dd0bfc291a682e60c39441d07ef0be026dceabee
[linux-2.6.git] / Documentation / kernel-parameters.txt
1 February 2003             Kernel Parameters                     v2.5.59
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 The text in square brackets at the beginning of the description states the
21 restrictions on the kernel for the said kernel parameter to be valid. The
22 restrictions 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.
30         DEVFS   devfs support is enabled.
31         DRM     Direct Rendering Management support is enabled.
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.
40         IP_PNP  IP DHCP, BOOTP, or RARP is enabled.
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.
74         SWSUSP  Software suspend is enabled.
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
87 In 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
93 Parameters denoted with BOOT are actually interpreted by the boot
94 loader, and have no meaning to the kernel directly.
95 Do not modify the syntax of boot loader parameters without extreme
96 need or coordination with <Documentation/i386/boot.txt>.
97
98 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
99 a trailing = on the name of any parameter states that that parameter will
100 be entered as an environment variable, whereas its absence indicates that
101 it will appear as a kernel argument readable via /proc/cmdline by programs
102 running 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
108         acpi=           [HW,ACPI] Advanced Configuration and Power Interface
109                         Format: { force | off | ht | strict | noirq }
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
114                         strict -- Be less tolerant of platforms that are not
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
122
123         acpi_sci=       [HW,ACPI] ACPI System Control Interrupt trigger mode
124                         Format: { level | edge | high | low }
125
126         acpi_irq_balance [HW,ACPI]
127                         ACPI will balance active IRQs
128                         default in APIC mode
129
130         acpi_irq_nobalance [HW,ACPI]
131                         ACPI will not move active IRQs (default)
132                         default in PIC mode
133
134         acpi_irq_pci=   [HW,ACPI] If irq_balance, clear listed IRQs for
135                         use by PCI
136                         Format: <irq>,<irq>...
137
138         acpi_irq_isa=   [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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>
151                         Each bit of the <int> indicates an ACPI debug layer,
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>
158                         Each bit of the <int> indicates an ACPI debug level,
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
165         acpi_generic_hotkey [HW,ACPI]
166                         Allow consolidated generic hotkey driver to
167                         override platform specific driver.
168                         See also Documentation/acpi-hotkey.txt.
169
170         enable_timer_pin_1 [i386,x86-64]
171                         Enable PIN 1 of APIC timer
172                         Can be useful to work around chipset bugs
173                         (in particular on some ATI chipsets).
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
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>
189
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.
199
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
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
222         apc=            [HW,SPARC]
223                         Power management functions (SPARCstation-4/5 + deriv.)
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
229         apic=           [APIC,i386] Change the output verbosity whilst booting
230                         Format: { quiet (default) | verbose | debug }
231                         Change the amount of debugging information output
232                         when initialising the APIC and IO-APIC components.
233
234         apm=            [APM] Advanced Power Management
235                         See header of arch/i386/kernel/apm.c.
236
237         applicom=       [HW]
238                         Format: <mem>,<irq>
239
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
254         atkbd.set=      [HW] Select keyboard code set
255                         Format: <int> (2 = AT (default), 3 = PS/2)
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))
262
263         atkbd.softrepeat= [HW]
264                         Use software keyboard repeat
265
266         autotest        [IA64]
267
268         awe=            [HW,OSS] AWE32/SB32/AWE64 wave table synth
269                         Format: <io>,<memsize>,<isapnp>
270
271         aztcd=          [HW,CD] Aztech CD268 CDROM driver
272                         Format: <io>,0x79 (?)
273
274         baycom_epp=     [HW,AX25]
275                         Format: <io>,<mode>
276
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
281         baycom_ser_fdx= [HW,AX25]
282                         BayCom Serial Port AX.25 Modem (Full Duplex Mode)
283                         Format: <io>,<irq>,<mode>[,<baud>]
284                         See header of drivers/net/hamradio/baycom_ser_fdx.c.
285
286         baycom_ser_hdx= [HW,AX25]
287                         BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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)
298         bttv.radio=     Most important insmod options are available as
299                         kernel args too.
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.
325                         0 -- check protection applied by kernel (includes
326                                 any implied execute protection).
327                         1 -- check protection requested by application.
328                         Default value is set via a kernel config option.
329                         Value can be changed at runtime via
330                                 /selinux/checkreqprot.
331
332         clock=          [BUGS=IA-32,HW] gettimeofday timesource override.
333                         Forces specified timesource (if avaliable) to be used
334                         when calculating gettimeofday(). If specicified
335                         timesource is not avalible, it defaults to PIT.
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
345                         Format:
346                         <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
347
348         com90io=        [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
349                         Format: <io>[,<irq>]
350
351         com90xx=        [HW,NET]
352                         ARCnet - COM90xx chipset (memory-mapped buffers)
353                         Format: <io>[,<irq>[,<memstart>]]
354
355         condev=         [HW,S390] console device
356         conmode=
357
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
378                         Format:
379                         <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
380
381         cpia_pp=        [HW,PPT]
382                         Format: { parport<nr> | auto | none }
383
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
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 }
396
397         cyclades=       [HW,SERIAL] Cyclades multi-serial port adapter.
398
399         dasd=           [HW,NET]
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.
418
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
436         earlyprintk=    [IA-32,X86-64]
437                         earlyprintk=vga
438                         earlyprintk=serial[,ttySn[,baudrate]]
439
440                         Append ",keep" to not disable it when the real console
441                         takes over.
442
443                         Only vga or serial at a time, not both.
444
445                         Currently only ttyS0 and ttyS1 are supported.
446
447                         Interaction with the standard serial driver is not
448                         very good.
449
450                         The VGA output is eventually overwritten by the real
451                         console.
452
453         eata=           [HW,SCSI]
454
455         eda=            [HW,PS2]
456
457         edb=            [HW,PS2]
458
459         edd=            [EDD]
460                         Format: {"of[f]" | "sk[ipmbr]"}
461                         See comment in arch/i386/boot/edd.S
462
463         eicon=          [HW,ISDN]
464                         Format: <id>,<membase>,<irq>
465
466         eisa_irq_edge=  [PARISC,HW]
467                         See header of drivers/parisc/eisa.c.
468
469         elanfreq=       [IA-32]
470                         See comment before function elanfreq_setup() in
471                         arch/i386/kernel/cpu/cpufreq/elanfreq.c.
472
473         elevator=       [IOSCHED]
474                         Format: {"as" | "cfq" | "deadline" | "noop"}
475                         See Documentation/block/as-iosched.txt and
476                         Documentation/block/deadline-iosched.txt for details.
477
478         elfcorehdr=     [IA-32, X86_64]
479                         Specifies physical address of start of kernel core
480                         image elf header. Generally kexec loader will
481                         pass this option to capture kernel.
482                         See Documentation/kdump/kdump.txt for details.
483
484         enforcing       [SELINUX] Set initial enforcing status.
485                         Format: {"0" | "1"}
486                         See security/selinux/Kconfig help text.
487                         0 -- permissive (log only, no denials).
488                         1 -- enforcing (deny and log).
489                         Default value is 0.
490                         Value can be changed at runtime via /selinux/enforce.
491
492         es1370=         [HW,OSS]
493                         Format: <lineout>[,<micbias>]
494                         See also header of sound/oss/es1370.c.
495
496         es1371=         [HW,OSS]
497                         Format: <spdif>,[<nomix>,[<amplifier>]]
498                         See also header of sound/oss/es1371.c.
499
500         ether=          [HW,NET] Ethernet cards parameters
501                         This option is obsoleted by the "netdev=" option, which
502                         has equivalent usage. See its documentation for details.
503
504         eurwdt=         [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
505                         Format: <io>[,<irq>]
506
507         fd_mcs=         [HW,SCSI]
508                         See header of drivers/scsi/fd_mcs.c.
509
510         fdomain=        [HW,SCSI]
511                         See header of drivers/scsi/fdomain.c.
512
513         floppy=         [HW]
514                         See Documentation/floppy.txt.
515
516         ftape=          [HW] Floppy Tape subsystem debugging options.
517                         See Documentation/ftape.txt.
518
519         gamecon.map[2|3]=
520                         [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
521                         support via parallel port (up to 5 devices per port)
522                         Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
523                         See also Documentation/input/joystick-parport.txt
524
525         gamma=          [HW,DRM]
526
527         gdth=           [HW,SCSI]
528                         See header of drivers/scsi/gdth.c.
529
530         gpt             [EFI] Forces disk with valid GPT signature but
531                         invalid Protective MBR to be treated as GPT.
532
533         gscd=           [HW,CD]
534                         Format: <io>
535
536         gt96100eth=     [NET] MIPS GT96100 Advanced Communication Controller
537
538         gus=            [HW,OSS]
539                         Format: <io>,<irq>,<dma>,<dma16>
540
541         gvp11=          [HW,SCSI]
542
543         hashdist=       [KNL,NUMA] Large hashes allocated during boot
544                         are distributed across NUMA nodes.  Defaults on
545                         for IA-64, off otherwise.
546                         Format: 0 | 1 (for off | on)
547
548         hcl=            [IA-64] SGI's Hardware Graph compatibility layer
549
550         hd=             [EIDE] (E)IDE hard drive subsystem geometry
551                         Format: <cyl>,<head>,<sect>
552
553         hd?=            [HW] (E)IDE subsystem
554         hd?lun=         See Documentation/ide.txt.
555
556         highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
557                         size of <nn>. This works even on boxes that have no
558                         highmem otherwise. This also works to reduce highmem
559                         size on bigger boxes.
560
561         hisax=          [HW,ISDN]
562                         See Documentation/isdn/README.HiSax.
563
564         hugepages=      [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
565
566         noirqbalance    [IA-32,SMP,KNL] Disable kernel irq balancing
567
568         i8042.direct    [HW] Put keyboard port into non-translated mode
569         i8042.dumbkbd   [HW] Pretend that controlled can only read data from
570                              keyboard and can not control its state
571                              (Don't attempt to blink the leds)
572         i8042.noaux     [HW] Don't check for auxiliary (== mouse) port
573         i8042.nokbd     [HW] Don't check/create keyboard port
574         i8042.nomux     [HW] Don't check presence of an active multiplexing
575                              controller
576         i8042.nopnp     [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
577                              controllers
578         i8042.panicblink=
579                         [HW] Frequency with which keyboard LEDs should blink
580                              when kernel panics (default is 0.5 sec)
581         i8042.reset     [HW] Reset the controller during init and cleanup
582         i8042.unlock    [HW] Unlock (ignore) the keylock
583
584         i810=           [HW,DRM]
585
586         i8k.ignore_dmi  [HW] Continue probing hardware even if DMI data
587                         indicates that the driver is running on unsupported
588                         hardware.
589         i8k.force       [HW] Activate i8k driver even if SMM BIOS signature
590                         does not match list of supported models.
591         i8k.power_status
592                         [HW] Report power status in /proc/i8k
593                         (disabled by default)
594         i8k.restricted  [HW] Allow controlling fans only if SYS_ADMIN
595                         capability is set.
596
597         ibmmcascsi=     [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
598                         See Documentation/mca.txt.
599
600         icn=            [HW,ISDN]
601                         Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
602
603         ide=            [HW] (E)IDE subsystem
604                         Format: ide=nodma or ide=doubler or ide=reverse
605                         See Documentation/ide.txt.
606
607         ide?=           [HW] (E)IDE subsystem
608                         Format: ide?=noprobe or chipset specific parameters.
609                         See Documentation/ide.txt.
610
611         idebus=         [HW] (E)IDE subsystem - VLB/PCI bus speed
612                         See Documentation/ide.txt.
613
614         idle=           [HW]
615                         Format: idle=poll or idle=halt
616
617         ihash_entries=  [KNL]
618                         Set number of hash buckets for inode cache.
619
620         in2000=         [HW,SCSI]
621                         See header of drivers/scsi/in2000.c.
622
623         init=           [KNL]
624                         Format: <full_path>
625                         Run specified binary instead of /sbin/init as init
626                         process.
627
628         initcall_debug  [KNL] Trace initcalls as they are executed.  Useful
629                         for working out where the kernel is dying during
630                         startup.
631
632         initrd=         [BOOT] Specify the location of the initial ramdisk
633
634         inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
635                         Format: <irq>
636
637         combined_mode=  [HW] control which driver uses IDE ports in combined
638                         mode: legacy IDE driver, libata, or both
639                         (in the libata case, libata.atapi_enabled=1 may be
640                         useful as well).  Note that using the ide or libata
641                         options may affect your device naming (e.g. by
642                         changing hdc to sdb).
643                         Format: combined (default), ide, or libata
644
645         inttest=        [IA64]
646
647         io7=            [HW] IO7 for Marvel based alpha systems
648                         See comment before marvel_specify_io7 in
649                         arch/alpha/kernel/core_marvel.c.
650
651         ip=             [IP_PNP]
652                         See Documentation/nfsroot.txt.
653
654         ip2=            [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
655                         See comment before ip2_setup() in drivers/char/ip2.c.
656
657         ips=            [HW,SCSI] Adaptec / IBM ServeRAID controller
658                         See header of drivers/scsi/ips.c.
659
660         irqfixup        [HW]
661                         When an interrupt is not handled search all handlers
662                         for it. Intended to get systems with badly broken
663                         firmware running.
664
665         irqpoll         [HW]
666                         When an interrupt is not handled search all handlers
667                         for it. Also check all handlers each timer
668                         interrupt. Intended to get systems with badly broken
669                         firmware running.
670
671         isapnp=         [ISAPNP]
672                         Format: <RDP>,<reset>,<pci_scan>,<verbosity>
673
674         isolcpus=       [KNL,SMP] Isolate CPUs from the general scheduler.
675                         Format: <cpu number>,...,<cpu number>
676                         This option can be used to specify one or more CPUs
677                         to isolate from the general SMP balancing and scheduling
678                         algorithms. The only way to move a process onto or off
679                         an "isolated" CPU is via the CPU affinity syscalls.
680                         <cpu number> begins at 0 and the maximum value is
681                         "number of CPUs in system - 1".
682
683                         This option is the preferred way to isolate CPUs. The
684                         alternative -- manually setting the CPU mask of all
685                         tasks in the system -- can cause problems and
686                         suboptimal load balancer performance.
687
688         isp16=          [HW,CD]
689                         Format: <io>,<irq>,<dma>,<setup>
690
691         iucv=           [HW,NET]
692
693         js=             [HW,JOY] Analog joystick
694                         See Documentation/input/joystick.txt.
695
696         keepinitrd      [HW,ARM]
697
698         kstack=N        [IA-32,X86-64] Print N words from the kernel stack
699                         in oops dumps.
700
701         l2cr=           [PPC]
702
703         lapic           [IA-32,APIC] Enable the local APIC even if BIOS
704                         disabled it.
705
706         lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
707                         Format: addr:<io>,irq:<irq>
708
709         llsc*=          [IA64] See function print_params() in
710                         arch/ia64/sn/kernel/llsc4.c.
711
712         load_ramdisk=   [RAM] List of ramdisks to load from floppy
713                         See Documentation/ramdisk.txt.
714
715         lockd.udpport=  [NFS]
716
717         lockd.tcpport=  [NFS]
718
719         logibm.irq=     [HW,MOUSE] Logitech Bus Mouse Driver
720                         Format: <irq>
721
722         loglevel=       All Kernel Messages with a loglevel smaller than the
723                         console loglevel will be printed to the console. It can
724                         also be changed with klogd or other programs. The
725                         loglevels are defined as follows:
726
727                         0 (KERN_EMERG)          system is unusable
728                         1 (KERN_ALERT)          action must be taken immediately
729                         2 (KERN_CRIT)           critical conditions
730                         3 (KERN_ERR)            error conditions
731                         4 (KERN_WARNING)        warning conditions
732                         5 (KERN_NOTICE)         normal but significant condition
733                         6 (KERN_INFO)           informational
734                         7 (KERN_DEBUG)          debug-level messages
735
736         log_buf_len=n   Sets the size of the printk ring buffer, in bytes.
737                         Format: { n | nk | nM }
738                         n must be a power of two.  The default size
739                         is set in the kernel config file.
740
741         lp=0            [LP]    Specify parallel ports to use, e.g,
742         lp=port[,port...]       lp=none,parport0 (lp0 not configured, lp1 uses
743         lp=reset                first parallel port). 'lp=0' disables the
744         lp=auto                 printer driver. 'lp=reset' (which can be
745                                 specified in addition to the ports) causes
746                                 attached printers to be reset. Using
747                                 lp=port1,port2,... specifies the parallel ports
748                                 to associate lp devices with, starting with
749                                 lp0. A port specification may be 'none' to skip
750                                 that lp device, or a parport name such as
751                                 'parport0'. Specifying 'lp=auto' instead of a
752                                 port specification list means that device IDs
753                                 from each port should be examined, to see if
754                                 an IEEE 1284-compliant printer is attached; if
755                                 so, the driver will manage that printer.
756                                 See also header of drivers/char/lp.c.
757
758         lpj=n           [KNL]
759                         Sets loops_per_jiffy to given constant, thus avoiding
760                         time-consuming boot-time autodetection (up to 250 ms per
761                         CPU). 0 enables autodetection (default). To determine
762                         the correct value for your kernel, boot with normal
763                         autodetection and see what value is printed. Note that
764                         on SMP systems the preset will be applied to all CPUs,
765                         which is likely to cause problems if your CPUs need
766                         significantly divergent settings. An incorrect value
767                         will cause delays in the kernel to be wrong, leading to
768                         unpredictable I/O errors and other breakage. Although
769                         unlikely, in the extreme case this might damage your
770                         hardware.
771
772         ltpc=           [NET]
773                         Format: <io>,<irq>,<dma>
774
775         mac5380=        [HW,SCSI] Format:
776                         <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
777
778         mac53c9x=       [HW,SCSI] Format:
779                         <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
780
781         machvec=        [IA64] Force the use of a particular machine-vector
782                         (machvec) in a generic kernel.
783                         Example: machvec=hpzx1_swiotlb
784
785         mad16=          [HW,OSS] Format:
786                         <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
787
788         maui=           [HW,OSS]
789                         Format: <io>,<irq>
790
791         max_loop=       [LOOP] Maximum number of loopback devices that can
792                         be mounted
793                         Format: <1-256>
794
795         maxcpus=        [SMP] Maximum number of processors that an SMP kernel
796                         should make use of
797
798         max_addr=[KMG]  [KNL,BOOT,ia64] All physical memory greater than or
799                         equal to this physical address is ignored.
800
801         max_luns=       [SCSI] Maximum number of LUNs to probe.
802                         Should be between 1 and 2^32-1.
803
804         max_report_luns=
805                         [SCSI] Maximum number of LUNs received.
806                         Should be between 1 and 16384.
807
808         mca-pentium     [BUGS=IA-32]
809
810         mcatest=        [IA-64]
811
812         mcd=            [HW,CD]
813                         Format: <port>,<irq>,<mitsumi_bug_93_wait>
814
815         mcdx=           [HW,CD]
816
817         mce             [IA-32] Machine Check Exception
818
819         md=             [HW] RAID subsystems devices and level
820                         See Documentation/md.txt.
821
822         mdacon=         [MDA]
823                         Format: <first>,<last>
824                         Specifies range of consoles to be captured by the MDA.
825
826         mem=nn[KMG]     [KNL,BOOT] Force usage of a specific amount of memory
827                         Amount of memory to be used when the kernel is not able
828                         to see the whole system memory or for test.
829                         [IA-32] Use together with memmap= to avoid physical
830                         address space collisions. Without memmap= PCI devices
831                         could be placed at addresses belonging to unused RAM.
832
833         mem=nopentium   [BUGS=IA-32] Disable usage of 4MB pages for kernel
834                         memory.
835
836         memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
837                         E820 memory map, as specified by the user.
838                         Such memmap=exactmap lines can be constructed based on
839                         BIOS output or other requirements. See the memmap=nn@ss
840                         option description.
841
842         memmap=nn[KMG]@ss[KMG]
843                         [KNL] Force usage of a specific region of memory
844                         Region of memory to be used, from ss to ss+nn.
845
846         memmap=nn[KMG]#ss[KMG]
847                         [KNL,ACPI] Mark specific memory as ACPI data.
848                         Region of memory to be used, from ss to ss+nn.
849
850         memmap=nn[KMG]$ss[KMG]
851                         [KNL,ACPI] Mark specific memory as reserved.
852                         Region of memory to be used, from ss to ss+nn.
853
854         meye.*=         [HW] Set MotionEye Camera parameters
855                         See Documentation/video4linux/meye.txt.
856
857         mga=            [HW,DRM]
858
859         mousedev.tap_time=
860                         [MOUSE] Maximum time between finger touching and
861                         leaving touchpad surface for touch to be considered
862                         a tap and be reported as a left button click (for
863                         touchpads working in absolute mode only).
864                         Format: <msecs>
865         mousedev.xres=  [MOUSE] Horizontal screen resolution, used for devices
866                         reporting absolute coordinates, such as tablets
867         mousedev.yres=  [MOUSE] Vertical screen resolution, used for devices
868                         reporting absolute coordinates, such as tablets
869
870         mpu401=         [HW,OSS]
871                         Format: <io>,<irq>
872
873         MTD_Partition=  [MTD]
874                         Format: <name>,<region-number>,<size>,<offset>
875
876         MTD_Region=     [MTD] Format:
877                         <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
878
879         mtdparts=       [MTD]
880                         See drivers/mtd/cmdline.c.
881
882         mtouchusb.raw_coordinates=
883                         [HW] Make the MicroTouch USB driver use raw coordinates
884                         ('y', default) or cooked coordinates ('n')
885
886         n2=             [NET] SDL Inc. RISCom/N2 synchronous serial card
887
888         NCR_D700=       [HW,SCSI]
889                         See header of drivers/scsi/NCR_D700.c.
890
891         ncr5380=        [HW,SCSI]
892
893         ncr53c400=      [HW,SCSI]
894
895         ncr53c400a=     [HW,SCSI]
896
897         ncr53c406a=     [HW,SCSI]
898
899         ncr53c8xx=      [HW,SCSI]
900
901         netdev=         [NET] Network devices parameters
902                         Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
903                         Note that mem_start is often overloaded to mean
904                         something different and driver-specific.
905                         This usage is only documented in each driver source
906                         file if at all.
907
908         nfsaddrs=       [NFS]
909                         See Documentation/nfsroot.txt.
910
911         nfsroot=        [NFS] nfs root filesystem for disk-less boxes.
912                         See Documentation/nfsroot.txt.
913
914         nfs.callback_tcpport=
915                         [NFS] set the TCP port on which the NFSv4 callback
916                         channel should listen.
917
918         nfs.idmap_cache_timeout=
919                         [NFS] set the maximum lifetime for idmapper cache
920                         entries.
921
922         nmi_watchdog=   [KNL,BUGS=IA-32] Debugging features for SMP kernels
923
924         no387           [BUGS=IA-32] Tells the kernel to use the 387 maths
925                         emulation library even if a 387 maths coprocessor
926                         is present.
927
928         noalign         [KNL,ARM]
929
930         noapic          [SMP,APIC] Tells the kernel to not make use of any
931                         IOAPICs that may be present in the system.
932
933         noasync         [HW,M68K] Disables async and sync negotiation for
934                         all devices.
935
936         nobats          [PPC] Do not use BATs for mapping kernel lowmem
937                         on "Classic" PPC cores.
938
939         nocache         [ARM]
940
941         nodisconnect    [HW,SCSI,M68K] Disables SCSI disconnects.
942
943         noexec          [IA-64]
944
945         noexec          [IA-32,X86-64]
946                         noexec=on: enable non-executable mappings (default)
947                         noexec=off: disable nn-executable mappings
948
949         nofxsr          [BUGS=IA-32]
950
951         nohlt           [BUGS=ARM]
952
953         no-hlt          [BUGS=IA-32] Tells the kernel that the hlt
954                         instruction doesn't work correctly and not to
955                         use it.
956
957         nohalt          [IA-64] Tells the kernel not to use the power saving
958                         function PAL_HALT_LIGHT when idle. This increases
959                         power-consumption. On the positive side, it reduces
960                         interrupt wake-up latency, which may improve performance
961                         in certain environments such as networked servers or
962                         real-time systems.
963
964         noirqdebug      [IA-32] Disables the code which attempts to detect and
965                         disable unhandled interrupt sources.
966
967         noisapnp        [ISAPNP] Disables ISA PnP code.
968
969         noinitrd        [RAM] Tells the kernel not to load any configured
970                         initial RAM disk.
971
972         nointroute      [IA-64]
973
974         nolapic         [IA-32,APIC] Do not enable or use the local APIC.
975
976         noltlbs         [PPC] Do not use large page/tlb entries for kernel
977                         lowmem mapping on PPC40x.
978
979         nomce           [IA-32] Machine Check Exception
980
981         noresidual      [PPC] Don't use residual data on PReP machines.
982
983         noresume        [SWSUSP] Disables resume and restores original swap
984                         space.
985
986         no-scroll       [VGA] Disables scrollback.
987                         This is required for the Braillex ib80-piezo Braille
988                         reader made by F.H. Papenmeier (Germany).
989
990         nosbagart       [IA-64]
991
992         nosmp           [SMP] Tells an SMP kernel to act as a UP kernel.
993
994         nosync          [HW,M68K] Disables sync negotiation for all devices.
995
996         notsc           [BUGS=IA-32] Disable Time Stamp Counter
997
998         nousb           [USB] Disable the USB subsystem
999
1000         nowb            [ARM]
1001
1002         nr_uarts=       [SERIAL] maximum number of UARTs to be registered.
1003
1004         opl3=           [HW,OSS]
1005                         Format: <io>
1006
1007         opl3sa=         [HW,OSS]
1008                         Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1009
1010         opl3sa2=        [HW,OSS] Format:
1011                         <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1012
1013         oprofile.timer= [HW]
1014                         Use timer interrupt instead of performance counters
1015
1016         optcd=          [HW,CD]
1017                         Format: <io>
1018
1019         osst=           [HW,SCSI] SCSI Tape Driver
1020                         Format: <buffer_size>,<write_threshold>
1021                         See also Documentation/scsi/st.txt.
1022
1023         panic=          [KNL] Kernel behaviour on panic
1024                         Format: <timeout>
1025
1026         parkbd.port=    [HW] Parallel port number the keyboard adapter is
1027                         connected to, default is 0.
1028                         Format: <parport#>
1029         parkbd.mode=    [HW] Parallel port keyboard adapter mode of operation,
1030                         0 for XT, 1 for AT (default is AT).
1031                         Format: <mode>
1032
1033         parport=        [HW,PPT] Specify parallel ports. 0 disables.
1034                         Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1035                         Use 'auto' to force the driver to use any
1036                         IRQ/DMA settings detected (the default is to
1037                         ignore detected IRQ/DMA settings because of
1038                         possible conflicts). You can specify the base
1039                         address, IRQ, and DMA settings; IRQ and DMA
1040                         should be numbers, or 'auto' (for using detected
1041                         settings on that particular port), or 'nofifo'
1042                         (to avoid using a FIFO even if it is detected).
1043                         Parallel ports are assigned in the order they
1044                         are specified on the command line, starting
1045                         with parport0.
1046
1047         parport_init_mode=      [HW,PPT]
1048                         Configure VIA parallel port to operate in
1049                         a specific mode. This is necessary on Pegasos
1050                         computer where firmware has no options for setting
1051                         up parallel port mode and sets it to spp.
1052                         Currently this function knows 686a and 8231 chips.
1053                         Format: [spp|ps2|epp|ecp|ecpepp]
1054
1055         pas2=           [HW,OSS] Format:
1056                         <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1057
1058         pas16=          [HW,SCSI]
1059                         See header of drivers/scsi/pas16.c.
1060
1061         pcbit=          [HW,ISDN]
1062
1063         pcd.            [PARIDE]
1064                         See header of drivers/block/paride/pcd.c.
1065                         See also Documentation/paride.txt.
1066
1067         pci=option[,option...]  [PCI] various PCI subsystem options:
1068                 off             [IA-32] don't probe for the PCI bus
1069                 bios            [IA-32] force use of PCI BIOS, don't access
1070                                 the hardware directly. Use this if your machine
1071                                 has a non-standard PCI host bridge.
1072                 nobios          [IA-32] disallow use of PCI BIOS, only direct
1073                                 hardware access methods are allowed. Use this
1074                                 if you experience crashes upon bootup and you
1075                                 suspect they are caused by the BIOS.
1076                 conf1           [IA-32] Force use of PCI Configuration
1077                                 Mechanism 1.
1078                 conf2           [IA-32] Force use of PCI Configuration
1079                                 Mechanism 2.
1080                 nosort          [IA-32] Don't sort PCI devices according to
1081                                 order given by the PCI BIOS. This sorting is
1082                                 done to get a device order compatible with
1083                                 older kernels.
1084                 biosirq         [IA-32] Use PCI BIOS calls to get the interrupt
1085                                 routing table. These calls are known to be buggy
1086                                 on several machines and they hang the machine
1087                                 when used, but on other computers it's the only
1088                                 way to get the interrupt routing table. Try
1089                                 this option if the kernel is unable to allocate
1090                                 IRQs or discover secondary PCI buses on your
1091                                 motherboard.
1092                 rom             [IA-32] Assign address space to expansion ROMs.
1093                                 Use with caution as certain devices share
1094                                 address decoders between ROMs and other
1095                                 resources.
1096                 irqmask=0xMMMM  [IA-32] Set a bit mask of IRQs allowed to be
1097                                 assigned automatically to PCI devices. You can
1098                                 make the kernel exclude IRQs of your ISA cards
1099                                 this way.
1100                 pirqaddr=0xAAAAA        [IA-32] Specify the physical address
1101                                 of the PIRQ table (normally generated
1102                                 by the BIOS) if it is outside the
1103                                 F0000h-100000h range.
1104                 lastbus=N       [IA-32] Scan all buses thru bus #N. Can be
1105                                 useful if the kernel is unable to find your
1106                                 secondary buses and you want to tell it
1107                                 explicitly which ones they are.
1108                 assign-busses   [IA-32] Always assign all PCI bus
1109                                 numbers ourselves, overriding
1110                                 whatever the firmware may have done.
1111                 usepirqmask     [IA-32] Honor the possible IRQ mask stored
1112                                 in the BIOS $PIR table. This is needed on
1113                                 some systems with broken BIOSes, notably
1114                                 some HP Pavilion N5400 and Omnibook XE3
1115                                 notebooks. This will have no effect if ACPI
1116                                 IRQ routing is enabled.
1117                 noacpi          [IA-32] Do not use ACPI for IRQ routing
1118                                 or for PCI scanning.
1119                 routeirq        Do IRQ routing for all PCI devices.
1120                                 This is normally done in pci_enable_device(),
1121                                 so this option is a temporary workaround
1122                                 for broken drivers that don't call it.
1123                 firmware        [ARM] Do not re-enumerate the bus but instead
1124                                 just use the configuration from the
1125                                 bootloader. This is currently used on
1126                                 IXP2000 systems where the bus has to be
1127                                 configured a certain way for adjunct CPUs.
1128
1129         pcmv=           [HW,PCMCIA] BadgePAD 4
1130
1131         pd.             [PARIDE]
1132                         See Documentation/paride.txt.
1133
1134         pdcchassis=     [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1135                         boot time.
1136                         Format: { 0 | 1 }
1137                         See arch/parisc/kernel/pdc_chassis.c
1138
1139         pf.             [PARIDE]
1140                         See Documentation/paride.txt.
1141
1142         pg.             [PARIDE]
1143                         See Documentation/paride.txt.
1144
1145         pirq=           [SMP,APIC] Manual mp-table setup
1146                         See Documentation/i386/IO-APIC.txt.
1147
1148         plip=           [PPT,NET] Parallel port network link
1149                         Format: { parport<nr> | timid | 0 }
1150                         See also Documentation/parport.txt.
1151
1152         pnpacpi=        [ACPI]
1153                         { off }
1154
1155         pnpbios=        [ISAPNP]
1156                         { on | off | curr | res | no-curr | no-res }
1157
1158         pnp_reserve_irq=
1159                         [ISAPNP] Exclude IRQs for the autoconfiguration
1160
1161         pnp_reserve_dma=
1162                         [ISAPNP] Exclude DMAs for the autoconfiguration
1163
1164         pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1165                         Ranges are in pairs (I/O port base and size).
1166
1167         pnp_reserve_mem=
1168                         [ISAPNP] Exclude memory regions for the
1169                         autoconfiguration.
1170                         Ranges are in pairs (memory base and size).
1171
1172         profile=        [KNL] Enable kernel profiling via /proc/profile
1173                         Format: [schedule,]<number>
1174                         Param: "schedule" - profile schedule points.
1175                         Param: <number> - step/bucket size as a power of 2 for
1176                                 statistical time based profiling.
1177
1178         processor.max_cstate=   [HW,ACPI]
1179                         Limit processor to maximum C-state
1180                         max_cstate=9 overrides any DMI blacklist limit.
1181
1182         processor.nocst [HW,ACPI]
1183                         Ignore the _CST method to determine C-states,
1184                         instead using the legacy FADT method
1185
1186         prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1187                         before loading.
1188                         See Documentation/ramdisk.txt.
1189
1190         psmouse.proto=  [HW,MOUSE] Highest PS2 mouse protocol extension to
1191                         probe for; one of (bare|imps|exps|lifebook|any).
1192         psmouse.rate=   [HW,MOUSE] Set desired mouse report rate, in reports
1193                         per second.
1194         psmouse.resetafter=     [HW,MOUSE]
1195                         Try to reset the device after so many bad packets
1196                         (0 = never).
1197         psmouse.resolution=
1198                         [HW,MOUSE] Set desired mouse resolution, in dpi.
1199         psmouse.smartscroll=
1200                         [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1201                         0 = disabled, 1 = enabled (default).
1202
1203         pss=            [HW,OSS] Personal Sound System (ECHO ESC614)
1204                         Format:
1205                         <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1206
1207         pt.             [PARIDE]
1208                         See Documentation/paride.txt.
1209
1210         quiet=          [KNL] Disable log messages
1211
1212         r128=           [HW,DRM]
1213
1214         raid=           [HW,RAID]
1215                         See Documentation/md.txt.
1216
1217         ramdisk=        [RAM] Sizes of RAM disks in kilobytes [deprecated]
1218                         See Documentation/ramdisk.txt.
1219
1220         ramdisk_blocksize=      [RAM]
1221                         See Documentation/ramdisk.txt.
1222
1223         ramdisk_size=   [RAM] Sizes of RAM disks in kilobytes
1224                         New name for the ramdisk parameter.
1225                         See Documentation/ramdisk.txt.
1226
1227         rdinit=         [KNL]
1228                         Format: <full_path>
1229                         Run specified binary instead of /init from the ramdisk,
1230                         used for early userspace startup. See initrd.
1231
1232         reboot=         [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1233                         Format: <reboot_mode>[,<reboot_mode2>[,...]]
1234                         See arch/*/kernel/reboot.c.
1235
1236         reserve=        [KNL,BUGS] Force the kernel to ignore some iomem area
1237
1238         resume=         [SWSUSP]
1239                         Specify the partition device for software suspend
1240
1241         rhash_entries=  [KNL,NET]
1242                         Set number of hash buckets for route cache
1243
1244         riscom8=        [HW,SERIAL]
1245                         Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1246
1247         ro              [KNL] Mount root device read-only on boot
1248
1249         root=           [KNL] Root filesystem
1250
1251         rootdelay=      [KNL] Delay (in seconds) to pause before attempting to
1252                         mount the root filesystem
1253
1254         rootflags=      [KNL] Set root filesystem mount option string
1255
1256         rootfstype=     [KNL] Set root filesystem type
1257
1258         rw              [KNL] Mount root device read-write on boot
1259
1260         S               [KNL] Run init in single mode
1261
1262         sa1100ir        [NET]
1263                         See drivers/net/irda/sa1100_ir.c.
1264
1265         sb=             [HW,OSS]
1266                         Format: <io>,<irq>,<dma>,<dma2>
1267
1268         sbni=           [NET] Granch SBNI12 leased line adapter
1269
1270         sbpcd=          [HW,CD] Soundblaster CD adapter
1271                         Format: <io>,<type>
1272                         See a comment before function sbpcd_setup() in
1273                         drivers/cdrom/sbpcd.c.
1274
1275         sc1200wdt=      [HW,WDT] SC1200 WDT (watchdog) driver
1276                         Format: <io>[,<timeout>[,<isapnp>]]
1277
1278         scsi_debug_*=   [SCSI]
1279                         See drivers/scsi/scsi_debug.c.
1280
1281         scsi_default_dev_flags=
1282                         [SCSI] SCSI default device flags
1283                         Format: <integer>
1284
1285         scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1286                         Format: <vendor>:<model>:<flags>
1287                         (flags are integer value)
1288
1289         scsi_logging=   [SCSI]
1290
1291         selinux         [SELINUX] Disable or enable SELinux at boot time.
1292                         Format: { "0" | "1" }
1293                         See security/selinux/Kconfig help text.
1294                         0 -- disable.
1295                         1 -- enable.
1296                         Default value is set via kernel config option.
1297                         If enabled at boot time, /selinux/disable can be used
1298                         later to disable prior to initial policy load.
1299
1300         serialnumber    [BUGS=IA-32]
1301
1302         sg_def_reserved_size=   [SCSI]
1303
1304         sgalaxy=        [HW,OSS]
1305                         Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1306
1307         shapers=        [NET]
1308                         Maximal number of shapers.
1309
1310         sim710=         [SCSI,HW]
1311                         See header of drivers/scsi/sim710.c.
1312
1313         simeth=         [IA-64]
1314         simscsi=
1315
1316         sjcd=           [HW,CD]
1317                         Format: <io>,<irq>,<dma>
1318                         See header of drivers/cdrom/sjcd.c.
1319
1320         slram=          [HW,MTD]
1321
1322         smart2=         [HW]
1323                         Format: <io1>[,<io2>[,...,<io8>]]
1324
1325         snd-ad1816a=    [HW,ALSA]
1326
1327         snd-ad1848=     [HW,ALSA]
1328
1329         snd-ali5451=    [HW,ALSA]
1330
1331         snd-als100=     [HW,ALSA]
1332
1333         snd-als4000=    [HW,ALSA]
1334
1335         snd-azt2320=    [HW,ALSA]
1336
1337         snd-cmi8330=    [HW,ALSA]
1338
1339         snd-cmipci=     [HW,ALSA]
1340
1341         snd-cs4231=     [HW,ALSA]
1342
1343         snd-cs4232=     [HW,ALSA]
1344
1345         snd-cs4236=     [HW,ALSA]
1346
1347         snd-cs4281=     [HW,ALSA]
1348
1349         snd-cs46xx=     [HW,ALSA]
1350
1351         snd-dt019x=     [HW,ALSA]
1352
1353         snd-dummy=      [HW,ALSA]
1354
1355         snd-emu10k1=    [HW,ALSA]
1356
1357         snd-ens1370=    [HW,ALSA]
1358
1359         snd-ens1371=    [HW,ALSA]
1360
1361         snd-es968=      [HW,ALSA]
1362
1363         snd-es1688=     [HW,ALSA]
1364
1365         snd-es18xx=     [HW,ALSA]
1366
1367         snd-es1938=     [HW,ALSA]
1368
1369         snd-es1968=     [HW,ALSA]
1370
1371         snd-fm801=      [HW,ALSA]
1372
1373         snd-gusclassic= [HW,ALSA]
1374
1375         snd-gusextreme= [HW,ALSA]
1376
1377         snd-gusmax=     [HW,ALSA]
1378
1379         snd-hdsp=       [HW,ALSA]
1380
1381         snd-ice1712=    [HW,ALSA]
1382
1383         snd-intel8x0=   [HW,ALSA]
1384
1385         snd-interwave=  [HW,ALSA]
1386
1387         snd-interwave-stb=
1388                         [HW,ALSA]
1389
1390         snd-korg1212=   [HW,ALSA]
1391
1392         snd-maestro3=   [HW,ALSA]
1393
1394         snd-mpu401=     [HW,ALSA]
1395
1396         snd-mtpav=      [HW,ALSA]
1397
1398         snd-nm256=      [HW,ALSA]
1399
1400         snd-opl3sa2=    [HW,ALSA]
1401
1402         snd-opti92x-ad1848=
1403                         [HW,ALSA]
1404
1405         snd-opti92x-cs4231=
1406                         [HW,ALSA]
1407
1408         snd-opti93x=    [HW,ALSA]
1409
1410         snd-pmac=       [HW,ALSA]
1411
1412         snd-rme32=      [HW,ALSA]
1413
1414         snd-rme96=      [HW,ALSA]
1415
1416         snd-rme9652=    [HW,ALSA]
1417
1418         snd-sb8=        [HW,ALSA]
1419
1420         snd-sb16=       [HW,ALSA]
1421
1422         snd-sbawe=      [HW,ALSA]
1423
1424         snd-serial=     [HW,ALSA]
1425
1426         snd-sgalaxy=    [HW,ALSA]
1427
1428         snd-sonicvibes= [HW,ALSA]
1429
1430         snd-sun-amd7930=
1431                         [HW,ALSA]
1432
1433         snd-sun-cs4231= [HW,ALSA]
1434
1435         snd-trident=    [HW,ALSA]
1436
1437         snd-usb-audio=  [HW,ALSA,USB]
1438
1439         snd-via82xx=    [HW,ALSA]
1440
1441         snd-virmidi=    [HW,ALSA]
1442
1443         snd-wavefront=  [HW,ALSA]
1444
1445         snd-ymfpci=     [HW,ALSA]
1446
1447         sonicvibes=     [HW,OSS]
1448                         Format: <reverb>
1449
1450         sonycd535=      [HW,CD]
1451                         Format: <io>[,<irq>]
1452
1453         sonypi.*=       [HW] Sony Programmable I/O Control Device driver
1454                         See Documentation/sonypi.txt
1455
1456         specialix=      [HW,SERIAL] Specialix multi-serial port adapter
1457                         See Documentation/specialix.txt.
1458
1459         spia_io_base=   [HW,MTD]
1460         spia_fio_base=
1461         spia_pedr=
1462         spia_peddr=
1463
1464         sscape=         [HW,OSS]
1465                         Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1466
1467         st=             [HW,SCSI] SCSI tape parameters (buffers, etc.)
1468                         See Documentation/scsi/st.txt.
1469
1470         st0x=           [HW,SCSI]
1471                         See header of drivers/scsi/seagate.c.
1472
1473         sti=            [PARISC,HW]
1474                         Format: <num>
1475                         Set the STI (builtin display/keyboard on the HP-PARISC
1476                         machines) console (graphic card) which should be used
1477                         as the initial boot-console.
1478                         See also comment in drivers/video/console/sticore.c.
1479
1480         sti_font=       [HW]
1481                         See comment in drivers/video/console/sticore.c.
1482
1483         stifb=          [HW]
1484                         Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1485
1486         swiotlb=        [IA-64] Number of I/O TLB slabs
1487
1488         switches=       [HW,M68k]
1489
1490         sym53c416=      [HW,SCSI]
1491                         See header of drivers/scsi/sym53c416.c.
1492
1493         t128=           [HW,SCSI]
1494                         See header of drivers/scsi/t128.c.
1495
1496         tdfx=           [HW,DRM]
1497
1498         thash_entries=  [KNL,NET]
1499                         Set number of hash buckets for TCP connection
1500
1501         time            Show timing data prefixed to each printk message line
1502
1503         tipar.timeout=  [HW,PPT]
1504                         Set communications timeout in tenths of a second
1505                         (default 15).
1506
1507         tipar.delay=    [HW,PPT]
1508                         Set inter-bit delay in microseconds (default 10).
1509
1510         tmc8xx=         [HW,SCSI]
1511                         See header of drivers/scsi/seagate.c.
1512
1513         tmscsim=        [HW,SCSI]
1514                         See comment before function dc390_setup() in
1515                         drivers/scsi/tmscsim.c.
1516
1517         tp720=          [HW,PS2]
1518
1519         trix=           [HW,OSS] MediaTrix AudioTrix Pro
1520                         Format:
1521                         <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1522
1523         tsdev.xres=     [TS] Horizontal screen resolution.
1524         tsdev.yres=     [TS] Vertical screen resolution.
1525
1526         turbografx.map[2|3]=    [HW,JOY]
1527                         TurboGraFX parallel port interface
1528                         Format:
1529                         <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1530                         See also Documentation/input/joystick-parport.txt
1531
1532         u14-34f=        [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1533                         See header of drivers/scsi/u14-34f.c.
1534
1535         uart401=        [HW,OSS]
1536                         Format: <io>,<irq>
1537
1538         uart6850=       [HW,OSS]
1539                         Format: <io>,<irq>
1540
1541         usbhid.mousepoll=
1542                         [USBHID] The interval which mice are to be polled at.
1543
1544         video=          [FB] Frame buffer configuration
1545                         See Documentation/fb/modedb.txt.
1546
1547         vga=            [BOOT,IA-32] Select a particular video mode
1548                         See Documentation/i386/boot.txt and
1549                         Documentation/svga.txt.
1550                         Use vga=ask for menu.
1551                         This is actually a boot loader parameter; the value is
1552                         passed to the kernel using a special protocol.
1553
1554         vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1555                         size of <nn>. This can be used to increase the
1556                         minimum size (128MB on x86). It can also be used to
1557                         decrease the size and leave more room for directly
1558                         mapped kernel RAM.
1559
1560         vmhalt=         [KNL,S390]
1561
1562         vmpoff=         [KNL,S390]
1563
1564         waveartist=     [HW,OSS]
1565                         Format: <io>,<irq>,<dma>,<dma2>
1566
1567         wd33c93=        [HW,SCSI]
1568                         See header of drivers/scsi/wd33c93.c.
1569
1570         wd7000=         [HW,SCSI]
1571                         See header of drivers/scsi/wd7000.c.
1572
1573         wdt=            [WDT] Watchdog
1574                         See Documentation/watchdog/watchdog.txt.
1575
1576         xd=             [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1577         xd_geo=         See header of drivers/block/xd.c.
1578
1579         xirc2ps_cs=     [NET,PCMCIA]
1580                         Format:
1581                         <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1582
1583
1584 ______________________________________________________________________
1585 Changelog:
1586
1587 2000-06-??      Mr. Unknown
1588         The last known update (for 2.4.0) - the changelog was not kept before.
1589
1590 2002-11-24      Petr Baudis <pasky@ucw.cz>
1591                 Randy Dunlap <randy.dunlap@verizon.net>
1592         Update for 2.5.49, description for most of the options introduced,
1593         references to other documentation (C files, READMEs, ..), added S390,
1594         PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1595         reformatting.
1596
1597 2005-10-19      Randy Dunlap <rdunlap@xenotime.net>
1598         Lots of typos, whitespace, some reformatting.
1599
1600 TODO:
1601
1602         Add documentation for ALSA options.
1603         Add more DRM drivers.