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