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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
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455 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
456 Format: <int>
457 0: polling mode
458 non-0: interrupt mode (default)
459
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460 eda= [HW,PS2]
461
462 edb= [HW,PS2]
463
464 edd= [EDD]
465 Format: {"of[f]" | "sk[ipmbr]"}
466 See comment in arch/i386/boot/edd.S
467
a9913044 468 eicon= [HW,ISDN]
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469 Format: <id>,<membase>,<irq>
470
471 eisa_irq_edge= [PARISC,HW]
472 See header of drivers/parisc/eisa.c.
473
474 elanfreq= [IA-32]
475 See comment before function elanfreq_setup() in
476 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
477
478 elevator= [IOSCHED]
16ab3adf 479 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
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480 See Documentation/block/as-iosched.txt and
481 Documentation/block/deadline-iosched.txt for details.
482
aac04b32 483 elfcorehdr= [IA-32, X86_64]
a9913044 484 Specifies physical address of start of kernel core
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485 image elf header. Generally kexec loader will
486 pass this option to capture kernel.
487 See Documentation/kdump/kdump.txt for details.
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488
489 enforcing [SELINUX] Set initial enforcing status.
490 Format: {"0" | "1"}
491 See security/selinux/Kconfig help text.
492 0 -- permissive (log only, no denials).
493 1 -- enforcing (deny and log).
494 Default value is 0.
495 Value can be changed at runtime via /selinux/enforce.
496
497 es1370= [HW,OSS]
498 Format: <lineout>[,<micbias>]
499 See also header of sound/oss/es1370.c.
500
501 es1371= [HW,OSS]
502 Format: <spdif>,[<nomix>,[<amplifier>]]
503 See also header of sound/oss/es1371.c.
a9913044 504
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505 ether= [HW,NET] Ethernet cards parameters
506 This option is obsoleted by the "netdev=" option, which
507 has equivalent usage. See its documentation for details.
508
509 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
510 Format: <io>[,<irq>]
511
512 fd_mcs= [HW,SCSI]
513 See header of drivers/scsi/fd_mcs.c.
514
515 fdomain= [HW,SCSI]
516 See header of drivers/scsi/fdomain.c.
517
518 floppy= [HW]
519 See Documentation/floppy.txt.
520
521 ftape= [HW] Floppy Tape subsystem debugging options.
522 See Documentation/ftape.txt.
523
524 gamecon.map[2|3]=
525 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
526 support via parallel port (up to 5 devices per port)
527 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
528 See also Documentation/input/joystick-parport.txt
529
530 gamma= [HW,DRM]
531
532 gdth= [HW,SCSI]
533 See header of drivers/scsi/gdth.c.
534
535 gpt [EFI] Forces disk with valid GPT signature but
536 invalid Protective MBR to be treated as GPT.
537
538 gscd= [HW,CD]
539 Format: <io>
540
541 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
542
543 gus= [HW,OSS]
544 Format: <io>,<irq>,<dma>,<dma16>
a9913044 545
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546 gvp11= [HW,SCSI]
547
548 hashdist= [KNL,NUMA] Large hashes allocated during boot
549 are distributed across NUMA nodes. Defaults on
550 for IA-64, off otherwise.
a9913044 551 Format: 0 | 1 (for off | on)
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552
553 hcl= [IA-64] SGI's Hardware Graph compatibility layer
554
555 hd= [EIDE] (E)IDE hard drive subsystem geometry
556 Format: <cyl>,<head>,<sect>
557
558 hd?= [HW] (E)IDE subsystem
559 hd?lun= See Documentation/ide.txt.
560
561 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
562 size of <nn>. This works even on boxes that have no
563 highmem otherwise. This also works to reduce highmem
564 size on bigger boxes.
565
566 hisax= [HW,ISDN]
567 See Documentation/isdn/README.HiSax.
568
569 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
570
571 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
572
573 i8042.direct [HW] Put keyboard port into non-translated mode
574 i8042.dumbkbd [HW] Pretend that controlled can only read data from
575 keyboard and can not control its state
576 (Don't attempt to blink the leds)
577 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 578 i8042.nokbd [HW] Don't check/create keyboard port
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579 i8042.nomux [HW] Don't check presence of an active multiplexing
580 controller
581 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
582 controllers
583 i8042.panicblink=
584 [HW] Frequency with which keyboard LEDs should blink
585 when kernel panics (default is 0.5 sec)
586 i8042.reset [HW] Reset the controller during init and cleanup
587 i8042.unlock [HW] Unlock (ignore) the keylock
588
589 i810= [HW,DRM]
590
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591 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
592 indicates that the driver is running on unsupported
593 hardware.
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594 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
595 does not match list of supported models.
596 i8k.power_status
597 [HW] Report power status in /proc/i8k
598 (disabled by default)
599 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
600 capability is set.
601
602 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
603 See Documentation/mca.txt.
604
605 icn= [HW,ISDN]
606 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
607
608 ide= [HW] (E)IDE subsystem
609 Format: ide=nodma or ide=doubler or ide=reverse
610 See Documentation/ide.txt.
611
612 ide?= [HW] (E)IDE subsystem
613 Format: ide?=noprobe or chipset specific parameters.
614 See Documentation/ide.txt.
a9913044 615
1da177e4
LT
616 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
617 See Documentation/ide.txt.
618
619 idle= [HW]
620 Format: idle=poll or idle=halt
a9913044 621
1da177e4
LT
622 ihash_entries= [KNL]
623 Set number of hash buckets for inode cache.
624
625 in2000= [HW,SCSI]
626 See header of drivers/scsi/in2000.c.
627
628 init= [KNL]
629 Format: <full_path>
630 Run specified binary instead of /sbin/init as init
631 process.
632
633 initcall_debug [KNL] Trace initcalls as they are executed. Useful
634 for working out where the kernel is dying during
635 startup.
636
637 initrd= [BOOT] Specify the location of the initial ramdisk
638
639 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
640 Format: <irq>
641
2bd0fa3b
JB
642 combined_mode= [HW] control which driver uses IDE ports in combined
643 mode: legacy IDE driver, libata, or both
644 (in the libata case, libata.atapi_enabled=1 may be
645 useful as well). Note that using the ide or libata
646 options may affect your device naming (e.g. by
647 changing hdc to sdb).
648 Format: combined (default), ide, or libata
649
1da177e4
LT
650 inttest= [IA64]
651
652 io7= [HW] IO7 for Marvel based alpha systems
653 See comment before marvel_specify_io7 in
654 arch/alpha/kernel/core_marvel.c.
655
656 ip= [IP_PNP]
657 See Documentation/nfsroot.txt.
658
659 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
660 See comment before ip2_setup() in drivers/char/ip2.c.
661
662 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
663 See header of drivers/scsi/ips.c.
664
200803df
AC
665 irqfixup [HW]
666 When an interrupt is not handled search all handlers
667 for it. Intended to get systems with badly broken
668 firmware running.
669
670 irqpoll [HW]
671 When an interrupt is not handled search all handlers
672 for it. Also check all handlers each timer
673 interrupt. Intended to get systems with badly broken
674 firmware running.
675
1da177e4 676 isapnp= [ISAPNP]
a9913044 677 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
678
679 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
680 Format: <cpu number>,...,<cpu number>
681 This option can be used to specify one or more CPUs
682 to isolate from the general SMP balancing and scheduling
683 algorithms. The only way to move a process onto or off
684 an "isolated" CPU is via the CPU affinity syscalls.
685 <cpu number> begins at 0 and the maximum value is
686 "number of CPUs in system - 1".
687
688 This option is the preferred way to isolate CPUs. The
a9913044
RD
689 alternative -- manually setting the CPU mask of all
690 tasks in the system -- can cause problems and
691 suboptimal load balancer performance.
1da177e4
LT
692
693 isp16= [HW,CD]
694 Format: <io>,<irq>,<dma>,<setup>
695
a9913044 696 iucv= [HW,NET]
1da177e4
LT
697
698 js= [HW,JOY] Analog joystick
699 See Documentation/input/joystick.txt.
700
701 keepinitrd [HW,ARM]
702
a9913044 703 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
704 in oops dumps.
705
706 l2cr= [PPC]
707
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RD
708 lapic [IA-32,APIC] Enable the local APIC even if BIOS
709 disabled it.
1da177e4
LT
710
711 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
712 Format: addr:<io>,irq:<irq>
713
a9913044
RD
714 llsc*= [IA64] See function print_params() in
715 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
716
717 load_ramdisk= [RAM] List of ramdisks to load from floppy
718 See Documentation/ramdisk.txt.
719
a6b25b67
RD
720 lockd.nlm_grace_period=P [NFS] Assign grace period.
721 Format: <integer>
1da177e4 722
a6b25b67
RD
723 lockd.nlm_tcpport=N [NFS] Assign TCP port.
724 Format: <integer>
725
726 lockd.nlm_timeout=T [NFS] Assign timeout value.
727 Format: <integer>
728
729 lockd.nlm_udpport=M [NFS] Assign UDP port.
730 Format: <integer>
1da177e4
LT
731
732 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
733 Format: <irq>
734
735 loglevel= All Kernel Messages with a loglevel smaller than the
736 console loglevel will be printed to the console. It can
737 also be changed with klogd or other programs. The
738 loglevels are defined as follows:
739
740 0 (KERN_EMERG) system is unusable
741 1 (KERN_ALERT) action must be taken immediately
742 2 (KERN_CRIT) critical conditions
743 3 (KERN_ERR) error conditions
744 4 (KERN_WARNING) warning conditions
745 5 (KERN_NOTICE) normal but significant condition
746 6 (KERN_INFO) informational
747 7 (KERN_DEBUG) debug-level messages
748
749 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
750 Format: { n | nk | nM }
751 n must be a power of two. The default size
752 is set in the kernel config file.
1da177e4
LT
753
754 lp=0 [LP] Specify parallel ports to use, e.g,
755 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
756 lp=reset first parallel port). 'lp=0' disables the
757 lp=auto printer driver. 'lp=reset' (which can be
758 specified in addition to the ports) causes
759 attached printers to be reset. Using
760 lp=port1,port2,... specifies the parallel ports
761 to associate lp devices with, starting with
762 lp0. A port specification may be 'none' to skip
763 that lp device, or a parport name such as
764 'parport0'. Specifying 'lp=auto' instead of a
765 port specification list means that device IDs
766 from each port should be examined, to see if
767 an IEEE 1284-compliant printer is attached; if
768 so, the driver will manage that printer.
769 See also header of drivers/char/lp.c.
770
771 lpj=n [KNL]
772 Sets loops_per_jiffy to given constant, thus avoiding
773 time-consuming boot-time autodetection (up to 250 ms per
774 CPU). 0 enables autodetection (default). To determine
775 the correct value for your kernel, boot with normal
776 autodetection and see what value is printed. Note that
777 on SMP systems the preset will be applied to all CPUs,
778 which is likely to cause problems if your CPUs need
779 significantly divergent settings. An incorrect value
780 will cause delays in the kernel to be wrong, leading to
781 unpredictable I/O errors and other breakage. Although
782 unlikely, in the extreme case this might damage your
783 hardware.
784
785 ltpc= [NET]
786 Format: <io>,<irq>,<dma>
787
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RD
788 mac5380= [HW,SCSI] Format:
789 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 790
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RD
791 mac53c9x= [HW,SCSI] Format:
792 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 793
a9913044
RD
794 machvec= [IA64] Force the use of a particular machine-vector
795 (machvec) in a generic kernel.
796 Example: machvec=hpzx1_swiotlb
1da177e4 797
a9913044
RD
798 mad16= [HW,OSS] Format:
799 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
800
801 maui= [HW,OSS]
802 Format: <io>,<irq>
a9913044
RD
803
804 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
805 be mounted
806 Format: <1-256>
807
808 maxcpus= [SMP] Maximum number of processors that an SMP kernel
809 should make use of
810
2b2c3750
BP
811 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
812 equal to this physical address is ignored.
813
a9913044 814 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
815 Should be between 1 and 2^32-1.
816
817 max_report_luns=
a9913044 818 [SCSI] Maximum number of LUNs received.
1da177e4
LT
819 Should be between 1 and 16384.
820
821 mca-pentium [BUGS=IA-32]
822
823 mcatest= [IA-64]
824
825 mcd= [HW,CD]
826 Format: <port>,<irq>,<mitsumi_bug_93_wait>
827
828 mcdx= [HW,CD]
829
830 mce [IA-32] Machine Check Exception
831
832 md= [HW] RAID subsystems devices and level
833 See Documentation/md.txt.
a9913044 834
1da177e4
LT
835 mdacon= [MDA]
836 Format: <first>,<last>
837 Specifies range of consoles to be captured by the MDA.
a9913044 838
1da177e4
LT
839 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
840 Amount of memory to be used when the kernel is not able
841 to see the whole system memory or for test.
842 [IA-32] Use together with memmap= to avoid physical
843 address space collisions. Without memmap= PCI devices
844 could be placed at addresses belonging to unused RAM.
845
846 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
847 memory.
848
69cda7b1 849 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
850 E820 memory map, as specified by the user.
851 Such memmap=exactmap lines can be constructed based on
852 BIOS output or other requirements. See the memmap=nn@ss
853 option description.
854
855 memmap=nn[KMG]@ss[KMG]
856 [KNL] Force usage of a specific region of memory
857 Region of memory to be used, from ss to ss+nn.
858
859 memmap=nn[KMG]#ss[KMG]
860 [KNL,ACPI] Mark specific memory as ACPI data.
861 Region of memory to be used, from ss to ss+nn.
862
863 memmap=nn[KMG]$ss[KMG]
864 [KNL,ACPI] Mark specific memory as reserved.
865 Region of memory to be used, from ss to ss+nn.
866
867 meye.*= [HW] Set MotionEye Camera parameters
868 See Documentation/video4linux/meye.txt.
869
870 mga= [HW,DRM]
871
198e2f18 872 migration_cost=
873 [KNL,SMP] debug: override scheduler migration costs
874 Format: <level-1-usecs>,<level-2-usecs>,...
875 This debugging option can be used to override the
876 default scheduler migration cost matrix. The numbers
877 are indexed by 'CPU domain distance'.
878 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
879 box will set up an intra-core migration cost of
880 1 msec, an inter-core migration cost of 2 msecs,
881 and an inter-node migration cost of 3 msecs.
882
883 WARNING: using the wrong values here can break
884 scheduler performance, so it's only for scheduler
885 development purposes, not production environments.
886
887 migration_debug=
888 [KNL,SMP] migration cost auto-detect verbosity
889 Format=<0|1|2>
890 If a system's migration matrix reported at bootup
891 seems erroneous then this option can be used to
892 increase verbosity of the detection process.
893 We default to 0 (no extra messages), 1 will print
894 some more information, and 2 will be really
895 verbose (probably only useful if you also have a
896 serial console attached to the system).
897
898 migration_factor=
899 [KNL,SMP] multiply/divide migration costs by a factor
900 Format=<percent>
901 This debug option can be used to proportionally
902 increase or decrease the auto-detected migration
903 costs for all entries of the migration matrix.
904 E.g. migration_factor=150 will increase migration
905 costs by 50%. (and thus the scheduler will be less
906 eager migrating cache-hot tasks)
907 migration_factor=80 will decrease migration costs
908 by 20%. (thus the scheduler will be more eager to
909 migrate tasks)
910
911 WARNING: using the wrong values here can break
912 scheduler performance, so it's only for scheduler
913 development purposes, not production environments.
914
1da177e4
LT
915 mousedev.tap_time=
916 [MOUSE] Maximum time between finger touching and
917 leaving touchpad surface for touch to be considered
918 a tap and be reported as a left button click (for
919 touchpads working in absolute mode only).
920 Format: <msecs>
921 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
922 reporting absolute coordinates, such as tablets
923 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
924 reporting absolute coordinates, such as tablets
925
926 mpu401= [HW,OSS]
927 Format: <io>,<irq>
928
929 MTD_Partition= [MTD]
930 Format: <name>,<region-number>,<size>,<offset>
931
a9913044
RD
932 MTD_Region= [MTD] Format:
933 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
934
935 mtdparts= [MTD]
936 See drivers/mtd/cmdline.c.
937
938 mtouchusb.raw_coordinates=
a9913044
RD
939 [HW] Make the MicroTouch USB driver use raw coordinates
940 ('y', default) or cooked coordinates ('n')
1da177e4
LT
941
942 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
943
944 NCR_D700= [HW,SCSI]
945 See header of drivers/scsi/NCR_D700.c.
946
947 ncr5380= [HW,SCSI]
948
949 ncr53c400= [HW,SCSI]
950
951 ncr53c400a= [HW,SCSI]
952
953 ncr53c406a= [HW,SCSI]
954
955 ncr53c8xx= [HW,SCSI]
956
957 netdev= [NET] Network devices parameters
958 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
959 Note that mem_start is often overloaded to mean
960 something different and driver-specific.
a9913044
RD
961 This usage is only documented in each driver source
962 file if at all.
963
1da177e4
LT
964 nfsaddrs= [NFS]
965 See Documentation/nfsroot.txt.
966
967 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
968 See Documentation/nfsroot.txt.
969
a72b4422
TM
970 nfs.callback_tcpport=
971 [NFS] set the TCP port on which the NFSv4 callback
972 channel should listen.
973
58df095b
TM
974 nfs.idmap_cache_timeout=
975 [NFS] set the maximum lifetime for idmapper cache
976 entries.
977
1da177e4
LT
978 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
979
980 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
981 emulation library even if a 387 maths coprocessor
982 is present.
983
a9913044
RD
984 noalign [KNL,ARM]
985
1da177e4
LT
986 noapic [SMP,APIC] Tells the kernel to not make use of any
987 IOAPICs that may be present in the system.
988
989 noasync [HW,M68K] Disables async and sync negotiation for
990 all devices.
991
992 nobats [PPC] Do not use BATs for mapping kernel lowmem
993 on "Classic" PPC cores.
994
995 nocache [ARM]
a9913044 996
1da177e4
LT
997 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
998
999 noexec [IA-64]
1000
a9913044 1001 noexec [IA-32,X86-64]
1da177e4
LT
1002 noexec=on: enable non-executable mappings (default)
1003 noexec=off: disable nn-executable mappings
1004
1005 nofxsr [BUGS=IA-32]
1006
1007 nohlt [BUGS=ARM]
a9913044 1008
1da177e4
LT
1009 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1010 instruction doesn't work correctly and not to
1011 use it.
1012
1013 nohalt [IA-64] Tells the kernel not to use the power saving
1014 function PAL_HALT_LIGHT when idle. This increases
1015 power-consumption. On the positive side, it reduces
1016 interrupt wake-up latency, which may improve performance
1017 in certain environments such as networked servers or
1018 real-time systems.
1019
1020 noirqdebug [IA-32] Disables the code which attempts to detect and
1021 disable unhandled interrupt sources.
1022
1023 noisapnp [ISAPNP] Disables ISA PnP code.
1024
1025 noinitrd [RAM] Tells the kernel not to load any configured
1026 initial RAM disk.
1027
1028 nointroute [IA-64]
1029
1030 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1031
1032 noltlbs [PPC] Do not use large page/tlb entries for kernel
1033 lowmem mapping on PPC40x.
1034
1035 nomce [IA-32] Machine Check Exception
1036
1037 noresidual [PPC] Don't use residual data on PReP machines.
1038
a9913044
RD
1039 noresume [SWSUSP] Disables resume and restores original swap
1040 space.
1041
1da177e4
LT
1042 no-scroll [VGA] Disables scrollback.
1043 This is required for the Braillex ib80-piezo Braille
1044 reader made by F.H. Papenmeier (Germany).
1045
1046 nosbagart [IA-64]
1047
1048 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1049
1050 nosync [HW,M68K] Disables sync negotiation for all devices.
1051
1052 notsc [BUGS=IA-32] Disable Time Stamp Counter
1053
1054 nousb [USB] Disable the USB subsystem
1055
1056 nowb [ARM]
a9913044 1057
a61c2d78
DJ
1058 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1059
1da177e4
LT
1060 opl3= [HW,OSS]
1061 Format: <io>
1062
1063 opl3sa= [HW,OSS]
1064 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1065
a9913044
RD
1066 opl3sa2= [HW,OSS] Format:
1067 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1068
1da177e4
LT
1069 oprofile.timer= [HW]
1070 Use timer interrupt instead of performance counters
1071
1072 optcd= [HW,CD]
1073 Format: <io>
1074
1075 osst= [HW,SCSI] SCSI Tape Driver
1076 Format: <buffer_size>,<write_threshold>
1077 See also Documentation/scsi/st.txt.
1078
1079 panic= [KNL] Kernel behaviour on panic
1080 Format: <timeout>
1081
1082 parkbd.port= [HW] Parallel port number the keyboard adapter is
1083 connected to, default is 0.
1084 Format: <parport#>
1085 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1086 0 for XT, 1 for AT (default is AT).
a9913044
RD
1087 Format: <mode>
1088
1089 parport= [HW,PPT] Specify parallel ports. 0 disables.
1090 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1091 Use 'auto' to force the driver to use any
1092 IRQ/DMA settings detected (the default is to
1093 ignore detected IRQ/DMA settings because of
1094 possible conflicts). You can specify the base
1095 address, IRQ, and DMA settings; IRQ and DMA
1096 should be numbers, or 'auto' (for using detected
1097 settings on that particular port), or 'nofifo'
1098 (to avoid using a FIFO even if it is detected).
1099 Parallel ports are assigned in the order they
1100 are specified on the command line, starting
1101 with parport0.
1102
1103 parport_init_mode= [HW,PPT]
1104 Configure VIA parallel port to operate in
1105 a specific mode. This is necessary on Pegasos
1106 computer where firmware has no options for setting
1107 up parallel port mode and sets it to spp.
1108 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1109 Format: [spp|ps2|epp|ecp|ecpepp]
1110
a9913044
RD
1111 pas2= [HW,OSS] Format:
1112 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1113
1da177e4
LT
1114 pas16= [HW,SCSI]
1115 See header of drivers/scsi/pas16.c.
1116
1117 pcbit= [HW,ISDN]
1118
1119 pcd. [PARIDE]
1120 See header of drivers/block/paride/pcd.c.
1121 See also Documentation/paride.txt.
1122
a9913044
RD
1123 pci=option[,option...] [PCI] various PCI subsystem options:
1124 off [IA-32] don't probe for the PCI bus
1125 bios [IA-32] force use of PCI BIOS, don't access
1126 the hardware directly. Use this if your machine
1127 has a non-standard PCI host bridge.
1128 nobios [IA-32] disallow use of PCI BIOS, only direct
1129 hardware access methods are allowed. Use this
1130 if you experience crashes upon bootup and you
1131 suspect they are caused by the BIOS.
1132 conf1 [IA-32] Force use of PCI Configuration
1133 Mechanism 1.
1134 conf2 [IA-32] Force use of PCI Configuration
1135 Mechanism 2.
1136 nosort [IA-32] Don't sort PCI devices according to
1137 order given by the PCI BIOS. This sorting is
1138 done to get a device order compatible with
1139 older kernels.
1140 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1141 routing table. These calls are known to be buggy
1142 on several machines and they hang the machine
1143 when used, but on other computers it's the only
1144 way to get the interrupt routing table. Try
1145 this option if the kernel is unable to allocate
1146 IRQs or discover secondary PCI buses on your
1147 motherboard.
1148 rom [IA-32] Assign address space to expansion ROMs.
1149 Use with caution as certain devices share
1150 address decoders between ROMs and other
1151 resources.
1152 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1153 assigned automatically to PCI devices. You can
1154 make the kernel exclude IRQs of your ISA cards
1155 this way.
120bb424 1156 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1157 of the PIRQ table (normally generated
1158 by the BIOS) if it is outside the
1159 F0000h-100000h range.
1160 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1161 useful if the kernel is unable to find your
1162 secondary buses and you want to tell it
1163 explicitly which ones they are.
1164 assign-busses [IA-32] Always assign all PCI bus
1165 numbers ourselves, overriding
1166 whatever the firmware may have done.
1167 usepirqmask [IA-32] Honor the possible IRQ mask stored
1168 in the BIOS $PIR table. This is needed on
1169 some systems with broken BIOSes, notably
1170 some HP Pavilion N5400 and Omnibook XE3
1171 notebooks. This will have no effect if ACPI
1172 IRQ routing is enabled.
1173 noacpi [IA-32] Do not use ACPI for IRQ routing
1174 or for PCI scanning.
1175 routeirq Do IRQ routing for all PCI devices.
1176 This is normally done in pci_enable_device(),
1177 so this option is a temporary workaround
1178 for broken drivers that don't call it.
1179 firmware [ARM] Do not re-enumerate the bus but instead
1180 just use the configuration from the
1181 bootloader. This is currently used on
1182 IXP2000 systems where the bus has to be
1183 configured a certain way for adjunct CPUs.
1da177e4
LT
1184
1185 pcmv= [HW,PCMCIA] BadgePAD 4
1186
1187 pd. [PARIDE]
1188 See Documentation/paride.txt.
1189
1190 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1191 boot time.
1192 Format: { 0 | 1 }
1193 See arch/parisc/kernel/pdc_chassis.c
1194
1195 pf. [PARIDE]
1196 See Documentation/paride.txt.
1197
1198 pg. [PARIDE]
1199 See Documentation/paride.txt.
1200
1201 pirq= [SMP,APIC] Manual mp-table setup
1202 See Documentation/i386/IO-APIC.txt.
1203
1204 plip= [PPT,NET] Parallel port network link
1205 Format: { parport<nr> | timid | 0 }
1206 See also Documentation/parport.txt.
1207
1208 pnpacpi= [ACPI]
1209 { off }
1210
1211 pnpbios= [ISAPNP]
1212 { on | off | curr | res | no-curr | no-res }
1213
1214 pnp_reserve_irq=
1215 [ISAPNP] Exclude IRQs for the autoconfiguration
1216
1217 pnp_reserve_dma=
1218 [ISAPNP] Exclude DMAs for the autoconfiguration
1219
1220 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1221 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1222
1223 pnp_reserve_mem=
a9913044
RD
1224 [ISAPNP] Exclude memory regions for the
1225 autoconfiguration.
1da177e4
LT
1226 Ranges are in pairs (memory base and size).
1227
1228 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1229 Format: [schedule,]<number>
1230 Param: "schedule" - profile schedule points.
1231 Param: <number> - step/bucket size as a power of 2 for
1232 statistical time based profiling.
1da177e4 1233
a9913044 1234 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1235 Limit processor to maximum C-state
1236 max_cstate=9 overrides any DMI blacklist limit.
1237
41c0d868
LB
1238 processor.nocst [HW,ACPI]
1239 Ignore the _CST method to determine C-states,
1240 instead using the legacy FADT method
1241
1da177e4
LT
1242 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1243 before loading.
1244 See Documentation/ramdisk.txt.
1245
a9913044
RD
1246 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1247 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1248 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1249 per second.
a9913044
RD
1250 psmouse.resetafter= [HW,MOUSE]
1251 Try to reset the device after so many bad packets
1da177e4
LT
1252 (0 = never).
1253 psmouse.resolution=
1254 [HW,MOUSE] Set desired mouse resolution, in dpi.
1255 psmouse.smartscroll=
a9913044 1256 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1257 0 = disabled, 1 = enabled (default).
1258
1259 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1260 Format:
1261 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1262
1263 pt. [PARIDE]
1264 See Documentation/paride.txt.
1265
1266 quiet= [KNL] Disable log messages
a9913044 1267
1da177e4
LT
1268 r128= [HW,DRM]
1269
1270 raid= [HW,RAID]
1271 See Documentation/md.txt.
1272
1273 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1274 See Documentation/ramdisk.txt.
1275
a9913044 1276 ramdisk_blocksize= [RAM]
1da177e4 1277 See Documentation/ramdisk.txt.
a9913044 1278
1da177e4
LT
1279 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1280 New name for the ramdisk parameter.
1281 See Documentation/ramdisk.txt.
1282
ffdfc409
OJ
1283 rdinit= [KNL]
1284 Format: <full_path>
1285 Run specified binary instead of /init from the ramdisk,
1286 used for early userspace startup. See initrd.
1287
1da177e4
LT
1288 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1289 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1290 See arch/*/kernel/reboot.c.
1291
1292 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1293
a9913044
RD
1294 resume= [SWSUSP]
1295 Specify the partition device for software suspend
1da177e4
LT
1296
1297 rhash_entries= [KNL,NET]
1298 Set number of hash buckets for route cache
1299
1300 riscom8= [HW,SERIAL]
1301 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1302
1303 ro [KNL] Mount root device read-only on boot
1304
1305 root= [KNL] Root filesystem
1306
1307 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1308 mount the root filesystem
1309
1310 rootflags= [KNL] Set root filesystem mount option string
1311
1312 rootfstype= [KNL] Set root filesystem type
1313
1314 rw [KNL] Mount root device read-write on boot
1315
1316 S [KNL] Run init in single mode
1317
1318 sa1100ir [NET]
1319 See drivers/net/irda/sa1100_ir.c.
1320
1321 sb= [HW,OSS]
1322 Format: <io>,<irq>,<dma>,<dma2>
1323
1324 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1325
1da177e4
LT
1326 sbpcd= [HW,CD] Soundblaster CD adapter
1327 Format: <io>,<type>
1328 See a comment before function sbpcd_setup() in
1329 drivers/cdrom/sbpcd.c.
1330
1331 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1332 Format: <io>[,<timeout>[,<isapnp>]]
1333
1334 scsi_debug_*= [SCSI]
1335 See drivers/scsi/scsi_debug.c.
1336
1337 scsi_default_dev_flags=
1338 [SCSI] SCSI default device flags
1339 Format: <integer>
1340
1341 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1342 Format: <vendor>:<model>:<flags>
1343 (flags are integer value)
1344
1345 scsi_logging= [SCSI]
1346
1347 selinux [SELINUX] Disable or enable SELinux at boot time.
1348 Format: { "0" | "1" }
1349 See security/selinux/Kconfig help text.
1350 0 -- disable.
1351 1 -- enable.
1352 Default value is set via kernel config option.
1353 If enabled at boot time, /selinux/disable can be used
1354 later to disable prior to initial policy load.
1355
1356 serialnumber [BUGS=IA-32]
1357
a9913044
RD
1358 sg_def_reserved_size= [SCSI]
1359
1da177e4
LT
1360 sgalaxy= [HW,OSS]
1361 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1362
1363 shapers= [NET]
1364 Maximal number of shapers.
a9913044 1365
1da177e4
LT
1366 sim710= [SCSI,HW]
1367 See header of drivers/scsi/sim710.c.
1368
1369 simeth= [IA-64]
1370 simscsi=
a9913044 1371
1da177e4
LT
1372 sjcd= [HW,CD]
1373 Format: <io>,<irq>,<dma>
1374 See header of drivers/cdrom/sjcd.c.
1375
1376 slram= [HW,MTD]
1377
1378 smart2= [HW]
1379 Format: <io1>[,<io2>[,...,<io8>]]
1380
1381 snd-ad1816a= [HW,ALSA]
1382
1383 snd-ad1848= [HW,ALSA]
1384
1385 snd-ali5451= [HW,ALSA]
1386
1387 snd-als100= [HW,ALSA]
1388
1389 snd-als4000= [HW,ALSA]
1390
1391 snd-azt2320= [HW,ALSA]
1392
1393 snd-cmi8330= [HW,ALSA]
1394
1395 snd-cmipci= [HW,ALSA]
1396
1397 snd-cs4231= [HW,ALSA]
1398
1399 snd-cs4232= [HW,ALSA]
1400
1401 snd-cs4236= [HW,ALSA]
1402
1403 snd-cs4281= [HW,ALSA]
1404
1405 snd-cs46xx= [HW,ALSA]
1406
1407 snd-dt019x= [HW,ALSA]
1408
1409 snd-dummy= [HW,ALSA]
1410
1411 snd-emu10k1= [HW,ALSA]
1412
1413 snd-ens1370= [HW,ALSA]
1414
1415 snd-ens1371= [HW,ALSA]
1416
1417 snd-es968= [HW,ALSA]
1418
1419 snd-es1688= [HW,ALSA]
1420
1421 snd-es18xx= [HW,ALSA]
1422
1423 snd-es1938= [HW,ALSA]
1424
1425 snd-es1968= [HW,ALSA]
1426
1427 snd-fm801= [HW,ALSA]
1428
1429 snd-gusclassic= [HW,ALSA]
1430
1431 snd-gusextreme= [HW,ALSA]
1432
1433 snd-gusmax= [HW,ALSA]
1434
1435 snd-hdsp= [HW,ALSA]
1436
1437 snd-ice1712= [HW,ALSA]
1438
1439 snd-intel8x0= [HW,ALSA]
1440
1441 snd-interwave= [HW,ALSA]
1442
1443 snd-interwave-stb=
1444 [HW,ALSA]
1445
1446 snd-korg1212= [HW,ALSA]
1447
1448 snd-maestro3= [HW,ALSA]
1449
1450 snd-mpu401= [HW,ALSA]
1451
1452 snd-mtpav= [HW,ALSA]
1453
1454 snd-nm256= [HW,ALSA]
1455
1456 snd-opl3sa2= [HW,ALSA]
1457
1458 snd-opti92x-ad1848=
1459 [HW,ALSA]
1460
1461 snd-opti92x-cs4231=
1462 [HW,ALSA]
1463
1464 snd-opti93x= [HW,ALSA]
1465
1466 snd-pmac= [HW,ALSA]
1467
1468 snd-rme32= [HW,ALSA]
1469
1470 snd-rme96= [HW,ALSA]
1471
1472 snd-rme9652= [HW,ALSA]
1473
1474 snd-sb8= [HW,ALSA]
1475
1476 snd-sb16= [HW,ALSA]
1477
1478 snd-sbawe= [HW,ALSA]
1479
1480 snd-serial= [HW,ALSA]
1481
1482 snd-sgalaxy= [HW,ALSA]
1483
1484 snd-sonicvibes= [HW,ALSA]
1485
1486 snd-sun-amd7930=
1487 [HW,ALSA]
1488
1489 snd-sun-cs4231= [HW,ALSA]
1490
1491 snd-trident= [HW,ALSA]
1492
1493 snd-usb-audio= [HW,ALSA,USB]
1494
1495 snd-via82xx= [HW,ALSA]
1496
1497 snd-virmidi= [HW,ALSA]
1498
1499 snd-wavefront= [HW,ALSA]
1500
1501 snd-ymfpci= [HW,ALSA]
a9913044 1502
1da177e4
LT
1503 sonicvibes= [HW,OSS]
1504 Format: <reverb>
a9913044 1505
1da177e4
LT
1506 sonycd535= [HW,CD]
1507 Format: <io>[,<irq>]
1508
1509 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1510 See Documentation/sonypi.txt
1511
1512 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1513 See Documentation/specialix.txt.
1514
1515 spia_io_base= [HW,MTD]
1516 spia_fio_base=
1517 spia_pedr=
1518 spia_peddr=
1519
1520 sscape= [HW,OSS]
1521 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1522
1da177e4
LT
1523 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1524 See Documentation/scsi/st.txt.
1525
1526 st0x= [HW,SCSI]
1527 See header of drivers/scsi/seagate.c.
1528
1529 sti= [PARISC,HW]
1530 Format: <num>
1531 Set the STI (builtin display/keyboard on the HP-PARISC
1532 machines) console (graphic card) which should be used
1533 as the initial boot-console.
1534 See also comment in drivers/video/console/sticore.c.
1535
1536 sti_font= [HW]
1537 See comment in drivers/video/console/sticore.c.
1538
1539 stifb= [HW]
1540 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1541
1da177e4 1542 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1543
1da177e4
LT
1544 switches= [HW,M68k]
1545
1546 sym53c416= [HW,SCSI]
1547 See header of drivers/scsi/sym53c416.c.
1548
1549 t128= [HW,SCSI]
1550 See header of drivers/scsi/t128.c.
1551
1552 tdfx= [HW,DRM]
1553
1554 thash_entries= [KNL,NET]
1555 Set number of hash buckets for TCP connection
1556
1557 time Show timing data prefixed to each printk message line
1558
1559 tipar.timeout= [HW,PPT]
1560 Set communications timeout in tenths of a second
1561 (default 15).
1562
1563 tipar.delay= [HW,PPT]
1564 Set inter-bit delay in microseconds (default 10).
1565
1566 tmc8xx= [HW,SCSI]
1567 See header of drivers/scsi/seagate.c.
1568
1569 tmscsim= [HW,SCSI]
1570 See comment before function dc390_setup() in
1571 drivers/scsi/tmscsim.c.
1572
1573 tp720= [HW,PS2]
1574
1575 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1576 Format:
1577 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1578
1da177e4
LT
1579 tsdev.xres= [TS] Horizontal screen resolution.
1580 tsdev.yres= [TS] Vertical screen resolution.
1581
a9913044
RD
1582 turbografx.map[2|3]= [HW,JOY]
1583 TurboGraFX parallel port interface
1584 Format:
1585 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1586 See also Documentation/input/joystick-parport.txt
1587
1588 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1589 See header of drivers/scsi/u14-34f.c.
1590
1591 uart401= [HW,OSS]
1592 Format: <io>,<irq>
1593
1594 uart6850= [HW,OSS]
1595 Format: <io>,<irq>
1596
1da177e4
LT
1597 usbhid.mousepoll=
1598 [USBHID] The interval which mice are to be polled at.
a9913044 1599
1da177e4
LT
1600 video= [FB] Frame buffer configuration
1601 See Documentation/fb/modedb.txt.
1602
1603 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1604 See Documentation/i386/boot.txt and
1605 Documentation/svga.txt.
1da177e4
LT
1606 Use vga=ask for menu.
1607 This is actually a boot loader parameter; the value is
1608 passed to the kernel using a special protocol.
1609
a9913044 1610 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1611 size of <nn>. This can be used to increase the
1612 minimum size (128MB on x86). It can also be used to
1613 decrease the size and leave more room for directly
1614 mapped kernel RAM.
1615
1616 vmhalt= [KNL,S390]
1617
a9913044
RD
1618 vmpoff= [KNL,S390]
1619
1da177e4
LT
1620 waveartist= [HW,OSS]
1621 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1622
1da177e4
LT
1623 wd33c93= [HW,SCSI]
1624 See header of drivers/scsi/wd33c93.c.
1625
1626 wd7000= [HW,SCSI]
1627 See header of drivers/scsi/wd7000.c.
1628
1629 wdt= [WDT] Watchdog
1630 See Documentation/watchdog/watchdog.txt.
1631
1632 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1633 xd_geo= See header of drivers/block/xd.c.
1634
1635 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1636 Format:
1637 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4
LT
1638
1639
a9913044 1640______________________________________________________________________
1da177e4
LT
1641Changelog:
1642
a9913044 16432000-06-?? Mr. Unknown
1da177e4 1644 The last known update (for 2.4.0) - the changelog was not kept before.
1da177e4 1645
a9913044
RD
16462002-11-24 Petr Baudis <pasky@ucw.cz>
1647 Randy Dunlap <randy.dunlap@verizon.net>
1da177e4
LT
1648 Update for 2.5.49, description for most of the options introduced,
1649 references to other documentation (C files, READMEs, ..), added S390,
1650 PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1651 reformatting.
a9913044
RD
1652
16532005-10-19 Randy Dunlap <rdunlap@xenotime.net>
1654 Lots of typos, whitespace, some reformatting.
1da177e4
LT
1655
1656TODO:
1657
1658 Add documentation for ALSA options.
1659 Add more DRM drivers.