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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
Ingo Molnar792908222006-12-06 20:40:51 -0800653 ignore_loglevel [KNL]
654 Ignore loglevel setting - this will print /all/
655 kernel messages to the console. Useful for debugging.
656
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 ihash_entries= [KNL]
658 Set number of hash buckets for inode cache.
659
660 in2000= [HW,SCSI]
661 See header of drivers/scsi/in2000.c.
662
663 init= [KNL]
664 Format: <full_path>
665 Run specified binary instead of /sbin/init as init
666 process.
667
668 initcall_debug [KNL] Trace initcalls as they are executed. Useful
669 for working out where the kernel is dying during
670 startup.
671
672 initrd= [BOOT] Specify the location of the initial ramdisk
673
674 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
675 Format: <irq>
676
Jesse Barnes2bd0fa32005-12-13 03:05:03 -0500677 combined_mode= [HW] control which driver uses IDE ports in combined
678 mode: legacy IDE driver, libata, or both
679 (in the libata case, libata.atapi_enabled=1 may be
680 useful as well). Note that using the ide or libata
681 options may affect your device naming (e.g. by
682 changing hdc to sdb).
683 Format: combined (default), ide, or libata
684
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 inttest= [IA64]
686
687 io7= [HW] IO7 for Marvel based alpha systems
688 See comment before marvel_specify_io7 in
689 arch/alpha/kernel/core_marvel.c.
690
691 ip= [IP_PNP]
692 See Documentation/nfsroot.txt.
693
694 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
695 See comment before ip2_setup() in drivers/char/ip2.c.
696
697 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
698 See header of drivers/scsi/ips.c.
699
Simon Horman72c4a132006-09-13 19:57:18 -0700700 ports= [IP_VS_FTP] IPVS ftp helper module
701 Default is 21.
702 Up to 8 (IP_VS_APP_MAX_PORTS) ports
703 may be specified.
704 Format: <port>,<port>....
705
Alan Cox200803d2005-06-28 20:45:18 -0700706 irqfixup [HW]
707 When an interrupt is not handled search all handlers
708 for it. Intended to get systems with badly broken
709 firmware running.
710
711 irqpoll [HW]
712 When an interrupt is not handled search all handlers
713 for it. Also check all handlers each timer
714 interrupt. Intended to get systems with badly broken
715 firmware running.
716
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700718 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719
720 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800721 Format:
722 <cpu number>,...,<cpu number>
723 or
724 <cpu number>-<cpu number> (must be a positive range in ascending order)
725 or a mixture
726 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 This option can be used to specify one or more CPUs
728 to isolate from the general SMP balancing and scheduling
729 algorithms. The only way to move a process onto or off
730 an "isolated" CPU is via the CPU affinity syscalls.
731 <cpu number> begins at 0 and the maximum value is
732 "number of CPUs in system - 1".
733
734 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700735 alternative -- manually setting the CPU mask of all
736 tasks in the system -- can cause problems and
737 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738
739 isp16= [HW,CD]
740 Format: <io>,<irq>,<dma>,<setup>
741
Randy Dunlapa9913042005-10-23 12:57:11 -0700742 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743
744 js= [HW,JOY] Analog joystick
745 See Documentation/input/joystick.txt.
746
747 keepinitrd [HW,ARM]
748
Randy Dunlapa9913042005-10-23 12:57:11 -0700749 kstack=N [IA-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 in oops dumps.
751
752 l2cr= [PPC]
753
Randy Dunlapa9913042005-10-23 12:57:11 -0700754 lapic [IA-32,APIC] Enable the local APIC even if BIOS
755 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756
757 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
758 Format: addr:<io>,irq:<irq>
759
Randy Dunlapa9913042005-10-23 12:57:11 -0700760 llsc*= [IA64] See function print_params() in
761 arch/ia64/sn/kernel/llsc4.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762
763 load_ramdisk= [RAM] List of ramdisks to load from floppy
764 See Documentation/ramdisk.txt.
765
Randy Dunlapa6b25b62006-01-14 13:21:19 -0800766 lockd.nlm_grace_period=P [NFS] Assign grace period.
767 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
Randy Dunlapa6b25b62006-01-14 13:21:19 -0800769 lockd.nlm_tcpport=N [NFS] Assign TCP port.
770 Format: <integer>
771
772 lockd.nlm_timeout=T [NFS] Assign timeout value.
773 Format: <integer>
774
775 lockd.nlm_udpport=M [NFS] Assign UDP port.
776 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
779 Format: <irq>
780
781 loglevel= All Kernel Messages with a loglevel smaller than the
782 console loglevel will be printed to the console. It can
783 also be changed with klogd or other programs. The
784 loglevels are defined as follows:
785
786 0 (KERN_EMERG) system is unusable
787 1 (KERN_ALERT) action must be taken immediately
788 2 (KERN_CRIT) critical conditions
789 3 (KERN_ERR) error conditions
790 4 (KERN_WARNING) warning conditions
791 5 (KERN_NOTICE) normal but significant condition
792 6 (KERN_INFO) informational
793 7 (KERN_DEBUG) debug-level messages
794
795 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -0700796 Format: { n | nk | nM }
797 n must be a power of two. The default size
798 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799
800 lp=0 [LP] Specify parallel ports to use, e.g,
801 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
802 lp=reset first parallel port). 'lp=0' disables the
803 lp=auto printer driver. 'lp=reset' (which can be
804 specified in addition to the ports) causes
805 attached printers to be reset. Using
806 lp=port1,port2,... specifies the parallel ports
807 to associate lp devices with, starting with
808 lp0. A port specification may be 'none' to skip
809 that lp device, or a parport name such as
810 'parport0'. Specifying 'lp=auto' instead of a
811 port specification list means that device IDs
812 from each port should be examined, to see if
813 an IEEE 1284-compliant printer is attached; if
814 so, the driver will manage that printer.
815 See also header of drivers/char/lp.c.
816
817 lpj=n [KNL]
818 Sets loops_per_jiffy to given constant, thus avoiding
819 time-consuming boot-time autodetection (up to 250 ms per
820 CPU). 0 enables autodetection (default). To determine
821 the correct value for your kernel, boot with normal
822 autodetection and see what value is printed. Note that
823 on SMP systems the preset will be applied to all CPUs,
824 which is likely to cause problems if your CPUs need
825 significantly divergent settings. An incorrect value
826 will cause delays in the kernel to be wrong, leading to
827 unpredictable I/O errors and other breakage. Although
828 unlikely, in the extreme case this might damage your
829 hardware.
830
831 ltpc= [NET]
832 Format: <io>,<irq>,<dma>
833
Randy Dunlapa9913042005-10-23 12:57:11 -0700834 mac5380= [HW,SCSI] Format:
835 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836
Randy Dunlapa9913042005-10-23 12:57:11 -0700837 mac53c9x= [HW,SCSI] Format:
838 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
Randy Dunlapa9913042005-10-23 12:57:11 -0700840 machvec= [IA64] Force the use of a particular machine-vector
841 (machvec) in a generic kernel.
842 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843
Randy Dunlapa9913042005-10-23 12:57:11 -0700844 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 be mounted
846 Format: <1-256>
847
848 maxcpus= [SMP] Maximum number of processors that an SMP kernel
849 should make use of
850
Bob Picco2b2c3752005-06-29 18:00:00 -0700851 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
852 equal to this physical address is ignored.
853
Randy Dunlapa9913042005-10-23 12:57:11 -0700854 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 Should be between 1 and 2^32-1.
856
857 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -0700858 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 Should be between 1 and 16384.
860
861 mca-pentium [BUGS=IA-32]
862
863 mcatest= [IA-64]
864
865 mcd= [HW,CD]
866 Format: <port>,<irq>,<mitsumi_bug_93_wait>
867
868 mcdx= [HW,CD]
869
870 mce [IA-32] Machine Check Exception
871
872 md= [HW] RAID subsystems devices and level
873 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -0700874
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 mdacon= [MDA]
876 Format: <first>,<last>
877 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -0700878
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
880 Amount of memory to be used when the kernel is not able
881 to see the whole system memory or for test.
882 [IA-32] Use together with memmap= to avoid physical
883 address space collisions. Without memmap= PCI devices
884 could be placed at addresses belonging to unused RAM.
885
886 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
887 memory.
888
akpm@osdl.org69cda7b2006-01-09 20:51:46 -0800889 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 E820 memory map, as specified by the user.
891 Such memmap=exactmap lines can be constructed based on
892 BIOS output or other requirements. See the memmap=nn@ss
893 option description.
894
895 memmap=nn[KMG]@ss[KMG]
896 [KNL] Force usage of a specific region of memory
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 ACPI data.
901 Region of memory to be used, from ss to ss+nn.
902
903 memmap=nn[KMG]$ss[KMG]
904 [KNL,ACPI] Mark specific memory as reserved.
905 Region of memory to be used, from ss to ss+nn.
906
907 meye.*= [HW] Set MotionEye Camera parameters
908 See Documentation/video4linux/meye.txt.
909
910 mga= [HW,DRM]
911
akpm@osdl.org198e2f12006-01-12 01:05:30 -0800912 migration_cost=
913 [KNL,SMP] debug: override scheduler migration costs
914 Format: <level-1-usecs>,<level-2-usecs>,...
915 This debugging option can be used to override the
916 default scheduler migration cost matrix. The numbers
917 are indexed by 'CPU domain distance'.
918 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
919 box will set up an intra-core migration cost of
920 1 msec, an inter-core migration cost of 2 msecs,
921 and an inter-node migration cost of 3 msecs.
922
923 WARNING: using the wrong values here can break
924 scheduler performance, so it's only for scheduler
925 development purposes, not production environments.
926
927 migration_debug=
928 [KNL,SMP] migration cost auto-detect verbosity
929 Format=<0|1|2>
930 If a system's migration matrix reported at bootup
931 seems erroneous then this option can be used to
932 increase verbosity of the detection process.
933 We default to 0 (no extra messages), 1 will print
934 some more information, and 2 will be really
935 verbose (probably only useful if you also have a
936 serial console attached to the system).
937
938 migration_factor=
939 [KNL,SMP] multiply/divide migration costs by a factor
940 Format=<percent>
941 This debug option can be used to proportionally
942 increase or decrease the auto-detected migration
943 costs for all entries of the migration matrix.
944 E.g. migration_factor=150 will increase migration
945 costs by 50%. (and thus the scheduler will be less
946 eager migrating cache-hot tasks)
947 migration_factor=80 will decrease migration costs
948 by 20%. (thus the scheduler will be more eager to
949 migrate tasks)
950
951 WARNING: using the wrong values here can break
952 scheduler performance, so it's only for scheduler
953 development purposes, not production environments.
954
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 mousedev.tap_time=
956 [MOUSE] Maximum time between finger touching and
957 leaving touchpad surface for touch to be considered
958 a tap and be reported as a left button click (for
959 touchpads working in absolute mode only).
960 Format: <msecs>
961 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
962 reporting absolute coordinates, such as tablets
963 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
964 reporting absolute coordinates, such as tablets
965
966 mpu401= [HW,OSS]
967 Format: <io>,<irq>
968
969 MTD_Partition= [MTD]
970 Format: <name>,<region-number>,<size>,<offset>
971
Randy Dunlapa9913042005-10-23 12:57:11 -0700972 MTD_Region= [MTD] Format:
973 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974
975 mtdparts= [MTD]
976 See drivers/mtd/cmdline.c.
977
978 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -0700979 [HW] Make the MicroTouch USB driver use raw coordinates
980 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981
982 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
983
984 NCR_D700= [HW,SCSI]
985 See header of drivers/scsi/NCR_D700.c.
986
987 ncr5380= [HW,SCSI]
988
989 ncr53c400= [HW,SCSI]
990
991 ncr53c400a= [HW,SCSI]
992
993 ncr53c406a= [HW,SCSI]
994
995 ncr53c8xx= [HW,SCSI]
996
997 netdev= [NET] Network devices parameters
998 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
999 Note that mem_start is often overloaded to mean
1000 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001001 This usage is only documented in each driver source
1002 file if at all.
1003
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 nfsaddrs= [NFS]
1005 See Documentation/nfsroot.txt.
1006
1007 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1008 See Documentation/nfsroot.txt.
1009
Trond Myklebusta72b4422006-01-03 09:55:41 +01001010 nfs.callback_tcpport=
1011 [NFS] set the TCP port on which the NFSv4 callback
1012 channel should listen.
1013
Trond Myklebust58df0952006-01-03 09:55:57 +01001014 nfs.idmap_cache_timeout=
1015 [NFS] set the maximum lifetime for idmapper cache
1016 entries.
1017
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1019
1020 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1021 emulation library even if a 387 maths coprocessor
1022 is present.
1023
Paul Menage3395ee02006-12-06 20:32:16 -08001024 noaliencache [MM, NUMA] Disables the allcoation of alien caches in
1025 the slab allocator. Saves per-node memory, but will
1026 impact performance on real NUMA hardware.
1027
Randy Dunlapa9913042005-10-23 12:57:11 -07001028 noalign [KNL,ARM]
1029
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030 noapic [SMP,APIC] Tells the kernel to not make use of any
1031 IOAPICs that may be present in the system.
1032
1033 noasync [HW,M68K] Disables async and sync negotiation for
1034 all devices.
1035
1036 nobats [PPC] Do not use BATs for mapping kernel lowmem
1037 on "Classic" PPC cores.
1038
1039 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001040
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001041 nodelayacct [KNL] Disable per-task delay accounting
1042
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1044
1045 noexec [IA-64]
1046
Randy Dunlapa9913042005-10-23 12:57:11 -07001047 noexec [IA-32,X86-64]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 noexec=on: enable non-executable mappings (default)
1049 noexec=off: disable nn-executable mappings
1050
Chuck Ebbert4f886512006-03-23 02:59:34 -08001051 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1052 register save and restore. The kernel will only save
1053 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054
1055 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001056
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1058 instruction doesn't work correctly and not to
1059 use it.
1060
1061 nohalt [IA-64] Tells the kernel not to use the power saving
1062 function PAL_HALT_LIGHT when idle. This increases
1063 power-consumption. On the positive side, it reduces
1064 interrupt wake-up latency, which may improve performance
1065 in certain environments such as networked servers or
1066 real-time systems.
1067
1068 noirqdebug [IA-32] Disables the code which attempts to detect and
1069 disable unhandled interrupt sources.
1070
1071 noisapnp [ISAPNP] Disables ISA PnP code.
1072
1073 noinitrd [RAM] Tells the kernel not to load any configured
1074 initial RAM disk.
1075
1076 nointroute [IA-64]
1077
1078 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1079
1080 noltlbs [PPC] Do not use large page/tlb entries for kernel
1081 lowmem mapping on PPC40x.
1082
Horms312f1f02006-02-22 09:57:55 +09001083 nomca [IA-64] Disable machine check abort handling
1084
Hormsabe37e52006-04-01 01:36:09 +02001085 nomce [IA-32] Machine Check Exception
1086
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 noresidual [PPC] Don't use residual data on PReP machines.
1088
Randy Dunlapa9913042005-10-23 12:57:11 -07001089 noresume [SWSUSP] Disables resume and restores original swap
1090 space.
1091
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 no-scroll [VGA] Disables scrollback.
1093 This is required for the Braillex ib80-piezo Braille
1094 reader made by F.H. Papenmeier (Germany).
1095
1096 nosbagart [IA-64]
1097
Chuck Ebbert4f886512006-03-23 02:59:34 -08001098 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1099
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1101
1102 nosync [HW,M68K] Disables sync negotiation for all devices.
1103
1104 notsc [BUGS=IA-32] Disable Time Stamp Counter
1105
1106 nousb [USB] Disable the USB subsystem
1107
1108 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001109
Dave Jonesa61c2d72006-01-07 23:18:19 +00001110 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1111
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 opl3= [HW,OSS]
1113 Format: <io>
1114
Randy Dunlapa9913042005-10-23 12:57:11 -07001115 opl3sa2= [HW,OSS] Format:
1116 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1117
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 oprofile.timer= [HW]
1119 Use timer interrupt instead of performance counters
1120
1121 optcd= [HW,CD]
1122 Format: <io>
1123
1124 osst= [HW,SCSI] SCSI Tape Driver
1125 Format: <buffer_size>,<write_threshold>
1126 See also Documentation/scsi/st.txt.
1127
1128 panic= [KNL] Kernel behaviour on panic
1129 Format: <timeout>
1130
1131 parkbd.port= [HW] Parallel port number the keyboard adapter is
1132 connected to, default is 0.
1133 Format: <parport#>
1134 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1135 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001136 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137
Randy Dunlapa9913042005-10-23 12:57:11 -07001138 parport= [HW,PPT] Specify parallel ports. 0 disables.
1139 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1140 Use 'auto' to force the driver to use any
1141 IRQ/DMA settings detected (the default is to
1142 ignore detected IRQ/DMA settings because of
1143 possible conflicts). You can specify the base
1144 address, IRQ, and DMA settings; IRQ and DMA
1145 should be numbers, or 'auto' (for using detected
1146 settings on that particular port), or 'nofifo'
1147 (to avoid using a FIFO even if it is detected).
1148 Parallel ports are assigned in the order they
1149 are specified on the command line, starting
1150 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151
Randy Dunlapa9913042005-10-23 12:57:11 -07001152 parport_init_mode= [HW,PPT]
1153 Configure VIA parallel port to operate in
1154 a specific mode. This is necessary on Pegasos
1155 computer where firmware has no options for setting
1156 up parallel port mode and sets it to spp.
1157 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 Format: [spp|ps2|epp|ecp|ecpepp]
1159
Randy Dunlapa9913042005-10-23 12:57:11 -07001160 pas2= [HW,OSS] Format:
1161 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1162
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 pas16= [HW,SCSI]
1164 See header of drivers/scsi/pas16.c.
1165
Andrew Mortondd287792006-03-23 03:00:57 -08001166 pause_on_oops=
1167 Halt all CPUs after the first oops has been printed for
1168 the specified number of seconds. This is to be used if
1169 your oopses keep scrolling off the screen.
1170
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 pcbit= [HW,ISDN]
1172
1173 pcd. [PARIDE]
1174 See header of drivers/block/paride/pcd.c.
1175 See also Documentation/paride.txt.
1176
Randy Dunlapa9913042005-10-23 12:57:11 -07001177 pci=option[,option...] [PCI] various PCI subsystem options:
1178 off [IA-32] don't probe for the PCI bus
1179 bios [IA-32] force use of PCI BIOS, don't access
1180 the hardware directly. Use this if your machine
1181 has a non-standard PCI host bridge.
1182 nobios [IA-32] disallow use of PCI BIOS, only direct
1183 hardware access methods are allowed. Use this
1184 if you experience crashes upon bootup and you
1185 suspect they are caused by the BIOS.
1186 conf1 [IA-32] Force use of PCI Configuration
1187 Mechanism 1.
1188 conf2 [IA-32] Force use of PCI Configuration
1189 Mechanism 2.
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001190 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1191 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001192 nomsi [MSI] If the PCI_MSI kernel config parameter is
1193 enabled, this kernel boot option can be used to
1194 disable the use of MSI interrupts system-wide.
Randy Dunlapa9913042005-10-23 12:57:11 -07001195 nosort [IA-32] Don't sort PCI devices according to
1196 order given by the PCI BIOS. This sorting is
1197 done to get a device order compatible with
1198 older kernels.
1199 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1200 routing table. These calls are known to be buggy
1201 on several machines and they hang the machine
1202 when used, but on other computers it's the only
1203 way to get the interrupt routing table. Try
1204 this option if the kernel is unable to allocate
1205 IRQs or discover secondary PCI buses on your
1206 motherboard.
1207 rom [IA-32] Assign address space to expansion ROMs.
1208 Use with caution as certain devices share
1209 address decoders between ROMs and other
1210 resources.
1211 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1212 assigned automatically to PCI devices. You can
1213 make the kernel exclude IRQs of your ISA cards
1214 this way.
jayalk@intworks.biz120bb422005-03-21 20:20:42 -08001215 pirqaddr=0xAAAAA [IA-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001216 of the PIRQ table (normally generated
1217 by the BIOS) if it is outside the
1218 F0000h-100000h range.
1219 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1220 useful if the kernel is unable to find your
1221 secondary buses and you want to tell it
1222 explicitly which ones they are.
1223 assign-busses [IA-32] Always assign all PCI bus
1224 numbers ourselves, overriding
1225 whatever the firmware may have done.
1226 usepirqmask [IA-32] Honor the possible IRQ mask stored
1227 in the BIOS $PIR table. This is needed on
1228 some systems with broken BIOSes, notably
1229 some HP Pavilion N5400 and Omnibook XE3
1230 notebooks. This will have no effect if ACPI
1231 IRQ routing is enabled.
1232 noacpi [IA-32] Do not use ACPI for IRQ routing
1233 or for PCI scanning.
1234 routeirq Do IRQ routing for all PCI devices.
1235 This is normally done in pci_enable_device(),
1236 so this option is a temporary workaround
1237 for broken drivers that don't call it.
1238 firmware [ARM] Do not re-enumerate the bus but instead
1239 just use the configuration from the
1240 bootloader. This is currently used on
1241 IXP2000 systems where the bus has to be
1242 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001243 noearly [X86] Don't do any early type 1 scanning.
1244 This might help on some broken boards which
1245 machine check when some devices' config space
1246 is read. But various workarounds are disabled
1247 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001248 bfsort Sort PCI devices into breadth-first order.
1249 This sorting is done to get a device
1250 order compatible with older (<= 2.4) kernels.
1251 nobfsort Don't sort PCI devices into breadth-first order.
1252
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 pcmv= [HW,PCMCIA] BadgePAD 4
1254
1255 pd. [PARIDE]
1256 See Documentation/paride.txt.
1257
1258 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1259 boot time.
1260 Format: { 0 | 1 }
1261 See arch/parisc/kernel/pdc_chassis.c
1262
1263 pf. [PARIDE]
1264 See Documentation/paride.txt.
1265
1266 pg. [PARIDE]
1267 See Documentation/paride.txt.
1268
1269 pirq= [SMP,APIC] Manual mp-table setup
1270 See Documentation/i386/IO-APIC.txt.
1271
1272 plip= [PPT,NET] Parallel port network link
1273 Format: { parport<nr> | timid | 0 }
1274 See also Documentation/parport.txt.
1275
1276 pnpacpi= [ACPI]
1277 { off }
1278
1279 pnpbios= [ISAPNP]
1280 { on | off | curr | res | no-curr | no-res }
1281
1282 pnp_reserve_irq=
1283 [ISAPNP] Exclude IRQs for the autoconfiguration
1284
1285 pnp_reserve_dma=
1286 [ISAPNP] Exclude DMAs for the autoconfiguration
1287
1288 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001289 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290
1291 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001292 [ISAPNP] Exclude memory regions for the
1293 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 Ranges are in pairs (memory base and size).
1295
1296 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001297 Format: [schedule,]<number>
1298 Param: "schedule" - profile schedule points.
1299 Param: <number> - step/bucket size as a power of 2 for
1300 statistical time based profiling.
Ingo Molnarece8a682006-12-06 20:37:24 -08001301 Param: "sleep" - profile D-state sleeping (millisecs)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302
Randy Dunlapa9913042005-10-23 12:57:11 -07001303 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 Limit processor to maximum C-state
1305 max_cstate=9 overrides any DMI blacklist limit.
1306
Len Brown41c0d862005-12-28 12:43:51 -05001307 processor.nocst [HW,ACPI]
1308 Ignore the _CST method to determine C-states,
1309 instead using the legacy FADT method
1310
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1312 before loading.
1313 See Documentation/ramdisk.txt.
1314
Randy Dunlapa9913042005-10-23 12:57:11 -07001315 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1316 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1318 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001319 psmouse.resetafter= [HW,MOUSE]
1320 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 (0 = never).
1322 psmouse.resolution=
1323 [HW,MOUSE] Set desired mouse resolution, in dpi.
1324 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001325 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326 0 = disabled, 1 = enabled (default).
1327
1328 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001329 Format:
1330 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331
1332 pt. [PARIDE]
1333 See Documentation/paride.txt.
1334
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001335 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001336
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 r128= [HW,DRM]
1338
1339 raid= [HW,RAID]
1340 See Documentation/md.txt.
1341
1342 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1343 See Documentation/ramdisk.txt.
1344
Randy Dunlapa9913042005-10-23 12:57:11 -07001345 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001347
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1349 New name for the ramdisk parameter.
1350 See Documentation/ramdisk.txt.
1351
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001352 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1353 RCU callbacks to process in one batch.
1354
1355 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1356 RCU callbacks over which batch limiting is disabled.
1357
1358 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1359 RCU callbacks below which batch limiting is re-enabled.
1360
Olof Johanssonffdfc402005-09-06 15:17:19 -07001361 rdinit= [KNL]
1362 Format: <full_path>
1363 Run specified binary instead of /init from the ramdisk,
1364 used for early userspace startup. See initrd.
1365
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1367 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Michael Opdenackerf3e299f2006-10-03 23:19:24 +02001368 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369
1370 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1371
Zachary Amsden461a9af2006-09-25 23:32:25 -07001372 reservetop= [IA-32]
1373 Format: nn[KMG]
1374 Reserves a hole at the top of the kernel virtual
1375 address space.
1376
Vivek Goyal7e962872006-09-27 01:50:44 -07001377 reset_devices [KNL] Force drivers to reset the underlying device
1378 during initialization.
1379
Randy Dunlapa9913042005-10-23 12:57:11 -07001380 resume= [SWSUSP]
1381 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001383 resume_offset= [SWSUSP]
1384 Specify the offset from the beginning of the partition
1385 given by "resume=" at which the swap header is located,
1386 in <PAGE_SIZE> units (needed only for swap files).
1387 See Documentation/power/swsusp-and-swap-files.txt
1388
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 rhash_entries= [KNL,NET]
1390 Set number of hash buckets for route cache
1391
1392 riscom8= [HW,SERIAL]
1393 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1394
1395 ro [KNL] Mount root device read-only on boot
1396
1397 root= [KNL] Root filesystem
1398
1399 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1400 mount the root filesystem
1401
1402 rootflags= [KNL] Set root filesystem mount option string
1403
1404 rootfstype= [KNL] Set root filesystem type
1405
1406 rw [KNL] Mount root device read-write on boot
1407
1408 S [KNL] Run init in single mode
1409
1410 sa1100ir [NET]
1411 See drivers/net/irda/sa1100_ir.c.
1412
1413 sb= [HW,OSS]
1414 Format: <io>,<irq>,<dma>,<dma2>
1415
1416 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 sbpcd= [HW,CD] Soundblaster CD adapter
1419 Format: <io>,<type>
1420 See a comment before function sbpcd_setup() in
1421 drivers/cdrom/sbpcd.c.
1422
1423 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1424 Format: <io>[,<timeout>[,<isapnp>]]
1425
1426 scsi_debug_*= [SCSI]
1427 See drivers/scsi/scsi_debug.c.
1428
1429 scsi_default_dev_flags=
1430 [SCSI] SCSI default device flags
1431 Format: <integer>
1432
1433 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1434 Format: <vendor>:<model>:<flags>
1435 (flags are integer value)
1436
1437 scsi_logging= [SCSI]
1438
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001439 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1440 discovered. async scans them in kernel threads,
1441 allowing boot to proceed. none ignores them, expecting
1442 user space to do the scan.
1443
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444 selinux [SELINUX] Disable or enable SELinux at boot time.
1445 Format: { "0" | "1" }
1446 See security/selinux/Kconfig help text.
1447 0 -- disable.
1448 1 -- enable.
1449 Default value is set via kernel config option.
1450 If enabled at boot time, /selinux/disable can be used
1451 later to disable prior to initial policy load.
1452
James Morris4e5ab4c2006-06-09 00:33:33 -07001453 selinux_compat_net =
1454 [SELINUX] Set initial selinux_compat_net flag value.
1455 Format: { "0" | "1" }
1456 0 -- use new secmark-based packet controls
1457 1 -- use legacy packet controls
1458 Default value is 0 (preferred).
1459 Value can be changed at runtime via
1460 /selinux/compat_net.
1461
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 serialnumber [BUGS=IA-32]
1463
Randy Dunlapa9913042005-10-23 12:57:11 -07001464 sg_def_reserved_size= [SCSI]
1465
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466 shapers= [NET]
1467 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001468
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 sim710= [SCSI,HW]
1470 See header of drivers/scsi/sim710.c.
1471
1472 simeth= [IA-64]
1473 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001474
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 sjcd= [HW,CD]
1476 Format: <io>,<irq>,<dma>
1477 See header of drivers/cdrom/sjcd.c.
1478
1479 slram= [HW,MTD]
1480
1481 smart2= [HW]
1482 Format: <io1>[,<io2>[,...,<io8>]]
1483
1484 snd-ad1816a= [HW,ALSA]
1485
1486 snd-ad1848= [HW,ALSA]
1487
1488 snd-ali5451= [HW,ALSA]
1489
1490 snd-als100= [HW,ALSA]
1491
1492 snd-als4000= [HW,ALSA]
1493
1494 snd-azt2320= [HW,ALSA]
1495
1496 snd-cmi8330= [HW,ALSA]
1497
1498 snd-cmipci= [HW,ALSA]
1499
1500 snd-cs4231= [HW,ALSA]
1501
1502 snd-cs4232= [HW,ALSA]
1503
1504 snd-cs4236= [HW,ALSA]
1505
1506 snd-cs4281= [HW,ALSA]
1507
1508 snd-cs46xx= [HW,ALSA]
1509
1510 snd-dt019x= [HW,ALSA]
1511
1512 snd-dummy= [HW,ALSA]
1513
1514 snd-emu10k1= [HW,ALSA]
1515
1516 snd-ens1370= [HW,ALSA]
1517
1518 snd-ens1371= [HW,ALSA]
1519
1520 snd-es968= [HW,ALSA]
1521
1522 snd-es1688= [HW,ALSA]
1523
1524 snd-es18xx= [HW,ALSA]
1525
1526 snd-es1938= [HW,ALSA]
1527
1528 snd-es1968= [HW,ALSA]
1529
1530 snd-fm801= [HW,ALSA]
1531
1532 snd-gusclassic= [HW,ALSA]
1533
1534 snd-gusextreme= [HW,ALSA]
1535
1536 snd-gusmax= [HW,ALSA]
1537
1538 snd-hdsp= [HW,ALSA]
1539
1540 snd-ice1712= [HW,ALSA]
1541
1542 snd-intel8x0= [HW,ALSA]
1543
1544 snd-interwave= [HW,ALSA]
1545
1546 snd-interwave-stb=
1547 [HW,ALSA]
1548
1549 snd-korg1212= [HW,ALSA]
1550
1551 snd-maestro3= [HW,ALSA]
1552
1553 snd-mpu401= [HW,ALSA]
1554
1555 snd-mtpav= [HW,ALSA]
1556
1557 snd-nm256= [HW,ALSA]
1558
1559 snd-opl3sa2= [HW,ALSA]
1560
1561 snd-opti92x-ad1848=
1562 [HW,ALSA]
1563
1564 snd-opti92x-cs4231=
1565 [HW,ALSA]
1566
1567 snd-opti93x= [HW,ALSA]
1568
1569 snd-pmac= [HW,ALSA]
1570
1571 snd-rme32= [HW,ALSA]
1572
1573 snd-rme96= [HW,ALSA]
1574
1575 snd-rme9652= [HW,ALSA]
1576
1577 snd-sb8= [HW,ALSA]
1578
1579 snd-sb16= [HW,ALSA]
1580
1581 snd-sbawe= [HW,ALSA]
1582
1583 snd-serial= [HW,ALSA]
1584
1585 snd-sgalaxy= [HW,ALSA]
1586
1587 snd-sonicvibes= [HW,ALSA]
1588
1589 snd-sun-amd7930=
1590 [HW,ALSA]
1591
1592 snd-sun-cs4231= [HW,ALSA]
1593
1594 snd-trident= [HW,ALSA]
1595
1596 snd-usb-audio= [HW,ALSA,USB]
1597
1598 snd-via82xx= [HW,ALSA]
1599
1600 snd-virmidi= [HW,ALSA]
1601
1602 snd-wavefront= [HW,ALSA]
1603
1604 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001605
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 sonycd535= [HW,CD]
1607 Format: <io>[,<irq>]
1608
1609 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1610 See Documentation/sonypi.txt
1611
1612 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1613 See Documentation/specialix.txt.
1614
1615 spia_io_base= [HW,MTD]
1616 spia_fio_base=
1617 spia_pedr=
1618 spia_peddr=
1619
1620 sscape= [HW,OSS]
1621 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07001622
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1624 See Documentation/scsi/st.txt.
1625
1626 st0x= [HW,SCSI]
1627 See header of drivers/scsi/seagate.c.
1628
1629 sti= [PARISC,HW]
1630 Format: <num>
1631 Set the STI (builtin display/keyboard on the HP-PARISC
1632 machines) console (graphic card) which should be used
1633 as the initial boot-console.
1634 See also comment in drivers/video/console/sticore.c.
1635
1636 sti_font= [HW]
1637 See comment in drivers/video/console/sticore.c.
1638
1639 stifb= [HW]
1640 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1641
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07001643
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644 switches= [HW,M68k]
1645
1646 sym53c416= [HW,SCSI]
1647 See header of drivers/scsi/sym53c416.c.
1648
1649 t128= [HW,SCSI]
1650 See header of drivers/scsi/t128.c.
1651
1652 tdfx= [HW,DRM]
1653
1654 thash_entries= [KNL,NET]
1655 Set number of hash buckets for TCP connection
1656
1657 time Show timing data prefixed to each printk message line
1658
john stultz734efb42006-06-26 00:25:05 -07001659 clocksource= [GENERIC_TIME] Override the default clocksource
1660 Override the default clocksource and use the clocksource
1661 with the name specified.
1662
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 tipar.timeout= [HW,PPT]
1664 Set communications timeout in tenths of a second
1665 (default 15).
1666
1667 tipar.delay= [HW,PPT]
1668 Set inter-bit delay in microseconds (default 10).
1669
1670 tmc8xx= [HW,SCSI]
1671 See header of drivers/scsi/seagate.c.
1672
1673 tmscsim= [HW,SCSI]
1674 See comment before function dc390_setup() in
1675 drivers/scsi/tmscsim.c.
1676
1677 tp720= [HW,PS2]
1678
1679 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07001680 Format:
1681 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1682
Linus Torvalds1da177e2005-04-16 15:20:36 -07001683 tsdev.xres= [TS] Horizontal screen resolution.
1684 tsdev.yres= [TS] Vertical screen resolution.
1685
Randy Dunlapa9913042005-10-23 12:57:11 -07001686 turbografx.map[2|3]= [HW,JOY]
1687 TurboGraFX parallel port interface
1688 Format:
1689 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690 See also Documentation/input/joystick-parport.txt
1691
1692 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1693 See header of drivers/scsi/u14-34f.c.
1694
1695 uart401= [HW,OSS]
1696 Format: <io>,<irq>
1697
1698 uart6850= [HW,OSS]
1699 Format: <io>,<irq>
1700
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 usbhid.mousepoll=
1702 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07001703
Ingo Molnare6e54942006-06-27 02:53:50 -07001704 vdso= [IA-32]
1705 vdso=1: enable VDSO (default)
1706 vdso=0: disable VDSO mapping
1707
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708 video= [FB] Frame buffer configuration
1709 See Documentation/fb/modedb.txt.
1710
1711 vga= [BOOT,IA-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07001712 See Documentation/i386/boot.txt and
1713 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 Use vga=ask for menu.
1715 This is actually a boot loader parameter; the value is
1716 passed to the kernel using a special protocol.
1717
Randy Dunlapa9913042005-10-23 12:57:11 -07001718 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 size of <nn>. This can be used to increase the
1720 minimum size (128MB on x86). It can also be used to
1721 decrease the size and leave more room for directly
1722 mapped kernel RAM.
1723
Peter Oberparleiter585c3042006-06-29 15:08:25 +02001724 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1725 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726
Peter Oberparleiter585c3042006-06-29 15:08:25 +02001727 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1728 Format: <command>
1729
1730 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1731 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07001732
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 waveartist= [HW,OSS]
1734 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07001735
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 wd33c93= [HW,SCSI]
1737 See header of drivers/scsi/wd33c93.c.
1738
1739 wd7000= [HW,SCSI]
1740 See header of drivers/scsi/wd7000.c.
1741
1742 wdt= [WDT] Watchdog
1743 See Documentation/watchdog/watchdog.txt.
1744
1745 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1746 xd_geo= See header of drivers/block/xd.c.
1747
1748 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07001749 Format:
1750 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751
Andi Kleena62eaf12006-02-16 23:41:58 +01001752 norandmaps Don't use address space randomization
1753 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1754
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755
Randy Dunlapa9913042005-10-23 12:57:11 -07001756______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757
1758TODO:
1759
1760 Add documentation for ALSA options.
1761 Add more DRM drivers.