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