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