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Stefan Richter0ee9d712006-04-01 01:42:29 +02001 Kernel Parameters
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 ~~~~~~~~~~~~~~~~~
3
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.
33 ALSA ALSA sound support is enabled.
34 APIC APIC support is enabled.
35 APM Advanced Power Management support is enabled.
36 AX25 Appropriate AX.25 support is enabled.
37 CD Appropriate CD support is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070038 DRM Direct Rendering Management support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
40 EFI EFI Partitioning (GPT) is enabled
41 EIDE EIDE/ATAPI support is enabled.
42 FB The frame buffer device is enabled.
43 HW Appropriate hardware is enabled.
44 IA-32 IA-32 aka i386 architecture is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070047 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LP Printer support is enabled.
52 LOOP Loopback device support is enabled.
53 M68k M68k architecture is enabled.
54 These options have more detailed description inside of
55 Documentation/m68k/kernel-options.txt.
56 MCA MCA bus support is enabled.
57 MDA MDA console support is enabled.
58 MOUSE Appropriate mouse support is enabled.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070059 MSI Message Signaled Interrupts (PCI).
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 MTD MTD support is enabled.
61 NET Appropriate network support is enabled.
62 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070063 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
78 Documentation/scsi/.
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070083 SWSUSP Software suspend is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
95
96In addition, the following text indicates that the option:
97
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
101
102Parameters denoted with BOOT are actually interpreted by the boot
103loader, and have no meaning to the kernel directly.
104Do not modify the syntax of boot loader parameters without extreme
105need or coordination with <Documentation/i386/boot.txt>.
106
107Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
108a trailing = on the name of any parameter states that that parameter will
109be entered as an environment variable, whereas its absence indicates that
110it will appear as a kernel argument readable via /proc/cmdline by programs
111running once the system is up.
112
jens m. noedler9c4751f2006-09-29 02:00:27 -0700113The number of kernel parameters is not limited, but the length of the
114complete command line (parameters including spaces etc.) is limited to
115a fixed number of characters. This limit depends on the architecture
116and is between 256 and 4096 characters. It is defined in the file
117./include/asm/setup.h as COMMAND_LINE_SIZE.
118
119
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 53c7xx= [HW,SCSI] Amiga SCSI controllers
121 See header of drivers/scsi/53c7xx.c.
122 See also Documentation/scsi/ncr53c7xx.txt.
123
Randy Dunlapa9913042005-10-23 12:57:11 -0700124 acpi= [HW,ACPI] Advanced Configuration and Power Interface
125 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 force -- enable ACPI if default was off
127 off -- disable ACPI if default was on
128 noirq -- do not use ACPI for IRQ routing
129 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700130 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 strictly ACPI specification compliant.
132
133 See also Documentation/pm.txt, pci=noacpi
134
135 acpi_sleep= [HW,ACPI] Sleep options
136 Format: { s3_bios, s3_mode }
137 See Documentation/power/video.txt
Randy Dunlapa9913042005-10-23 12:57:11 -0700138
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700140 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Randy Dunlapa9913042005-10-23 12:57:11 -0700142 acpi_irq_balance [HW,ACPI]
143 ACPI will balance active IRQs
144 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
Randy Dunlapa9913042005-10-23 12:57:11 -0700146 acpi_irq_nobalance [HW,ACPI]
147 ACPI will not move active IRQs (default)
148 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149
Randy Dunlapa9913042005-10-23 12:57:11 -0700150 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
151 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 Format: <irq>,<irq>...
153
Randy Dunlapa9913042005-10-23 12:57:11 -0700154 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 Format: <irq>,<irq>...
156
Len Browna1f9e652006-01-25 23:47:36 -0500157 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
158 Format: To spoof as Windows 98: ="Microsoft Windows"
159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 acpi_osi= [HW,ACPI] empty param disables _OSI
161
162 acpi_serialize [HW,ACPI] force serialization of AML methods
163
164 acpi_skip_timer_override [HW,ACPI]
165 Recognize and ignore IRQ0/pin2 Interrupt Override.
166 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100167 acpi_use_timer_override [HW,ACPI}
168 Use timer override. For some broken Nvidia NF5 boards
169 that require a timer override, but don't have
170 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
172 acpi_dbg_layer= [HW,ACPI]
173 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700174 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 1: enable, 0: disable. It is useful for boot time
176 debugging. After system has booted up, it can be set
177 via /proc/acpi/debug_layer.
178
179 acpi_dbg_level= [HW,ACPI]
180 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700181 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 1: enable, 0: disable. It is useful for boot time
183 debugging. After system has booted up, it can be set
184 via /proc/acpi/debug_level.
185
186 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
187
Luming Yu30e332f2005-08-12 00:31:00 -0400188 acpi_generic_hotkey [HW,ACPI]
189 Allow consolidated generic hotkey driver to
Randy Dunlapa9913042005-10-23 12:57:11 -0700190 override platform specific driver.
Luming Yu30e332f2005-08-12 00:31:00 -0400191 See also Documentation/acpi-hotkey.txt.
192
john stultz5d0cf412006-06-26 00:25:12 -0700193 acpi_pm_good [IA-32,X86-64]
194 Override the pmtimer bug detection: force the kernel
195 to assume that this machine's pmtimer latches its value
196 and always returns good values.
197
Chuck Ebbert66759a02005-09-12 18:49:25 +0200198 enable_timer_pin_1 [i386,x86-64]
199 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700200 Can be useful to work around chipset bugs
201 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200202 The kernel tries to set a reasonable default.
203
204 disable_timer_pin_1 [i386,x86-64]
205 Disable PIN 1 of APIC timer
206 Can be useful to work around chipset bugs.
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 ad1816= [HW,OSS]
209 Format: <io>,<irq>,<dma>,<dma2>
210 See also Documentation/sound/oss/AD1816.
211
212 ad1848= [HW,OSS]
213 Format: <io>,<irq>,<dma>,<dma2>,<type>
214
215 adlib= [HW,OSS]
216 Format: <io>
Randy Dunlapa9913042005-10-23 12:57:11 -0700217
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 advansys= [HW,SCSI]
219 See header of drivers/scsi/advansys.c.
220
221 advwdt= [HW,WDT] Advantech WDT
222 Format: <iostart>,<iostop>
223
224 aedsp16= [HW,OSS] Audio Excel DSP 16
225 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
226 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 aha152x= [HW,SCSI]
229 See Documentation/scsi/aha152x.txt.
230
231 aha1542= [HW,SCSI]
232 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
233
234 aic7xxx= [HW,SCSI]
235 See Documentation/scsi/aic7xxx.txt.
236
237 aic79xx= [HW,SCSI]
238 See Documentation/scsi/aic79xx.txt.
239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 amijoy.map= [HW,JOY] Amiga joystick support
241 Map of devices attached to JOY0DAT and JOY1DAT
242 Format: <a>,<b>
243 See also Documentation/kernel/input/joystick.txt
244
245 analog.map= [HW,JOY] Analog joystick and gamepad support
246 Specifies type or capabilities of an analog joystick
247 connected to one of 16 gameports
248 Format: <type1>,<type2>,..<type16>
249
Randy Dunlapa9913042005-10-23 12:57:11 -0700250 apc= [HW,SPARC]
251 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 Format: noidle
253 Disable APC CPU standby support. SPARCstation-Fox does
254 not play well with APC CPU idle - disable it if you have
255 APC and your system crashes randomly.
256
Randy Dunlapa9913042005-10-23 12:57:11 -0700257 apic= [APIC,i386] Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 Format: { quiet (default) | verbose | debug }
259 Change the amount of debugging information output
260 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 apm= [APM] Advanced Power Management
263 See header of arch/i386/kernel/apm.c.
264
265 applicom= [HW]
266 Format: <mem>,<irq>
Randy Dunlapa9913042005-10-23 12:57:11 -0700267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
269 Format: <io>,<irq>,<nodeID>
270
271 ataflop= [HW,M68k]
272
273 atarimouse= [HW,MOUSE] Atari Mouse
274
275 atascsi= [HW,SCSI] Atari SCSI
276
277 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
278 EzKey and similar keyboards
279
280 atkbd.reset= [HW] Reset keyboard during initialization
281
Randy Dunlapa9913042005-10-23 12:57:11 -0700282 atkbd.set= [HW] Select keyboard code set
283 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
285 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
286 keyboards
287
288 atkbd.softraw= [HW] Choose between synthetic and real raw mode
289 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700290
291 atkbd.softrepeat= [HW]
292 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
294 autotest [IA64]
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 aztcd= [HW,CD] Aztech CD268 CDROM driver
297 Format: <io>,0x79 (?)
298
299 baycom_epp= [HW,AX25]
300 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700301
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
303 Format: <io>,<mode>
304 See header of drivers/net/hamradio/baycom_par.c.
305
Randy Dunlapa9913042005-10-23 12:57:11 -0700306 baycom_ser_fdx= [HW,AX25]
307 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 Format: <io>,<irq>,<mode>[,<baud>]
309 See header of drivers/net/hamradio/baycom_ser_fdx.c.
310
Randy Dunlapa9913042005-10-23 12:57:11 -0700311 baycom_ser_hdx= [HW,AX25]
312 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 Format: <io>,<irq>,<mode>
314 See header of drivers/net/hamradio/baycom_ser_hdx.c.
315
316 blkmtd_device= [HW,MTD]
317 blkmtd_erasesz=
318 blkmtd_ro=
319 blkmtd_bs=
320 blkmtd_count=
321
322 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700323 bttv.radio= Most important insmod options are available as
324 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
326 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
327
328 BusLogic= [HW,SCSI]
329 See drivers/scsi/BusLogic.c, comment before function
330 BusLogic_ParseDriverOptions().
331
332 c101= [NET] Moxa C101 synchronous serial card
333
334 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
335 Sometimes CPU hardware bugs make them report the cache
336 size incorrectly. The kernel will attempt work arounds
337 to fix known problems, but for some CPUs it is not
338 possible to determine what the correct size should be.
339 This option provides an override for these situations.
340
341 cdu31a= [HW,CD]
342 Format: <io>,<irq>[,PAS]
343 See header of drivers/cdrom/cdu31a.c.
344
345 chandev= [HW,NET] Generic channel device initialisation
346
347 checkreqprot [SELINUX] Set initial checkreqprot flag value.
348 Format: { "0" | "1" }
349 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700350 0 -- check protection applied by kernel (includes
351 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 1 -- check protection requested by application.
353 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700354 Value can be changed at runtime via
355 /selinux/checkreqprot.
356
john stultz734efb42006-06-26 00:25:05 -0700357 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
358 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200359 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700360 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200361 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 Format: { pit | tsc | cyclone | pmtmr }
363
Andi Kleenf9262c12006-03-08 17:57:25 -0800364 disable_8254_timer
365 enable_8254_timer
366 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
367 over the 8254 in addition to over the IO-APIC. The
368 kernel tries to set a sensible default.
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 hpet= [IA-32,HPET] option to disable HPET and use PIT.
371 Format: disable
372
373 cm206= [HW,CD]
374 Format: { auto | [<io>,][<irq>] }
375
376 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700377 Format:
378 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379
380 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
381 Format: <io>[,<irq>]
382
Randy Dunlapa9913042005-10-23 12:57:11 -0700383 com90xx= [HW,NET]
384 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 Format: <io>[,<irq>[,<memstart>]]
386
387 condev= [HW,S390] console device
388 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700389
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 console= [KNL] Output console device and options.
391
392 tty<n> Use the virtual console device <n>.
393
394 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800395 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800397 the form "bbbbpnf", where "bbbb" is the baud rate,
398 "p" is parity ("n", "o", or "e"), "n" is number of
399 bits, and "f" is flow control ("r" for RTS or
400 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800402 See Documentation/serial-console.txt for more
403 information. See
404 Documentation/networking/netconsole.txt for an
405 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406
407 uart,io,<addr>[,options]
408 uart,mmio,<addr>[,options]
409 Start an early, polled-mode console on the 8250/16550
410 UART at the specified I/O port or MMIO address,
411 switching to the matching ttyS device later. The
412 options are the same as for ttyS, above.
413
414 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700415 Format:
416 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
418 cpia_pp= [HW,PPT]
419 Format: { parport<nr> | auto | none }
420
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700421 crashkernel=nn[KMG]@ss[KMG]
422 [KNL] Reserve a chunk of physical memory to
423 hold a kernel to switch to with kexec on panic.
424
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 cs4232= [HW,OSS]
426 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
427
428 cs89x0_dma= [HW,NET]
429 Format: <dma>
430
431 cs89x0_media= [HW,NET]
432 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
Randy Dunlapa9913042005-10-23 12:57:11 -0700435
436 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 See header of drivers/s390/block/dasd_devmap.c.
438
439 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
440 (one device per port)
441 Format: <port#>,<type>
442 See also Documentation/input/joystick-parport.txt
443
444 debug [KNL] Enable kernel debugging (events log level).
445
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700446 debug_locks_verbose=
447 [KNL] verbose self-tests
448 Format=<0|1>
449 Print debugging info while doing the locking API
450 self-tests.
451 We default to 0 (no extra messages), setting it to
452 1 will print _a lot_ more information - normally
453 only useful to kernel developers.
454
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 decnet= [HW,NET]
456 Format: <area>[,<node>]
457 See also Documentation/networking/decnet.txt.
458
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 dhash_entries= [KNL]
460 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700461
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 digi= [HW,SERIAL]
463 IO parameters + enable/disable command.
464
465 digiepca= [HW,SERIAL]
466 See drivers/char/README.epca and
467 Documentation/digiepca.txt.
468
469 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
470 support available.
471 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
472
473 dmasound= [HW,OSS] Sound subsystem buffers
474
475 dscc4.setup= [NET]
476
477 dtc3181e= [HW,SCSI]
478
Randy Dunlapa9913042005-10-23 12:57:11 -0700479 earlyprintk= [IA-32,X86-64]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 earlyprintk=vga
481 earlyprintk=serial[,ttySn[,baudrate]]
482
Randy Dunlapa9913042005-10-23 12:57:11 -0700483 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 takes over.
485
486 Only vga or serial at a time, not both.
487
488 Currently only ttyS0 and ttyS1 are supported.
489
490 Interaction with the standard serial driver is not
491 very good.
492
493 The VGA output is eventually overwritten by the real
494 console.
495
496 eata= [HW,SCSI]
497
Len Brown53f11d42005-12-05 16:46:36 -0500498 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
499 Format: <int>
500 0: polling mode
501 non-0: interrupt mode (default)
502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 eda= [HW,PS2]
504
505 edb= [HW,PS2]
506
507 edd= [EDD]
508 Format: {"of[f]" | "sk[ipmbr]"}
509 See comment in arch/i386/boot/edd.S
510
Randy Dunlapa9913042005-10-23 12:57:11 -0700511 eicon= [HW,ISDN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 Format: <id>,<membase>,<irq>
513
514 eisa_irq_edge= [PARISC,HW]
515 See header of drivers/parisc/eisa.c.
516
517 elanfreq= [IA-32]
518 See comment before function elanfreq_setup() in
519 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
520
521 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800522 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700523 See Documentation/block/as-iosched.txt and
524 Documentation/block/deadline-iosched.txt for details.
525
Vivek Goyalaac04b32006-01-09 20:51:47 -0800526 elfcorehdr= [IA-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700527 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800528 image elf header. Generally kexec loader will
529 pass this option to capture kernel.
530 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
532 enforcing [SELINUX] Set initial enforcing status.
533 Format: {"0" | "1"}
534 See security/selinux/Kconfig help text.
535 0 -- permissive (log only, no denials).
536 1 -- enforcing (deny and log).
537 Default value is 0.
538 Value can be changed at runtime via /selinux/enforce.
539
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 es1371= [HW,OSS]
541 Format: <spdif>,[<nomix>,[<amplifier>]]
542 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700543
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 ether= [HW,NET] Ethernet cards parameters
545 This option is obsoleted by the "netdev=" option, which
546 has equivalent usage. See its documentation for details.
547
548 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
549 Format: <io>[,<irq>]
550
551 fd_mcs= [HW,SCSI]
552 See header of drivers/scsi/fd_mcs.c.
553
554 fdomain= [HW,SCSI]
555 See header of drivers/scsi/fdomain.c.
556
557 floppy= [HW]
558 See Documentation/floppy.txt.
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 gamecon.map[2|3]=
561 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
562 support via parallel port (up to 5 devices per port)
563 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
564 See also Documentation/input/joystick-parport.txt
565
566 gamma= [HW,DRM]
567
568 gdth= [HW,SCSI]
569 See header of drivers/scsi/gdth.c.
570
571 gpt [EFI] Forces disk with valid GPT signature but
572 invalid Protective MBR to be treated as GPT.
573
574 gscd= [HW,CD]
575 Format: <io>
576
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 gvp11= [HW,SCSI]
578
579 hashdist= [KNL,NUMA] Large hashes allocated during boot
580 are distributed across NUMA nodes. Defaults on
581 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700582 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583
584 hcl= [IA-64] SGI's Hardware Graph compatibility layer
585
586 hd= [EIDE] (E)IDE hard drive subsystem geometry
587 Format: <cyl>,<head>,<sect>
588
589 hd?= [HW] (E)IDE subsystem
590 hd?lun= See Documentation/ide.txt.
591
592 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
593 size of <nn>. This works even on boxes that have no
594 highmem otherwise. This also works to reduce highmem
595 size on bigger boxes.
596
597 hisax= [HW,ISDN]
598 See Documentation/isdn/README.HiSax.
599
600 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
601
602 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
603
604 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200605 i8042.dumbkbd [HW] Pretend that controller can only read data from
606 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 (Don't attempt to blink the leds)
608 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500609 i8042.nokbd [HW] Don't check/create keyboard port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 i8042.nomux [HW] Don't check presence of an active multiplexing
611 controller
612 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
613 controllers
614 i8042.panicblink=
615 [HW] Frequency with which keyboard LEDs should blink
616 when kernel panics (default is 0.5 sec)
617 i8042.reset [HW] Reset the controller during init and cleanup
618 i8042.unlock [HW] Unlock (ignore) the keylock
619
620 i810= [HW,DRM]
621
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700622 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
623 indicates that the driver is running on unsupported
624 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
626 does not match list of supported models.
627 i8k.power_status
628 [HW] Report power status in /proc/i8k
629 (disabled by default)
630 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
631 capability is set.
632
633 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
634 See Documentation/mca.txt.
635
636 icn= [HW,ISDN]
637 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
638
639 ide= [HW] (E)IDE subsystem
640 Format: ide=nodma or ide=doubler or ide=reverse
641 See Documentation/ide.txt.
642
643 ide?= [HW] (E)IDE subsystem
644 Format: ide?=noprobe or chipset specific parameters.
645 See Documentation/ide.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -0700646
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
648 See Documentation/ide.txt.
649
650 idle= [HW]
651 Format: idle=poll or idle=halt
Randy Dunlapa9913042005-10-23 12:57:11 -0700652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 ihash_entries= [KNL]
654 Set number of hash buckets for inode cache.
655
656 in2000= [HW,SCSI]
657 See header of drivers/scsi/in2000.c.
658
659 init= [KNL]
660 Format: <full_path>
661 Run specified binary instead of /sbin/init as init
662 process.
663
664 initcall_debug [KNL] Trace initcalls as they are executed. Useful
665 for working out where the kernel is dying during
666 startup.
667
668 initrd= [BOOT] Specify the location of the initial ramdisk
669
670 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
671 Format: <irq>
672
Jesse Barnes2bd0fa32005-12-13 03:05:03 -0500673 combined_mode= [HW] control which driver uses IDE ports in combined
674 mode: legacy IDE driver, libata, or both
675 (in the libata case, libata.atapi_enabled=1 may be
676 useful as well). Note that using the ide or libata
677 options may affect your device naming (e.g. by
678 changing hdc to sdb).
679 Format: combined (default), ide, or libata
680
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 inttest= [IA64]
682
683 io7= [HW] IO7 for Marvel based alpha systems
684 See comment before marvel_specify_io7 in
685 arch/alpha/kernel/core_marvel.c.
686
687 ip= [IP_PNP]
688 See Documentation/nfsroot.txt.
689
690 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
691 See comment before ip2_setup() in drivers/char/ip2.c.
692
693 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
694 See header of drivers/scsi/ips.c.
695
Simon Horman72c4a132006-09-13 19:57:18 -0700696 ports= [IP_VS_FTP] IPVS ftp helper module
697 Default is 21.
698 Up to 8 (IP_VS_APP_MAX_PORTS) ports
699 may be specified.
700 Format: <port>,<port>....
701
Alan Cox200803d2005-06-28 20:45:18 -0700702 irqfixup [HW]
703 When an interrupt is not handled search all handlers
704 for it. Intended to get systems with badly broken
705 firmware running.
706
707 irqpoll [HW]
708 When an interrupt is not handled search all handlers
709 for it. Also check all handlers each timer
710 interrupt. Intended to get systems with badly broken
711 firmware running.
712
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700714 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
716 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800717 Format:
718 <cpu number>,...,<cpu number>
719 or
720 <cpu number>-<cpu number> (must be a positive range in ascending order)
721 or a mixture
722 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 This option can be used to specify one or more CPUs
724 to isolate from the general SMP balancing and scheduling
725 algorithms. The only way to move a process onto or off
726 an "isolated" CPU is via the CPU affinity syscalls.
727 <cpu number> begins at 0 and the maximum value is
728 "number of CPUs in system - 1".
729
730 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700731 alternative -- manually setting the CPU mask of all
732 tasks in the system -- can cause problems and
733 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734
735 isp16= [HW,CD]
736 Format: <io>,<irq>,<dma>,<setup>
737
Randy Dunlapa9913042005-10-23 12:57:11 -0700738 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739
740 js= [HW,JOY] Analog joystick
741 See Documentation/input/joystick.txt.
742
743 keepinitrd [HW,ARM]
744
Randy Dunlapa9913042005-10-23 12:57:11 -0700745 kstack=N [IA-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 in oops dumps.
747
748 l2cr= [PPC]
749
Randy Dunlapa9913042005-10-23 12:57:11 -0700750 lapic [IA-32,APIC] Enable the local APIC even if BIOS
751 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752
753 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
754 Format: addr:<io>,irq:<irq>
755
Randy Dunlapa9913042005-10-23 12:57:11 -0700756 llsc*= [IA64] See function print_params() in
757 arch/ia64/sn/kernel/llsc4.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758
759 load_ramdisk= [RAM] List of ramdisks to load from floppy
760 See Documentation/ramdisk.txt.
761
Randy Dunlapa6b25b62006-01-14 13:21:19 -0800762 lockd.nlm_grace_period=P [NFS] Assign grace period.
763 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
Randy Dunlapa6b25b62006-01-14 13:21:19 -0800765 lockd.nlm_tcpport=N [NFS] Assign TCP port.
766 Format: <integer>
767
768 lockd.nlm_timeout=T [NFS] Assign timeout value.
769 Format: <integer>
770
771 lockd.nlm_udpport=M [NFS] Assign UDP port.
772 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773
774 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
775 Format: <irq>
776
777 loglevel= All Kernel Messages with a loglevel smaller than the
778 console loglevel will be printed to the console. It can
779 also be changed with klogd or other programs. The
780 loglevels are defined as follows:
781
782 0 (KERN_EMERG) system is unusable
783 1 (KERN_ALERT) action must be taken immediately
784 2 (KERN_CRIT) critical conditions
785 3 (KERN_ERR) error conditions
786 4 (KERN_WARNING) warning conditions
787 5 (KERN_NOTICE) normal but significant condition
788 6 (KERN_INFO) informational
789 7 (KERN_DEBUG) debug-level messages
790
791 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -0700792 Format: { n | nk | nM }
793 n must be a power of two. The default size
794 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795
796 lp=0 [LP] Specify parallel ports to use, e.g,
797 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
798 lp=reset first parallel port). 'lp=0' disables the
799 lp=auto printer driver. 'lp=reset' (which can be
800 specified in addition to the ports) causes
801 attached printers to be reset. Using
802 lp=port1,port2,... specifies the parallel ports
803 to associate lp devices with, starting with
804 lp0. A port specification may be 'none' to skip
805 that lp device, or a parport name such as
806 'parport0'. Specifying 'lp=auto' instead of a
807 port specification list means that device IDs
808 from each port should be examined, to see if
809 an IEEE 1284-compliant printer is attached; if
810 so, the driver will manage that printer.
811 See also header of drivers/char/lp.c.
812
813 lpj=n [KNL]
814 Sets loops_per_jiffy to given constant, thus avoiding
815 time-consuming boot-time autodetection (up to 250 ms per
816 CPU). 0 enables autodetection (default). To determine
817 the correct value for your kernel, boot with normal
818 autodetection and see what value is printed. Note that
819 on SMP systems the preset will be applied to all CPUs,
820 which is likely to cause problems if your CPUs need
821 significantly divergent settings. An incorrect value
822 will cause delays in the kernel to be wrong, leading to
823 unpredictable I/O errors and other breakage. Although
824 unlikely, in the extreme case this might damage your
825 hardware.
826
827 ltpc= [NET]
828 Format: <io>,<irq>,<dma>
829
Randy Dunlapa9913042005-10-23 12:57:11 -0700830 mac5380= [HW,SCSI] Format:
831 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832
Randy Dunlapa9913042005-10-23 12:57:11 -0700833 mac53c9x= [HW,SCSI] Format:
834 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835
Randy Dunlapa9913042005-10-23 12:57:11 -0700836 machvec= [IA64] Force the use of a particular machine-vector
837 (machvec) in a generic kernel.
838 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
Randy Dunlapa9913042005-10-23 12:57:11 -0700840 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 be mounted
842 Format: <1-256>
843
844 maxcpus= [SMP] Maximum number of processors that an SMP kernel
845 should make use of
846
Bob Picco2b2c3752005-06-29 18:00:00 -0700847 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
848 equal to this physical address is ignored.
849
Randy Dunlapa9913042005-10-23 12:57:11 -0700850 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 Should be between 1 and 2^32-1.
852
853 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -0700854 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 Should be between 1 and 16384.
856
857 mca-pentium [BUGS=IA-32]
858
859 mcatest= [IA-64]
860
861 mcd= [HW,CD]
862 Format: <port>,<irq>,<mitsumi_bug_93_wait>
863
864 mcdx= [HW,CD]
865
866 mce [IA-32] Machine Check Exception
867
868 md= [HW] RAID subsystems devices and level
869 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -0700870
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 mdacon= [MDA]
872 Format: <first>,<last>
873 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -0700874
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
876 Amount of memory to be used when the kernel is not able
877 to see the whole system memory or for test.
878 [IA-32] Use together with memmap= to avoid physical
879 address space collisions. Without memmap= PCI devices
880 could be placed at addresses belonging to unused RAM.
881
882 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
883 memory.
884
akpm@osdl.org69cda7b2006-01-09 20:51:46 -0800885 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 E820 memory map, as specified by the user.
887 Such memmap=exactmap lines can be constructed based on
888 BIOS output or other requirements. See the memmap=nn@ss
889 option description.
890
891 memmap=nn[KMG]@ss[KMG]
892 [KNL] Force usage of a specific region of memory
893 Region of memory to be used, from ss to ss+nn.
894
895 memmap=nn[KMG]#ss[KMG]
896 [KNL,ACPI] Mark specific memory as ACPI data.
897 Region of memory to be used, from ss to ss+nn.
898
899 memmap=nn[KMG]$ss[KMG]
900 [KNL,ACPI] Mark specific memory as reserved.
901 Region of memory to be used, from ss to ss+nn.
902
903 meye.*= [HW] Set MotionEye Camera parameters
904 See Documentation/video4linux/meye.txt.
905
906 mga= [HW,DRM]
907
akpm@osdl.org198e2f12006-01-12 01:05:30 -0800908 migration_cost=
909 [KNL,SMP] debug: override scheduler migration costs
910 Format: <level-1-usecs>,<level-2-usecs>,...
911 This debugging option can be used to override the
912 default scheduler migration cost matrix. The numbers
913 are indexed by 'CPU domain distance'.
914 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
915 box will set up an intra-core migration cost of
916 1 msec, an inter-core migration cost of 2 msecs,
917 and an inter-node migration cost of 3 msecs.
918
919 WARNING: using the wrong values here can break
920 scheduler performance, so it's only for scheduler
921 development purposes, not production environments.
922
923 migration_debug=
924 [KNL,SMP] migration cost auto-detect verbosity
925 Format=<0|1|2>
926 If a system's migration matrix reported at bootup
927 seems erroneous then this option can be used to
928 increase verbosity of the detection process.
929 We default to 0 (no extra messages), 1 will print
930 some more information, and 2 will be really
931 verbose (probably only useful if you also have a
932 serial console attached to the system).
933
934 migration_factor=
935 [KNL,SMP] multiply/divide migration costs by a factor
936 Format=<percent>
937 This debug option can be used to proportionally
938 increase or decrease the auto-detected migration
939 costs for all entries of the migration matrix.
940 E.g. migration_factor=150 will increase migration
941 costs by 50%. (and thus the scheduler will be less
942 eager migrating cache-hot tasks)
943 migration_factor=80 will decrease migration costs
944 by 20%. (thus the scheduler will be more eager to
945 migrate tasks)
946
947 WARNING: using the wrong values here can break
948 scheduler performance, so it's only for scheduler
949 development purposes, not production environments.
950
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 mousedev.tap_time=
952 [MOUSE] Maximum time between finger touching and
953 leaving touchpad surface for touch to be considered
954 a tap and be reported as a left button click (for
955 touchpads working in absolute mode only).
956 Format: <msecs>
957 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
958 reporting absolute coordinates, such as tablets
959 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
960 reporting absolute coordinates, such as tablets
961
962 mpu401= [HW,OSS]
963 Format: <io>,<irq>
964
965 MTD_Partition= [MTD]
966 Format: <name>,<region-number>,<size>,<offset>
967
Randy Dunlapa9913042005-10-23 12:57:11 -0700968 MTD_Region= [MTD] Format:
969 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970
971 mtdparts= [MTD]
972 See drivers/mtd/cmdline.c.
973
974 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -0700975 [HW] Make the MicroTouch USB driver use raw coordinates
976 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977
978 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
979
980 NCR_D700= [HW,SCSI]
981 See header of drivers/scsi/NCR_D700.c.
982
983 ncr5380= [HW,SCSI]
984
985 ncr53c400= [HW,SCSI]
986
987 ncr53c400a= [HW,SCSI]
988
989 ncr53c406a= [HW,SCSI]
990
991 ncr53c8xx= [HW,SCSI]
992
993 netdev= [NET] Network devices parameters
994 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
995 Note that mem_start is often overloaded to mean
996 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -0700997 This usage is only documented in each driver source
998 file if at all.
999
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 nfsaddrs= [NFS]
1001 See Documentation/nfsroot.txt.
1002
1003 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1004 See Documentation/nfsroot.txt.
1005
Trond Myklebusta72b4422006-01-03 09:55:41 +01001006 nfs.callback_tcpport=
1007 [NFS] set the TCP port on which the NFSv4 callback
1008 channel should listen.
1009
Trond Myklebust58df0952006-01-03 09:55:57 +01001010 nfs.idmap_cache_timeout=
1011 [NFS] set the maximum lifetime for idmapper cache
1012 entries.
1013
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1015
1016 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1017 emulation library even if a 387 maths coprocessor
1018 is present.
1019
Paul Menage3395ee02006-12-06 20:32:16 -08001020 noaliencache [MM, NUMA] Disables the allcoation of alien caches in
1021 the slab allocator. Saves per-node memory, but will
1022 impact performance on real NUMA hardware.
1023
Randy Dunlapa9913042005-10-23 12:57:11 -07001024 noalign [KNL,ARM]
1025
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 noapic [SMP,APIC] Tells the kernel to not make use of any
1027 IOAPICs that may be present in the system.
1028
1029 noasync [HW,M68K] Disables async and sync negotiation for
1030 all devices.
1031
1032 nobats [PPC] Do not use BATs for mapping kernel lowmem
1033 on "Classic" PPC cores.
1034
1035 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001036
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001037 nodelayacct [KNL] Disable per-task delay accounting
1038
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1040
1041 noexec [IA-64]
1042
Randy Dunlapa9913042005-10-23 12:57:11 -07001043 noexec [IA-32,X86-64]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 noexec=on: enable non-executable mappings (default)
1045 noexec=off: disable nn-executable mappings
1046
Chuck Ebbert4f886512006-03-23 02:59:34 -08001047 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1048 register save and restore. The kernel will only save
1049 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050
1051 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001052
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1054 instruction doesn't work correctly and not to
1055 use it.
1056
1057 nohalt [IA-64] Tells the kernel not to use the power saving
1058 function PAL_HALT_LIGHT when idle. This increases
1059 power-consumption. On the positive side, it reduces
1060 interrupt wake-up latency, which may improve performance
1061 in certain environments such as networked servers or
1062 real-time systems.
1063
1064 noirqdebug [IA-32] Disables the code which attempts to detect and
1065 disable unhandled interrupt sources.
1066
1067 noisapnp [ISAPNP] Disables ISA PnP code.
1068
1069 noinitrd [RAM] Tells the kernel not to load any configured
1070 initial RAM disk.
1071
1072 nointroute [IA-64]
1073
1074 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1075
1076 noltlbs [PPC] Do not use large page/tlb entries for kernel
1077 lowmem mapping on PPC40x.
1078
Horms312f1f02006-02-22 09:57:55 +09001079 nomca [IA-64] Disable machine check abort handling
1080
Hormsabe37e52006-04-01 01:36:09 +02001081 nomce [IA-32] Machine Check Exception
1082
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 noresidual [PPC] Don't use residual data on PReP machines.
1084
Randy Dunlapa9913042005-10-23 12:57:11 -07001085 noresume [SWSUSP] Disables resume and restores original swap
1086 space.
1087
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 no-scroll [VGA] Disables scrollback.
1089 This is required for the Braillex ib80-piezo Braille
1090 reader made by F.H. Papenmeier (Germany).
1091
1092 nosbagart [IA-64]
1093
Chuck Ebbert4f886512006-03-23 02:59:34 -08001094 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1095
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1097
1098 nosync [HW,M68K] Disables sync negotiation for all devices.
1099
1100 notsc [BUGS=IA-32] Disable Time Stamp Counter
1101
1102 nousb [USB] Disable the USB subsystem
1103
1104 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001105
Dave Jonesa61c2d72006-01-07 23:18:19 +00001106 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1107
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 opl3= [HW,OSS]
1109 Format: <io>
1110
Randy Dunlapa9913042005-10-23 12:57:11 -07001111 opl3sa2= [HW,OSS] Format:
1112 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1113
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114 oprofile.timer= [HW]
1115 Use timer interrupt instead of performance counters
1116
1117 optcd= [HW,CD]
1118 Format: <io>
1119
1120 osst= [HW,SCSI] SCSI Tape Driver
1121 Format: <buffer_size>,<write_threshold>
1122 See also Documentation/scsi/st.txt.
1123
1124 panic= [KNL] Kernel behaviour on panic
1125 Format: <timeout>
1126
1127 parkbd.port= [HW] Parallel port number the keyboard adapter is
1128 connected to, default is 0.
1129 Format: <parport#>
1130 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1131 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001132 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133
Randy Dunlapa9913042005-10-23 12:57:11 -07001134 parport= [HW,PPT] Specify parallel ports. 0 disables.
1135 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1136 Use 'auto' to force the driver to use any
1137 IRQ/DMA settings detected (the default is to
1138 ignore detected IRQ/DMA settings because of
1139 possible conflicts). You can specify the base
1140 address, IRQ, and DMA settings; IRQ and DMA
1141 should be numbers, or 'auto' (for using detected
1142 settings on that particular port), or 'nofifo'
1143 (to avoid using a FIFO even if it is detected).
1144 Parallel ports are assigned in the order they
1145 are specified on the command line, starting
1146 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147
Randy Dunlapa9913042005-10-23 12:57:11 -07001148 parport_init_mode= [HW,PPT]
1149 Configure VIA parallel port to operate in
1150 a specific mode. This is necessary on Pegasos
1151 computer where firmware has no options for setting
1152 up parallel port mode and sets it to spp.
1153 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 Format: [spp|ps2|epp|ecp|ecpepp]
1155
Randy Dunlapa9913042005-10-23 12:57:11 -07001156 pas2= [HW,OSS] Format:
1157 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1158
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 pas16= [HW,SCSI]
1160 See header of drivers/scsi/pas16.c.
1161
Andrew Mortondd287792006-03-23 03:00:57 -08001162 pause_on_oops=
1163 Halt all CPUs after the first oops has been printed for
1164 the specified number of seconds. This is to be used if
1165 your oopses keep scrolling off the screen.
1166
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167 pcbit= [HW,ISDN]
1168
1169 pcd. [PARIDE]
1170 See header of drivers/block/paride/pcd.c.
1171 See also Documentation/paride.txt.
1172
Randy Dunlapa9913042005-10-23 12:57:11 -07001173 pci=option[,option...] [PCI] various PCI subsystem options:
1174 off [IA-32] don't probe for the PCI bus
1175 bios [IA-32] force use of PCI BIOS, don't access
1176 the hardware directly. Use this if your machine
1177 has a non-standard PCI host bridge.
1178 nobios [IA-32] disallow use of PCI BIOS, only direct
1179 hardware access methods are allowed. Use this
1180 if you experience crashes upon bootup and you
1181 suspect they are caused by the BIOS.
1182 conf1 [IA-32] Force use of PCI Configuration
1183 Mechanism 1.
1184 conf2 [IA-32] Force use of PCI Configuration
1185 Mechanism 2.
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001186 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1187 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001188 nomsi [MSI] If the PCI_MSI kernel config parameter is
1189 enabled, this kernel boot option can be used to
1190 disable the use of MSI interrupts system-wide.
Randy Dunlapa9913042005-10-23 12:57:11 -07001191 nosort [IA-32] Don't sort PCI devices according to
1192 order given by the PCI BIOS. This sorting is
1193 done to get a device order compatible with
1194 older kernels.
1195 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1196 routing table. These calls are known to be buggy
1197 on several machines and they hang the machine
1198 when used, but on other computers it's the only
1199 way to get the interrupt routing table. Try
1200 this option if the kernel is unable to allocate
1201 IRQs or discover secondary PCI buses on your
1202 motherboard.
1203 rom [IA-32] Assign address space to expansion ROMs.
1204 Use with caution as certain devices share
1205 address decoders between ROMs and other
1206 resources.
1207 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1208 assigned automatically to PCI devices. You can
1209 make the kernel exclude IRQs of your ISA cards
1210 this way.
jayalk@intworks.biz120bb422005-03-21 20:20:42 -08001211 pirqaddr=0xAAAAA [IA-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001212 of the PIRQ table (normally generated
1213 by the BIOS) if it is outside the
1214 F0000h-100000h range.
1215 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1216 useful if the kernel is unable to find your
1217 secondary buses and you want to tell it
1218 explicitly which ones they are.
1219 assign-busses [IA-32] Always assign all PCI bus
1220 numbers ourselves, overriding
1221 whatever the firmware may have done.
1222 usepirqmask [IA-32] Honor the possible IRQ mask stored
1223 in the BIOS $PIR table. This is needed on
1224 some systems with broken BIOSes, notably
1225 some HP Pavilion N5400 and Omnibook XE3
1226 notebooks. This will have no effect if ACPI
1227 IRQ routing is enabled.
1228 noacpi [IA-32] Do not use ACPI for IRQ routing
1229 or for PCI scanning.
1230 routeirq Do IRQ routing for all PCI devices.
1231 This is normally done in pci_enable_device(),
1232 so this option is a temporary workaround
1233 for broken drivers that don't call it.
1234 firmware [ARM] Do not re-enumerate the bus but instead
1235 just use the configuration from the
1236 bootloader. This is currently used on
1237 IXP2000 systems where the bus has to be
1238 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001239 noearly [X86] Don't do any early type 1 scanning.
1240 This might help on some broken boards which
1241 machine check when some devices' config space
1242 is read. But various workarounds are disabled
1243 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001244 bfsort Sort PCI devices into breadth-first order.
1245 This sorting is done to get a device
1246 order compatible with older (<= 2.4) kernels.
1247 nobfsort Don't sort PCI devices into breadth-first order.
1248
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 pcmv= [HW,PCMCIA] BadgePAD 4
1250
1251 pd. [PARIDE]
1252 See Documentation/paride.txt.
1253
1254 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1255 boot time.
1256 Format: { 0 | 1 }
1257 See arch/parisc/kernel/pdc_chassis.c
1258
1259 pf. [PARIDE]
1260 See Documentation/paride.txt.
1261
1262 pg. [PARIDE]
1263 See Documentation/paride.txt.
1264
1265 pirq= [SMP,APIC] Manual mp-table setup
1266 See Documentation/i386/IO-APIC.txt.
1267
1268 plip= [PPT,NET] Parallel port network link
1269 Format: { parport<nr> | timid | 0 }
1270 See also Documentation/parport.txt.
1271
1272 pnpacpi= [ACPI]
1273 { off }
1274
1275 pnpbios= [ISAPNP]
1276 { on | off | curr | res | no-curr | no-res }
1277
1278 pnp_reserve_irq=
1279 [ISAPNP] Exclude IRQs for the autoconfiguration
1280
1281 pnp_reserve_dma=
1282 [ISAPNP] Exclude DMAs for the autoconfiguration
1283
1284 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001285 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286
1287 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001288 [ISAPNP] Exclude memory regions for the
1289 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290 Ranges are in pairs (memory base and size).
1291
1292 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001293 Format: [schedule,]<number>
1294 Param: "schedule" - profile schedule points.
1295 Param: <number> - step/bucket size as a power of 2 for
1296 statistical time based profiling.
Ingo Molnarece8a682006-12-06 20:37:24 -08001297 Param: "sleep" - profile D-state sleeping (millisecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298
Randy Dunlapa9913042005-10-23 12:57:11 -07001299 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 Limit processor to maximum C-state
1301 max_cstate=9 overrides any DMI blacklist limit.
1302
Len Brown41c0d862005-12-28 12:43:51 -05001303 processor.nocst [HW,ACPI]
1304 Ignore the _CST method to determine C-states,
1305 instead using the legacy FADT method
1306
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1308 before loading.
1309 See Documentation/ramdisk.txt.
1310
Randy Dunlapa9913042005-10-23 12:57:11 -07001311 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1312 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1314 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001315 psmouse.resetafter= [HW,MOUSE]
1316 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 (0 = never).
1318 psmouse.resolution=
1319 [HW,MOUSE] Set desired mouse resolution, in dpi.
1320 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001321 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 0 = disabled, 1 = enabled (default).
1323
1324 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001325 Format:
1326 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327
1328 pt. [PARIDE]
1329 See Documentation/paride.txt.
1330
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001331 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001332
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 r128= [HW,DRM]
1334
1335 raid= [HW,RAID]
1336 See Documentation/md.txt.
1337
1338 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1339 See Documentation/ramdisk.txt.
1340
Randy Dunlapa9913042005-10-23 12:57:11 -07001341 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001343
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1345 New name for the ramdisk parameter.
1346 See Documentation/ramdisk.txt.
1347
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001348 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1349 RCU callbacks to process in one batch.
1350
1351 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1352 RCU callbacks over which batch limiting is disabled.
1353
1354 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1355 RCU callbacks below which batch limiting is re-enabled.
1356
Olof Johanssonffdfc402005-09-06 15:17:19 -07001357 rdinit= [KNL]
1358 Format: <full_path>
1359 Run specified binary instead of /init from the ramdisk,
1360 used for early userspace startup. See initrd.
1361
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1363 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Michael Opdenackerf3e299f2006-10-03 23:19:24 +02001364 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365
1366 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1367
Zachary Amsden461a9af2006-09-25 23:32:25 -07001368 reservetop= [IA-32]
1369 Format: nn[KMG]
1370 Reserves a hole at the top of the kernel virtual
1371 address space.
1372
Vivek Goyal7e962872006-09-27 01:50:44 -07001373 reset_devices [KNL] Force drivers to reset the underlying device
1374 during initialization.
1375
Randy Dunlapa9913042005-10-23 12:57:11 -07001376 resume= [SWSUSP]
1377 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001379 resume_offset= [SWSUSP]
1380 Specify the offset from the beginning of the partition
1381 given by "resume=" at which the swap header is located,
1382 in <PAGE_SIZE> units (needed only for swap files).
1383 See Documentation/power/swsusp-and-swap-files.txt
1384
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385 rhash_entries= [KNL,NET]
1386 Set number of hash buckets for route cache
1387
1388 riscom8= [HW,SERIAL]
1389 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1390
1391 ro [KNL] Mount root device read-only on boot
1392
1393 root= [KNL] Root filesystem
1394
1395 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1396 mount the root filesystem
1397
1398 rootflags= [KNL] Set root filesystem mount option string
1399
1400 rootfstype= [KNL] Set root filesystem type
1401
1402 rw [KNL] Mount root device read-write on boot
1403
1404 S [KNL] Run init in single mode
1405
1406 sa1100ir [NET]
1407 See drivers/net/irda/sa1100_ir.c.
1408
1409 sb= [HW,OSS]
1410 Format: <io>,<irq>,<dma>,<dma2>
1411
1412 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001413
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414 sbpcd= [HW,CD] Soundblaster CD adapter
1415 Format: <io>,<type>
1416 See a comment before function sbpcd_setup() in
1417 drivers/cdrom/sbpcd.c.
1418
1419 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1420 Format: <io>[,<timeout>[,<isapnp>]]
1421
1422 scsi_debug_*= [SCSI]
1423 See drivers/scsi/scsi_debug.c.
1424
1425 scsi_default_dev_flags=
1426 [SCSI] SCSI default device flags
1427 Format: <integer>
1428
1429 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1430 Format: <vendor>:<model>:<flags>
1431 (flags are integer value)
1432
1433 scsi_logging= [SCSI]
1434
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001435 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1436 discovered. async scans them in kernel threads,
1437 allowing boot to proceed. none ignores them, expecting
1438 user space to do the scan.
1439
Linus Torvalds1da177e2005-04-16 15:20:36 -07001440 selinux [SELINUX] Disable or enable SELinux at boot time.
1441 Format: { "0" | "1" }
1442 See security/selinux/Kconfig help text.
1443 0 -- disable.
1444 1 -- enable.
1445 Default value is set via kernel config option.
1446 If enabled at boot time, /selinux/disable can be used
1447 later to disable prior to initial policy load.
1448
James Morris4e5ab4c2006-06-09 00:33:33 -07001449 selinux_compat_net =
1450 [SELINUX] Set initial selinux_compat_net flag value.
1451 Format: { "0" | "1" }
1452 0 -- use new secmark-based packet controls
1453 1 -- use legacy packet controls
1454 Default value is 0 (preferred).
1455 Value can be changed at runtime via
1456 /selinux/compat_net.
1457
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 serialnumber [BUGS=IA-32]
1459
Randy Dunlapa9913042005-10-23 12:57:11 -07001460 sg_def_reserved_size= [SCSI]
1461
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 shapers= [NET]
1463 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001464
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465 sim710= [SCSI,HW]
1466 See header of drivers/scsi/sim710.c.
1467
1468 simeth= [IA-64]
1469 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001470
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 sjcd= [HW,CD]
1472 Format: <io>,<irq>,<dma>
1473 See header of drivers/cdrom/sjcd.c.
1474
1475 slram= [HW,MTD]
1476
1477 smart2= [HW]
1478 Format: <io1>[,<io2>[,...,<io8>]]
1479
1480 snd-ad1816a= [HW,ALSA]
1481
1482 snd-ad1848= [HW,ALSA]
1483
1484 snd-ali5451= [HW,ALSA]
1485
1486 snd-als100= [HW,ALSA]
1487
1488 snd-als4000= [HW,ALSA]
1489
1490 snd-azt2320= [HW,ALSA]
1491
1492 snd-cmi8330= [HW,ALSA]
1493
1494 snd-cmipci= [HW,ALSA]
1495
1496 snd-cs4231= [HW,ALSA]
1497
1498 snd-cs4232= [HW,ALSA]
1499
1500 snd-cs4236= [HW,ALSA]
1501
1502 snd-cs4281= [HW,ALSA]
1503
1504 snd-cs46xx= [HW,ALSA]
1505
1506 snd-dt019x= [HW,ALSA]
1507
1508 snd-dummy= [HW,ALSA]
1509
1510 snd-emu10k1= [HW,ALSA]
1511
1512 snd-ens1370= [HW,ALSA]
1513
1514 snd-ens1371= [HW,ALSA]
1515
1516 snd-es968= [HW,ALSA]
1517
1518 snd-es1688= [HW,ALSA]
1519
1520 snd-es18xx= [HW,ALSA]
1521
1522 snd-es1938= [HW,ALSA]
1523
1524 snd-es1968= [HW,ALSA]
1525
1526 snd-fm801= [HW,ALSA]
1527
1528 snd-gusclassic= [HW,ALSA]
1529
1530 snd-gusextreme= [HW,ALSA]
1531
1532 snd-gusmax= [HW,ALSA]
1533
1534 snd-hdsp= [HW,ALSA]
1535
1536 snd-ice1712= [HW,ALSA]
1537
1538 snd-intel8x0= [HW,ALSA]
1539
1540 snd-interwave= [HW,ALSA]
1541
1542 snd-interwave-stb=
1543 [HW,ALSA]
1544
1545 snd-korg1212= [HW,ALSA]
1546
1547 snd-maestro3= [HW,ALSA]
1548
1549 snd-mpu401= [HW,ALSA]
1550
1551 snd-mtpav= [HW,ALSA]
1552
1553 snd-nm256= [HW,ALSA]
1554
1555 snd-opl3sa2= [HW,ALSA]
1556
1557 snd-opti92x-ad1848=
1558 [HW,ALSA]
1559
1560 snd-opti92x-cs4231=
1561 [HW,ALSA]
1562
1563 snd-opti93x= [HW,ALSA]
1564
1565 snd-pmac= [HW,ALSA]
1566
1567 snd-rme32= [HW,ALSA]
1568
1569 snd-rme96= [HW,ALSA]
1570
1571 snd-rme9652= [HW,ALSA]
1572
1573 snd-sb8= [HW,ALSA]
1574
1575 snd-sb16= [HW,ALSA]
1576
1577 snd-sbawe= [HW,ALSA]
1578
1579 snd-serial= [HW,ALSA]
1580
1581 snd-sgalaxy= [HW,ALSA]
1582
1583 snd-sonicvibes= [HW,ALSA]
1584
1585 snd-sun-amd7930=
1586 [HW,ALSA]
1587
1588 snd-sun-cs4231= [HW,ALSA]
1589
1590 snd-trident= [HW,ALSA]
1591
1592 snd-usb-audio= [HW,ALSA,USB]
1593
1594 snd-via82xx= [HW,ALSA]
1595
1596 snd-virmidi= [HW,ALSA]
1597
1598 snd-wavefront= [HW,ALSA]
1599
1600 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001601
Linus Torvalds1da177e2005-04-16 15:20:36 -07001602 sonycd535= [HW,CD]
1603 Format: <io>[,<irq>]
1604
1605 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1606 See Documentation/sonypi.txt
1607
1608 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1609 See Documentation/specialix.txt.
1610
1611 spia_io_base= [HW,MTD]
1612 spia_fio_base=
1613 spia_pedr=
1614 spia_peddr=
1615
1616 sscape= [HW,OSS]
1617 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07001618
Linus Torvalds1da177e2005-04-16 15:20:36 -07001619 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1620 See Documentation/scsi/st.txt.
1621
1622 st0x= [HW,SCSI]
1623 See header of drivers/scsi/seagate.c.
1624
1625 sti= [PARISC,HW]
1626 Format: <num>
1627 Set the STI (builtin display/keyboard on the HP-PARISC
1628 machines) console (graphic card) which should be used
1629 as the initial boot-console.
1630 See also comment in drivers/video/console/sticore.c.
1631
1632 sti_font= [HW]
1633 See comment in drivers/video/console/sticore.c.
1634
1635 stifb= [HW]
1636 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1637
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07001639
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 switches= [HW,M68k]
1641
1642 sym53c416= [HW,SCSI]
1643 See header of drivers/scsi/sym53c416.c.
1644
1645 t128= [HW,SCSI]
1646 See header of drivers/scsi/t128.c.
1647
1648 tdfx= [HW,DRM]
1649
1650 thash_entries= [KNL,NET]
1651 Set number of hash buckets for TCP connection
1652
1653 time Show timing data prefixed to each printk message line
1654
john stultz734efb42006-06-26 00:25:05 -07001655 clocksource= [GENERIC_TIME] Override the default clocksource
1656 Override the default clocksource and use the clocksource
1657 with the name specified.
1658
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 tipar.timeout= [HW,PPT]
1660 Set communications timeout in tenths of a second
1661 (default 15).
1662
1663 tipar.delay= [HW,PPT]
1664 Set inter-bit delay in microseconds (default 10).
1665
1666 tmc8xx= [HW,SCSI]
1667 See header of drivers/scsi/seagate.c.
1668
1669 tmscsim= [HW,SCSI]
1670 See comment before function dc390_setup() in
1671 drivers/scsi/tmscsim.c.
1672
1673 tp720= [HW,PS2]
1674
1675 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07001676 Format:
1677 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1678
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 tsdev.xres= [TS] Horizontal screen resolution.
1680 tsdev.yres= [TS] Vertical screen resolution.
1681
Randy Dunlapa9913042005-10-23 12:57:11 -07001682 turbografx.map[2|3]= [HW,JOY]
1683 TurboGraFX parallel port interface
1684 Format:
1685 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001686 See also Documentation/input/joystick-parport.txt
1687
1688 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1689 See header of drivers/scsi/u14-34f.c.
1690
1691 uart401= [HW,OSS]
1692 Format: <io>,<irq>
1693
1694 uart6850= [HW,OSS]
1695 Format: <io>,<irq>
1696
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 usbhid.mousepoll=
1698 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07001699
Ingo Molnare6e54942006-06-27 02:53:50 -07001700 vdso= [IA-32]
1701 vdso=1: enable VDSO (default)
1702 vdso=0: disable VDSO mapping
1703
Linus Torvalds1da177e2005-04-16 15:20:36 -07001704 video= [FB] Frame buffer configuration
1705 See Documentation/fb/modedb.txt.
1706
1707 vga= [BOOT,IA-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07001708 See Documentation/i386/boot.txt and
1709 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 Use vga=ask for menu.
1711 This is actually a boot loader parameter; the value is
1712 passed to the kernel using a special protocol.
1713
Randy Dunlapa9913042005-10-23 12:57:11 -07001714 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 size of <nn>. This can be used to increase the
1716 minimum size (128MB on x86). It can also be used to
1717 decrease the size and leave more room for directly
1718 mapped kernel RAM.
1719
Peter Oberparleiter585c3042006-06-29 15:08:25 +02001720 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1721 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722
Peter Oberparleiter585c3042006-06-29 15:08:25 +02001723 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1724 Format: <command>
1725
1726 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1727 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07001728
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 waveartist= [HW,OSS]
1730 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07001731
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 wd33c93= [HW,SCSI]
1733 See header of drivers/scsi/wd33c93.c.
1734
1735 wd7000= [HW,SCSI]
1736 See header of drivers/scsi/wd7000.c.
1737
1738 wdt= [WDT] Watchdog
1739 See Documentation/watchdog/watchdog.txt.
1740
1741 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1742 xd_geo= See header of drivers/block/xd.c.
1743
1744 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001745 Format:
1746 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747
Andi Kleena62eaf12006-02-16 23:41:58 +01001748 norandmaps Don't use address space randomization
1749 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1750
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751
Randy Dunlapa9913042005-10-23 12:57:11 -07001752______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753
1754TODO:
1755
1756 Add documentation for ALSA options.
1757 Add more DRM drivers.