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 state 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 suspension 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 }
 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] ACPI will balance active IRQs
 127                                 default in APIC mode
 128
 129         acpi_irq_nobalance      [HW,ACPI] ACPI will not move active IRQs (default)
 130                                 default in PIC mode
 131
 132         acpi_irq_pci=   [HW,ACPI] If irq_balance, Clear listed IRQs for use by PCI
 133                         Format: <irq>,<irq>...
 134
 135         acpi_irq_isa=   [HW,ACPI] If irq_balance, Mark listed IRQs used by ISA
 136                         Format: <irq>,<irq>...
 137
 138         acpi_osi=       [HW,ACPI] empty param disables _OSI
 139
 140         acpi_serialize  [HW,ACPI] force serialization of AML methods
 141
 142         acpi_skip_timer_override [HW,ACPI]
 143                         Recognize and ignore IRQ0/pin2 Interrupt Override.
 144                         For broken nForce2 BIOS resulting in XT-PIC timer.
 145
 146         acpi_dbg_layer= [HW,ACPI]
 147                         Format: <int>
 148                         Each bit of the <int> indicates an acpi debug layer,
 149                         1: enable, 0: disable. It is useful for boot time
 150                         debugging. After system has booted up, it can be set
 151                         via /proc/acpi/debug_layer.
 152
 153         acpi_dbg_level= [HW,ACPI]
 154                         Format: <int>
 155                         Each bit of the <int> indicates an acpi debug level,
 156                         1: enable, 0: disable. It is useful for boot time
 157                         debugging. After system has booted up, it can be set
 158                         via /proc/acpi/debug_level.
 159
 160         acpi_fake_ecdt  [HW,ACPI] Workaround failure due to BIOS lacking ECDT
 161
 162         acpi_generic_hotkey [HW,ACPI]
 163                         Allow consolidated generic hotkey driver to
 164                         over-ride platform specific driver.
 165                         See also Documentation/acpi-hotkey.txt.
 166
 167         ad1816=         [HW,OSS]
 168                         Format: <io>,<irq>,<dma>,<dma2>
 169                         See also Documentation/sound/oss/AD1816.
 170
 171         ad1848=         [HW,OSS]
 172                         Format: <io>,<irq>,<dma>,<dma2>,<type>
 173
 174         adlib=          [HW,OSS]
 175                         Format: <io>
 176
 177         advansys=       [HW,SCSI]
 178                         See header of drivers/scsi/advansys.c.
 179
 180         advwdt=         [HW,WDT] Advantech WDT
 181                         Format: <iostart>,<iostop>
 182
 183         aedsp16=        [HW,OSS] Audio Excel DSP 16
 184                         Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
 185                         See also header of sound/oss/aedsp16.c.
 186
 187         aha152x=        [HW,SCSI]
 188                         See Documentation/scsi/aha152x.txt.
 189
 190         aha1542=        [HW,SCSI]
 191                         Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
 192
 193         aic7xxx=        [HW,SCSI]
 194                         See Documentation/scsi/aic7xxx.txt.
 195
 196         aic79xx=        [HW,SCSI]
 197                         See Documentation/scsi/aic79xx.txt.
 198
 199         AM53C974=       [HW,SCSI]
 200                         Format: <host-scsi-id>,<target-scsi-id>,<max-rate>,<max-offset>
 201                         See also header of drivers/scsi/AM53C974.c.
 202
 203         amijoy.map=     [HW,JOY] Amiga joystick support
 204                         Map of devices attached to JOY0DAT and JOY1DAT
 205                         Format: <a>,<b>
 206                         See also Documentation/kernel/input/joystick.txt
 207
 208         analog.map=     [HW,JOY] Analog joystick and gamepad support
 209                         Specifies type or capabilities of an analog joystick
 210                         connected to one of 16 gameports
 211                         Format: <type1>,<type2>,..<type16>
 212
 213         apc=            [HW,SPARC] Power management functions (SPARCstation-4/5 + deriv.)
 214                         Format: noidle
 215                         Disable APC CPU standby support. SPARCstation-Fox does
 216                         not play well with APC CPU idle - disable it if you have
 217                         APC and your system crashes randomly.
 218
 219         apic=           [APIC,i386] Change the output verbosity  whilst booting
 220                         Format: { quiet (default) | verbose | debug }
 221                         Change the amount of debugging information output
 222                         when initialising the APIC and IO-APIC components.
 223
 224         apm=            [APM] Advanced Power Management
 225                         See header of arch/i386/kernel/apm.c.
 226
 227         applicom=       [HW]
 228                         Format: <mem>,<irq>
 229
 230         arcrimi=        [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
 231                         Format: <io>,<irq>,<nodeID>
 232
 233         ataflop=        [HW,M68k]
 234
 235         atarimouse=     [HW,MOUSE] Atari Mouse
 236
 237         atascsi=        [HW,SCSI] Atari SCSI
 238
 239         atkbd.extra=    [HW] Enable extra LEDs and keys on IBM RapidAccess,
 240                         EzKey and similar keyboards
 241
 242         atkbd.reset=    [HW] Reset keyboard during initialization
 243
 244         atkbd.set=      [HW] Select keyboard code set
 245                         Format: <int> (2 = AT (default) 3 = PS/2)
 246
 247         atkbd.scroll=   [HW] Enable scroll wheel on MS Office and similar
 248                         keyboards
 249
 250         atkbd.softraw=  [HW] Choose between synthetic and real raw mode
 251                         Format: <bool> (0 = real, 1 = synthetic (default))
 252
 253         atkbd.softrepeat=
 254                         [HW] Use software keyboard repeat
 255
 256         autotest        [IA64]
 257
 258         awe=            [HW,OSS] AWE32/SB32/AWE64 wave table synth
 259                         Format: <io>,<memsize>,<isapnp>
 260
 261         aztcd=          [HW,CD] Aztech CD268 CDROM driver
 262                         Format: <io>,0x79 (?)
 263
 264         baycom_epp=     [HW,AX25]
 265                         Format: <io>,<mode>
 266
 267         baycom_par=     [HW,AX25] BayCom Parallel Port AX.25 Modem
 268                         Format: <io>,<mode>
 269                         See header of drivers/net/hamradio/baycom_par.c.
 270
 271         baycom_ser_fdx= [HW,AX25] BayCom Serial Port AX.25 Modem (Full Duplex Mode)
 272                         Format: <io>,<irq>,<mode>[,<baud>]
 273                         See header of drivers/net/hamradio/baycom_ser_fdx.c.
 274
 275         baycom_ser_hdx= [HW,AX25] BayCom Serial Port AX.25 Modem (Half Duplex Mode)
 276                         Format: <io>,<irq>,<mode>
 277                         See header of drivers/net/hamradio/baycom_ser_hdx.c.
 278
 279         blkmtd_device=  [HW,MTD]
 280         blkmtd_erasesz=
 281         blkmtd_ro=
 282         blkmtd_bs=
 283         blkmtd_count=
 284
 285         bttv.card=      [HW,V4L] bttv (bt848 + bt878 based grabber cards)
 286         bttv.radio=     Most important insmod options are available as kernel args too.
 287         bttv.pll=       See Documentation/video4linux/bttv/Insmod-options
 288         bttv.tuner=     and Documentation/video4linux/bttv/CARDLIST
 289
 290         BusLogic=       [HW,SCSI]
 291                         See drivers/scsi/BusLogic.c, comment before function
 292                         BusLogic_ParseDriverOptions().
 293
 294         c101=           [NET] Moxa C101 synchronous serial card
 295
 296         cachesize=      [BUGS=IA-32] Override level 2 CPU cache size detection.
 297                         Sometimes CPU hardware bugs make them report the cache
 298                         size incorrectly. The kernel will attempt work arounds
 299                         to fix known problems, but for some CPUs it is not
 300                         possible to determine what the correct size should be.
 301                         This option provides an override for these situations.
 302
 303         cdu31a=         [HW,CD]
 304                         Format: <io>,<irq>[,PAS]
 305                         See header of drivers/cdrom/cdu31a.c.
 306
 307         chandev=        [HW,NET] Generic channel device initialisation
 308
 309         checkreqprot    [SELINUX] Set initial checkreqprot flag value.
 310                         Format: { "0" | "1" }
 311                         See security/selinux/Kconfig help text.
 312                         0 -- check protection applied by kernel (includes any implied execute protection).
 313                         1 -- check protection requested by application.
 314                         Default value is set via a kernel config option.
 315                         Value can be changed at runtime via /selinux/checkreqprot.
 316
 317         clock=          [BUGS=IA-32, HW] gettimeofday timesource override.
 318                         Forces specified timesource (if avaliable) to be used
 319                         when calculating gettimeofday(). If specicified timesource
 320                         is not avalible, it defaults to PIT.
 321                         Format: { pit | tsc | cyclone | pmtmr }
 322
 323         hpet=           [IA-32,HPET] option to disable HPET and use PIT.
 324                         Format: disable
 325
 326         cm206=          [HW,CD]
 327                         Format: { auto | [<io>,][<irq>] }
 328
 329         com20020=       [HW,NET] ARCnet - COM20020 chipset
 330                         Format: <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
 331
 332         com90io=        [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
 333                         Format: <io>[,<irq>]
 334
 335         com90xx=        [HW,NET] ARCnet - COM90xx chipset (memory-mapped buffers)
 336                         Format: <io>[,<irq>[,<memstart>]]
 337
 338         condev=         [HW,S390] console device
 339         conmode=
 340
 341         console=        [KNL] Output console device and options.
 342
 343                 tty<n>  Use the virtual console device <n>.
 344
 345                 ttyS<n>[,options]
 346                         Use the specified serial port.  The options are of
 347                         the form "bbbbpn", where "bbbb" is the baud rate,
 348                         "p" is parity ("n", "o", or "e"), and "n" is bits.
 349                         Default is "9600n8".
 350
 351                         See also Documentation/serial-console.txt.
 352
 353                 uart,io,<addr>[,options]
 354                 uart,mmio,<addr>[,options]
 355                         Start an early, polled-mode console on the 8250/16550
 356                         UART at the specified I/O port or MMIO address,
 357                         switching to the matching ttyS device later.  The
 358                         options are the same as for ttyS, above.
 359
 360         cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
 361                         Format: <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
 362
 363         cpia_pp=        [HW,PPT]
 364                         Format: { parport<nr> | auto | none }
 365
 366         crashkernel=nn[KMG]@ss[KMG]
 367                         [KNL] Reserve a chunk of physical memory to
 368                         hold a kernel to switch to with kexec on panic.
 369
 370         cs4232=         [HW,OSS]
 371                         Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
 372
 373         cs89x0_dma=     [HW,NET]
 374                         Format: <dma>
 375
 376         cs89x0_media=   [HW,NET]
 377                         Format: { rj45 | aui | bnc }
 378
 379         cyclades=       [HW,SERIAL] Cyclades multi-serial port adapter.
 380
 381         dasd=           [HW,NET]
 382                         See header of drivers/s390/block/dasd_devmap.c.
 383
 384         db9.dev[2|3]=   [HW,JOY] Multisystem joystick support via parallel port
 385                         (one device per port)
 386                         Format: <port#>,<type>
 387                         See also Documentation/input/joystick-parport.txt
 388
 389         debug           [KNL] Enable kernel debugging (events log level).
 390
 391         decnet=         [HW,NET]
 392                         Format: <area>[,<node>]
 393                         See also Documentation/networking/decnet.txt.
 394
 395         devfs=          [DEVFS]
 396                         See Documentation/filesystems/devfs/boot-options.
 397
 398         dhash_entries=  [KNL]
 399                         Set number of hash buckets for dentry cache.
 400
 401         digi=           [HW,SERIAL]
 402                         IO parameters + enable/disable command.
 403
 404         digiepca=       [HW,SERIAL]
 405                         See drivers/char/README.epca and
 406                         Documentation/digiepca.txt.
 407
 408         dmascc=         [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
 409                         support available.
 410                         Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
 411
 412         dmasound=       [HW,OSS] Sound subsystem buffers
 413
 414         dscc4.setup=    [NET]
 415
 416         dtc3181e=       [HW,SCSI]
 417
 418         earlyprintk=    [IA-32, X86-64]
 419                         earlyprintk=vga
 420                         earlyprintk=serial[,ttySn[,baudrate]]
 421
 422                         Append ,keep to not disable it when the real console
 423                         takes over.
 424
 425                         Only vga or serial at a time, not both.
 426
 427                         Currently only ttyS0 and ttyS1 are supported.
 428
 429                         Interaction with the standard serial driver is not
 430                         very good.
 431
 432                         The VGA output is eventually overwritten by the real
 433                         console.
 434
 435         eata=           [HW,SCSI]
 436
 437         eda=            [HW,PS2]
 438
 439         edb=            [HW,PS2]
 440
 441         edd=            [EDD]
 442                         Format: {"of[f]" | "sk[ipmbr]"}
 443                         See comment in arch/i386/boot/edd.S
 444
 445         eicon=          [HW,ISDN]
 446                         Format: <id>,<membase>,<irq>
 447
 448         eisa_irq_edge=  [PARISC,HW]
 449                         See header of drivers/parisc/eisa.c.
 450
 451         elanfreq=       [IA-32]
 452                         See comment before function elanfreq_setup() in
 453                         arch/i386/kernel/cpu/cpufreq/elanfreq.c.
 454
 455         elevator=       [IOSCHED]
 456                         Format: {"as"|"cfq"|"deadline"|"noop"}
 457                         See Documentation/block/as-iosched.txt
 458                         and Documentation/block/deadline-iosched.txt for details.
 459         elfcorehdr=     [IA-32]
 460                         Specifies physical address of start of kernel core image
 461                         elf header.
 462                         See Documentation/kdump.txt for details.
 463
 464         enforcing       [SELINUX] Set initial enforcing status.
 465                         Format: {"0" | "1"}
 466                         See security/selinux/Kconfig help text.
 467                         0 -- permissive (log only, no denials).
 468                         1 -- enforcing (deny and log).
 469                         Default value is 0.
 470                         Value can be changed at runtime via /selinux/enforce.
 471
 472         es1370=         [HW,OSS]
 473                         Format: <lineout>[,<micbias>]
 474                         See also header of sound/oss/es1370.c.
 475
 476         es1371=         [HW,OSS]
 477                         Format: <spdif>,[<nomix>,[<amplifier>]]
 478                         See also header of sound/oss/es1371.c.
 479
 480         ether=          [HW,NET] Ethernet cards parameters
 481                         This option is obsoleted by the "netdev=" option, which
 482                         has equivalent usage. See its documentation for details.
 483
 484         eurwdt=         [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
 485                         Format: <io>[,<irq>]
 486
 487         fd_mcs=         [HW,SCSI]
 488                         See header of drivers/scsi/fd_mcs.c.
 489
 490         fdomain=        [HW,SCSI]
 491                         See header of drivers/scsi/fdomain.c.
 492
 493         floppy=         [HW]
 494                         See Documentation/floppy.txt.
 495
 496         ftape=          [HW] Floppy Tape subsystem debugging options.
 497                         See Documentation/ftape.txt.
 498
 499         gamecon.map[2|3]=
 500                         [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
 501                         support via parallel port (up to 5 devices per port)
 502                         Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
 503                         See also Documentation/input/joystick-parport.txt
 504
 505         gamma=          [HW,DRM]
 506
 507         gdth=           [HW,SCSI]
 508                         See header of drivers/scsi/gdth.c.
 509
 510         gpt             [EFI] Forces disk with valid GPT signature but
 511                         invalid Protective MBR to be treated as GPT.
 512
 513         gscd=           [HW,CD]
 514                         Format: <io>
 515
 516         gt96100eth=     [NET] MIPS GT96100 Advanced Communication Controller
 517
 518         gus=            [HW,OSS]
 519                         Format: <io>,<irq>,<dma>,<dma16>
 520
 521         gvp11=          [HW,SCSI]
 522
 523         hashdist=       [KNL,NUMA] Large hashes allocated during boot
 524                         are distributed across NUMA nodes.  Defaults on
 525                         for IA-64, off otherwise.
 526
 527         hcl=            [IA-64] SGI's Hardware Graph compatibility layer
 528
 529         hd=             [EIDE] (E)IDE hard drive subsystem geometry
 530                         Format: <cyl>,<head>,<sect>
 531
 532         hd?=            [HW] (E)IDE subsystem
 533         hd?lun=         See Documentation/ide.txt.
 534
 535         highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
 536                         size of <nn>. This works even on boxes that have no
 537                         highmem otherwise. This also works to reduce highmem
 538                         size on bigger boxes.
 539
 540         hisax=          [HW,ISDN]
 541                         See Documentation/isdn/README.HiSax.
 542
 543         hugepages=      [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
 544
 545         noirqbalance    [IA-32,SMP,KNL] Disable kernel irq balancing
 546
 547         i8042.direct    [HW] Put keyboard port into non-translated mode
 548         i8042.dumbkbd   [HW] Pretend that controlled can only read data from
 549                              keyboard and can not control its state
 550                              (Don't attempt to blink the leds)
 551         i8042.noaux     [HW] Don't check for auxiliary (== mouse) port
 552         i8042.nokbd     [HW] Don't check/create keyboard port
 553         i8042.nomux     [HW] Don't check presence of an active multiplexing
 554                              controller
 555         i8042.nopnp     [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
 556                              controllers
 557         i8042.panicblink=
 558                         [HW] Frequency with which keyboard LEDs should blink
 559                              when kernel panics (default is 0.5 sec)
 560         i8042.reset     [HW] Reset the controller during init and cleanup
 561         i8042.unlock    [HW] Unlock (ignore) the keylock
 562
 563         i810=           [HW,DRM]
 564
 565         i8k.ignore_dmi  [HW] Continue probing hardware even if DMI data
 566                         indicates that the driver is running on unsupported
 567                         hardware.
 568         i8k.force       [HW] Activate i8k driver even if SMM BIOS signature
 569                         does not match list of supported models.
 570         i8k.power_status
 571                         [HW] Report power status in /proc/i8k
 572                         (disabled by default)
 573         i8k.restricted  [HW] Allow controlling fans only if SYS_ADMIN
 574                         capability is set.
 575
 576         ibmmcascsi=     [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
 577                         See Documentation/mca.txt.
 578
 579         icn=            [HW,ISDN]
 580                         Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
 581
 582         ide=            [HW] (E)IDE subsystem
 583                         Format: ide=nodma or ide=doubler or ide=reverse
 584                         See Documentation/ide.txt.
 585
 586         ide?=           [HW] (E)IDE subsystem
 587                         Format: ide?=noprobe or chipset specific parameters.
 588                         See Documentation/ide.txt.
 589
 590         idebus=         [HW] (E)IDE subsystem - VLB/PCI bus speed
 591                         See Documentation/ide.txt.
 592
 593         idle=           [HW]
 594                         Format: idle=poll or idle=halt
 595
 596         ihash_entries=  [KNL]
 597                         Set number of hash buckets for inode cache.
 598
 599         in2000=         [HW,SCSI]
 600                         See header of drivers/scsi/in2000.c.
 601
 602         init=           [KNL]
 603                         Format: <full_path>
 604                         Run specified binary instead of /sbin/init as init
 605                         process.
 606
 607         initcall_debug  [KNL] Trace initcalls as they are executed.  Useful
 608                         for working out where the kernel is dying during
 609                         startup.
 610
 611         initrd=         [BOOT] Specify the location of the initial ramdisk
 612
 613         inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
 614                         Format: <irq>
 615
 616         inttest=        [IA64]
 617
 618         io7=            [HW] IO7 for Marvel based alpha systems
 619                         See comment before marvel_specify_io7 in
 620                         arch/alpha/kernel/core_marvel.c.
 621
 622         ip=             [IP_PNP]
 623                         See Documentation/nfsroot.txt.
 624
 625         ip2=            [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
 626                         See comment before ip2_setup() in drivers/char/ip2.c.
 627
 628         ips=            [HW,SCSI] Adaptec / IBM ServeRAID controller
 629                         See header of drivers/scsi/ips.c.
 630
 631         irqfixup        [HW]
 632                         When an interrupt is not handled search all handlers
 633                         for it. Intended to get systems with badly broken
 634                         firmware running.
 635
 636         irqpoll         [HW]
 637                         When an interrupt is not handled search all handlers
 638                         for it. Also check all handlers each timer
 639                         interrupt. Intended to get systems with badly broken
 640                         firmware running.
 641
 642         isapnp=         [ISAPNP]
 643                         Format: <RDP>, <reset>, <pci_scan>, <verbosity>
 644
 645         isolcpus=       [KNL,SMP] Isolate CPUs from the general scheduler.
 646                         Format: <cpu number>,...,<cpu number>
 647                         This option can be used to specify one or more CPUs
 648                         to isolate from the general SMP balancing and scheduling
 649                         algorithms. The only way to move a process onto or off
 650                         an "isolated" CPU is via the CPU affinity syscalls.
 651                         <cpu number> begins at 0 and the maximum value is
 652                         "number of CPUs in system - 1".
 653
 654                         This option is the preferred way to isolate CPUs. The
 655                         alternative - manually setting the CPU mask of all tasks
 656                         in the system can cause problems and suboptimal load
 657                         balancer performance.
 658
 659         isp16=          [HW,CD]
 660                         Format: <io>,<irq>,<dma>,<setup>
 661
 662         iucv=           [HW,NET]
 663
 664         js=             [HW,JOY] Analog joystick
 665                         See Documentation/input/joystick.txt.
 666
 667         keepinitrd      [HW,ARM]
 668
 669         kstack=N        [IA-32, X86-64] Print N words from the kernel stack
 670                         in oops dumps.
 671
 672         l2cr=           [PPC]
 673
 674         lapic           [IA-32,APIC] Enable the local APIC even if BIOS disabled it.
 675
 676         lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
 677                         Format: addr:<io>,irq:<irq>
 678
 679         llsc*=          [IA64]
 680                         See function print_params() in arch/ia64/sn/kernel/llsc4.c.
 681
 682         load_ramdisk=   [RAM] List of ramdisks to load from floppy
 683                         See Documentation/ramdisk.txt.
 684
 685         lockd.udpport=  [NFS]
 686
 687         lockd.tcpport=  [NFS]
 688
 689         logibm.irq=     [HW,MOUSE] Logitech Bus Mouse Driver
 690                         Format: <irq>
 691
 692         loglevel=       All Kernel Messages with a loglevel smaller than the
 693                         console loglevel will be printed to the console. It can
 694                         also be changed with klogd or other programs. The
 695                         loglevels are defined as follows:
 696
 697                         0 (KERN_EMERG)          system is unusable
 698                         1 (KERN_ALERT)          action must be taken immediately
 699                         2 (KERN_CRIT)           critical conditions
 700                         3 (KERN_ERR)            error conditions
 701                         4 (KERN_WARNING)        warning conditions
 702                         5 (KERN_NOTICE)         normal but significant condition
 703                         6 (KERN_INFO)           informational
 704                         7 (KERN_DEBUG)          debug-level messages
 705
 706         log_buf_len=n   Sets the size of the printk ring buffer, in bytes.
 707                         Format is n, nk, nM.  n must be a power of two.  The
 708                         default is set in kernel config.
 709
 710         lp=0            [LP]    Specify parallel ports to use, e.g,
 711         lp=port[,port...]       lp=none,parport0 (lp0 not configured, lp1 uses
 712         lp=reset                first parallel port). 'lp=0' disables the
 713         lp=auto                 printer driver. 'lp=reset' (which can be
 714                                 specified in addition to the ports) causes
 715                                 attached printers to be reset. Using
 716                                 lp=port1,port2,... specifies the parallel ports
 717                                 to associate lp devices with, starting with
 718                                 lp0. A port specification may be 'none' to skip
 719                                 that lp device, or a parport name such as
 720                                 'parport0'. Specifying 'lp=auto' instead of a
 721                                 port specification list means that device IDs
 722                                 from each port should be examined, to see if
 723                                 an IEEE 1284-compliant printer is attached; if
 724                                 so, the driver will manage that printer.
 725                                 See also header of drivers/char/lp.c.
 726
 727         lpj=n           [KNL]
 728                         Sets loops_per_jiffy to given constant, thus avoiding
 729                         time-consuming boot-time autodetection (up to 250 ms per
 730                         CPU). 0 enables autodetection (default). To determine
 731                         the correct value for your kernel, boot with normal
 732                         autodetection and see what value is printed. Note that
 733                         on SMP systems the preset will be applied to all CPUs,
 734                         which is likely to cause problems if your CPUs need
 735                         significantly divergent settings. An incorrect value
 736                         will cause delays in the kernel to be wrong, leading to
 737                         unpredictable I/O errors and other breakage. Although
 738                         unlikely, in the extreme case this might damage your
 739                         hardware.
 740
 741         ltpc=           [NET]
 742                         Format: <io>,<irq>,<dma>
 743
 744         mac5380=        [HW,SCSI]
 745                         Format: <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 746
 747         mac53c9x=       [HW,SCSI]
 748                         Format: <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 749
 750         machvec=        [IA64]
 751                         Force the use of a particular machine-vector (machvec) in a generic
 752                         kernel.  Example: machvec=hpzx1_swiotlb
 753
 754         mad16=          [HW,OSS]
 755                         Format: <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
 756
 757         maui=           [HW,OSS]
 758                         Format: <io>,<irq>
 759
 760         max_loop=       [LOOP] Maximum number of loopback devices that can
 761                         be mounted
 762                         Format: <1-256>
 763
 764         maxcpus=        [SMP] Maximum number of processors that an SMP kernel
 765                         should make use of
 766
 767         max_addr=[KMG]  [KNL,BOOT,ia64] All physical memory greater than or
 768                         equal to this physical address is ignored.
 769
 770         max_luns=       [SCSI] Maximum number of LUNs to probe
 771                         Should be between 1 and 2^32-1.
 772
 773         max_report_luns=
 774                         [SCSI] Maximum number of LUNs received
 775                         Should be between 1 and 16384.
 776
 777         mca-pentium     [BUGS=IA-32]
 778
 779         mcatest=        [IA-64]
 780
 781         mcd=            [HW,CD]
 782                         Format: <port>,<irq>,<mitsumi_bug_93_wait>
 783
 784         mcdx=           [HW,CD]
 785
 786         mce             [IA-32] Machine Check Exception
 787
 788         md=             [HW] RAID subsystems devices and level
 789                         See Documentation/md.txt.
 790
 791         mdacon=         [MDA]
 792                         Format: <first>,<last>
 793                         Specifies range of consoles to be captured by the MDA.
 794
 795         mem=nn[KMG]     [KNL,BOOT] Force usage of a specific amount of memory
 796                         Amount of memory to be used when the kernel is not able
 797                         to see the whole system memory or for test.
 798                         [IA-32] Use together with memmap= to avoid physical
 799                         address space collisions. Without memmap= PCI devices
 800                         could be placed at addresses belonging to unused RAM.
 801
 802         mem=nopentium   [BUGS=IA-32] Disable usage of 4MB pages for kernel
 803                         memory.
 804
 805         memmap=exactmap [KNL,IA-32] Enable setting of an exact
 806                         E820 memory map, as specified by the user.
 807                         Such memmap=exactmap lines can be constructed based on
 808                         BIOS output or other requirements. See the memmap=nn@ss
 809                         option description.
 810
 811         memmap=nn[KMG]@ss[KMG]
 812                         [KNL] Force usage of a specific region of memory
 813                         Region of memory to be used, from ss to ss+nn.
 814
 815         memmap=nn[KMG]#ss[KMG]
 816                         [KNL,ACPI] Mark specific memory as ACPI data.
 817                         Region of memory to be used, from ss to ss+nn.
 818
 819         memmap=nn[KMG]$ss[KMG]
 820                         [KNL,ACPI] Mark specific memory as reserved.
 821                         Region of memory to be used, from ss to ss+nn.
 822
 823         meye.*=         [HW] Set MotionEye Camera parameters
 824                         See Documentation/video4linux/meye.txt.
 825
 826         mga=            [HW,DRM]
 827
 828         mousedev.tap_time=
 829                         [MOUSE] Maximum time between finger touching and
 830                         leaving touchpad surface for touch to be considered
 831                         a tap and be reported as a left button click (for
 832                         touchpads working in absolute mode only).
 833                         Format: <msecs>
 834         mousedev.xres=  [MOUSE] Horizontal screen resolution, used for devices
 835                         reporting absolute coordinates, such as tablets
 836         mousedev.yres=  [MOUSE] Vertical screen resolution, used for devices
 837                         reporting absolute coordinates, such as tablets
 838
 839         mpu401=         [HW,OSS]
 840                         Format: <io>,<irq>
 841
 842         MTD_Partition=  [MTD]
 843                         Format: <name>,<region-number>,<size>,<offset>
 844
 845         MTD_Region=     [MTD]
 846                         Format: <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
 847
 848         mtdparts=       [MTD]
 849                         See drivers/mtd/cmdline.c.
 850
 851         mtouchusb.raw_coordinates=
 852                         [HW] Make the MicroTouch USB driver use raw coordinates ('y', default)
 853                         or cooked coordinates ('n')
 854
 855         n2=             [NET] SDL Inc. RISCom/N2 synchronous serial card
 856
 857         NCR_D700=       [HW,SCSI]
 858                         See header of drivers/scsi/NCR_D700.c.
 859
 860         ncr5380=        [HW,SCSI]
 861
 862         ncr53c400=      [HW,SCSI]
 863
 864         ncr53c400a=     [HW,SCSI]
 865
 866         ncr53c406a=     [HW,SCSI]
 867
 868         ncr53c8xx=      [HW,SCSI]
 869
 870         netdev=         [NET] Network devices parameters
 871                         Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
 872                         Note that mem_start is often overloaded to mean
 873                         something different and driver-specific.
 874
 875         nfsaddrs=       [NFS]
 876                         See Documentation/nfsroot.txt.
 877
 878         nfsroot=        [NFS] nfs root filesystem for disk-less boxes.
 879                         See Documentation/nfsroot.txt.
 880
 881         nmi_watchdog=   [KNL,BUGS=IA-32] Debugging features for SMP kernels
 882
 883         no387           [BUGS=IA-32] Tells the kernel to use the 387 maths
 884                         emulation library even if a 387 maths coprocessor
 885                         is present.
 886
 887         noalign         [KNL,ARM]
 888
 889         noapic          [SMP,APIC] Tells the kernel to not make use of any
 890                         IOAPICs that may be present in the system.
 891
 892         noasync         [HW,M68K] Disables async and sync negotiation for
 893                         all devices.
 894
 895         nobats          [PPC] Do not use BATs for mapping kernel lowmem
 896                         on "Classic" PPC cores.
 897
 898         nocache         [ARM]
 899
 900         nodisconnect    [HW,SCSI,M68K] Disables SCSI disconnects.
 901
 902         noexec          [IA-64]
 903
 904         noexec          [IA-32, X86-64]
 905                         noexec=on: enable non-executable mappings (default)
 906                         noexec=off: disable nn-executable mappings
 907
 908         nofxsr          [BUGS=IA-32]
 909
 910         nohlt           [BUGS=ARM]
 911
 912         no-hlt          [BUGS=IA-32] Tells the kernel that the hlt
 913                         instruction doesn't work correctly and not to
 914                         use it.
 915
 916         nohalt          [IA-64] Tells the kernel not to use the power saving
 917                         function PAL_HALT_LIGHT when idle. This increases
 918                         power-consumption. On the positive side, it reduces
 919                         interrupt wake-up latency, which may improve performance
 920                         in certain environments such as networked servers or
 921                         real-time systems.
 922
 923         noirqdebug      [IA-32] Disables the code which attempts to detect and
 924                         disable unhandled interrupt sources.
 925
 926         noisapnp        [ISAPNP] Disables ISA PnP code.
 927
 928         noinitrd        [RAM] Tells the kernel not to load any configured
 929                         initial RAM disk.
 930
 931         nointroute      [IA-64]
 932
 933         nolapic         [IA-32,APIC] Do not enable or use the local APIC.
 934
 935         noltlbs         [PPC] Do not use large page/tlb entries for kernel
 936                         lowmem mapping on PPC40x.
 937
 938         nomce           [IA-32] Machine Check Exception
 939
 940         noresidual      [PPC] Don't use residual data on PReP machines.
 941
 942         noresume        [SWSUSP] Disables resume and restore original swap space.
 943
 944         no-scroll       [VGA] Disables scrollback.
 945                         This is required for the Braillex ib80-piezo Braille
 946                         reader made by F.H. Papenmeier (Germany).
 947
 948         nosbagart       [IA-64]
 949
 950         nosmp           [SMP] Tells an SMP kernel to act as a UP kernel.
 951
 952         nosync          [HW,M68K] Disables sync negotiation for all devices.
 953
 954         notsc           [BUGS=IA-32] Disable Time Stamp Counter
 955
 956         nousb           [USB] Disable the USB subsystem
 957
 958         nowb            [ARM]
 959
 960         opl3=           [HW,OSS]
 961                         Format: <io>
 962
 963         opl3sa=         [HW,OSS]
 964                         Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
 965
 966         opl3sa2=        [HW,OSS]
 967                         Format: <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
 968
 969         oprofile.timer= [HW]
 970                         Use timer interrupt instead of performance counters
 971
 972         optcd=          [HW,CD]
 973                         Format: <io>
 974
 975         osst=           [HW,SCSI] SCSI Tape Driver
 976                         Format: <buffer_size>,<write_threshold>
 977                         See also Documentation/scsi/st.txt.
 978
 979         panic=          [KNL] Kernel behaviour on panic
 980                         Format: <timeout>
 981
 982         parkbd.port=    [HW] Parallel port number the keyboard adapter is
 983                         connected to, default is 0.
 984                         Format: <parport#>
 985         parkbd.mode=    [HW] Parallel port keyboard adapter mode of operation,
 986                         0 for XT, 1 for AT (default is AT).
 987                         Format: <mode>
 988
 989         parport=0       [HW,PPT]        Specify parallel ports. 0 disables.
 990         parport=auto                    Use 'auto' to force the driver to use
 991         parport=0xBBB[,IRQ[,DMA]]       any IRQ/DMA settings detected (the
 992                                         default is to ignore detected IRQ/DMA
 993                                         settings because of possible
 994                                         conflicts). You can specify the base
 995                                         address, IRQ, and DMA settings; IRQ and
 996                                         DMA should be numbers, or 'auto' (for
 997                                         using detected settings on that
 998                                         particular port), or 'nofifo' (to avoid
 999                                         using a FIFO even if it is detected).
1000                                         Parallel ports are assigned in the
1001                                         order they are specified on the command
1002                                         line, starting with parport0.
1003
1004         parport_init_mode=
1005                         [HW,PPT]        Configure VIA parallel port to
1006                                         operate in specific mode. This is
1007                                         necessary on Pegasos computer where
1008                                         firmware has no options for setting up
1009                                         parallel port mode and sets it to
1010                                         spp. Currently this function knows
1011                                         686a and 8231 chips.
1012                         Format: [spp|ps2|epp|ecp|ecpepp]
1013
1014         pas2=           [HW,OSS]
1015                         Format: <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1016
1017         pas16=          [HW,SCSI]
1018                         See header of drivers/scsi/pas16.c.
1019
1020         pcbit=          [HW,ISDN]
1021
1022         pcd.            [PARIDE]
1023                         See header of drivers/block/paride/pcd.c.
1024                         See also Documentation/paride.txt.
1025
1026         pci=option[,option...]          [PCI] various PCI subsystem options:
1027                 off                     [IA-32] don't probe for the PCI bus
1028                 bios                    [IA-32] force use of PCI BIOS, don't access
1029                                         the hardware directly. Use this if your machine
1030                                         has a non-standard PCI host bridge.
1031                 nobios                  [IA-32] disallow use of PCI BIOS, only direct
1032                                         hardware access methods are allowed. Use this
1033                                         if you experience crashes upon bootup and you
1034                                         suspect they are caused by the BIOS.
1035                 conf1                   [IA-32] Force use of PCI Configuration Mechanism 1.
1036                 conf2                   [IA-32] Force use of PCI Configuration Mechanism 2.
1037                 nosort                  [IA-32] Don't sort PCI devices according to
1038                                         order given by the PCI BIOS. This sorting is done
1039                                         to get a device order compatible with older kernels.
1040                 biosirq                 [IA-32] Use PCI BIOS calls to get the interrupt
1041                                         routing table. These calls are known to be buggy
1042                                         on several machines and they hang the machine when used,
1043                                         but on other computers it's the only way to get the
1044                                         interrupt routing table. Try this option if the kernel
1045                                         is unable to allocate IRQs or discover secondary PCI
1046                                         buses on your motherboard.
1047                 rom                     [IA-32] Assign address space to expansion ROMs.
1048                                         Use with caution as certain devices share address
1049                                         decoders between ROMs and other resources.
1050                 irqmask=0xMMMM          [IA-32] Set a bit mask of IRQs allowed to be assigned
1051                                         automatically to PCI devices. You can make the kernel
1052                                         exclude IRQs of your ISA cards this way.
1053                 pirqaddr=0xAAAAA        [IA-32] Specify the physical address
1054                                         of the PIRQ table (normally generated
1055                                         by the BIOS) if it is outside the
1056                                         F0000h-100000h range.
1057                 lastbus=N               [IA-32] Scan all buses till bus #N. Can be useful
1058                                         if the kernel is unable to find your secondary buses
1059                                         and you want to tell it explicitly which ones they are.
1060                 assign-busses           [IA-32] Always assign all PCI bus
1061                                         numbers ourselves, overriding
1062                                         whatever the firmware may have
1063                                         done.
1064                 usepirqmask             [IA-32] Honor the possible IRQ mask
1065                                         stored in the BIOS $PIR table. This is
1066                                         needed on some systems with broken
1067                                         BIOSes, notably some HP Pavilion N5400
1068                                         and Omnibook XE3 notebooks. This will
1069                                         have no effect if ACPI IRQ routing is
1070                                         enabled.
1071                 noacpi                  [IA-32] Do not use ACPI for IRQ routing
1072                                         or for PCI scanning.
1073                 routeirq                Do IRQ routing for all PCI devices.
1074                                         This is normally done in pci_enable_device(),
1075                                         so this option is a temporary workaround
1076                                         for broken drivers that don't call it.
1077
1078                 firmware                [ARM] Do not re-enumerate the bus but
1079                                         instead just use the configuration
1080                                         from the bootloader. This is currently
1081                                         used on IXP2000 systems where the
1082                                         bus has to be configured a certain way
1083                                         for adjunct CPUs.
1084
1085         pcmv=           [HW,PCMCIA] BadgePAD 4
1086
1087         pd.             [PARIDE]
1088                         See Documentation/paride.txt.
1089
1090         pdcchassis=     [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1091                         boot time.
1092                         Format: { 0 | 1 }
1093                         See arch/parisc/kernel/pdc_chassis.c
1094
1095         pf.             [PARIDE]
1096                         See Documentation/paride.txt.
1097
1098         pg.             [PARIDE]
1099                         See Documentation/paride.txt.
1100
1101         pirq=           [SMP,APIC] Manual mp-table setup
1102                         See Documentation/i386/IO-APIC.txt.
1103
1104         plip=           [PPT,NET] Parallel port network link
1105                         Format: { parport<nr> | timid | 0 }
1106                         See also Documentation/parport.txt.
1107
1108         pnpacpi=        [ACPI]
1109                         { off }
1110
1111         pnpbios=        [ISAPNP]
1112                         { on | off | curr | res | no-curr | no-res }
1113
1114         pnp_reserve_irq=
1115                         [ISAPNP] Exclude IRQs for the autoconfiguration
1116
1117         pnp_reserve_dma=
1118                         [ISAPNP] Exclude DMAs for the autoconfiguration
1119
1120         pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1121                         Ranges are in pairs (I/O port base and size).
1122
1123         pnp_reserve_mem=
1124                         [ISAPNP] Exclude memory regions for the autoconfiguration
1125                         Ranges are in pairs (memory base and size).
1126
1127         profile=        [KNL] Enable kernel profiling via /proc/profile
1128                         { schedule | <number> }
1129                         (param: schedule - profile schedule points}
1130                         (param: profile step/bucket size as a power of 2 for
1131                                 statistical time based profiling)
1132
1133         processor.max_cstate=   [HW, ACPI]
1134                         Limit processor to maximum C-state
1135                         max_cstate=9 overrides any DMI blacklist limit.
1136
1137         prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1138                         before loading.
1139                         See Documentation/ramdisk.txt.
1140
1141         psmouse.proto=  [HW,MOUSE] Highest PS2 mouse protocol extension to
1142                         probe for (bare|imps|exps|lifebook|any).
1143         psmouse.rate=   [HW,MOUSE] Set desired mouse report rate, in reports
1144                         per second.
1145         psmouse.resetafter=
1146                         [HW,MOUSE] Try to reset the device after so many bad packets
1147                         (0 = never).
1148         psmouse.resolution=
1149                         [HW,MOUSE] Set desired mouse resolution, in dpi.
1150         psmouse.smartscroll=
1151                         [HW,MOUSE] Controls Logitech smartscroll autorepeat,
1152                         0 = disabled, 1 = enabled (default).
1153
1154         pss=            [HW,OSS] Personal Sound System (ECHO ESC614)
1155                         Format: <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1156
1157         pt.             [PARIDE]
1158                         See Documentation/paride.txt.
1159
1160         quiet=          [KNL] Disable log messages
1161
1162         r128=           [HW,DRM]
1163
1164         raid=           [HW,RAID]
1165                         See Documentation/md.txt.
1166
1167         ramdisk=        [RAM] Sizes of RAM disks in kilobytes [deprecated]
1168                         See Documentation/ramdisk.txt.
1169
1170         ramdisk_blocksize=
1171                         [RAM]
1172                         See Documentation/ramdisk.txt.
1173
1174         ramdisk_size=   [RAM] Sizes of RAM disks in kilobytes
1175                         New name for the ramdisk parameter.
1176                         See Documentation/ramdisk.txt.
1177
1178         rdinit=         [KNL]
1179                         Format: <full_path>
1180                         Run specified binary instead of /init from the ramdisk,
1181                         used for early userspace startup. See initrd.
1182
1183         reboot=         [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1184                         Format: <reboot_mode>[,<reboot_mode2>[,...]]
1185                         See arch/*/kernel/reboot.c.
1186
1187         reserve=        [KNL,BUGS] Force the kernel to ignore some iomem area
1188
1189         resume=         [SWSUSP] Specify the partition device for software suspension
1190
1191         rhash_entries=  [KNL,NET]
1192                         Set number of hash buckets for route cache
1193
1194         riscom8=        [HW,SERIAL]
1195                         Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1196
1197         ro              [KNL] Mount root device read-only on boot
1198
1199         root=           [KNL] Root filesystem
1200
1201         rootdelay=      [KNL] Delay (in seconds) to pause before attempting to
1202                         mount the root filesystem
1203
1204         rootflags=      [KNL] Set root filesystem mount option string
1205
1206         rootfstype=     [KNL] Set root filesystem type
1207
1208         rw              [KNL] Mount root device read-write on boot
1209
1210         S               [KNL] Run init in single mode
1211
1212         sa1100ir        [NET]
1213                         See drivers/net/irda/sa1100_ir.c.
1214
1215         sb=             [HW,OSS]
1216                         Format: <io>,<irq>,<dma>,<dma2>
1217
1218         sbni=           [NET] Granch SBNI12 leased line adapter
1219
1220         sbpcd=          [HW,CD] Soundblaster CD adapter
1221                         Format: <io>,<type>
1222                         See a comment before function sbpcd_setup() in
1223                         drivers/cdrom/sbpcd.c.
1224
1225         sc1200wdt=      [HW,WDT] SC1200 WDT (watchdog) driver
1226                         Format: <io>[,<timeout>[,<isapnp>]]
1227
1228         scsi_debug_*=   [SCSI]
1229                         See drivers/scsi/scsi_debug.c.
1230
1231         scsi_default_dev_flags=
1232                         [SCSI] SCSI default device flags
1233                         Format: <integer>
1234
1235         scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1236                         Format: <vendor>:<model>:<flags>
1237                         (flags are integer value)
1238
1239         scsi_logging=   [SCSI]
1240
1241         selinux         [SELINUX] Disable or enable SELinux at boot time.
1242                         Format: { "0" | "1" }
1243                         See security/selinux/Kconfig help text.
1244                         0 -- disable.
1245                         1 -- enable.
1246                         Default value is set via kernel config option.
1247                         If enabled at boot time, /selinux/disable can be used
1248                         later to disable prior to initial policy load.
1249
1250         serialnumber    [BUGS=IA-32]
1251
1252         sg_def_reserved_size=
1253                         [SCSI]
1254
1255         sgalaxy=        [HW,OSS]
1256                         Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1257
1258         shapers=        [NET]
1259                         Maximal number of shapers.
1260
1261         sim710=         [SCSI,HW]
1262                         See header of drivers/scsi/sim710.c.
1263
1264         simeth=         [IA-64]
1265         simscsi=
1266
1267         sjcd=           [HW,CD]
1268                         Format: <io>,<irq>,<dma>
1269                         See header of drivers/cdrom/sjcd.c.
1270
1271         slram=          [HW,MTD]
1272
1273         smart2=         [HW]
1274                         Format: <io1>[,<io2>[,...,<io8>]]
1275
1276         snd-ad1816a=    [HW,ALSA]
1277
1278         snd-ad1848=     [HW,ALSA]
1279
1280         snd-ali5451=    [HW,ALSA]
1281
1282         snd-als100=     [HW,ALSA]
1283
1284         snd-als4000=    [HW,ALSA]
1285
1286         snd-azt2320=    [HW,ALSA]
1287
1288         snd-cmi8330=    [HW,ALSA]
1289
1290         snd-cmipci=     [HW,ALSA]
1291
1292         snd-cs4231=     [HW,ALSA]
1293
1294         snd-cs4232=     [HW,ALSA]
1295
1296         snd-cs4236=     [HW,ALSA]
1297
1298         snd-cs4281=     [HW,ALSA]
1299
1300         snd-cs46xx=     [HW,ALSA]
1301
1302         snd-dt019x=     [HW,ALSA]
1303
1304         snd-dummy=      [HW,ALSA]
1305
1306         snd-emu10k1=    [HW,ALSA]
1307
1308         snd-ens1370=    [HW,ALSA]
1309
1310         snd-ens1371=    [HW,ALSA]
1311
1312         snd-es968=      [HW,ALSA]
1313
1314         snd-es1688=     [HW,ALSA]
1315
1316         snd-es18xx=     [HW,ALSA]
1317
1318         snd-es1938=     [HW,ALSA]
1319
1320         snd-es1968=     [HW,ALSA]
1321
1322         snd-fm801=      [HW,ALSA]
1323
1324         snd-gusclassic= [HW,ALSA]
1325
1326         snd-gusextreme= [HW,ALSA]
1327
1328         snd-gusmax=     [HW,ALSA]
1329
1330         snd-hdsp=       [HW,ALSA]
1331
1332         snd-ice1712=    [HW,ALSA]
1333
1334         snd-intel8x0=   [HW,ALSA]
1335
1336         snd-interwave=  [HW,ALSA]
1337
1338         snd-interwave-stb=
1339                         [HW,ALSA]
1340
1341         snd-korg1212=   [HW,ALSA]
1342
1343         snd-maestro3=   [HW,ALSA]
1344
1345         snd-mpu401=     [HW,ALSA]
1346
1347         snd-mtpav=      [HW,ALSA]
1348
1349         snd-nm256=      [HW,ALSA]
1350
1351         snd-opl3sa2=    [HW,ALSA]
1352
1353         snd-opti92x-ad1848=
1354                         [HW,ALSA]
1355
1356         snd-opti92x-cs4231=
1357                         [HW,ALSA]
1358
1359         snd-opti93x=    [HW,ALSA]
1360
1361         snd-pmac=       [HW,ALSA]
1362
1363         snd-rme32=      [HW,ALSA]
1364
1365         snd-rme96=      [HW,ALSA]
1366
1367         snd-rme9652=    [HW,ALSA]
1368
1369         snd-sb8=        [HW,ALSA]
1370
1371         snd-sb16=       [HW,ALSA]
1372
1373         snd-sbawe=      [HW,ALSA]
1374
1375         snd-serial=     [HW,ALSA]
1376
1377         snd-sgalaxy=    [HW,ALSA]
1378
1379         snd-sonicvibes= [HW,ALSA]
1380
1381         snd-sun-amd7930=
1382                         [HW,ALSA]
1383
1384         snd-sun-cs4231= [HW,ALSA]
1385
1386         snd-trident=    [HW,ALSA]
1387
1388         snd-usb-audio=  [HW,ALSA,USB]
1389
1390         snd-via82xx=    [HW,ALSA]
1391
1392         snd-virmidi=    [HW,ALSA]
1393
1394         snd-wavefront=  [HW,ALSA]
1395
1396         snd-ymfpci=     [HW,ALSA]
1397
1398         sonicvibes=     [HW,OSS]
1399                         Format: <reverb>
1400
1401         sonycd535=      [HW,CD]
1402                         Format: <io>[,<irq>]
1403
1404         sonypi.*=       [HW] Sony Programmable I/O Control Device driver
1405                         See Documentation/sonypi.txt
1406
1407         specialix=      [HW,SERIAL] Specialix multi-serial port adapter
1408                         See Documentation/specialix.txt.
1409
1410         spia_io_base=   [HW,MTD]
1411         spia_fio_base=
1412         spia_pedr=
1413         spia_peddr=
1414
1415         sscape=         [HW,OSS]
1416                         Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1417
1418         st=             [HW,SCSI] SCSI tape parameters (buffers, etc.)
1419                         See Documentation/scsi/st.txt.
1420
1421         st0x=           [HW,SCSI]
1422                         See header of drivers/scsi/seagate.c.
1423
1424         sti=            [PARISC,HW]
1425                         Format: <num>
1426                         Set the STI (builtin display/keyboard on the HP-PARISC
1427                         machines) console (graphic card) which should be used
1428                         as the initial boot-console.
1429                         See also comment in drivers/video/console/sticore.c.
1430
1431         sti_font=       [HW]
1432                         See comment in drivers/video/console/sticore.c.
1433
1434         stifb=          [HW]
1435                         Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1436
1437         stram_swap=     [HW,M68k]
1438
1439         swiotlb=        [IA-64] Number of I/O TLB slabs
1440
1441         switches=       [HW,M68k]
1442
1443         sym53c416=      [HW,SCSI]
1444                         See header of drivers/scsi/sym53c416.c.
1445
1446         t128=           [HW,SCSI]
1447                         See header of drivers/scsi/t128.c.
1448
1449         tdfx=           [HW,DRM]
1450
1451         thash_entries=  [KNL,NET]
1452                         Set number of hash buckets for TCP connection
1453
1454         time            Show timing data prefixed to each printk message line
1455
1456         tipar.timeout=  [HW,PPT]
1457                         Set communications timeout in tenths of a second
1458                         (default 15).
1459
1460         tipar.delay=    [HW,PPT]
1461                         Set inter-bit delay in microseconds (default 10).
1462
1463         tmc8xx=         [HW,SCSI]
1464                         See header of drivers/scsi/seagate.c.
1465
1466         tmscsim=        [HW,SCSI]
1467                         See comment before function dc390_setup() in
1468                         drivers/scsi/tmscsim.c.
1469
1470         tp720=          [HW,PS2]
1471
1472         trix=           [HW,OSS] MediaTrix AudioTrix Pro
1473                         Format: <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1474
1475         tsdev.xres=     [TS] Horizontal screen resolution.
1476         tsdev.yres=     [TS] Vertical screen resolution.
1477
1478         turbografx.map[2|3]=
1479                         [HW,JOY] TurboGraFX parallel port interface
1480                         Format: <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1481                         See also Documentation/input/joystick-parport.txt
1482
1483         u14-34f=        [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1484                         See header of drivers/scsi/u14-34f.c.
1485
1486         uart401=        [HW,OSS]
1487                         Format: <io>,<irq>
1488
1489         uart6850=       [HW,OSS]
1490                         Format: <io>,<irq>
1491
1492         usb-handoff     [HW] Enable early USB BIOS -> OS handoff
1493
1494         usbhid.mousepoll=
1495                         [USBHID] The interval which mice are to be polled at.
1496
1497         video=          [FB] Frame buffer configuration
1498                         See Documentation/fb/modedb.txt.
1499
1500         vga=            [BOOT,IA-32] Select a particular video mode
1501                         See Documentation/i386/boot.txt and Documentation/svga.txt.
1502                         Use vga=ask for menu.
1503                         This is actually a boot loader parameter; the value is
1504                         passed to the kernel using a special protocol.
1505
1506         vmalloc=nn[KMG] [KNL,BOOT] forces the vmalloc area to have an exact
1507                         size of <nn>. This can be used to increase the
1508                         minimum size (128MB on x86). It can also be used to
1509                         decrease the size and leave more room for directly
1510                         mapped kernel RAM.
1511
1512         vmhalt=         [KNL,S390]
1513
1514         vmpoff=         [KNL,S390]
1515
1516         waveartist=     [HW,OSS]
1517                         Format: <io>,<irq>,<dma>,<dma2>
1518
1519         wd33c93=        [HW,SCSI]
1520                         See header of drivers/scsi/wd33c93.c.
1521
1522         wd7000=         [HW,SCSI]
1523                         See header of drivers/scsi/wd7000.c.
1524
1525         wdt=            [WDT] Watchdog
1526                         See Documentation/watchdog/watchdog.txt.
1527
1528         xd=             [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1529         xd_geo=         See header of drivers/block/xd.c.
1530
1531         xirc2ps_cs=     [NET,PCMCIA]
1532                         Format: <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1533
1534
1535
1536 Changelog:
1537
1538         The last known update (for 2.4.0) - the changelog was not kept before.
1539         2000-06-??      Mr. Unknown
1540
1541         Update for 2.5.49, description for most of the options introduced,
1542         references to other documentation (C files, READMEs, ..), added S390,
1543         PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1544         reformatting.
1545         2002-11-24      Petr Baudis <pasky@ucw.cz>
1546                         Randy Dunlap <randy.dunlap@verizon.net>
1547
1548 TODO:
1549
1550         Add documentation for ALSA options.
1551         Add more DRM drivers.