time delay (in seconds) used
2210 for newly-detected USB devices (default 2). This
2211 is the time required before an idle device will be
2212 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002213 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002214
Linus Torvalds1da177e2005-04-16 15:20:36 -07002215 usbhid.mousepoll=
2216 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002217
Paul Jackson200001e2008-06-25 05:44:46 -07002218 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2219 kernel's map of available physical RAM.
2220
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002221 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002222 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002223 vdso=1: enable VDSO (default)
2224 vdso=0: disable VDSO mapping
2225
Roland McGrathaf65d642008-01-30 13:30:43 +01002226 vdso32= [X86-32,X86-64]
2227 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2228 vdso32=1: enable 32-bit VDSO (default)
2229 vdso32=0: disable 32-bit VDSO mapping
2230
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002231 vector= [IA-64,SMP]
2232 vector=percpu: enable percpu vector domain
2233
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 video= [FB] Frame buffer configuration
2235 See Documentation/fb/modedb.txt.
2236
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002237 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002238 See Documentation/i386/boot.txt and
2239 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240 Use vga=ask for menu.
2241 This is actually a boot loader parameter; the value is
2242 passed to the kernel using a special protocol.
2243
Randy Dunlapa9913042005-10-23 12:57:11 -07002244 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245 size of <nn>. This can be used to increase the
2246 minimum size (128MB on x86). It can also be used to
2247 decrease the size and leave more room for directly
2248 mapped kernel RAM.
2249
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002250 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2251 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002253 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2254 Format: <command>
2255
2256 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2257 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002258
Linus Torvalds1da177e2005-04-16 15:20:36 -07002259 waveartist= [HW,OSS]
2260 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002261
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 wd33c93= [HW,SCSI]
2263 See header of drivers/scsi/wd33c93.c.
2264
2265 wd7000= [HW,SCSI]
2266 See header of drivers/scsi/wd7000.c.
2267
2268 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002269 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270
2271 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2272 xd_geo= See header of drivers/block/xd.c.
2273
2274 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002275 Format:
2276 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002277
Andi Kleena62eaf12006-02-16 23:41:58 +01002278 norandmaps Don't use address space randomization
2279 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2280
Randy Dunlapa9913042005-10-23 12:57:11 -07002281______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282
2283TODO:
2284
2285 Add documentation for ALSA options.
2286 Add more DRM drivers.