err.no Git - linux-2.6/blob - 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.nomux     [HW] Don't check presence of an active multiplexing
 553                              controller
 554         i8042.nopnp     [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
 555                              controllers
 556         i8042.panicblink=
 557                         [HW] Frequency with which keyboard LEDs should blink
 558                              when kernel panics (default is 0.5 sec)
 559         i8042.reset     [HW] Reset the controller during init and cleanup
 560         i8042.unlock    [HW] Unlock (ignore) the keylock
 561
 562         i810=           [HW,DRM]
 563
 564         i8k.ignore_dmi  [HW] Continue probing hardware even if DMI data
 565                         indicates that the driver is running on unsupported
 566                         hardware.
 567         i8k.force       [HW] Activate i8k driver even if SMM BIOS signature
 568                         does not match list of supported models.
 569         i8k.power_status
 570                         [HW] Report power status in /proc/i8k
 571                         (disabled by default)
 572         i8k.restricted  [HW] Allow controlling fans only if SYS_ADMIN
 573                         capability is set.
 574
 575         ibmmcascsi=     [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
 576                         See Documentation/mca.txt.
 577
 578         icn=            [HW,ISDN]
 579                         Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
 580
 581         ide=            [HW] (E)IDE subsystem
 582                         Format: ide=nodma or ide=doubler or ide=reverse
 583                         See Documentation/ide.txt.
 584
 585         ide?=           [HW] (E)IDE subsystem
 586                         Format: ide?=noprobe or chipset specific parameters.
 587                         See Documentation/ide.txt.
 588
 589         idebus=         [HW] (E)IDE subsystem - VLB/PCI bus speed
 590                         See Documentation/ide.txt.
 591
 592         idle=           [HW]
 593                         Format: idle=poll or idle=halt
 594
 595         ihash_entries=  [KNL]
 596                         Set number of hash buckets for inode cache.
 597
 598         in2000=         [HW,SCSI]
 599                         See header of drivers/scsi/in2000.c.
 600
 601         init=           [KNL]
 602                         Format: <full_path>
 603                         Run specified binary instead of /sbin/init as init
 604                         process.
 605
 606         initcall_debug  [KNL] Trace initcalls as they are executed.  Useful
 607                         for working out where the kernel is dying during
 608                         startup.
 609
 610         initrd=         [BOOT] Specify the location of the initial ramdisk
 611
 612         inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
 613                         Format: <irq>
 614
 615         inttest=        [IA64]
 616
 617         io7=            [HW] IO7 for Marvel based alpha systems
 618                         See comment before marvel_specify_io7 in
 619                         arch/alpha/kernel/core_marvel.c.
 620
 621         ip=             [IP_PNP]
 622                         See Documentation/nfsroot.txt.
 623
 624         ip2=            [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
 625                         See comment before ip2_setup() in drivers/char/ip2.c.
 626
 627         ips=            [HW,SCSI] Adaptec / IBM ServeRAID controller
 628                         See header of drivers/scsi/ips.c.
 629
 630         irqfixup        [HW]
 631                         When an interrupt is not handled search all handlers
 632                         for it. Intended to get systems with badly broken
 633                         firmware running.
 634
 635         irqpoll         [HW]
 636                         When an interrupt is not handled search all handlers
 637                         for it. Also check all handlers each timer
 638                         interrupt. Intended to get systems with badly broken
 639                         firmware running.
 640
 641         isapnp=         [ISAPNP]
 642                         Format: <RDP>, <reset>, <pci_scan>, <verbosity>
 643
 644         isolcpus=       [KNL,SMP] Isolate CPUs from the general scheduler.
 645                         Format: <cpu number>,...,<cpu number>
 646                         This option can be used to specify one or more CPUs
 647                         to isolate from the general SMP balancing and scheduling
 648                         algorithms. The only way to move a process onto or off
 649                         an "isolated" CPU is via the CPU affinity syscalls.
 650                         <cpu number> begins at 0 and the maximum value is
 651                         "number of CPUs in system - 1".
 652
 653                         This option is the preferred way to isolate CPUs. The
 654                         alternative - manually setting the CPU mask of all tasks
 655                         in the system can cause problems and suboptimal load
 656                         balancer performance.
 657
 658         isp16=          [HW,CD]
 659                         Format: <io>,<irq>,<dma>,<setup>
 660
 661         iucv=           [HW,NET]
 662
 663         js=             [HW,JOY] Analog joystick
 664                         See Documentation/input/joystick.txt.
 665
 666         keepinitrd      [HW,ARM]
 667
 668         kstack=N        [IA-32, X86-64] Print N words from the kernel stack
 669                         in oops dumps.
 670
 671         l2cr=           [PPC]
 672
 673         lapic           [IA-32,APIC] Enable the local APIC even if BIOS disabled it.
 674
 675         lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
 676                         Format: addr:<io>,irq:<irq>
 677
 678         llsc*=          [IA64]
 679                         See function print_params() in arch/ia64/sn/kernel/llsc4.c.
 680
 681         load_ramdisk=   [RAM] List of ramdisks to load from floppy
 682                         See Documentation/ramdisk.txt.
 683
 684         lockd.udpport=  [NFS]
 685
 686         lockd.tcpport=  [NFS]
 687
 688         logibm.irq=     [HW,MOUSE] Logitech Bus Mouse Driver
 689                         Format: <irq>
 690
 691         loglevel=       All Kernel Messages with a loglevel smaller than the
 692                         console loglevel will be printed to the console. It can
 693                         also be changed with klogd or other programs. The
 694                         loglevels are defined as follows:
 695
 696                         0 (KERN_EMERG)          system is unusable
 697                         1 (KERN_ALERT)          action must be taken immediately
 698                         2 (KERN_CRIT)           critical conditions
 699                         3 (KERN_ERR)            error conditions
 700                         4 (KERN_WARNING)        warning conditions
 701                         5 (KERN_NOTICE)         normal but significant condition
 702                         6 (KERN_INFO)           informational
 703                         7 (KERN_DEBUG)          debug-level messages
 704
 705         log_buf_len=n   Sets the size of the printk ring buffer, in bytes.
 706                         Format is n, nk, nM.  n must be a power of two.  The
 707                         default is set in kernel config.
 708
 709         lp=0            [LP]    Specify parallel ports to use, e.g,
 710         lp=port[,port...]       lp=none,parport0 (lp0 not configured, lp1 uses
 711         lp=reset                first parallel port). 'lp=0' disables the
 712         lp=auto                 printer driver. 'lp=reset' (which can be
 713                                 specified in addition to the ports) causes
 714                                 attached printers to be reset. Using
 715                                 lp=port1,port2,... specifies the parallel ports
 716                                 to associate lp devices with, starting with
 717                                 lp0. A port specification may be 'none' to skip
 718                                 that lp device, or a parport name such as
 719                                 'parport0'. Specifying 'lp=auto' instead of a
 720                                 port specification list means that device IDs
 721                                 from each port should be examined, to see if
 722                                 an IEEE 1284-compliant printer is attached; if
 723                                 so, the driver will manage that printer.
 724                                 See also header of drivers/char/lp.c.
 725
 726         lpj=n           [KNL]
 727                         Sets loops_per_jiffy to given constant, thus avoiding
 728                         time-consuming boot-time autodetection (up to 250 ms per
 729                         CPU). 0 enables autodetection (default). To determine
 730                         the correct value for your kernel, boot with normal
 731                         autodetection and see what value is printed. Note that
 732                         on SMP systems the preset will be applied to all CPUs,
 733                         which is likely to cause problems if your CPUs need
 734                         significantly divergent settings. An incorrect value
 735                         will cause delays in the kernel to be wrong, leading to
 736                         unpredictable I/O errors and other breakage. Although
 737                         unlikely, in the extreme case this might damage your
 738                         hardware.
 739
 740         ltpc=           [NET]
 741                         Format: <io>,<irq>,<dma>
 742
 743         mac5380=        [HW,SCSI]
 744                         Format: <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 745
 746         mac53c9x=       [HW,SCSI]
 747                         Format: <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 748
 749         machvec=        [IA64]
 750                         Force the use of a particular machine-vector (machvec) in a generic
 751                         kernel.  Example: machvec=hpzx1_swiotlb
 752
 753         mad16=          [HW,OSS]
 754                         Format: <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
 755
 756         maui=           [HW,OSS]
 757                         Format: <io>,<irq>
 758
 759         max_loop=       [LOOP] Maximum number of loopback devices that can
 760                         be mounted
 761                         Format: <1-256>
 762
 763         maxcpus=        [SMP] Maximum number of processors that an SMP kernel
 764                         should make use of
 765
 766         max_addr=[KMG]  [KNL,BOOT,ia64] All physical memory greater than or
 767                         equal to this physical address is ignored.
 768
 769         max_luns=       [SCSI] Maximum number of LUNs to probe
 770                         Should be between 1 and 2^32-1.
 771
 772         max_report_luns=
 773                         [SCSI] Maximum number of LUNs received
 774                         Should be between 1 and 16384.
 775
 776         mca-pentium     [BUGS=IA-32]
 777
 778         mcatest=        [IA-64]
 779
 780         mcd=            [HW,CD]
 781                         Format: <port>,<irq>,<mitsumi_bug_93_wait>
 782
 783         mcdx=           [HW,CD]
 784
 785         mce             [IA-32] Machine Check Exception
 786
 787         md=             [HW] RAID subsystems devices and level
 788                         See Documentation/md.txt.
 789
 790         mdacon=         [MDA]
 791                         Format: <first>,<last>
 792                         Specifies range of consoles to be captured by the MDA.
 793
 794         mem=nn[KMG]     [KNL,BOOT] Force usage of a specific amount of memory
 795                         Amount of memory to be used when the kernel is not able
 796                         to see the whole system memory or for test.
 797                         [IA-32] Use together with memmap= to avoid physical
 798                         address space collisions. Without memmap= PCI devices
 799                         could be placed at addresses belonging to unused RAM.
 800
 801         mem=nopentium   [BUGS=IA-32] Disable usage of 4MB pages for kernel
 802                         memory.
 803
 804         memmap=exactmap [KNL,IA-32] Enable setting of an exact
 805                         E820 memory map, as specified by the user.
 806                         Such memmap=exactmap lines can be constructed based on
 807                         BIOS output or other requirements. See the memmap=nn@ss
 808                         option description.
 809
 810         memmap=nn[KMG]@ss[KMG]
 811                         [KNL] Force usage of a specific region of memory
 812                         Region of memory to be used, from ss to ss+nn.
 813
 814         memmap=nn[KMG]#ss[KMG]
 815                         [KNL,ACPI] Mark specific memory as ACPI data.
 816                         Region of memory to be used, from ss to ss+nn.
 817
 818         memmap=nn[KMG]$ss[KMG]
 819                         [KNL,ACPI] Mark specific memory as reserved.
 820                         Region of memory to be used, from ss to ss+nn.
 821
 822         meye.*=         [HW] Set MotionEye Camera parameters
 823                         See Documentation/video4linux/meye.txt.
 824
 825         mga=            [HW,DRM]
 826
 827         mousedev.tap_time=
 828                         [MOUSE] Maximum time between finger touching and
 829                         leaving touchpad surface for touch to be considered
 830                         a tap and be reported as a left button click (for
 831                         touchpads working in absolute mode only).
 832                         Format: <msecs>
 833         mousedev.xres=  [MOUSE] Horizontal screen resolution, used for devices
 834                         reporting absolute coordinates, such as tablets
 835         mousedev.yres=  [MOUSE] Vertical screen resolution, used for devices
 836                         reporting absolute coordinates, such as tablets
 837
 838         mpu401=         [HW,OSS]
 839                         Format: <io>,<irq>
 840
 841         MTD_Partition=  [MTD]
 842                         Format: <name>,<region-number>,<size>,<offset>
 843
 844         MTD_Region=     [MTD]
 845                         Format: <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
 846
 847         mtdparts=       [MTD]
 848                         See drivers/mtd/cmdline.c.
 849
 850         mtouchusb.raw_coordinates=
 851                         [HW] Make the MicroTouch USB driver use raw coordinates ('y', default)
 852                         or cooked coordinates ('n')
 853
 854         n2=             [NET] SDL Inc. RISCom/N2 synchronous serial card
 855
 856         NCR_D700=       [HW,SCSI]
 857                         See header of drivers/scsi/NCR_D700.c.
 858
 859         ncr5380=        [HW,SCSI]
 860
 861         ncr53c400=      [HW,SCSI]
 862
 863         ncr53c400a=     [HW,SCSI]
 864
 865         ncr53c406a=     [HW,SCSI]
 866
 867         ncr53c8xx=      [HW,SCSI]
 868
 869         netdev=         [NET] Network devices parameters
 870                         Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
 871                         Note that mem_start is often overloaded to mean
 872                         something different and driver-specific.
 873
 874         nfsaddrs=       [NFS]
 875                         See Documentation/nfsroot.txt.
 876
 877         nfsroot=        [NFS] nfs root filesystem for disk-less boxes.
 878                         See Documentation/nfsroot.txt.
 879
 880         nmi_watchdog=   [KNL,BUGS=IA-32] Debugging features for SMP kernels
 881
 882         no387           [BUGS=IA-32] Tells the kernel to use the 387 maths
 883                         emulation library even if a 387 maths coprocessor
 884                         is present.
 885
 886         noalign         [KNL,ARM]
 887
 888         noapic          [SMP,APIC] Tells the kernel to not make use of any
 889                         IOAPICs that may be present in the system.
 890
 891         noasync         [HW,M68K] Disables async and sync negotiation for
 892                         all devices.
 893
 894         nobats          [PPC] Do not use BATs for mapping kernel lowmem
 895                         on "Classic" PPC cores.
 896
 897         nocache         [ARM]
 898
 899         nodisconnect    [HW,SCSI,M68K] Disables SCSI disconnects.
 900
 901         noexec          [IA-64]
 902
 903         noexec          [IA-32, X86-64]
 904                         noexec=on: enable non-executable mappings (default)
 905                         noexec=off: disable nn-executable mappings
 906
 907         nofxsr          [BUGS=IA-32]
 908
 909         nohlt           [BUGS=ARM]
 910
 911         no-hlt          [BUGS=IA-32] Tells the kernel that the hlt
 912                         instruction doesn't work correctly and not to
 913                         use it.
 914
 915         nohalt          [IA-64] Tells the kernel not to use the power saving
 916                         function PAL_HALT_LIGHT when idle. This increases
 917                         power-consumption. On the positive side, it reduces
 918                         interrupt wake-up latency, which may improve performance
 919                         in certain environments such as networked servers or
 920                         real-time systems.
 921
 922         noirqdebug      [IA-32] Disables the code which attempts to detect and
 923                         disable unhandled interrupt sources.
 924
 925         noisapnp        [ISAPNP] Disables ISA PnP code.
 926
 927         noinitrd        [RAM] Tells the kernel not to load any configured
 928                         initial RAM disk.
 929
 930         nointroute      [IA-64]
 931
 932         nolapic         [IA-32,APIC] Do not enable or use the local APIC.
 933
 934         noltlbs         [PPC] Do not use large page/tlb entries for kernel
 935                         lowmem mapping on PPC40x.
 936
 937         nomce           [IA-32] Machine Check Exception
 938
 939         noresidual      [PPC] Don't use residual data on PReP machines.
 940
 941         noresume        [SWSUSP] Disables resume and restore original swap space.
 942
 943         no-scroll       [VGA] Disables scrollback.
 944                         This is required for the Braillex ib80-piezo Braille
 945                         reader made by F.H. Papenmeier (Germany).
 946
 947         nosbagart       [IA-64]
 948
 949         nosmp           [SMP] Tells an SMP kernel to act as a UP kernel.
 950
 951         nosync          [HW,M68K] Disables sync negotiation for all devices.
 952
 953         notsc           [BUGS=IA-32] Disable Time Stamp Counter
 954
 955         nousb           [USB] Disable the USB subsystem
 956
 957         nowb            [ARM]
 958
 959         opl3=           [HW,OSS]
 960                         Format: <io>
 961
 962         opl3sa=         [HW,OSS]
 963                         Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
 964
 965         opl3sa2=        [HW,OSS]
 966                         Format: <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
 967
 968         oprofile.timer= [HW]
 969                         Use timer interrupt instead of performance counters
 970
 971         optcd=          [HW,CD]
 972                         Format: <io>
 973
 974         osst=           [HW,SCSI] SCSI Tape Driver
 975                         Format: <buffer_size>,<write_threshold>
 976                         See also Documentation/scsi/st.txt.
 977
 978         panic=          [KNL] Kernel behaviour on panic
 979                         Format: <timeout>
 980
 981         parkbd.port=    [HW] Parallel port number the keyboard adapter is
 982                         connected to, default is 0.
 983                         Format: <parport#>
 984         parkbd.mode=    [HW] Parallel port keyboard adapter mode of operation,
 985                         0 for XT, 1 for AT (default is AT).
 986                         Format: <mode>
 987
 988         parport=0       [HW,PPT]        Specify parallel ports. 0 disables.
 989         parport=auto                    Use 'auto' to force the driver to use
 990         parport=0xBBB[,IRQ[,DMA]]       any IRQ/DMA settings detected (the
 991                                         default is to ignore detected IRQ/DMA
 992                                         settings because of possible
 993                                         conflicts). You can specify the base
 994                                         address, IRQ, and DMA settings; IRQ and
 995                                         DMA should be numbers, or 'auto' (for
 996                                         using detected settings on that
 997                                         particular port), or 'nofifo' (to avoid
 998                                         using a FIFO even if it is detected).
 999                                         Parallel ports are assigned in the
1000                                         order they are specified on the command
1001                                         line, starting with parport0.
1002
1003         parport_init_mode=
1004                         [HW,PPT]        Configure VIA parallel port to
1005                                         operate in specific mode. This is
1006                                         necessary on Pegasos computer where
1007                                         firmware has no options for setting up
1008                                         parallel port mode and sets it to
1009                                         spp. Currently this function knows
1010                                         686a and 8231 chips.
1011                         Format: [spp|ps2|epp|ecp|ecpepp]
1012
1013         pas2=           [HW,OSS]
1014                         Format: <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1015
1016         pas16=          [HW,SCSI]
1017                         See header of drivers/scsi/pas16.c.
1018
1019         pcbit=          [HW,ISDN]
1020
1021         pcd.            [PARIDE]
1022                         See header of drivers/block/paride/pcd.c.
1023                         See also Documentation/paride.txt.
1024
1025         pci=option[,option...]          [PCI] various PCI subsystem options:
1026                 off                     [IA-32] don't probe for the PCI bus
1027                 bios                    [IA-32] force use of PCI BIOS, don't access
1028                                         the hardware directly. Use this if your machine
1029                                         has a non-standard PCI host bridge.
1030                 nobios                  [IA-32] disallow use of PCI BIOS, only direct
1031                                         hardware access methods are allowed. Use this
1032                                         if you experience crashes upon bootup and you
1033                                         suspect they are caused by the BIOS.
1034                 conf1                   [IA-32] Force use of PCI Configuration Mechanism 1.
1035                 conf2                   [IA-32] Force use of PCI Configuration Mechanism 2.
1036                 nosort                  [IA-32] Don't sort PCI devices according to
1037                                         order given by the PCI BIOS. This sorting is done
1038                                         to get a device order compatible with older kernels.
1039                 biosirq                 [IA-32] Use PCI BIOS calls to get the interrupt
1040                                         routing table. These calls are known to be buggy
1041                                         on several machines and they hang the machine when used,
1042                                         but on other computers it's the only way to get the
1043                                         interrupt routing table. Try this option if the kernel
1044                                         is unable to allocate IRQs or discover secondary PCI
1045                                         buses on your motherboard.
1046                 rom                     [IA-32] Assign address space to expansion ROMs.
1047                                         Use with caution as certain devices share address
1048                                         decoders between ROMs and other resources.
1049                 irqmask=0xMMMM          [IA-32] Set a bit mask of IRQs allowed to be assigned
1050                                         automatically to PCI devices. You can make the kernel
1051                                         exclude IRQs of your ISA cards this way.
1052                 pirqaddr=0xAAAAA        [IA-32] Specify the physical address
1053                                         of the PIRQ table (normally generated
1054                                         by the BIOS) if it is outside the
1055                                         F0000h-100000h range.
1056                 lastbus=N               [IA-32] Scan all buses till bus #N. Can be useful
1057                                         if the kernel is unable to find your secondary buses
1058                                         and you want to tell it explicitly which ones they are.
1059                 assign-busses           [IA-32] Always assign all PCI bus
1060                                         numbers ourselves, overriding
1061                                         whatever the firmware may have
1062                                         done.
1063                 usepirqmask             [IA-32] Honor the possible IRQ mask
1064                                         stored in the BIOS $PIR table. This is
1065                                         needed on some systems with broken
1066                                         BIOSes, notably some HP Pavilion N5400
1067                                         and Omnibook XE3 notebooks. This will
1068                                         have no effect if ACPI IRQ routing is
1069                                         enabled.
1070                 noacpi                  [IA-32] Do not use ACPI for IRQ routing
1071                                         or for PCI scanning.
1072                 routeirq                Do IRQ routing for all PCI devices.
1073                                         This is normally done in pci_enable_device(),
1074                                         so this option is a temporary workaround
1075                                         for broken drivers that don't call it.
1076
1077                 firmware                [ARM] Do not re-enumerate the bus but
1078                                         instead just use the configuration
1079                                         from the bootloader. This is currently
1080                                         used on IXP2000 systems where the
1081                                         bus has to be configured a certain way
1082                                         for adjunct CPUs.
1083
1084         pcmv=           [HW,PCMCIA] BadgePAD 4
1085
1086         pd.             [PARIDE]
1087                         See Documentation/paride.txt.
1088
1089         pdcchassis=     [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1090                         boot time.
1091                         Format: { 0 | 1 }
1092                         See arch/parisc/kernel/pdc_chassis.c
1093
1094         pf.             [PARIDE]
1095                         See Documentation/paride.txt.
1096
1097         pg.             [PARIDE]
1098                         See Documentation/paride.txt.
1099
1100         pirq=           [SMP,APIC] Manual mp-table setup
1101                         See Documentation/i386/IO-APIC.txt.
1102
1103         plip=           [PPT,NET] Parallel port network link
1104                         Format: { parport<nr> | timid | 0 }
1105                         See also Documentation/parport.txt.
1106
1107         pnpacpi=        [ACPI]
1108                         { off }
1109
1110         pnpbios=        [ISAPNP]
1111                         { on | off | curr | res | no-curr | no-res }
1112
1113         pnp_reserve_irq=
1114                         [ISAPNP] Exclude IRQs for the autoconfiguration
1115
1116         pnp_reserve_dma=
1117                         [ISAPNP] Exclude DMAs for the autoconfiguration
1118
1119         pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1120                         Ranges are in pairs (I/O port base and size).
1121
1122         pnp_reserve_mem=
1123                         [ISAPNP] Exclude memory regions for the autoconfiguration
1124                         Ranges are in pairs (memory base and size).
1125
1126         profile=        [KNL] Enable kernel profiling via /proc/profile
1127                         { schedule | <number> }
1128                         (param: schedule - profile schedule points}
1129                         (param: profile step/bucket size as a power of 2 for
1130                                 statistical time based profiling)
1131
1132         processor.max_cstate=   [HW, ACPI]
1133                         Limit processor to maximum C-state
1134                         max_cstate=9 overrides any DMI blacklist limit.
1135
1136         prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1137                         before loading.
1138                         See Documentation/ramdisk.txt.
1139
1140         psmouse.proto=  [HW,MOUSE] Highest PS2 mouse protocol extension to
1141                         probe for (bare|imps|exps|lifebook|any).
1142         psmouse.rate=   [HW,MOUSE] Set desired mouse report rate, in reports
1143                         per second.
1144         psmouse.resetafter=
1145                         [HW,MOUSE] Try to reset the device after so many bad packets
1146                         (0 = never).
1147         psmouse.resolution=
1148                         [HW,MOUSE] Set desired mouse resolution, in dpi.
1149         psmouse.smartscroll=
1150                         [HW,MOUSE] Controls Logitech smartscroll autorepeat,
1151                         0 = disabled, 1 = enabled (default).
1152
1153         pss=            [HW,OSS] Personal Sound System (ECHO ESC614)
1154                         Format: <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1155
1156         pt.             [PARIDE]
1157                         See Documentation/paride.txt.
1158
1159         quiet=          [KNL] Disable log messages
1160
1161         r128=           [HW,DRM]
1162
1163         raid=           [HW,RAID]
1164                         See Documentation/md.txt.
1165
1166         ramdisk=        [RAM] Sizes of RAM disks in kilobytes [deprecated]
1167                         See Documentation/ramdisk.txt.
1168
1169         ramdisk_blocksize=
1170                         [RAM]
1171                         See Documentation/ramdisk.txt.
1172
1173         ramdisk_size=   [RAM] Sizes of RAM disks in kilobytes
1174                         New name for the ramdisk parameter.
1175                         See Documentation/ramdisk.txt.
1176
1177         reboot=         [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1178                         Format: <reboot_mode>[,<reboot_mode2>[,...]]
1179                         See arch/*/kernel/reboot.c.
1180
1181         reserve=        [KNL,BUGS] Force the kernel to ignore some iomem area
1182
1183         resume=         [SWSUSP] Specify the partition device for software suspension
1184
1185         rhash_entries=  [KNL,NET]
1186                         Set number of hash buckets for route cache
1187
1188         riscom8=        [HW,SERIAL]
1189                         Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1190
1191         ro              [KNL] Mount root device read-only on boot
1192
1193         root=           [KNL] Root filesystem
1194
1195         rootdelay=      [KNL] Delay (in seconds) to pause before attempting to
1196                         mount the root filesystem
1197
1198         rootflags=      [KNL] Set root filesystem mount option string
1199
1200         rootfstype=     [KNL] Set root filesystem type
1201
1202         rw              [KNL] Mount root device read-write on boot
1203
1204         S               [KNL] Run init in single mode
1205
1206         sa1100ir        [NET]
1207                         See drivers/net/irda/sa1100_ir.c.
1208
1209         sb=             [HW,OSS]
1210                         Format: <io>,<irq>,<dma>,<dma2>
1211
1212         sbni=           [NET] Granch SBNI12 leased line adapter
1213
1214         sbpcd=          [HW,CD] Soundblaster CD adapter
1215                         Format: <io>,<type>
1216                         See a comment before function sbpcd_setup() in
1217                         drivers/cdrom/sbpcd.c.
1218
1219         sc1200wdt=      [HW,WDT] SC1200 WDT (watchdog) driver
1220                         Format: <io>[,<timeout>[,<isapnp>]]
1221
1222         scsi_debug_*=   [SCSI]
1223                         See drivers/scsi/scsi_debug.c.
1224
1225         scsi_default_dev_flags=
1226                         [SCSI] SCSI default device flags
1227                         Format: <integer>
1228
1229         scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1230                         Format: <vendor>:<model>:<flags>
1231                         (flags are integer value)
1232
1233         scsi_logging=   [SCSI]
1234
1235         selinux         [SELINUX] Disable or enable SELinux at boot time.
1236                         Format: { "0" | "1" }
1237                         See security/selinux/Kconfig help text.
1238                         0 -- disable.
1239                         1 -- enable.
1240                         Default value is set via kernel config option.
1241                         If enabled at boot time, /selinux/disable can be used
1242                         later to disable prior to initial policy load.
1243
1244         serialnumber    [BUGS=IA-32]
1245
1246         sg_def_reserved_size=
1247                         [SCSI]
1248
1249         sgalaxy=        [HW,OSS]
1250                         Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1251
1252         shapers=        [NET]
1253                         Maximal number of shapers.
1254
1255         sim710=         [SCSI,HW]
1256                         See header of drivers/scsi/sim710.c.
1257
1258         simeth=         [IA-64]
1259         simscsi=
1260
1261         sjcd=           [HW,CD]
1262                         Format: <io>,<irq>,<dma>
1263                         See header of drivers/cdrom/sjcd.c.
1264
1265         slram=          [HW,MTD]
1266
1267         smart2=         [HW]
1268                         Format: <io1>[,<io2>[,...,<io8>]]
1269
1270         snd-ad1816a=    [HW,ALSA]
1271
1272         snd-ad1848=     [HW,ALSA]
1273
1274         snd-ali5451=    [HW,ALSA]
1275
1276         snd-als100=     [HW,ALSA]
1277
1278         snd-als4000=    [HW,ALSA]
1279
1280         snd-azt2320=    [HW,ALSA]
1281
1282         snd-cmi8330=    [HW,ALSA]
1283
1284         snd-cmipci=     [HW,ALSA]
1285
1286         snd-cs4231=     [HW,ALSA]
1287
1288         snd-cs4232=     [HW,ALSA]
1289
1290         snd-cs4236=     [HW,ALSA]
1291
1292         snd-cs4281=     [HW,ALSA]
1293
1294         snd-cs46xx=     [HW,ALSA]
1295
1296         snd-dt019x=     [HW,ALSA]
1297
1298         snd-dummy=      [HW,ALSA]
1299
1300         snd-emu10k1=    [HW,ALSA]
1301
1302         snd-ens1370=    [HW,ALSA]
1303
1304         snd-ens1371=    [HW,ALSA]
1305
1306         snd-es968=      [HW,ALSA]
1307
1308         snd-es1688=     [HW,ALSA]
1309
1310         snd-es18xx=     [HW,ALSA]
1311
1312         snd-es1938=     [HW,ALSA]
1313
1314         snd-es1968=     [HW,ALSA]
1315
1316         snd-fm801=      [HW,ALSA]
1317
1318         snd-gusclassic= [HW,ALSA]
1319
1320         snd-gusextreme= [HW,ALSA]
1321
1322         snd-gusmax=     [HW,ALSA]
1323
1324         snd-hdsp=       [HW,ALSA]
1325
1326         snd-ice1712=    [HW,ALSA]
1327
1328         snd-intel8x0=   [HW,ALSA]
1329
1330         snd-interwave=  [HW,ALSA]
1331
1332         snd-interwave-stb=
1333                         [HW,ALSA]
1334
1335         snd-korg1212=   [HW,ALSA]
1336
1337         snd-maestro3=   [HW,ALSA]
1338
1339         snd-mpu401=     [HW,ALSA]
1340
1341         snd-mtpav=      [HW,ALSA]
1342
1343         snd-nm256=      [HW,ALSA]
1344
1345         snd-opl3sa2=    [HW,ALSA]
1346
1347         snd-opti92x-ad1848=
1348                         [HW,ALSA]
1349
1350         snd-opti92x-cs4231=
1351                         [HW,ALSA]
1352
1353         snd-opti93x=    [HW,ALSA]
1354
1355         snd-pmac=       [HW,ALSA]
1356
1357         snd-rme32=      [HW,ALSA]
1358
1359         snd-rme96=      [HW,ALSA]
1360
1361         snd-rme9652=    [HW,ALSA]
1362
1363         snd-sb8=        [HW,ALSA]
1364
1365         snd-sb16=       [HW,ALSA]
1366
1367         snd-sbawe=      [HW,ALSA]
1368
1369         snd-serial=     [HW,ALSA]
1370
1371         snd-sgalaxy=    [HW,ALSA]
1372
1373         snd-sonicvibes= [HW,ALSA]
1374
1375         snd-sun-amd7930=
1376                         [HW,ALSA]
1377
1378         snd-sun-cs4231= [HW,ALSA]
1379
1380         snd-trident=    [HW,ALSA]
1381
1382         snd-usb-audio=  [HW,ALSA,USB]
1383
1384         snd-via82xx=    [HW,ALSA]
1385
1386         snd-virmidi=    [HW,ALSA]
1387
1388         snd-wavefront=  [HW,ALSA]
1389
1390         snd-ymfpci=     [HW,ALSA]
1391
1392         sonicvibes=     [HW,OSS]
1393                         Format: <reverb>
1394
1395         sonycd535=      [HW,CD]
1396                         Format: <io>[,<irq>]
1397
1398         sonypi.*=       [HW] Sony Programmable I/O Control Device driver
1399                         See Documentation/sonypi.txt
1400
1401         specialix=      [HW,SERIAL] Specialix multi-serial port adapter
1402                         See Documentation/specialix.txt.
1403
1404         spia_io_base=   [HW,MTD]
1405         spia_fio_base=
1406         spia_pedr=
1407         spia_peddr=
1408
1409         sscape=         [HW,OSS]
1410                         Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1411
1412         st=             [HW,SCSI] SCSI tape parameters (buffers, etc.)
1413                         See Documentation/scsi/st.txt.
1414
1415         st0x=           [HW,SCSI]
1416                         See header of drivers/scsi/seagate.c.
1417
1418         sti=            [PARISC,HW]
1419                         Format: <num>
1420                         Set the STI (builtin display/keyboard on the HP-PARISC
1421                         machines) console (graphic card) which should be used
1422                         as the initial boot-console.
1423                         See also comment in drivers/video/console/sticore.c.
1424
1425         sti_font=       [HW]
1426                         See comment in drivers/video/console/sticore.c.
1427
1428         stifb=          [HW]
1429                         Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1430
1431         stram_swap=     [HW,M68k]
1432
1433         swiotlb=        [IA-64] Number of I/O TLB slabs
1434
1435         switches=       [HW,M68k]
1436
1437         sym53c416=      [HW,SCSI]
1438                         See header of drivers/scsi/sym53c416.c.
1439
1440         t128=           [HW,SCSI]
1441                         See header of drivers/scsi/t128.c.
1442
1443         tdfx=           [HW,DRM]
1444
1445         thash_entries=  [KNL,NET]
1446                         Set number of hash buckets for TCP connection
1447
1448         time            Show timing data prefixed to each printk message line
1449
1450         tipar.timeout=  [HW,PPT]
1451                         Set communications timeout in tenths of a second
1452                         (default 15).
1453
1454         tipar.delay=    [HW,PPT]
1455                         Set inter-bit delay in microseconds (default 10).
1456
1457         tmc8xx=         [HW,SCSI]
1458                         See header of drivers/scsi/seagate.c.
1459
1460         tmscsim=        [HW,SCSI]
1461                         See comment before function dc390_setup() in
1462                         drivers/scsi/tmscsim.c.
1463
1464         tp720=          [HW,PS2]
1465
1466         trix=           [HW,OSS] MediaTrix AudioTrix Pro
1467                         Format: <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1468
1469         tsdev.xres=     [TS] Horizontal screen resolution.
1470         tsdev.yres=     [TS] Vertical screen resolution.
1471
1472         turbografx.map[2|3]=
1473                         [HW,JOY] TurboGraFX parallel port interface
1474                         Format: <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1475                         See also Documentation/input/joystick-parport.txt
1476
1477         u14-34f=        [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1478                         See header of drivers/scsi/u14-34f.c.
1479
1480         uart401=        [HW,OSS]
1481                         Format: <io>,<irq>
1482
1483         uart6850=       [HW,OSS]
1484                         Format: <io>,<irq>
1485
1486         usb-handoff     [HW] Enable early USB BIOS -> OS handoff
1487
1488         usbhid.mousepoll=
1489                         [USBHID] The interval which mice are to be polled at.
1490
1491         video=          [FB] Frame buffer configuration
1492                         See Documentation/fb/modedb.txt.
1493
1494         vga=            [BOOT,IA-32] Select a particular video mode
1495                         See Documentation/i386/boot.txt and Documentation/svga.txt.
1496                         Use vga=ask for menu.
1497                         This is actually a boot loader parameter; the value is
1498                         passed to the kernel using a special protocol.
1499
1500         vmalloc=nn[KMG] [KNL,BOOT] forces the vmalloc area to have an exact
1501                         size of <nn>. This can be used to increase the
1502                         minimum size (128MB on x86). It can also be used to
1503                         decrease the size and leave more room for directly
1504                         mapped kernel RAM.
1505
1506         vmhalt=         [KNL,S390]
1507
1508         vmpoff=         [KNL,S390]
1509
1510         waveartist=     [HW,OSS]
1511                         Format: <io>,<irq>,<dma>,<dma2>
1512
1513         wd33c93=        [HW,SCSI]
1514                         See header of drivers/scsi/wd33c93.c.
1515
1516         wd7000=         [HW,SCSI]
1517                         See header of drivers/scsi/wd7000.c.
1518
1519         wdt=            [WDT] Watchdog
1520                         See Documentation/watchdog/watchdog.txt.
1521
1522         xd=             [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1523         xd_geo=         See header of drivers/block/xd.c.
1524
1525         xirc2ps_cs=     [NET,PCMCIA]
1526                         Format: <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1527
1528
1529
1530 Changelog:
1531
1532         The last known update (for 2.4.0) - the changelog was not kept before.
1533         2000-06-??      Mr. Unknown
1534
1535         Update for 2.5.49, description for most of the options introduced,
1536         references to other documentation (C files, READMEs, ..), added S390,
1537         PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1538         reformatting.
1539         2002-11-24      Petr Baudis <pasky@ucw.cz>
1540                         Randy Dunlap <randy.dunlap@verizon.net>
1541
1542 TODO:
1543
1544         Add documentation for ALSA options.
1545         Add more DRM drivers.