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1February 2003 Kernel Parameters v2.5.59
2 ~~~~~~~~~~~~~~~~~
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
a9913044 20The text in square brackets at the beginning of the description states the
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21restrictions on the kernel for the said kernel parameter to be valid. The
22restrictions referred to are that the relevant option is valid if:
23
24 ACPI ACPI support is enabled.
25 ALSA ALSA sound support is enabled.
26 APIC APIC support is enabled.
27 APM Advanced Power Management support is enabled.
28 AX25 Appropriate AX.25 support is enabled.
29 CD Appropriate CD support is enabled.
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30 DEVFS devfs support is enabled.
31 DRM Direct Rendering Management support is enabled.
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32 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
33 EFI EFI Partitioning (GPT) is enabled
34 EIDE EIDE/ATAPI support is enabled.
35 FB The frame buffer device is enabled.
36 HW Appropriate hardware is enabled.
37 IA-32 IA-32 aka i386 architecture is enabled.
38 IA-64 IA-64 architecture is enabled.
39 IOSCHED More than one I/O scheduler is enabled.
41e2e8be 40 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
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41 ISAPNP ISA PnP code is enabled.
42 ISDN Appropriate ISDN support is enabled.
43 JOY Appropriate joystick support is enabled.
44 LP Printer support is enabled.
45 LOOP Loopback device support is enabled.
46 M68k M68k architecture is enabled.
47 These options have more detailed description inside of
48 Documentation/m68k/kernel-options.txt.
49 MCA MCA bus support is enabled.
50 MDA MDA console support is enabled.
51 MOUSE Appropriate mouse support is enabled.
52 MTD MTD support is enabled.
53 NET Appropriate network support is enabled.
54 NUMA NUMA support is enabled.
55 NFS Appropriate NFS support is enabled.
56 OSS OSS sound support is enabled.
57 PARIDE The ParIDE subsystem is enabled.
58 PARISC The PA-RISC architecture is enabled.
59 PCI PCI bus support is enabled.
60 PCMCIA The PCMCIA subsystem is enabled.
61 PNP Plug & Play support is enabled.
62 PPC PowerPC architecture is enabled.
63 PPT Parallel port support is enabled.
64 PS2 Appropriate PS/2 support is enabled.
65 RAM RAM disk support is enabled.
66 S390 S390 architecture is enabled.
67 SCSI Appropriate SCSI support is enabled.
68 A lot of drivers has their options described inside of
69 Documentation/scsi/.
70 SELINUX SELinux support is enabled.
71 SERIAL Serial support is enabled.
72 SMP The kernel is an SMP kernel.
73 SPARC Sparc architecture is enabled.
a9913044 74 SWSUSP Software suspend is enabled.
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75 TS Appropriate touchscreen support is enabled.
76 USB USB support is enabled.
77 USBHID USB Human Interface Device support is enabled.
78 V4L Video For Linux support is enabled.
79 VGA The VGA console has been enabled.
80 VT Virtual terminal support is enabled.
81 WDT Watchdog support is enabled.
82 XT IBM PC/XT MFM hard disk support is enabled.
83 X86-64 X86-64 architecture is enabled.
84 More X86-64 boot options can be found in
85 Documentation/x86_64/boot-options.txt .
86
87In addition, the following text indicates that the option:
88
89 BUGS= Relates to possible processor bugs on the said processor.
90 KNL Is a kernel start-up parameter.
91 BOOT Is a boot loader parameter.
92
93Parameters denoted with BOOT are actually interpreted by the boot
94loader, and have no meaning to the kernel directly.
95Do not modify the syntax of boot loader parameters without extreme
96need or coordination with <Documentation/i386/boot.txt>.
97
98Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
99a trailing = on the name of any parameter states that that parameter will
100be entered as an environment variable, whereas its absence indicates that
101it will appear as a kernel argument readable via /proc/cmdline by programs
102running once the system is up.
103
104 53c7xx= [HW,SCSI] Amiga SCSI controllers
105 See header of drivers/scsi/53c7xx.c.
106 See also Documentation/scsi/ncr53c7xx.txt.
107
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108 acpi= [HW,ACPI] Advanced Configuration and Power Interface
109 Format: { force | off | ht | strict | noirq }
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110 force -- enable ACPI if default was off
111 off -- disable ACPI if default was on
112 noirq -- do not use ACPI for IRQ routing
113 ht -- run only enough ACPI to enable Hyper Threading
a9913044 114 strict -- Be less tolerant of platforms that are not
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115 strictly ACPI specification compliant.
116
117 See also Documentation/pm.txt, pci=noacpi
118
119 acpi_sleep= [HW,ACPI] Sleep options
120 Format: { s3_bios, s3_mode }
121 See Documentation/power/video.txt
a9913044 122
1da177e4 123 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 124 Format: { level | edge | high | low }
1da177e4 125
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126 acpi_irq_balance [HW,ACPI]
127 ACPI will balance active IRQs
128 default in APIC mode
1da177e4 129
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130 acpi_irq_nobalance [HW,ACPI]
131 ACPI will not move active IRQs (default)
132 default in PIC mode
1da177e4 133
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134 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
135 use by PCI
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136 Format: <irq>,<irq>...
137
a9913044 138 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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139 Format: <irq>,<irq>...
140
141 acpi_osi= [HW,ACPI] empty param disables _OSI
142
143 acpi_serialize [HW,ACPI] force serialization of AML methods
144
145 acpi_skip_timer_override [HW,ACPI]
146 Recognize and ignore IRQ0/pin2 Interrupt Override.
147 For broken nForce2 BIOS resulting in XT-PIC timer.
148
149 acpi_dbg_layer= [HW,ACPI]
150 Format: <int>
a9913044 151 Each bit of the <int> indicates an ACPI debug layer,
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152 1: enable, 0: disable. It is useful for boot time
153 debugging. After system has booted up, it can be set
154 via /proc/acpi/debug_layer.
155
156 acpi_dbg_level= [HW,ACPI]
157 Format: <int>
a9913044 158 Each bit of the <int> indicates an ACPI debug level,
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159 1: enable, 0: disable. It is useful for boot time
160 debugging. After system has booted up, it can be set
161 via /proc/acpi/debug_level.
162
163 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
164
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165 acpi_generic_hotkey [HW,ACPI]
166 Allow consolidated generic hotkey driver to
a9913044 167 override platform specific driver.
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168 See also Documentation/acpi-hotkey.txt.
169
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170 enable_timer_pin_1 [i386,x86-64]
171 Enable PIN 1 of APIC timer
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172 Can be useful to work around chipset bugs
173 (in particular on some ATI chipsets).
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174 The kernel tries to set a reasonable default.
175
176 disable_timer_pin_1 [i386,x86-64]
177 Disable PIN 1 of APIC timer
178 Can be useful to work around chipset bugs.
179
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180 ad1816= [HW,OSS]
181 Format: <io>,<irq>,<dma>,<dma2>
182 See also Documentation/sound/oss/AD1816.
183
184 ad1848= [HW,OSS]
185 Format: <io>,<irq>,<dma>,<dma2>,<type>
186
187 adlib= [HW,OSS]
188 Format: <io>
a9913044 189
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190 advansys= [HW,SCSI]
191 See header of drivers/scsi/advansys.c.
192
193 advwdt= [HW,WDT] Advantech WDT
194 Format: <iostart>,<iostop>
195
196 aedsp16= [HW,OSS] Audio Excel DSP 16
197 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
198 See also header of sound/oss/aedsp16.c.
a9913044 199
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200 aha152x= [HW,SCSI]
201 See Documentation/scsi/aha152x.txt.
202
203 aha1542= [HW,SCSI]
204 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
205
206 aic7xxx= [HW,SCSI]
207 See Documentation/scsi/aic7xxx.txt.
208
209 aic79xx= [HW,SCSI]
210 See Documentation/scsi/aic79xx.txt.
211
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212 amijoy.map= [HW,JOY] Amiga joystick support
213 Map of devices attached to JOY0DAT and JOY1DAT
214 Format: <a>,<b>
215 See also Documentation/kernel/input/joystick.txt
216
217 analog.map= [HW,JOY] Analog joystick and gamepad support
218 Specifies type or capabilities of an analog joystick
219 connected to one of 16 gameports
220 Format: <type1>,<type2>,..<type16>
221
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222 apc= [HW,SPARC]
223 Power management functions (SPARCstation-4/5 + deriv.)
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224 Format: noidle
225 Disable APC CPU standby support. SPARCstation-Fox does
226 not play well with APC CPU idle - disable it if you have
227 APC and your system crashes randomly.
228
a9913044 229 apic= [APIC,i386] Change the output verbosity whilst booting
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230 Format: { quiet (default) | verbose | debug }
231 Change the amount of debugging information output
232 when initialising the APIC and IO-APIC components.
a9913044 233
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234 apm= [APM] Advanced Power Management
235 See header of arch/i386/kernel/apm.c.
236
237 applicom= [HW]
238 Format: <mem>,<irq>
a9913044 239
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240 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
241 Format: <io>,<irq>,<nodeID>
242
243 ataflop= [HW,M68k]
244
245 atarimouse= [HW,MOUSE] Atari Mouse
246
247 atascsi= [HW,SCSI] Atari SCSI
248
249 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
250 EzKey and similar keyboards
251
252 atkbd.reset= [HW] Reset keyboard during initialization
253
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254 atkbd.set= [HW] Select keyboard code set
255 Format: <int> (2 = AT (default), 3 = PS/2)
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256
257 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
258 keyboards
259
260 atkbd.softraw= [HW] Choose between synthetic and real raw mode
261 Format: <bool> (0 = real, 1 = synthetic (default))
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262
263 atkbd.softrepeat= [HW]
264 Use software keyboard repeat
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265
266 autotest [IA64]
267
268 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
269 Format: <io>,<memsize>,<isapnp>
a9913044 270
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271 aztcd= [HW,CD] Aztech CD268 CDROM driver
272 Format: <io>,0x79 (?)
273
274 baycom_epp= [HW,AX25]
275 Format: <io>,<mode>
a9913044 276
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277 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
278 Format: <io>,<mode>
279 See header of drivers/net/hamradio/baycom_par.c.
280
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281 baycom_ser_fdx= [HW,AX25]
282 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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283 Format: <io>,<irq>,<mode>[,<baud>]
284 See header of drivers/net/hamradio/baycom_ser_fdx.c.
285
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286 baycom_ser_hdx= [HW,AX25]
287 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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288 Format: <io>,<irq>,<mode>
289 See header of drivers/net/hamradio/baycom_ser_hdx.c.
290
291 blkmtd_device= [HW,MTD]
292 blkmtd_erasesz=
293 blkmtd_ro=
294 blkmtd_bs=
295 blkmtd_count=
296
297 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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298 bttv.radio= Most important insmod options are available as
299 kernel args too.
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300 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
301 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
302
303 BusLogic= [HW,SCSI]
304 See drivers/scsi/BusLogic.c, comment before function
305 BusLogic_ParseDriverOptions().
306
307 c101= [NET] Moxa C101 synchronous serial card
308
309 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
310 Sometimes CPU hardware bugs make them report the cache
311 size incorrectly. The kernel will attempt work arounds
312 to fix known problems, but for some CPUs it is not
313 possible to determine what the correct size should be.
314 This option provides an override for these situations.
315
316 cdu31a= [HW,CD]
317 Format: <io>,<irq>[,PAS]
318 See header of drivers/cdrom/cdu31a.c.
319
320 chandev= [HW,NET] Generic channel device initialisation
321
322 checkreqprot [SELINUX] Set initial checkreqprot flag value.
323 Format: { "0" | "1" }
324 See security/selinux/Kconfig help text.
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325 0 -- check protection applied by kernel (includes
326 any implied execute protection).
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327 1 -- check protection requested by application.
328 Default value is set via a kernel config option.
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329 Value can be changed at runtime via
330 /selinux/checkreqprot.
331
332 clock= [BUGS=IA-32,HW] gettimeofday timesource override.
1da177e4 333 Forces specified timesource (if avaliable) to be used
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334 when calculating gettimeofday(). If specicified
335 timesource is not avalible, it defaults to PIT.
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336 Format: { pit | tsc | cyclone | pmtmr }
337
338 hpet= [IA-32,HPET] option to disable HPET and use PIT.
339 Format: disable
340
341 cm206= [HW,CD]
342 Format: { auto | [<io>,][<irq>] }
343
344 com20020= [HW,NET] ARCnet - COM20020 chipset
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345 Format:
346 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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347
348 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
349 Format: <io>[,<irq>]
350
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351 com90xx= [HW,NET]
352 ARCnet - COM90xx chipset (memory-mapped buffers)
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353 Format: <io>[,<irq>[,<memstart>]]
354
355 condev= [HW,S390] console device
356 conmode=
a9913044 357
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358 console= [KNL] Output console device and options.
359
360 tty<n> Use the virtual console device <n>.
361
362 ttyS<n>[,options]
363 Use the specified serial port. The options are of
364 the form "bbbbpn", where "bbbb" is the baud rate,
365 "p" is parity ("n", "o", or "e"), and "n" is bits.
366 Default is "9600n8".
367
368 See also Documentation/serial-console.txt.
369
370 uart,io,<addr>[,options]
371 uart,mmio,<addr>[,options]
372 Start an early, polled-mode console on the 8250/16550
373 UART at the specified I/O port or MMIO address,
374 switching to the matching ttyS device later. The
375 options are the same as for ttyS, above.
376
377 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
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378 Format:
379 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
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380
381 cpia_pp= [HW,PPT]
382 Format: { parport<nr> | auto | none }
383
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384 crashkernel=nn[KMG]@ss[KMG]
385 [KNL] Reserve a chunk of physical memory to
386 hold a kernel to switch to with kexec on panic.
387
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388 cs4232= [HW,OSS]
389 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
390
391 cs89x0_dma= [HW,NET]
392 Format: <dma>
393
394 cs89x0_media= [HW,NET]
395 Format: { rj45 | aui | bnc }
a9913044 396
1da177e4 397 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
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398
399 dasd= [HW,NET]
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400 See header of drivers/s390/block/dasd_devmap.c.
401
402 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
403 (one device per port)
404 Format: <port#>,<type>
405 See also Documentation/input/joystick-parport.txt
406
407 debug [KNL] Enable kernel debugging (events log level).
408
409 decnet= [HW,NET]
410 Format: <area>[,<node>]
411 See also Documentation/networking/decnet.txt.
412
413 devfs= [DEVFS]
414 See Documentation/filesystems/devfs/boot-options.
415
416 dhash_entries= [KNL]
417 Set number of hash buckets for dentry cache.
a9913044 418
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419 digi= [HW,SERIAL]
420 IO parameters + enable/disable command.
421
422 digiepca= [HW,SERIAL]
423 See drivers/char/README.epca and
424 Documentation/digiepca.txt.
425
426 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
427 support available.
428 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
429
430 dmasound= [HW,OSS] Sound subsystem buffers
431
432 dscc4.setup= [NET]
433
434 dtc3181e= [HW,SCSI]
435
a9913044 436 earlyprintk= [IA-32,X86-64]
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437 earlyprintk=vga
438 earlyprintk=serial[,ttySn[,baudrate]]
439
a9913044 440 Append ",keep" to not disable it when the real console
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441 takes over.
442
443 Only vga or serial at a time, not both.
444
445 Currently only ttyS0 and ttyS1 are supported.
446
447 Interaction with the standard serial driver is not
448 very good.
449
450 The VGA output is eventually overwritten by the real
451 console.
452
453 eata= [HW,SCSI]
454
455 eda= [HW,PS2]
456
457 edb= [HW,PS2]
458
459 edd= [EDD]
460 Format: {"of[f]" | "sk[ipmbr]"}
461 See comment in arch/i386/boot/edd.S
462
a9913044 463 eicon= [HW,ISDN]
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464 Format: <id>,<membase>,<irq>
465
466 eisa_irq_edge= [PARISC,HW]
467 See header of drivers/parisc/eisa.c.
468
469 elanfreq= [IA-32]
470 See comment before function elanfreq_setup() in
471 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
472
473 elevator= [IOSCHED]
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474 Format: {"as" | "cfq" | "deadline" | "noop"}
475 See Documentation/block/as-iosched.txt and
476 Documentation/block/deadline-iosched.txt for details.
477
aac04b32 478 elfcorehdr= [IA-32, X86_64]
a9913044 479 Specifies physical address of start of kernel core
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480 image elf header. Generally kexec loader will
481 pass this option to capture kernel.
482 See Documentation/kdump/kdump.txt for details.
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483
484 enforcing [SELINUX] Set initial enforcing status.
485 Format: {"0" | "1"}
486 See security/selinux/Kconfig help text.
487 0 -- permissive (log only, no denials).
488 1 -- enforcing (deny and log).
489 Default value is 0.
490 Value can be changed at runtime via /selinux/enforce.
491
492 es1370= [HW,OSS]
493 Format: <lineout>[,<micbias>]
494 See also header of sound/oss/es1370.c.
495
496 es1371= [HW,OSS]
497 Format: <spdif>,[<nomix>,[<amplifier>]]
498 See also header of sound/oss/es1371.c.
a9913044 499
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500 ether= [HW,NET] Ethernet cards parameters
501 This option is obsoleted by the "netdev=" option, which
502 has equivalent usage. See its documentation for details.
503
504 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
505 Format: <io>[,<irq>]
506
507 fd_mcs= [HW,SCSI]
508 See header of drivers/scsi/fd_mcs.c.
509
510 fdomain= [HW,SCSI]
511 See header of drivers/scsi/fdomain.c.
512
513 floppy= [HW]
514 See Documentation/floppy.txt.
515
516 ftape= [HW] Floppy Tape subsystem debugging options.
517 See Documentation/ftape.txt.
518
519 gamecon.map[2|3]=
520 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
521 support via parallel port (up to 5 devices per port)
522 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
523 See also Documentation/input/joystick-parport.txt
524
525 gamma= [HW,DRM]
526
527 gdth= [HW,SCSI]
528 See header of drivers/scsi/gdth.c.
529
530 gpt [EFI] Forces disk with valid GPT signature but
531 invalid Protective MBR to be treated as GPT.
532
533 gscd= [HW,CD]
534 Format: <io>
535
536 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
537
538 gus= [HW,OSS]
539 Format: <io>,<irq>,<dma>,<dma16>
a9913044 540
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541 gvp11= [HW,SCSI]
542
543 hashdist= [KNL,NUMA] Large hashes allocated during boot
544 are distributed across NUMA nodes. Defaults on
545 for IA-64, off otherwise.
a9913044 546 Format: 0 | 1 (for off | on)
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547
548 hcl= [IA-64] SGI's Hardware Graph compatibility layer
549
550 hd= [EIDE] (E)IDE hard drive subsystem geometry
551 Format: <cyl>,<head>,<sect>
552
553 hd?= [HW] (E)IDE subsystem
554 hd?lun= See Documentation/ide.txt.
555
556 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
557 size of <nn>. This works even on boxes that have no
558 highmem otherwise. This also works to reduce highmem
559 size on bigger boxes.
560
561 hisax= [HW,ISDN]
562 See Documentation/isdn/README.HiSax.
563
564 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
565
566 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
567
568 i8042.direct [HW] Put keyboard port into non-translated mode
569 i8042.dumbkbd [HW] Pretend that controlled can only read data from
570 keyboard and can not control its state
571 (Don't attempt to blink the leds)
572 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 573 i8042.nokbd [HW] Don't check/create keyboard port
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574 i8042.nomux [HW] Don't check presence of an active multiplexing
575 controller
576 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
577 controllers
578 i8042.panicblink=
579 [HW] Frequency with which keyboard LEDs should blink
580 when kernel panics (default is 0.5 sec)
581 i8042.reset [HW] Reset the controller during init and cleanup
582 i8042.unlock [HW] Unlock (ignore) the keylock
583
584 i810= [HW,DRM]
585
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586 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
587 indicates that the driver is running on unsupported
588 hardware.
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589 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
590 does not match list of supported models.
591 i8k.power_status
592 [HW] Report power status in /proc/i8k
593 (disabled by default)
594 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
595 capability is set.
596
597 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
598 See Documentation/mca.txt.
599
600 icn= [HW,ISDN]
601 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
602
603 ide= [HW] (E)IDE subsystem
604 Format: ide=nodma or ide=doubler or ide=reverse
605 See Documentation/ide.txt.
606
607 ide?= [HW] (E)IDE subsystem
608 Format: ide?=noprobe or chipset specific parameters.
609 See Documentation/ide.txt.
a9913044 610
1da177e4
LT
611 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
612 See Documentation/ide.txt.
613
614 idle= [HW]
615 Format: idle=poll or idle=halt
a9913044 616
1da177e4
LT
617 ihash_entries= [KNL]
618 Set number of hash buckets for inode cache.
619
620 in2000= [HW,SCSI]
621 See header of drivers/scsi/in2000.c.
622
623 init= [KNL]
624 Format: <full_path>
625 Run specified binary instead of /sbin/init as init
626 process.
627
628 initcall_debug [KNL] Trace initcalls as they are executed. Useful
629 for working out where the kernel is dying during
630 startup.
631
632 initrd= [BOOT] Specify the location of the initial ramdisk
633
634 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
635 Format: <irq>
636
2bd0fa3b
JB
637 combined_mode= [HW] control which driver uses IDE ports in combined
638 mode: legacy IDE driver, libata, or both
639 (in the libata case, libata.atapi_enabled=1 may be
640 useful as well). Note that using the ide or libata
641 options may affect your device naming (e.g. by
642 changing hdc to sdb).
643 Format: combined (default), ide, or libata
644
1da177e4
LT
645 inttest= [IA64]
646
647 io7= [HW] IO7 for Marvel based alpha systems
648 See comment before marvel_specify_io7 in
649 arch/alpha/kernel/core_marvel.c.
650
651 ip= [IP_PNP]
652 See Documentation/nfsroot.txt.
653
654 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
655 See comment before ip2_setup() in drivers/char/ip2.c.
656
657 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
658 See header of drivers/scsi/ips.c.
659
200803df
AC
660 irqfixup [HW]
661 When an interrupt is not handled search all handlers
662 for it. Intended to get systems with badly broken
663 firmware running.
664
665 irqpoll [HW]
666 When an interrupt is not handled search all handlers
667 for it. Also check all handlers each timer
668 interrupt. Intended to get systems with badly broken
669 firmware running.
670
1da177e4 671 isapnp= [ISAPNP]
a9913044 672 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
673
674 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
675 Format: <cpu number>,...,<cpu number>
676 This option can be used to specify one or more CPUs
677 to isolate from the general SMP balancing and scheduling
678 algorithms. The only way to move a process onto or off
679 an "isolated" CPU is via the CPU affinity syscalls.
680 <cpu number> begins at 0 and the maximum value is
681 "number of CPUs in system - 1".
682
683 This option is the preferred way to isolate CPUs. The
a9913044
RD
684 alternative -- manually setting the CPU mask of all
685 tasks in the system -- can cause problems and
686 suboptimal load balancer performance.
1da177e4
LT
687
688 isp16= [HW,CD]
689 Format: <io>,<irq>,<dma>,<setup>
690
a9913044 691 iucv= [HW,NET]
1da177e4
LT
692
693 js= [HW,JOY] Analog joystick
694 See Documentation/input/joystick.txt.
695
696 keepinitrd [HW,ARM]
697
a9913044 698 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
699 in oops dumps.
700
701 l2cr= [PPC]
702
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RD
703 lapic [IA-32,APIC] Enable the local APIC even if BIOS
704 disabled it.
1da177e4
LT
705
706 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
707 Format: addr:<io>,irq:<irq>
708
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RD
709 llsc*= [IA64] See function print_params() in
710 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
711
712 load_ramdisk= [RAM] List of ramdisks to load from floppy
713 See Documentation/ramdisk.txt.
714
715 lockd.udpport= [NFS]
716
717 lockd.tcpport= [NFS]
718
719 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
720 Format: <irq>
721
722 loglevel= All Kernel Messages with a loglevel smaller than the
723 console loglevel will be printed to the console. It can
724 also be changed with klogd or other programs. The
725 loglevels are defined as follows:
726
727 0 (KERN_EMERG) system is unusable
728 1 (KERN_ALERT) action must be taken immediately
729 2 (KERN_CRIT) critical conditions
730 3 (KERN_ERR) error conditions
731 4 (KERN_WARNING) warning conditions
732 5 (KERN_NOTICE) normal but significant condition
733 6 (KERN_INFO) informational
734 7 (KERN_DEBUG) debug-level messages
735
736 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
737 Format: { n | nk | nM }
738 n must be a power of two. The default size
739 is set in the kernel config file.
1da177e4
LT
740
741 lp=0 [LP] Specify parallel ports to use, e.g,
742 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
743 lp=reset first parallel port). 'lp=0' disables the
744 lp=auto printer driver. 'lp=reset' (which can be
745 specified in addition to the ports) causes
746 attached printers to be reset. Using
747 lp=port1,port2,... specifies the parallel ports
748 to associate lp devices with, starting with
749 lp0. A port specification may be 'none' to skip
750 that lp device, or a parport name such as
751 'parport0'. Specifying 'lp=auto' instead of a
752 port specification list means that device IDs
753 from each port should be examined, to see if
754 an IEEE 1284-compliant printer is attached; if
755 so, the driver will manage that printer.
756 See also header of drivers/char/lp.c.
757
758 lpj=n [KNL]
759 Sets loops_per_jiffy to given constant, thus avoiding
760 time-consuming boot-time autodetection (up to 250 ms per
761 CPU). 0 enables autodetection (default). To determine
762 the correct value for your kernel, boot with normal
763 autodetection and see what value is printed. Note that
764 on SMP systems the preset will be applied to all CPUs,
765 which is likely to cause problems if your CPUs need
766 significantly divergent settings. An incorrect value
767 will cause delays in the kernel to be wrong, leading to
768 unpredictable I/O errors and other breakage. Although
769 unlikely, in the extreme case this might damage your
770 hardware.
771
772 ltpc= [NET]
773 Format: <io>,<irq>,<dma>
774
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RD
775 mac5380= [HW,SCSI] Format:
776 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 777
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RD
778 mac53c9x= [HW,SCSI] Format:
779 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 780
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RD
781 machvec= [IA64] Force the use of a particular machine-vector
782 (machvec) in a generic kernel.
783 Example: machvec=hpzx1_swiotlb
1da177e4 784
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RD
785 mad16= [HW,OSS] Format:
786 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
787
788 maui= [HW,OSS]
789 Format: <io>,<irq>
a9913044
RD
790
791 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
792 be mounted
793 Format: <1-256>
794
795 maxcpus= [SMP] Maximum number of processors that an SMP kernel
796 should make use of
797
2b2c3750
BP
798 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
799 equal to this physical address is ignored.
800
a9913044 801 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
802 Should be between 1 and 2^32-1.
803
804 max_report_luns=
a9913044 805 [SCSI] Maximum number of LUNs received.
1da177e4
LT
806 Should be between 1 and 16384.
807
808 mca-pentium [BUGS=IA-32]
809
810 mcatest= [IA-64]
811
812 mcd= [HW,CD]
813 Format: <port>,<irq>,<mitsumi_bug_93_wait>
814
815 mcdx= [HW,CD]
816
817 mce [IA-32] Machine Check Exception
818
819 md= [HW] RAID subsystems devices and level
820 See Documentation/md.txt.
a9913044 821
1da177e4
LT
822 mdacon= [MDA]
823 Format: <first>,<last>
824 Specifies range of consoles to be captured by the MDA.
a9913044 825
1da177e4
LT
826 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
827 Amount of memory to be used when the kernel is not able
828 to see the whole system memory or for test.
829 [IA-32] Use together with memmap= to avoid physical
830 address space collisions. Without memmap= PCI devices
831 could be placed at addresses belonging to unused RAM.
832
833 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
834 memory.
835
69cda7b1 836 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
837 E820 memory map, as specified by the user.
838 Such memmap=exactmap lines can be constructed based on
839 BIOS output or other requirements. See the memmap=nn@ss
840 option description.
841
842 memmap=nn[KMG]@ss[KMG]
843 [KNL] Force usage of a specific region of memory
844 Region of memory to be used, from ss to ss+nn.
845
846 memmap=nn[KMG]#ss[KMG]
847 [KNL,ACPI] Mark specific memory as ACPI data.
848 Region of memory to be used, from ss to ss+nn.
849
850 memmap=nn[KMG]$ss[KMG]
851 [KNL,ACPI] Mark specific memory as reserved.
852 Region of memory to be used, from ss to ss+nn.
853
854 meye.*= [HW] Set MotionEye Camera parameters
855 See Documentation/video4linux/meye.txt.
856
857 mga= [HW,DRM]
858
198e2f18 859 migration_cost=
860 [KNL,SMP] debug: override scheduler migration costs
861 Format: <level-1-usecs>,<level-2-usecs>,...
862 This debugging option can be used to override the
863 default scheduler migration cost matrix. The numbers
864 are indexed by 'CPU domain distance'.
865 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
866 box will set up an intra-core migration cost of
867 1 msec, an inter-core migration cost of 2 msecs,
868 and an inter-node migration cost of 3 msecs.
869
870 WARNING: using the wrong values here can break
871 scheduler performance, so it's only for scheduler
872 development purposes, not production environments.
873
874 migration_debug=
875 [KNL,SMP] migration cost auto-detect verbosity
876 Format=<0|1|2>
877 If a system's migration matrix reported at bootup
878 seems erroneous then this option can be used to
879 increase verbosity of the detection process.
880 We default to 0 (no extra messages), 1 will print
881 some more information, and 2 will be really
882 verbose (probably only useful if you also have a
883 serial console attached to the system).
884
885 migration_factor=
886 [KNL,SMP] multiply/divide migration costs by a factor
887 Format=<percent>
888 This debug option can be used to proportionally
889 increase or decrease the auto-detected migration
890 costs for all entries of the migration matrix.
891 E.g. migration_factor=150 will increase migration
892 costs by 50%. (and thus the scheduler will be less
893 eager migrating cache-hot tasks)
894 migration_factor=80 will decrease migration costs
895 by 20%. (thus the scheduler will be more eager to
896 migrate tasks)
897
898 WARNING: using the wrong values here can break
899 scheduler performance, so it's only for scheduler
900 development purposes, not production environments.
901
1da177e4
LT
902 mousedev.tap_time=
903 [MOUSE] Maximum time between finger touching and
904 leaving touchpad surface for touch to be considered
905 a tap and be reported as a left button click (for
906 touchpads working in absolute mode only).
907 Format: <msecs>
908 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
909 reporting absolute coordinates, such as tablets
910 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
911 reporting absolute coordinates, such as tablets
912
913 mpu401= [HW,OSS]
914 Format: <io>,<irq>
915
916 MTD_Partition= [MTD]
917 Format: <name>,<region-number>,<size>,<offset>
918
a9913044
RD
919 MTD_Region= [MTD] Format:
920 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
921
922 mtdparts= [MTD]
923 See drivers/mtd/cmdline.c.
924
925 mtouchusb.raw_coordinates=
a9913044
RD
926 [HW] Make the MicroTouch USB driver use raw coordinates
927 ('y', default) or cooked coordinates ('n')
1da177e4
LT
928
929 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
930
931 NCR_D700= [HW,SCSI]
932 See header of drivers/scsi/NCR_D700.c.
933
934 ncr5380= [HW,SCSI]
935
936 ncr53c400= [HW,SCSI]
937
938 ncr53c400a= [HW,SCSI]
939
940 ncr53c406a= [HW,SCSI]
941
942 ncr53c8xx= [HW,SCSI]
943
944 netdev= [NET] Network devices parameters
945 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
946 Note that mem_start is often overloaded to mean
947 something different and driver-specific.
a9913044
RD
948 This usage is only documented in each driver source
949 file if at all.
950
1da177e4
LT
951 nfsaddrs= [NFS]
952 See Documentation/nfsroot.txt.
953
954 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
955 See Documentation/nfsroot.txt.
956
a72b4422
TM
957 nfs.callback_tcpport=
958 [NFS] set the TCP port on which the NFSv4 callback
959 channel should listen.
960
58df095b
TM
961 nfs.idmap_cache_timeout=
962 [NFS] set the maximum lifetime for idmapper cache
963 entries.
964
1da177e4
LT
965 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
966
967 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
968 emulation library even if a 387 maths coprocessor
969 is present.
970
a9913044
RD
971 noalign [KNL,ARM]
972
1da177e4
LT
973 noapic [SMP,APIC] Tells the kernel to not make use of any
974 IOAPICs that may be present in the system.
975
976 noasync [HW,M68K] Disables async and sync negotiation for
977 all devices.
978
979 nobats [PPC] Do not use BATs for mapping kernel lowmem
980 on "Classic" PPC cores.
981
982 nocache [ARM]
a9913044 983
1da177e4
LT
984 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
985
986 noexec [IA-64]
987
a9913044 988 noexec [IA-32,X86-64]
1da177e4
LT
989 noexec=on: enable non-executable mappings (default)
990 noexec=off: disable nn-executable mappings
991
992 nofxsr [BUGS=IA-32]
993
994 nohlt [BUGS=ARM]
a9913044 995
1da177e4
LT
996 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
997 instruction doesn't work correctly and not to
998 use it.
999
1000 nohalt [IA-64] Tells the kernel not to use the power saving
1001 function PAL_HALT_LIGHT when idle. This increases
1002 power-consumption. On the positive side, it reduces
1003 interrupt wake-up latency, which may improve performance
1004 in certain environments such as networked servers or
1005 real-time systems.
1006
1007 noirqdebug [IA-32] Disables the code which attempts to detect and
1008 disable unhandled interrupt sources.
1009
1010 noisapnp [ISAPNP] Disables ISA PnP code.
1011
1012 noinitrd [RAM] Tells the kernel not to load any configured
1013 initial RAM disk.
1014
1015 nointroute [IA-64]
1016
1017 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1018
1019 noltlbs [PPC] Do not use large page/tlb entries for kernel
1020 lowmem mapping on PPC40x.
1021
1022 nomce [IA-32] Machine Check Exception
1023
1024 noresidual [PPC] Don't use residual data on PReP machines.
1025
a9913044
RD
1026 noresume [SWSUSP] Disables resume and restores original swap
1027 space.
1028
1da177e4
LT
1029 no-scroll [VGA] Disables scrollback.
1030 This is required for the Braillex ib80-piezo Braille
1031 reader made by F.H. Papenmeier (Germany).
1032
1033 nosbagart [IA-64]
1034
1035 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1036
1037 nosync [HW,M68K] Disables sync negotiation for all devices.
1038
1039 notsc [BUGS=IA-32] Disable Time Stamp Counter
1040
1041 nousb [USB] Disable the USB subsystem
1042
1043 nowb [ARM]
a9913044 1044
a61c2d78
DJ
1045 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1046
1da177e4
LT
1047 opl3= [HW,OSS]
1048 Format: <io>
1049
1050 opl3sa= [HW,OSS]
1051 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1052
a9913044
RD
1053 opl3sa2= [HW,OSS] Format:
1054 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1055
1da177e4
LT
1056 oprofile.timer= [HW]
1057 Use timer interrupt instead of performance counters
1058
1059 optcd= [HW,CD]
1060 Format: <io>
1061
1062 osst= [HW,SCSI] SCSI Tape Driver
1063 Format: <buffer_size>,<write_threshold>
1064 See also Documentation/scsi/st.txt.
1065
1066 panic= [KNL] Kernel behaviour on panic
1067 Format: <timeout>
1068
1069 parkbd.port= [HW] Parallel port number the keyboard adapter is
1070 connected to, default is 0.
1071 Format: <parport#>
1072 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1073 0 for XT, 1 for AT (default is AT).
a9913044
RD
1074 Format: <mode>
1075
1076 parport= [HW,PPT] Specify parallel ports. 0 disables.
1077 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1078 Use 'auto' to force the driver to use any
1079 IRQ/DMA settings detected (the default is to
1080 ignore detected IRQ/DMA settings because of
1081 possible conflicts). You can specify the base
1082 address, IRQ, and DMA settings; IRQ and DMA
1083 should be numbers, or 'auto' (for using detected
1084 settings on that particular port), or 'nofifo'
1085 (to avoid using a FIFO even if it is detected).
1086 Parallel ports are assigned in the order they
1087 are specified on the command line, starting
1088 with parport0.
1089
1090 parport_init_mode= [HW,PPT]
1091 Configure VIA parallel port to operate in
1092 a specific mode. This is necessary on Pegasos
1093 computer where firmware has no options for setting
1094 up parallel port mode and sets it to spp.
1095 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1096 Format: [spp|ps2|epp|ecp|ecpepp]
1097
a9913044
RD
1098 pas2= [HW,OSS] Format:
1099 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1100
1da177e4
LT
1101 pas16= [HW,SCSI]
1102 See header of drivers/scsi/pas16.c.
1103
1104 pcbit= [HW,ISDN]
1105
1106 pcd. [PARIDE]
1107 See header of drivers/block/paride/pcd.c.
1108 See also Documentation/paride.txt.
1109
a9913044
RD
1110 pci=option[,option...] [PCI] various PCI subsystem options:
1111 off [IA-32] don't probe for the PCI bus
1112 bios [IA-32] force use of PCI BIOS, don't access
1113 the hardware directly. Use this if your machine
1114 has a non-standard PCI host bridge.
1115 nobios [IA-32] disallow use of PCI BIOS, only direct
1116 hardware access methods are allowed. Use this
1117 if you experience crashes upon bootup and you
1118 suspect they are caused by the BIOS.
1119 conf1 [IA-32] Force use of PCI Configuration
1120 Mechanism 1.
1121 conf2 [IA-32] Force use of PCI Configuration
1122 Mechanism 2.
1123 nosort [IA-32] Don't sort PCI devices according to
1124 order given by the PCI BIOS. This sorting is
1125 done to get a device order compatible with
1126 older kernels.
1127 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1128 routing table. These calls are known to be buggy
1129 on several machines and they hang the machine
1130 when used, but on other computers it's the only
1131 way to get the interrupt routing table. Try
1132 this option if the kernel is unable to allocate
1133 IRQs or discover secondary PCI buses on your
1134 motherboard.
1135 rom [IA-32] Assign address space to expansion ROMs.
1136 Use with caution as certain devices share
1137 address decoders between ROMs and other
1138 resources.
1139 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1140 assigned automatically to PCI devices. You can
1141 make the kernel exclude IRQs of your ISA cards
1142 this way.
120bb424 1143 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1144 of the PIRQ table (normally generated
1145 by the BIOS) if it is outside the
1146 F0000h-100000h range.
1147 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1148 useful if the kernel is unable to find your
1149 secondary buses and you want to tell it
1150 explicitly which ones they are.
1151 assign-busses [IA-32] Always assign all PCI bus
1152 numbers ourselves, overriding
1153 whatever the firmware may have done.
1154 usepirqmask [IA-32] Honor the possible IRQ mask stored
1155 in the BIOS $PIR table. This is needed on
1156 some systems with broken BIOSes, notably
1157 some HP Pavilion N5400 and Omnibook XE3
1158 notebooks. This will have no effect if ACPI
1159 IRQ routing is enabled.
1160 noacpi [IA-32] Do not use ACPI for IRQ routing
1161 or for PCI scanning.
1162 routeirq Do IRQ routing for all PCI devices.
1163 This is normally done in pci_enable_device(),
1164 so this option is a temporary workaround
1165 for broken drivers that don't call it.
1166 firmware [ARM] Do not re-enumerate the bus but instead
1167 just use the configuration from the
1168 bootloader. This is currently used on
1169 IXP2000 systems where the bus has to be
1170 configured a certain way for adjunct CPUs.
1da177e4
LT
1171
1172 pcmv= [HW,PCMCIA] BadgePAD 4
1173
1174 pd. [PARIDE]
1175 See Documentation/paride.txt.
1176
1177 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1178 boot time.
1179 Format: { 0 | 1 }
1180 See arch/parisc/kernel/pdc_chassis.c
1181
1182 pf. [PARIDE]
1183 See Documentation/paride.txt.
1184
1185 pg. [PARIDE]
1186 See Documentation/paride.txt.
1187
1188 pirq= [SMP,APIC] Manual mp-table setup
1189 See Documentation/i386/IO-APIC.txt.
1190
1191 plip= [PPT,NET] Parallel port network link
1192 Format: { parport<nr> | timid | 0 }
1193 See also Documentation/parport.txt.
1194
1195 pnpacpi= [ACPI]
1196 { off }
1197
1198 pnpbios= [ISAPNP]
1199 { on | off | curr | res | no-curr | no-res }
1200
1201 pnp_reserve_irq=
1202 [ISAPNP] Exclude IRQs for the autoconfiguration
1203
1204 pnp_reserve_dma=
1205 [ISAPNP] Exclude DMAs for the autoconfiguration
1206
1207 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1208 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1209
1210 pnp_reserve_mem=
a9913044
RD
1211 [ISAPNP] Exclude memory regions for the
1212 autoconfiguration.
1da177e4
LT
1213 Ranges are in pairs (memory base and size).
1214
1215 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1216 Format: [schedule,]<number>
1217 Param: "schedule" - profile schedule points.
1218 Param: <number> - step/bucket size as a power of 2 for
1219 statistical time based profiling.
1da177e4 1220
a9913044 1221 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1222 Limit processor to maximum C-state
1223 max_cstate=9 overrides any DMI blacklist limit.
1224
41c0d868
LB
1225 processor.nocst [HW,ACPI]
1226 Ignore the _CST method to determine C-states,
1227 instead using the legacy FADT method
1228
1da177e4
LT
1229 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1230 before loading.
1231 See Documentation/ramdisk.txt.
1232
a9913044
RD
1233 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1234 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1235 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1236 per second.
a9913044
RD
1237 psmouse.resetafter= [HW,MOUSE]
1238 Try to reset the device after so many bad packets
1da177e4
LT
1239 (0 = never).
1240 psmouse.resolution=
1241 [HW,MOUSE] Set desired mouse resolution, in dpi.
1242 psmouse.smartscroll=
a9913044 1243 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1244 0 = disabled, 1 = enabled (default).
1245
1246 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1247 Format:
1248 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1249
1250 pt. [PARIDE]
1251 See Documentation/paride.txt.
1252
1253 quiet= [KNL] Disable log messages
a9913044 1254
1da177e4
LT
1255 r128= [HW,DRM]
1256
1257 raid= [HW,RAID]
1258 See Documentation/md.txt.
1259
1260 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1261 See Documentation/ramdisk.txt.
1262
a9913044 1263 ramdisk_blocksize= [RAM]
1da177e4 1264 See Documentation/ramdisk.txt.
a9913044 1265
1da177e4
LT
1266 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1267 New name for the ramdisk parameter.
1268 See Documentation/ramdisk.txt.
1269
ffdfc409
OJ
1270 rdinit= [KNL]
1271 Format: <full_path>
1272 Run specified binary instead of /init from the ramdisk,
1273 used for early userspace startup. See initrd.
1274
1da177e4
LT
1275 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1276 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1277 See arch/*/kernel/reboot.c.
1278
1279 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1280
a9913044
RD
1281 resume= [SWSUSP]
1282 Specify the partition device for software suspend
1da177e4
LT
1283
1284 rhash_entries= [KNL,NET]
1285 Set number of hash buckets for route cache
1286
1287 riscom8= [HW,SERIAL]
1288 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1289
1290 ro [KNL] Mount root device read-only on boot
1291
1292 root= [KNL] Root filesystem
1293
1294 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1295 mount the root filesystem
1296
1297 rootflags= [KNL] Set root filesystem mount option string
1298
1299 rootfstype= [KNL] Set root filesystem type
1300
1301 rw [KNL] Mount root device read-write on boot
1302
1303 S [KNL] Run init in single mode
1304
1305 sa1100ir [NET]
1306 See drivers/net/irda/sa1100_ir.c.
1307
1308 sb= [HW,OSS]
1309 Format: <io>,<irq>,<dma>,<dma2>
1310
1311 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1312
1da177e4
LT
1313 sbpcd= [HW,CD] Soundblaster CD adapter
1314 Format: <io>,<type>
1315 See a comment before function sbpcd_setup() in
1316 drivers/cdrom/sbpcd.c.
1317
1318 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1319 Format: <io>[,<timeout>[,<isapnp>]]
1320
1321 scsi_debug_*= [SCSI]
1322 See drivers/scsi/scsi_debug.c.
1323
1324 scsi_default_dev_flags=
1325 [SCSI] SCSI default device flags
1326 Format: <integer>
1327
1328 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1329 Format: <vendor>:<model>:<flags>
1330 (flags are integer value)
1331
1332 scsi_logging= [SCSI]
1333
1334 selinux [SELINUX] Disable or enable SELinux at boot time.
1335 Format: { "0" | "1" }
1336 See security/selinux/Kconfig help text.
1337 0 -- disable.
1338 1 -- enable.
1339 Default value is set via kernel config option.
1340 If enabled at boot time, /selinux/disable can be used
1341 later to disable prior to initial policy load.
1342
1343 serialnumber [BUGS=IA-32]
1344
a9913044
RD
1345 sg_def_reserved_size= [SCSI]
1346
1da177e4
LT
1347 sgalaxy= [HW,OSS]
1348 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1349
1350 shapers= [NET]
1351 Maximal number of shapers.
a9913044 1352
1da177e4
LT
1353 sim710= [SCSI,HW]
1354 See header of drivers/scsi/sim710.c.
1355
1356 simeth= [IA-64]
1357 simscsi=
a9913044 1358
1da177e4
LT
1359 sjcd= [HW,CD]
1360 Format: <io>,<irq>,<dma>
1361 See header of drivers/cdrom/sjcd.c.
1362
1363 slram= [HW,MTD]
1364
1365 smart2= [HW]
1366 Format: <io1>[,<io2>[,...,<io8>]]
1367
1368 snd-ad1816a= [HW,ALSA]
1369
1370 snd-ad1848= [HW,ALSA]
1371
1372 snd-ali5451= [HW,ALSA]
1373
1374 snd-als100= [HW,ALSA]
1375
1376 snd-als4000= [HW,ALSA]
1377
1378 snd-azt2320= [HW,ALSA]
1379
1380 snd-cmi8330= [HW,ALSA]
1381
1382 snd-cmipci= [HW,ALSA]
1383
1384 snd-cs4231= [HW,ALSA]
1385
1386 snd-cs4232= [HW,ALSA]
1387
1388 snd-cs4236= [HW,ALSA]
1389
1390 snd-cs4281= [HW,ALSA]
1391
1392 snd-cs46xx= [HW,ALSA]
1393
1394 snd-dt019x= [HW,ALSA]
1395
1396 snd-dummy= [HW,ALSA]
1397
1398 snd-emu10k1= [HW,ALSA]
1399
1400 snd-ens1370= [HW,ALSA]
1401
1402 snd-ens1371= [HW,ALSA]
1403
1404 snd-es968= [HW,ALSA]
1405
1406 snd-es1688= [HW,ALSA]
1407
1408 snd-es18xx= [HW,ALSA]
1409
1410 snd-es1938= [HW,ALSA]
1411
1412 snd-es1968= [HW,ALSA]
1413
1414 snd-fm801= [HW,ALSA]
1415
1416 snd-gusclassic= [HW,ALSA]
1417
1418 snd-gusextreme= [HW,ALSA]
1419
1420 snd-gusmax= [HW,ALSA]
1421
1422 snd-hdsp= [HW,ALSA]
1423
1424 snd-ice1712= [HW,ALSA]
1425
1426 snd-intel8x0= [HW,ALSA]
1427
1428 snd-interwave= [HW,ALSA]
1429
1430 snd-interwave-stb=
1431 [HW,ALSA]
1432
1433 snd-korg1212= [HW,ALSA]
1434
1435 snd-maestro3= [HW,ALSA]
1436
1437 snd-mpu401= [HW,ALSA]
1438
1439 snd-mtpav= [HW,ALSA]
1440
1441 snd-nm256= [HW,ALSA]
1442
1443 snd-opl3sa2= [HW,ALSA]
1444
1445 snd-opti92x-ad1848=
1446 [HW,ALSA]
1447
1448 snd-opti92x-cs4231=
1449 [HW,ALSA]
1450
1451 snd-opti93x= [HW,ALSA]
1452
1453 snd-pmac= [HW,ALSA]
1454
1455 snd-rme32= [HW,ALSA]
1456
1457 snd-rme96= [HW,ALSA]
1458
1459 snd-rme9652= [HW,ALSA]
1460
1461 snd-sb8= [HW,ALSA]
1462
1463 snd-sb16= [HW,ALSA]
1464
1465 snd-sbawe= [HW,ALSA]
1466
1467 snd-serial= [HW,ALSA]
1468
1469 snd-sgalaxy= [HW,ALSA]
1470
1471 snd-sonicvibes= [HW,ALSA]
1472
1473 snd-sun-amd7930=
1474 [HW,ALSA]
1475
1476 snd-sun-cs4231= [HW,ALSA]
1477
1478 snd-trident= [HW,ALSA]
1479
1480 snd-usb-audio= [HW,ALSA,USB]
1481
1482 snd-via82xx= [HW,ALSA]
1483
1484 snd-virmidi= [HW,ALSA]
1485
1486 snd-wavefront= [HW,ALSA]
1487
1488 snd-ymfpci= [HW,ALSA]
a9913044 1489
1da177e4
LT
1490 sonicvibes= [HW,OSS]
1491 Format: <reverb>
a9913044 1492
1da177e4
LT
1493 sonycd535= [HW,CD]
1494 Format: <io>[,<irq>]
1495
1496 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1497 See Documentation/sonypi.txt
1498
1499 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1500 See Documentation/specialix.txt.
1501
1502 spia_io_base= [HW,MTD]
1503 spia_fio_base=
1504 spia_pedr=
1505 spia_peddr=
1506
1507 sscape= [HW,OSS]
1508 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1509
1da177e4
LT
1510 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1511 See Documentation/scsi/st.txt.
1512
1513 st0x= [HW,SCSI]
1514 See header of drivers/scsi/seagate.c.
1515
1516 sti= [PARISC,HW]
1517 Format: <num>
1518 Set the STI (builtin display/keyboard on the HP-PARISC
1519 machines) console (graphic card) which should be used
1520 as the initial boot-console.
1521 See also comment in drivers/video/console/sticore.c.
1522
1523 sti_font= [HW]
1524 See comment in drivers/video/console/sticore.c.
1525
1526 stifb= [HW]
1527 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1528
1da177e4 1529 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1530
1da177e4
LT
1531 switches= [HW,M68k]
1532
1533 sym53c416= [HW,SCSI]
1534 See header of drivers/scsi/sym53c416.c.
1535
1536 t128= [HW,SCSI]
1537 See header of drivers/scsi/t128.c.
1538
1539 tdfx= [HW,DRM]
1540
1541 thash_entries= [KNL,NET]
1542 Set number of hash buckets for TCP connection
1543
1544 time Show timing data prefixed to each printk message line
1545
1546 tipar.timeout= [HW,PPT]
1547 Set communications timeout in tenths of a second
1548 (default 15).
1549
1550 tipar.delay= [HW,PPT]
1551 Set inter-bit delay in microseconds (default 10).
1552
1553 tmc8xx= [HW,SCSI]
1554 See header of drivers/scsi/seagate.c.
1555
1556 tmscsim= [HW,SCSI]
1557 See comment before function dc390_setup() in
1558 drivers/scsi/tmscsim.c.
1559
1560 tp720= [HW,PS2]
1561
1562 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1563 Format:
1564 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1565
1da177e4
LT
1566 tsdev.xres= [TS] Horizontal screen resolution.
1567 tsdev.yres= [TS] Vertical screen resolution.
1568
a9913044
RD
1569 turbografx.map[2|3]= [HW,JOY]
1570 TurboGraFX parallel port interface
1571 Format:
1572 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1573 See also Documentation/input/joystick-parport.txt
1574
1575 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1576 See header of drivers/scsi/u14-34f.c.
1577
1578 uart401= [HW,OSS]
1579 Format: <io>,<irq>
1580
1581 uart6850= [HW,OSS]
1582 Format: <io>,<irq>
1583
1da177e4
LT
1584 usbhid.mousepoll=
1585 [USBHID] The interval which mice are to be polled at.
a9913044 1586
1da177e4
LT
1587 video= [FB] Frame buffer configuration
1588 See Documentation/fb/modedb.txt.
1589
1590 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1591 See Documentation/i386/boot.txt and
1592 Documentation/svga.txt.
1da177e4
LT
1593 Use vga=ask for menu.
1594 This is actually a boot loader parameter; the value is
1595 passed to the kernel using a special protocol.
1596
a9913044 1597 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1598 size of <nn>. This can be used to increase the
1599 minimum size (128MB on x86). It can also be used to
1600 decrease the size and leave more room for directly
1601 mapped kernel RAM.
1602
1603 vmhalt= [KNL,S390]
1604
a9913044
RD
1605 vmpoff= [KNL,S390]
1606
1da177e4
LT
1607 waveartist= [HW,OSS]
1608 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1609
1da177e4
LT
1610 wd33c93= [HW,SCSI]
1611 See header of drivers/scsi/wd33c93.c.
1612
1613 wd7000= [HW,SCSI]
1614 See header of drivers/scsi/wd7000.c.
1615
1616 wdt= [WDT] Watchdog
1617 See Documentation/watchdog/watchdog.txt.
1618
1619 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1620 xd_geo= See header of drivers/block/xd.c.
1621
1622 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1623 Format:
1624 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4
LT
1625
1626
a9913044 1627______________________________________________________________________
1da177e4
LT
1628Changelog:
1629
a9913044 16302000-06-?? Mr. Unknown
1da177e4 1631 The last known update (for 2.4.0) - the changelog was not kept before.
1da177e4 1632
a9913044
RD
16332002-11-24 Petr Baudis <pasky@ucw.cz>
1634 Randy Dunlap <randy.dunlap@verizon.net>
1da177e4
LT
1635 Update for 2.5.49, description for most of the options introduced,
1636 references to other documentation (C files, READMEs, ..), added S390,
1637 PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1638 reformatting.
a9913044
RD
1639
16402005-10-19 Randy Dunlap <rdunlap@xenotime.net>
1641 Lots of typos, whitespace, some reformatting.
1da177e4
LT
1642
1643TODO:
1644
1645 Add documentation for ALSA options.
1646 Add more DRM drivers.