1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
3
4 The 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
7 case insensitive manner), and with descriptions where known.
8
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14 Module parameters for modules that are built into the kernel image
15 are 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
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
31
32 ACPI ACPI support is enabled.
33 ALSA ALSA sound support is enabled.
34 APIC APIC support is enabled.
35 APM Advanced Power Management support is enabled.
36 AX25 Appropriate AX.25 support is enabled.
37 CD Appropriate CD support is enabled.
38 DEVFS devfs support is enabled.
39 DRM Direct Rendering Management support is enabled.
40 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
45 IA-32 IA-32 aka i386 architecture is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
78 Documentation/scsi/.
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
83 SWSUSP Software suspend is enabled.
84 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
95
96 In addition, the following text indicates that the option:
97
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
101
102 Parameters denoted with BOOT are actually interpreted by the boot
103 loader, and have no meaning to the kernel directly.
104 Do not modify the syntax of boot loader parameters without extreme
105 need or coordination with <Documentation/i386/boot.txt>.
106
107 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
108 a trailing = on the name of any parameter states that that parameter will
109 be entered as an environment variable, whereas its absence indicates that
110 it will appear as a kernel argument readable via /proc/cmdline by programs
111 running once the system is up.
112
113 53c7xx= [HW,SCSI] Amiga SCSI controllers
114 See header of drivers/scsi/53c7xx.c.
115 See also Documentation/scsi/ncr53c7xx.txt.
116
117 acpi= [HW,ACPI] Advanced Configuration and Power Interface
118 Format: { force | off | ht | strict | noirq }
119 force -- enable ACPI if default was off
120 off -- disable ACPI if default was on
121 noirq -- do not use ACPI for IRQ routing
122 ht -- run only enough ACPI to enable Hyper Threading
123 strict -- Be less tolerant of platforms that are not
124 strictly ACPI specification compliant.
125
126 See also Documentation/pm.txt, pci=noacpi
127
128 acpi_sleep= [HW,ACPI] Sleep options
129 Format: { s3_bios, s3_mode }
130 See Documentation/power/video.txt
131
132 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
133 Format: { level | edge | high | low }
134
135 acpi_irq_balance [HW,ACPI]
136 ACPI will balance active IRQs
137 default in APIC mode
138
139 acpi_irq_nobalance [HW,ACPI]
140 ACPI will not move active IRQs (default)
141 default in PIC mode
142
143 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
144 use by PCI
145 Format: <irq>,<irq>...
146
147 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
148 Format: <irq>,<irq>...
149
150 acpi_osi= [HW,ACPI] empty param disables _OSI
151
152 acpi_serialize [HW,ACPI] force serialization of AML methods
153
154 acpi_skip_timer_override [HW,ACPI]
155 Recognize and ignore IRQ0/pin2 Interrupt Override.
156 For broken nForce2 BIOS resulting in XT-PIC timer.
157
158 acpi_dbg_layer= [HW,ACPI]
159 Format: <int>
160 Each bit of the <int> indicates an ACPI debug layer,
161 1: enable, 0: disable. It is useful for boot time
162 debugging. After system has booted up, it can be set
163 via /proc/acpi/debug_layer.
164
165 acpi_dbg_level= [HW,ACPI]
166 Format: <int>
167 Each bit of the <int> indicates an ACPI debug level,
168 1: enable, 0: disable. It is useful for boot time
169 debugging. After system has booted up, it can be set
170 via /proc/acpi/debug_level.
171
172 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
173
174 acpi_generic_hotkey [HW,ACPI]
175 Allow consolidated generic hotkey driver to
176 override platform specific driver.
177 See also Documentation/acpi-hotkey.txt.
178
179 enable_timer_pin_1 [i386,x86-64]
180 Enable PIN 1 of APIC timer
181 Can be useful to work around chipset bugs
182 (in particular on some ATI chipsets).
183 The kernel tries to set a reasonable default.
184
185 disable_timer_pin_1 [i386,x86-64]
186 Disable PIN 1 of APIC timer
187 Can be useful to work around chipset bugs.
188
189 ad1816= [HW,OSS]
190 Format: <io>,<irq>,<dma>,<dma2>
191 See also Documentation/sound/oss/AD1816.
192
193 ad1848= [HW,OSS]
194 Format: <io>,<irq>,<dma>,<dma2>,<type>
195
196 adlib= [HW,OSS]
197 Format: <io>
198
199 advansys= [HW,SCSI]
200 See header of drivers/scsi/advansys.c.
201
202 advwdt= [HW,WDT] Advantech WDT
203 Format: <iostart>,<iostop>
204
205 aedsp16= [HW,OSS] Audio Excel DSP 16
206 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
207 See also header of sound/oss/aedsp16.c.
208
209 aha152x= [HW,SCSI]
210 See Documentation/scsi/aha152x.txt.
211
212 aha1542= [HW,SCSI]
213 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
214
215 aic7xxx= [HW,SCSI]
216 See Documentation/scsi/aic7xxx.txt.
217
218 aic79xx= [HW,SCSI]
219 See Documentation/scsi/aic79xx.txt.
220
221 amijoy.map= [HW,JOY] Amiga joystick support
222 Map of devices attached to JOY0DAT and JOY1DAT
223 Format: <a>,<b>
224 See also Documentation/kernel/input/joystick.txt
225
226 analog.map= [HW,JOY] Analog joystick and gamepad support
227 Specifies type or capabilities of an analog joystick
228 connected to one of 16 gameports
229 Format: <type1>,<type2>,..<type16>
230
231 apc= [HW,SPARC]
232 Power management functions (SPARCstation-4/5 + deriv.)
233 Format: noidle
234 Disable APC CPU standby support. SPARCstation-Fox does
235 not play well with APC CPU idle - disable it if you have
236 APC and your system crashes randomly.
237
238 apic= [APIC,i386] Change the output verbosity whilst booting
239 Format: { quiet (default) | verbose | debug }
240 Change the amount of debugging information output
241 when initialising the APIC and IO-APIC components.
242
243 apm= [APM] Advanced Power Management
244 See header of arch/i386/kernel/apm.c.
245
246 applicom= [HW]
247 Format: <mem>,<irq>
248
249 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
250 Format: <io>,<irq>,<nodeID>
251
252 ataflop= [HW,M68k]
253
254 atarimouse= [HW,MOUSE] Atari Mouse
255
256 atascsi= [HW,SCSI] Atari SCSI
257
258 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
259 EzKey and similar keyboards
260
261 atkbd.reset= [HW] Reset keyboard during initialization
262
263 atkbd.set= [HW] Select keyboard code set
264 Format: <int> (2 = AT (default), 3 = PS/2)
265
266 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
267 keyboards
268
269 atkbd.softraw= [HW] Choose between synthetic and real raw mode
270 Format: <bool> (0 = real, 1 = synthetic (default))
271
272 atkbd.softrepeat= [HW]
273 Use software keyboard repeat
274
275 autotest [IA64]
276
277 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
278 Format: <io>,<memsize>,<isapnp>
279
280 aztcd= [HW,CD] Aztech CD268 CDROM driver
281 Format: <io>,0x79 (?)
282
283 baycom_epp= [HW,AX25]
284 Format: <io>,<mode>
285
286 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
287 Format: <io>,<mode>
288 See header of drivers/net/hamradio/baycom_par.c.
289
290 baycom_ser_fdx= [HW,AX25]
291 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
292 Format: <io>,<irq>,<mode>[,<baud>]
293 See header of drivers/net/hamradio/baycom_ser_fdx.c.
294
295 baycom_ser_hdx= [HW,AX25]
296 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
297 Format: <io>,<irq>,<mode>
298 See header of drivers/net/hamradio/baycom_ser_hdx.c.
299
300 blkmtd_device= [HW,MTD]
301 blkmtd_erasesz=
302 blkmtd_ro=
303 blkmtd_bs=
304 blkmtd_count=
305
306 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
307 bttv.radio= Most important insmod options are available as
308 kernel args too.
309 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
310 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
311
312 BusLogic= [HW,SCSI]
313 See drivers/scsi/BusLogic.c, comment before function
314 BusLogic_ParseDriverOptions().
315
316 c101= [NET] Moxa C101 synchronous serial card
317
318 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
319 Sometimes CPU hardware bugs make them report the cache
320 size incorrectly. The kernel will attempt work arounds
321 to fix known problems, but for some CPUs it is not
322 possible to determine what the correct size should be.
323 This option provides an override for these situations.
324
325 cdu31a= [HW,CD]
326 Format: <io>,<irq>[,PAS]
327 See header of drivers/cdrom/cdu31a.c.
328
329 chandev= [HW,NET] Generic channel device initialisation
330
331 checkreqprot [SELINUX] Set initial checkreqprot flag value.
332 Format: { "0" | "1" }
333 See security/selinux/Kconfig help text.
334 0 -- check protection applied by kernel (includes
335 any implied execute protection).
336 1 -- check protection requested by application.
337 Default value is set via a kernel config option.
338 Value can be changed at runtime via
339 /selinux/checkreqprot.
340
341 clock= [BUGS=IA-32,HW] gettimeofday timesource override.
342 Forces specified timesource (if avaliable) to be used
343 when calculating gettimeofday(). If specicified
344 timesource is not avalible, it defaults to PIT.
345 Format: { pit | tsc | cyclone | pmtmr }
346
347 disable_8254_timer
348 enable_8254_timer
349 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
350 over the 8254 in addition to over the IO-APIC. The
351 kernel tries to set a sensible default.
352
353 hpet= [IA-32,HPET] option to disable HPET and use PIT.
354 Format: disable
355
356 cm206= [HW,CD]
357 Format: { auto | [<io>,][<irq>] }
358
359 com20020= [HW,NET] ARCnet - COM20020 chipset
360 Format:
361 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
362
363 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
364 Format: <io>[,<irq>]
365
366 com90xx= [HW,NET]
367 ARCnet - COM90xx chipset (memory-mapped buffers)
368 Format: <io>[,<irq>[,<memstart>]]
369
370 condev= [HW,S390] console device
371 conmode=
372
373 console= [KNL] Output console device and options.
374
375 tty<n> Use the virtual console device <n>.
376
377 ttyS<n>[,options]
378 ttyUSB0[,options]
379 Use the specified serial port. The options are of
380 the form "bbbbpnf", where "bbbb" is the baud rate,
381 "p" is parity ("n", "o", or "e"), "n" is number of
382 bits, and "f" is flow control ("r" for RTS or
383 omit it). Default is "9600n8".
384
385 See Documentation/serial-console.txt for more
386 information. See
387 Documentation/networking/netconsole.txt for an
388 alternative.
389
390 uart,io,<addr>[,options]
391 uart,mmio,<addr>[,options]
392 Start an early, polled-mode console on the 8250/16550
393 UART at the specified I/O port or MMIO address,
394 switching to the matching ttyS device later. The
395 options are the same as for ttyS, above.
396
397 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
398 Format:
399 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
400
401 cpia_pp= [HW,PPT]
402 Format: { parport<nr> | auto | none }
403
404 crashkernel=nn[KMG]@ss[KMG]
405 [KNL] Reserve a chunk of physical memory to
406 hold a kernel to switch to with kexec on panic.
407
408 cs4232= [HW,OSS]
409 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
410
411 cs89x0_dma= [HW,NET]
412 Format: <dma>
413
414 cs89x0_media= [HW,NET]
415 Format: { rj45 | aui | bnc }
416
417 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
418
419 dasd= [HW,NET]
420 See header of drivers/s390/block/dasd_devmap.c.
421
422 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
423 (one device per port)
424 Format: <port#>,<type>
425 See also Documentation/input/joystick-parport.txt
426
427 debug [KNL] Enable kernel debugging (events log level).
428
429 decnet= [HW,NET]
430 Format: <area>[,<node>]
431 See also Documentation/networking/decnet.txt.
432
433 devfs= [DEVFS]
434 See Documentation/filesystems/devfs/boot-options.
435
436 dhash_entries= [KNL]
437 Set number of hash buckets for dentry cache.
438
439 digi= [HW,SERIAL]
440 IO parameters + enable/disable command.
441
442 digiepca= [HW,SERIAL]
443 See drivers/char/README.epca and
444 Documentation/digiepca.txt.
445
446 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
447 support available.
448 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
449
450 dmasound= [HW,OSS] Sound subsystem buffers
451
452 dscc4.setup= [NET]
453
454 dtc3181e= [HW,SCSI]
455
456 earlyprintk= [IA-32,X86-64]
457 earlyprintk=vga
458 earlyprintk=serial[,ttySn[,baudrate]]
459
460 Append ",keep" to not disable it when the real console
461 takes over.
462
463 Only vga or serial at a time, not both.
464
465 Currently only ttyS0 and ttyS1 are supported.
466
467 Interaction with the standard serial driver is not
468 very good.
469
470 The VGA output is eventually overwritten by the real
471 console.
472
473 eata= [HW,SCSI]
474
475 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
476 Format: <int>
477 0: polling mode
478 non-0: interrupt mode (default)
479
480 eda= [HW,PS2]
481
482 edb= [HW,PS2]
483
484 edd= [EDD]
485 Format: {"of[f]" | "sk[ipmbr]"}
486 See comment in arch/i386/boot/edd.S
487
488 eicon= [HW,ISDN]
489 Format: <id>,<membase>,<irq>
490
491 eisa_irq_edge= [PARISC,HW]
492 See header of drivers/parisc/eisa.c.
493
494 elanfreq= [IA-32]
495 See comment before function elanfreq_setup() in
496 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
497
498 elevator= [IOSCHED]
499 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
500 See Documentation/block/as-iosched.txt and
501 Documentation/block/deadline-iosched.txt for details.
502
503 elfcorehdr= [IA-32, X86_64]
504 Specifies physical address of start of kernel core
505 image elf header. Generally kexec loader will
506 pass this option to capture kernel.
507 See Documentation/kdump/kdump.txt for details.
508
509 enforcing [SELINUX] Set initial enforcing status.
510 Format: {"0" | "1"}
511 See security/selinux/Kconfig help text.
512 0 -- permissive (log only, no denials).
513 1 -- enforcing (deny and log).
514 Default value is 0.
515 Value can be changed at runtime via /selinux/enforce.
516
517 es1370= [HW,OSS]
518 Format: <lineout>[,<micbias>]
519 See also header of sound/oss/es1370.c.
520
521 es1371= [HW,OSS]
522 Format: <spdif>,[<nomix>,[<amplifier>]]
523 See also header of sound/oss/es1371.c.
524
525 ether= [HW,NET] Ethernet cards parameters
526 This option is obsoleted by the "netdev=" option, which
527 has equivalent usage. See its documentation for details.
528
529 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
530 Format: <io>[,<irq>]
531
532 fd_mcs= [HW,SCSI]
533 See header of drivers/scsi/fd_mcs.c.
534
535 fdomain= [HW,SCSI]
536 See header of drivers/scsi/fdomain.c.
537
538 floppy= [HW]
539 See Documentation/floppy.txt.
540
541 ftape= [HW] Floppy Tape subsystem debugging options.
542 See Documentation/ftape.txt.
543
544 gamecon.map[2|3]=
545 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
546 support via parallel port (up to 5 devices per port)
547 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
548 See also Documentation/input/joystick-parport.txt
549
550 gamma= [HW,DRM]
551
552 gdth= [HW,SCSI]
553 See header of drivers/scsi/gdth.c.
554
555 gpt [EFI] Forces disk with valid GPT signature but
556 invalid Protective MBR to be treated as GPT.
557
558 gscd= [HW,CD]
559 Format: <io>
560
561 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
562
563 gus= [HW,OSS]
564 Format: <io>,<irq>,<dma>,<dma16>
565
566 gvp11= [HW,SCSI]
567
568 hashdist= [KNL,NUMA] Large hashes allocated during boot
569 are distributed across NUMA nodes. Defaults on
570 for IA-64, off otherwise.
571 Format: 0 | 1 (for off | on)
572
573 hcl= [IA-64] SGI's Hardware Graph compatibility layer
574
575 hd= [EIDE] (E)IDE hard drive subsystem geometry
576 Format: <cyl>,<head>,<sect>
577
578 hd?= [HW] (E)IDE subsystem
579 hd?lun= See Documentation/ide.txt.
580
581 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
582 size of <nn>. This works even on boxes that have no
583 highmem otherwise. This also works to reduce highmem
584 size on bigger boxes.
585
586 hisax= [HW,ISDN]
587 See Documentation/isdn/README.HiSax.
588
589 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
590
591 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
592
593 i8042.direct [HW] Put keyboard port into non-translated mode
594 i8042.dumbkbd [HW] Pretend that controlled can only read data from
595 keyboard and can not control its state
596 (Don't attempt to blink the leds)
597 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
598 i8042.nokbd [HW] Don't check/create keyboard port
599 i8042.nomux [HW] Don't check presence of an active multiplexing
600 controller
601 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
602 controllers
603 i8042.panicblink=
604 [HW] Frequency with which keyboard LEDs should blink
605 when kernel panics (default is 0.5 sec)
606 i8042.reset [HW] Reset the controller during init and cleanup
607 i8042.unlock [HW] Unlock (ignore) the keylock
608
609 i810= [HW,DRM]
610
611 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
612 indicates that the driver is running on unsupported
613 hardware.
614 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
615 does not match list of supported models.
616 i8k.power_status
617 [HW] Report power status in /proc/i8k
618 (disabled by default)
619 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
620 capability is set.
621
622 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
623 See Documentation/mca.txt.
624
625 icn= [HW,ISDN]
626 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
627
628 ide= [HW] (E)IDE subsystem
629 Format: ide=nodma or ide=doubler or ide=reverse
630 See Documentation/ide.txt.
631
632 ide?= [HW] (E)IDE subsystem
633 Format: ide?=noprobe or chipset specific parameters.
634 See Documentation/ide.txt.
635
636 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
637 See Documentation/ide.txt.
638
639 idle= [HW]
640 Format: idle=poll or idle=halt
641
642 ihash_entries= [KNL]
643 Set number of hash buckets for inode cache.
644
645 in2000= [HW,SCSI]
646 See header of drivers/scsi/in2000.c.
647
648 init= [KNL]
649 Format: <full_path>
650 Run specified binary instead of /sbin/init as init
651 process.
652
653 initcall_debug [KNL] Trace initcalls as they are executed. Useful
654 for working out where the kernel is dying during
655 startup.
656
657 initrd= [BOOT] Specify the location of the initial ramdisk
658
659 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
660 Format: <irq>
661
662 combined_mode= [HW] control which driver uses IDE ports in combined
663 mode: legacy IDE driver, libata, or both
664 (in the libata case, libata.atapi_enabled=1 may be
665 useful as well). Note that using the ide or libata
666 options may affect your device naming (e.g. by
667 changing hdc to sdb).
668 Format: combined (default), ide, or libata
669
670 inttest= [IA64]
671
672 io7= [HW] IO7 for Marvel based alpha systems
673 See comment before marvel_specify_io7 in
674 arch/alpha/kernel/core_marvel.c.
675
676 ip= [IP_PNP]
677 See Documentation/nfsroot.txt.
678
679 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
680 See comment before ip2_setup() in drivers/char/ip2.c.
681
682 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
683 See header of drivers/scsi/ips.c.
684
685 irqfixup [HW]
686 When an interrupt is not handled search all handlers
687 for it. Intended to get systems with badly broken
688 firmware running.
689
690 irqpoll [HW]
691 When an interrupt is not handled search all handlers
692 for it. Also check all handlers each timer
693 interrupt. Intended to get systems with badly broken
694 firmware running.
695
696 isapnp= [ISAPNP]
697 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
698
699 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
700 Format: <cpu number>,...,<cpu number>
701 This option can be used to specify one or more CPUs
702 to isolate from the general SMP balancing and scheduling
703 algorithms. The only way to move a process onto or off
704 an "isolated" CPU is via the CPU affinity syscalls.
705 <cpu number> begins at 0 and the maximum value is
706 "number of CPUs in system - 1".
707
708 This option is the preferred way to isolate CPUs. The
709 alternative -- manually setting the CPU mask of all
710 tasks in the system -- can cause problems and
711 suboptimal load balancer performance.
712
713 isp16= [HW,CD]
714 Format: <io>,<irq>,<dma>,<setup>
715
716 iucv= [HW,NET]
717
718 js= [HW,JOY] Analog joystick
719 See Documentation/input/joystick.txt.
720
721 keepinitrd [HW,ARM]
722
723 kstack=N [IA-32,X86-64] Print N words from the kernel stack
724 in oops dumps.
725
726 l2cr= [PPC]
727
728 lapic [IA-32,APIC] Enable the local APIC even if BIOS
729 disabled it.
730
731 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
732 Format: addr:<io>,irq:<irq>
733
734 llsc*= [IA64] See function print_params() in
735 arch/ia64/sn/kernel/llsc4.c.
736
737 load_ramdisk= [RAM] List of ramdisks to load from floppy
738 See Documentation/ramdisk.txt.
739
740 lockd.nlm_grace_period=P [NFS] Assign grace period.
741 Format: <integer>
742
743 lockd.nlm_tcpport=N [NFS] Assign TCP port.
744 Format: <integer>
745
746 lockd.nlm_timeout=T [NFS] Assign timeout value.
747 Format: <integer>
748
749 lockd.nlm_udpport=M [NFS] Assign UDP port.
750 Format: <integer>
751
752 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
753 Format: <irq>
754
755 loglevel= All Kernel Messages with a loglevel smaller than the
756 console loglevel will be printed to the console. It can
757 also be changed with klogd or other programs. The
758 loglevels are defined as follows:
759
760 0 (KERN_EMERG) system is unusable
761 1 (KERN_ALERT) action must be taken immediately
762 2 (KERN_CRIT) critical conditions
763 3 (KERN_ERR) error conditions
764 4 (KERN_WARNING) warning conditions
765 5 (KERN_NOTICE) normal but significant condition
766 6 (KERN_INFO) informational
767 7 (KERN_DEBUG) debug-level messages
768
769 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
770 Format: { n | nk | nM }
771 n must be a power of two. The default size
772 is set in the kernel config file.
773
774 lp=0 [LP] Specify parallel ports to use, e.g,
775 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
776 lp=reset first parallel port). 'lp=0' disables the
777 lp=auto printer driver. 'lp=reset' (which can be
778 specified in addition to the ports) causes
779 attached printers to be reset. Using
780 lp=port1,port2,... specifies the parallel ports
781 to associate lp devices with, starting with
782 lp0. A port specification may be 'none' to skip
783 that lp device, or a parport name such as
784 'parport0'. Specifying 'lp=auto' instead of a
785 port specification list means that device IDs
786 from each port should be examined, to see if
787 an IEEE 1284-compliant printer is attached; if
788 so, the driver will manage that printer.
789 See also header of drivers/char/lp.c.
790
791 lpj=n [KNL]
792 Sets loops_per_jiffy to given constant, thus avoiding
793 time-consuming boot-time autodetection (up to 250 ms per
794 CPU). 0 enables autodetection (default). To determine
795 the correct value for your kernel, boot with normal
796 autodetection and see what value is printed. Note that
797 on SMP systems the preset will be applied to all CPUs,
798 which is likely to cause problems if your CPUs need
799 significantly divergent settings. An incorrect value
800 will cause delays in the kernel to be wrong, leading to
801 unpredictable I/O errors and other breakage. Although
802 unlikely, in the extreme case this might damage your
803 hardware.
804
805 ltpc= [NET]
806 Format: <io>,<irq>,<dma>
807
808 mac5380= [HW,SCSI] Format:
809 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
810
811 mac53c9x= [HW,SCSI] Format:
812 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
813
814 machvec= [IA64] Force the use of a particular machine-vector
815 (machvec) in a generic kernel.
816 Example: machvec=hpzx1_swiotlb
817
818 mad16= [HW,OSS] Format:
819 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
820
821 maui= [HW,OSS]
822 Format: <io>,<irq>
823
824 max_loop= [LOOP] Maximum number of loopback devices that can
825 be mounted
826 Format: <1-256>
827
828 maxcpus= [SMP] Maximum number of processors that an SMP kernel
829 should make use of
830
831 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
832 equal to this physical address is ignored.
833
834 max_luns= [SCSI] Maximum number of LUNs to probe.
835 Should be between 1 and 2^32-1.
836
837 max_report_luns=
838 [SCSI] Maximum number of LUNs received.
839 Should be between 1 and 16384.
840
841 mca-pentium [BUGS=IA-32]
842
843 mcatest= [IA-64]
844
845 mcd= [HW,CD]
846 Format: <port>,<irq>,<mitsumi_bug_93_wait>
847
848 mcdx= [HW,CD]
849
850 mce [IA-32] Machine Check Exception
851
852 md= [HW] RAID subsystems devices and level
853 See Documentation/md.txt.
854
855 mdacon= [MDA]
856 Format: <first>,<last>
857 Specifies range of consoles to be captured by the MDA.
858
859 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
860 Amount of memory to be used when the kernel is not able
861 to see the whole system memory or for test.
862 [IA-32] Use together with memmap= to avoid physical
863 address space collisions. Without memmap= PCI devices
864 could be placed at addresses belonging to unused RAM.
865
866 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
867 memory.
868
869 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
870 E820 memory map, as specified by the user.
871 Such memmap=exactmap lines can be constructed based on
872 BIOS output or other requirements. See the memmap=nn@ss
873 option description.
874
875 memmap=nn[KMG]@ss[KMG]
876 [KNL] Force usage of a specific region of memory
877 Region of memory to be used, from ss to ss+nn.
878
879 memmap=nn[KMG]#ss[KMG]
880 [KNL,ACPI] Mark specific memory as ACPI data.
881 Region of memory to be used, from ss to ss+nn.
882
883 memmap=nn[KMG]$ss[KMG]
884 [KNL,ACPI] Mark specific memory as reserved.
885 Region of memory to be used, from ss to ss+nn.
886
887 meye.*= [HW] Set MotionEye Camera parameters
888 See Documentation/video4linux/meye.txt.
889
890 mga= [HW,DRM]
891
892 migration_cost=
893 [KNL,SMP] debug: override scheduler migration costs
894 Format: <level-1-usecs>,<level-2-usecs>,...
895 This debugging option can be used to override the
896 default scheduler migration cost matrix. The numbers
897 are indexed by 'CPU domain distance'.
898 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
899 box will set up an intra-core migration cost of
900 1 msec, an inter-core migration cost of 2 msecs,
901 and an inter-node migration cost of 3 msecs.
902
903 WARNING: using the wrong values here can break
904 scheduler performance, so it's only for scheduler
905 development purposes, not production environments.
906
907 migration_debug=
908 [KNL,SMP] migration cost auto-detect verbosity
909 Format=<0|1|2>
910 If a system's migration matrix reported at bootup
911 seems erroneous then this option can be used to
912 increase verbosity of the detection process.
913 We default to 0 (no extra messages), 1 will print
914 some more information, and 2 will be really
915 verbose (probably only useful if you also have a
916 serial console attached to the system).
917
918 migration_factor=
919 [KNL,SMP] multiply/divide migration costs by a factor
920 Format=<percent>
921 This debug option can be used to proportionally
922 increase or decrease the auto-detected migration
923 costs for all entries of the migration matrix.
924 E.g. migration_factor=150 will increase migration
925 costs by 50%. (and thus the scheduler will be less
926 eager migrating cache-hot tasks)
927 migration_factor=80 will decrease migration costs
928 by 20%. (thus the scheduler will be more eager to
929 migrate tasks)
930
931 WARNING: using the wrong values here can break
932 scheduler performance, so it's only for scheduler
933 development purposes, not production environments.
934
935 mousedev.tap_time=
936 [MOUSE] Maximum time between finger touching and
937 leaving touchpad surface for touch to be considered
938 a tap and be reported as a left button click (for
939 touchpads working in absolute mode only).
940 Format: <msecs>
941 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
942 reporting absolute coordinates, such as tablets
943 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
944 reporting absolute coordinates, such as tablets
945
946 mpu401= [HW,OSS]
947 Format: <io>,<irq>
948
949 MTD_Partition= [MTD]
950 Format: <name>,<region-number>,<size>,<offset>
951
952 MTD_Region= [MTD] Format:
953 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
954
955 mtdparts= [MTD]
956 See drivers/mtd/cmdline.c.
957
958 mtouchusb.raw_coordinates=
959 [HW] Make the MicroTouch USB driver use raw coordinates
960 ('y', default) or cooked coordinates ('n')
961
962 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
963
964 NCR_D700= [HW,SCSI]
965 See header of drivers/scsi/NCR_D700.c.
966
967 ncr5380= [HW,SCSI]
968
969 ncr53c400= [HW,SCSI]
970
971 ncr53c400a= [HW,SCSI]
972
973 ncr53c406a= [HW,SCSI]
974
975 ncr53c8xx= [HW,SCSI]
976
977 netdev= [NET] Network devices parameters
978 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
979 Note that mem_start is often overloaded to mean
980 something different and driver-specific.
981 This usage is only documented in each driver source
982 file if at all.
983
984 nfsaddrs= [NFS]
985 See Documentation/nfsroot.txt.
986
987 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
988 See Documentation/nfsroot.txt.
989
990 nfs.callback_tcpport=
991 [NFS] set the TCP port on which the NFSv4 callback
992 channel should listen.
993
994 nfs.idmap_cache_timeout=
995 [NFS] set the maximum lifetime for idmapper cache
996 entries.
997
998 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
999
1000 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1001 emulation library even if a 387 maths coprocessor
1002 is present.
1003
1004 noalign [KNL,ARM]
1005
1006 noapic [SMP,APIC] Tells the kernel to not make use of any
1007 IOAPICs that may be present in the system.
1008
1009 noasync [HW,M68K] Disables async and sync negotiation for
1010 all devices.
1011
1012 nobats [PPC] Do not use BATs for mapping kernel lowmem
1013 on "Classic" PPC cores.
1014
1015 nocache [ARM]
1016
1017 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1018
1019 noexec [IA-64]
1020
1021 noexec [IA-32,X86-64]
1022 noexec=on: enable non-executable mappings (default)
1023 noexec=off: disable nn-executable mappings
1024
1025 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1026 register save and restore. The kernel will only save
1027 legacy floating-point registers on task switch.
1028
1029 nohlt [BUGS=ARM]
1030
1031 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1032 instruction doesn't work correctly and not to
1033 use it.
1034
1035 nohalt [IA-64] Tells the kernel not to use the power saving
1036 function PAL_HALT_LIGHT when idle. This increases
1037 power-consumption. On the positive side, it reduces
1038 interrupt wake-up latency, which may improve performance
1039 in certain environments such as networked servers or
1040 real-time systems.
1041
1042 noirqdebug [IA-32] Disables the code which attempts to detect and
1043 disable unhandled interrupt sources.
1044
1045 noisapnp [ISAPNP] Disables ISA PnP code.
1046
1047 noinitrd [RAM] Tells the kernel not to load any configured
1048 initial RAM disk.
1049
1050 nointroute [IA-64]
1051
1052 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1053
1054 noltlbs [PPC] Do not use large page/tlb entries for kernel
1055 lowmem mapping on PPC40x.
1056
1057 nomca [IA-64] Disable machine check abort handling
1058
1059 nomce [IA-32] Machine Check Exception
1060
1061 noresidual [PPC] Don't use residual data on PReP machines.
1062
1063 noresume [SWSUSP] Disables resume and restores original swap
1064 space.
1065
1066 no-scroll [VGA] Disables scrollback.
1067 This is required for the Braillex ib80-piezo Braille
1068 reader made by F.H. Papenmeier (Germany).
1069
1070 nosbagart [IA-64]
1071
1072 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1073
1074 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1075
1076 nosync [HW,M68K] Disables sync negotiation for all devices.
1077
1078 notsc [BUGS=IA-32] Disable Time Stamp Counter
1079
1080 nousb [USB] Disable the USB subsystem
1081
1082 nowb [ARM]
1083
1084 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1085
1086 opl3= [HW,OSS]
1087 Format: <io>
1088
1089 opl3sa= [HW,OSS]
1090 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1091
1092 opl3sa2= [HW,OSS] Format:
1093 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1094
1095 oprofile.timer= [HW]
1096 Use timer interrupt instead of performance counters
1097
1098 optcd= [HW,CD]
1099 Format: <io>
1100
1101 osst= [HW,SCSI] SCSI Tape Driver
1102 Format: <buffer_size>,<write_threshold>
1103 See also Documentation/scsi/st.txt.
1104
1105 panic= [KNL] Kernel behaviour on panic
1106 Format: <timeout>
1107
1108 parkbd.port= [HW] Parallel port number the keyboard adapter is
1109 connected to, default is 0.
1110 Format: <parport#>
1111 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1112 0 for XT, 1 for AT (default is AT).
1113 Format: <mode>
1114
1115 parport= [HW,PPT] Specify parallel ports. 0 disables.
1116 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1117 Use 'auto' to force the driver to use any
1118 IRQ/DMA settings detected (the default is to
1119 ignore detected IRQ/DMA settings because of
1120 possible conflicts). You can specify the base
1121 address, IRQ, and DMA settings; IRQ and DMA
1122 should be numbers, or 'auto' (for using detected
1123 settings on that particular port), or 'nofifo'
1124 (to avoid using a FIFO even if it is detected).
1125 Parallel ports are assigned in the order they
1126 are specified on the command line, starting
1127 with parport0.
1128
1129 parport_init_mode= [HW,PPT]
1130 Configure VIA parallel port to operate in
1131 a specific mode. This is necessary on Pegasos
1132 computer where firmware has no options for setting
1133 up parallel port mode and sets it to spp.
1134 Currently this function knows 686a and 8231 chips.
1135 Format: [spp|ps2|epp|ecp|ecpepp]
1136
1137 pas2= [HW,OSS] Format:
1138 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1139
1140 pas16= [HW,SCSI]
1141 See header of drivers/scsi/pas16.c.
1142
1143 pause_on_oops=
1144 Halt all CPUs after the first oops has been printed for
1145 the specified number of seconds. This is to be used if
1146 your oopses keep scrolling off the screen.
1147
1148 pcbit= [HW,ISDN]
1149
1150 pcd. [PARIDE]
1151 See header of drivers/block/paride/pcd.c.
1152 See also Documentation/paride.txt.
1153
1154 pci=option[,option...] [PCI] various PCI subsystem options:
1155 off [IA-32] don't probe for the PCI bus
1156 bios [IA-32] force use of PCI BIOS, don't access
1157 the hardware directly. Use this if your machine
1158 has a non-standard PCI host bridge.
1159 nobios [IA-32] disallow use of PCI BIOS, only direct
1160 hardware access methods are allowed. Use this
1161 if you experience crashes upon bootup and you
1162 suspect they are caused by the BIOS.
1163 conf1 [IA-32] Force use of PCI Configuration
1164 Mechanism 1.
1165 conf2 [IA-32] Force use of PCI Configuration
1166 Mechanism 2.
1167 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1168 Configuration
1169 nomsi [MSI] If the PCI_MSI kernel config parameter is
1170 enabled, this kernel boot option can be used to
1171 disable the use of MSI interrupts system-wide.
1172 nosort [IA-32] Don't sort PCI devices according to
1173 order given by the PCI BIOS. This sorting is
1174 done to get a device order compatible with
1175 older kernels.
1176 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1177 routing table. These calls are known to be buggy
1178 on several machines and they hang the machine
1179 when used, but on other computers it's the only
1180 way to get the interrupt routing table. Try
1181 this option if the kernel is unable to allocate
1182 IRQs or discover secondary PCI buses on your
1183 motherboard.
1184 rom [IA-32] Assign address space to expansion ROMs.
1185 Use with caution as certain devices share
1186 address decoders between ROMs and other
1187 resources.
1188 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1189 assigned automatically to PCI devices. You can
1190 make the kernel exclude IRQs of your ISA cards
1191 this way.
1192 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1193 of the PIRQ table (normally generated
1194 by the BIOS) if it is outside the
1195 F0000h-100000h range.
1196 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1197 useful if the kernel is unable to find your
1198 secondary buses and you want to tell it
1199 explicitly which ones they are.
1200 assign-busses [IA-32] Always assign all PCI bus
1201 numbers ourselves, overriding
1202 whatever the firmware may have done.
1203 usepirqmask [IA-32] Honor the possible IRQ mask stored
1204 in the BIOS $PIR table. This is needed on
1205 some systems with broken BIOSes, notably
1206 some HP Pavilion N5400 and Omnibook XE3
1207 notebooks. This will have no effect if ACPI
1208 IRQ routing is enabled.
1209 noacpi [IA-32] Do not use ACPI for IRQ routing
1210 or for PCI scanning.
1211 routeirq Do IRQ routing for all PCI devices.
1212 This is normally done in pci_enable_device(),
1213 so this option is a temporary workaround
1214 for broken drivers that don't call it.
1215 firmware [ARM] Do not re-enumerate the bus but instead
1216 just use the configuration from the
1217 bootloader. This is currently used on
1218 IXP2000 systems where the bus has to be
1219 configured a certain way for adjunct CPUs.
1220
1221 pcmv= [HW,PCMCIA] BadgePAD 4
1222
1223 pd. [PARIDE]
1224 See Documentation/paride.txt.
1225
1226 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1227 boot time.
1228 Format: { 0 | 1 }
1229 See arch/parisc/kernel/pdc_chassis.c
1230
1231 pf. [PARIDE]
1232 See Documentation/paride.txt.
1233
1234 pg. [PARIDE]
1235 See Documentation/paride.txt.
1236
1237 pirq= [SMP,APIC] Manual mp-table setup
1238 See Documentation/i386/IO-APIC.txt.
1239
1240 plip= [PPT,NET] Parallel port network link
1241 Format: { parport<nr> | timid | 0 }
1242 See also Documentation/parport.txt.
1243
1244 pnpacpi= [ACPI]
1245 { off }
1246
1247 pnpbios= [ISAPNP]
1248 { on | off | curr | res | no-curr | no-res }
1249
1250 pnp_reserve_irq=
1251 [ISAPNP] Exclude IRQs for the autoconfiguration
1252
1253 pnp_reserve_dma=
1254 [ISAPNP] Exclude DMAs for the autoconfiguration
1255
1256 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1257 Ranges are in pairs (I/O port base and size).
1258
1259 pnp_reserve_mem=
1260 [ISAPNP] Exclude memory regions for the
1261 autoconfiguration.
1262 Ranges are in pairs (memory base and size).
1263
1264 profile= [KNL] Enable kernel profiling via /proc/profile
1265 Format: [schedule,]<number>
1266 Param: "schedule" - profile schedule points.
1267 Param: <number> - step/bucket size as a power of 2 for
1268 statistical time based profiling.
1269
1270 processor.max_cstate= [HW,ACPI]
1271 Limit processor to maximum C-state
1272 max_cstate=9 overrides any DMI blacklist limit.
1273
1274 processor.nocst [HW,ACPI]
1275 Ignore the _CST method to determine C-states,
1276 instead using the legacy FADT method
1277
1278 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1279 before loading.
1280 See Documentation/ramdisk.txt.
1281
1282 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1283 probe for; one of (bare|imps|exps|lifebook|any).
1284 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1285 per second.
1286 psmouse.resetafter= [HW,MOUSE]
1287 Try to reset the device after so many bad packets
1288 (0 = never).
1289 psmouse.resolution=
1290 [HW,MOUSE] Set desired mouse resolution, in dpi.
1291 psmouse.smartscroll=
1292 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1293 0 = disabled, 1 = enabled (default).
1294
1295 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1296 Format:
1297 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1298
1299 pt. [PARIDE]
1300 See Documentation/paride.txt.
1301
1302 quiet= [KNL] Disable log messages
1303
1304 r128= [HW,DRM]
1305
1306 raid= [HW,RAID]
1307 See Documentation/md.txt.
1308
1309 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1310 See Documentation/ramdisk.txt.
1311
1312 ramdisk_blocksize= [RAM]
1313 See Documentation/ramdisk.txt.
1314
1315 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1316 New name for the ramdisk parameter.
1317 See Documentation/ramdisk.txt.
1318
1319 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1320 RCU callbacks to process in one batch.
1321
1322 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1323 RCU callbacks over which batch limiting is disabled.
1324
1325 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1326 RCU callbacks below which batch limiting is re-enabled.
1327
1328 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1329 RCU callbacks to queued before forcing reschedule
1330 on all cpus.
1331
1332 rdinit= [KNL]
1333 Format: <full_path>
1334 Run specified binary instead of /init from the ramdisk,
1335 used for early userspace startup. See initrd.
1336
1337 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1338 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1339 See arch/*/kernel/reboot.c.
1340
1341 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1342
1343 resume= [SWSUSP]
1344 Specify the partition device for software suspend
1345
1346 rhash_entries= [KNL,NET]
1347 Set number of hash buckets for route cache
1348
1349 riscom8= [HW,SERIAL]
1350 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1351
1352 ro [KNL] Mount root device read-only on boot
1353
1354 root= [KNL] Root filesystem
1355
1356 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1357 mount the root filesystem
1358
1359 rootflags= [KNL] Set root filesystem mount option string
1360
1361 rootfstype= [KNL] Set root filesystem type
1362
1363 rw [KNL] Mount root device read-write on boot
1364
1365 S [KNL] Run init in single mode
1366
1367 sa1100ir [NET]
1368 See drivers/net/irda/sa1100_ir.c.
1369
1370 sb= [HW,OSS]
1371 Format: <io>,<irq>,<dma>,<dma2>
1372
1373 sbni= [NET] Granch SBNI12 leased line adapter
1374
1375 sbpcd= [HW,CD] Soundblaster CD adapter
1376 Format: <io>,<type>
1377 See a comment before function sbpcd_setup() in
1378 drivers/cdrom/sbpcd.c.
1379
1380 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1381 Format: <io>[,<timeout>[,<isapnp>]]
1382
1383 scsi_debug_*= [SCSI]
1384 See drivers/scsi/scsi_debug.c.
1385
1386 scsi_default_dev_flags=
1387 [SCSI] SCSI default device flags
1388 Format: <integer>
1389
1390 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1391 Format: <vendor>:<model>:<flags>
1392 (flags are integer value)
1393
1394 scsi_logging= [SCSI]
1395
1396 selinux [SELINUX] Disable or enable SELinux at boot time.
1397 Format: { "0" | "1" }
1398 See security/selinux/Kconfig help text.
1399 0 -- disable.
1400 1 -- enable.
1401 Default value is set via kernel config option.
1402 If enabled at boot time, /selinux/disable can be used
1403 later to disable prior to initial policy load.
1404
1405 serialnumber [BUGS=IA-32]
1406
1407 sg_def_reserved_size= [SCSI]
1408
1409 sgalaxy= [HW,OSS]
1410 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1411
1412 shapers= [NET]
1413 Maximal number of shapers.
1414
1415 sim710= [SCSI,HW]
1416 See header of drivers/scsi/sim710.c.
1417
1418 simeth= [IA-64]
1419 simscsi=
1420
1421 sjcd= [HW,CD]
1422 Format: <io>,<irq>,<dma>
1423 See header of drivers/cdrom/sjcd.c.
1424
1425 slram= [HW,MTD]
1426
1427 smart2= [HW]
1428 Format: <io1>[,<io2>[,...,<io8>]]
1429
1430 snd-ad1816a= [HW,ALSA]
1431
1432 snd-ad1848= [HW,ALSA]
1433
1434 snd-ali5451= [HW,ALSA]
1435
1436 snd-als100= [HW,ALSA]
1437
1438 snd-als4000= [HW,ALSA]
1439
1440 snd-azt2320= [HW,ALSA]
1441
1442 snd-cmi8330= [HW,ALSA]
1443
1444 snd-cmipci= [HW,ALSA]
1445
1446 snd-cs4231= [HW,ALSA]
1447
1448 snd-cs4232= [HW,ALSA]
1449
1450 snd-cs4236= [HW,ALSA]
1451
1452 snd-cs4281= [HW,ALSA]
1453
1454 snd-cs46xx= [HW,ALSA]
1455
1456 snd-dt019x= [HW,ALSA]
1457
1458 snd-dummy= [HW,ALSA]
1459
1460 snd-emu10k1= [HW,ALSA]
1461
1462 snd-ens1370= [HW,ALSA]
1463
1464 snd-ens1371= [HW,ALSA]
1465
1466 snd-es968= [HW,ALSA]
1467
1468 snd-es1688= [HW,ALSA]
1469
1470 snd-es18xx= [HW,ALSA]
1471
1472 snd-es1938= [HW,ALSA]
1473
1474 snd-es1968= [HW,ALSA]
1475
1476 snd-fm801= [HW,ALSA]
1477
1478 snd-gusclassic= [HW,ALSA]
1479
1480 snd-gusextreme= [HW,ALSA]
1481
1482 snd-gusmax= [HW,ALSA]
1483
1484 snd-hdsp= [HW,ALSA]
1485
1486 snd-ice1712= [HW,ALSA]
1487
1488 snd-intel8x0= [HW,ALSA]
1489
1490 snd-interwave= [HW,ALSA]
1491
1492 snd-interwave-stb=
1493 [HW,ALSA]
1494
1495 snd-korg1212= [HW,ALSA]
1496
1497 snd-maestro3= [HW,ALSA]
1498
1499 snd-mpu401= [HW,ALSA]
1500
1501 snd-mtpav= [HW,ALSA]
1502
1503 snd-nm256= [HW,ALSA]
1504
1505 snd-opl3sa2= [HW,ALSA]
1506
1507 snd-opti92x-ad1848=
1508 [HW,ALSA]
1509
1510 snd-opti92x-cs4231=
1511 [HW,ALSA]
1512
1513 snd-opti93x= [HW,ALSA]
1514
1515 snd-pmac= [HW,ALSA]
1516
1517 snd-rme32= [HW,ALSA]
1518
1519 snd-rme96= [HW,ALSA]
1520
1521 snd-rme9652= [HW,ALSA]
1522
1523 snd-sb8= [HW,ALSA]
1524
1525 snd-sb16= [HW,ALSA]
1526
1527 snd-sbawe= [HW,ALSA]
1528
1529 snd-serial= [HW,ALSA]
1530
1531 snd-sgalaxy= [HW,ALSA]
1532
1533 snd-sonicvibes= [HW,ALSA]
1534
1535 snd-sun-amd7930=
1536 [HW,ALSA]
1537
1538 snd-sun-cs4231= [HW,ALSA]
1539
1540 snd-trident= [HW,ALSA]
1541
1542 snd-usb-audio= [HW,ALSA,USB]
1543
1544 snd-via82xx= [HW,ALSA]
1545
1546 snd-virmidi= [HW,ALSA]
1547
1548 snd-wavefront= [HW,ALSA]
1549
1550 snd-ymfpci= [HW,ALSA]
1551
1552 sonicvibes= [HW,OSS]
1553 Format: <reverb>
1554
1555 sonycd535= [HW,CD]
1556 Format: <io>[,<irq>]
1557
1558 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1559 See Documentation/sonypi.txt
1560
1561 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1562 See Documentation/specialix.txt.
1563
1564 spia_io_base= [HW,MTD]
1565 spia_fio_base=
1566 spia_pedr=
1567 spia_peddr=
1568
1569 sscape= [HW,OSS]
1570 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1571
1572 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1573 See Documentation/scsi/st.txt.
1574
1575 st0x= [HW,SCSI]
1576 See header of drivers/scsi/seagate.c.
1577
1578 sti= [PARISC,HW]
1579 Format: <num>
1580 Set the STI (builtin display/keyboard on the HP-PARISC
1581 machines) console (graphic card) which should be used
1582 as the initial boot-console.
1583 See also comment in drivers/video/console/sticore.c.
1584
1585 sti_font= [HW]
1586 See comment in drivers/video/console/sticore.c.
1587
1588 stifb= [HW]
1589 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1590
1591 swiotlb= [IA-64] Number of I/O TLB slabs
1592
1593 switches= [HW,M68k]
1594
1595 sym53c416= [HW,SCSI]
1596 See header of drivers/scsi/sym53c416.c.
1597
1598 t128= [HW,SCSI]
1599 See header of drivers/scsi/t128.c.
1600
1601 tdfx= [HW,DRM]
1602
1603 thash_entries= [KNL,NET]
1604 Set number of hash buckets for TCP connection
1605
1606 time Show timing data prefixed to each printk message line
1607
1608 tipar.timeout= [HW,PPT]
1609 Set communications timeout in tenths of a second
1610 (default 15).
1611
1612 tipar.delay= [HW,PPT]
1613 Set inter-bit delay in microseconds (default 10).
1614
1615 tmc8xx= [HW,SCSI]
1616 See header of drivers/scsi/seagate.c.
1617
1618 tmscsim= [HW,SCSI]
1619 See comment before function dc390_setup() in
1620 drivers/scsi/tmscsim.c.
1621
1622 tp720= [HW,PS2]
1623
1624 trix= [HW,OSS] MediaTrix AudioTrix Pro
1625 Format:
1626 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1627
1628 tsdev.xres= [TS] Horizontal screen resolution.
1629 tsdev.yres= [TS] Vertical screen resolution.
1630
1631 turbografx.map[2|3]= [HW,JOY]
1632 TurboGraFX parallel port interface
1633 Format:
1634 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1635 See also Documentation/input/joystick-parport.txt
1636
1637 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1638 See header of drivers/scsi/u14-34f.c.
1639
1640 uart401= [HW,OSS]
1641 Format: <io>,<irq>
1642
1643 uart6850= [HW,OSS]
1644 Format: <io>,<irq>
1645
1646 usbhid.mousepoll=
1647 [USBHID] The interval which mice are to be polled at.
1648
1649 video= [FB] Frame buffer configuration
1650 See Documentation/fb/modedb.txt.
1651
1652 vga= [BOOT,IA-32] Select a particular video mode
1653 See Documentation/i386/boot.txt and
1654 Documentation/svga.txt.
1655 Use vga=ask for menu.
1656 This is actually a boot loader parameter; the value is
1657 passed to the kernel using a special protocol.
1658
1659 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1660 size of <nn>. This can be used to increase the
1661 minimum size (128MB on x86). It can also be used to
1662 decrease the size and leave more room for directly
1663 mapped kernel RAM.
1664
1665 vmhalt= [KNL,S390]
1666
1667 vmpoff= [KNL,S390]
1668
1669 waveartist= [HW,OSS]
1670 Format: <io>,<irq>,<dma>,<dma2>
1671
1672 wd33c93= [HW,SCSI]
1673 See header of drivers/scsi/wd33c93.c.
1674
1675 wd7000= [HW,SCSI]
1676 See header of drivers/scsi/wd7000.c.
1677
1678 wdt= [WDT] Watchdog
1679 See Documentation/watchdog/watchdog.txt.
1680
1681 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1682 xd_geo= See header of drivers/block/xd.c.
1683
1684 xirc2ps_cs= [NET,PCMCIA]
1685 Format:
1686 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1687
1688 norandmaps Don't use address space randomization
1689 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1690
1691
1692 ______________________________________________________________________
1693
1694 TODO:
1695
1696 Add documentation for ALSA options.
1697 Add more DRM drivers.
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