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   1 February 2003             Kernel Parameters                     v2.5.59
   2                           ~~~~~~~~~~~~~~~~~
   3
   4 The following is a consolidated list of the kernel parameters as implemented
   5 (mostly) by the __setup() macro and sorted into English Dictionary order
   6 (defined as ignoring all punctuation and sorting digits before letters in a
   7 case insensitive manner), and with descriptions where known.
   8
   9 Module parameters for loadable modules are specified only as the
  10 parameter name with optional '=' and value as appropriate, such as:
  11
  12         modprobe usbcore blinkenlights=1
  13
  14 Module parameters for modules that are built into the kernel image
  15 are specified on the kernel command line with the module name plus
  16 '.' plus parameter name, with '=' and value if appropriate, such as:
  17
  18         usbcore.blinkenlights=1
  19
  20 The text in square brackets at the beginning of the description 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         enable_timer_pin_1 [i386,x86-64]
 168                         Enable PIN 1 of APIC timer
 169                         Can be useful to work around chipset bugs (in particular on some ATI chipsets)
 170                         The kernel tries to set a reasonable default.
 171
 172         disable_timer_pin_1 [i386,x86-64]
 173                         Disable PIN 1 of APIC timer
 174                         Can be useful to work around chipset bugs.
 175
 176         ad1816=         [HW,OSS]
 177                         Format: <io>,<irq>,<dma>,<dma2>
 178                         See also Documentation/sound/oss/AD1816.
 179
 180         ad1848=         [HW,OSS]
 181                         Format: <io>,<irq>,<dma>,<dma2>,<type>
 182
 183         adlib=          [HW,OSS]
 184                         Format: <io>
 185
 186         advansys=       [HW,SCSI]
 187                         See header of drivers/scsi/advansys.c.
 188
 189         advwdt=         [HW,WDT] Advantech WDT
 190                         Format: <iostart>,<iostop>
 191
 192         aedsp16=        [HW,OSS] Audio Excel DSP 16
 193                         Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
 194                         See also header of sound/oss/aedsp16.c.
 195
 196         aha152x=        [HW,SCSI]
 197                         See Documentation/scsi/aha152x.txt.
 198
 199         aha1542=        [HW,SCSI]
 200                         Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
 201
 202         aic7xxx=        [HW,SCSI]
 203                         See Documentation/scsi/aic7xxx.txt.
 204
 205         aic79xx=        [HW,SCSI]
 206                         See Documentation/scsi/aic79xx.txt.
 207
 208         AM53C974=       [HW,SCSI]
 209                         Format: <host-scsi-id>,<target-scsi-id>,<max-rate>,<max-offset>
 210                         See also header of drivers/scsi/AM53C974.c.
 211
 212         amijoy.map=     [HW,JOY] Amiga joystick support
 213                         Map of devices attached to JOY0DAT and JOY1DAT
 214                         Format: <a>,<b>
 215                         See also Documentation/kernel/input/joystick.txt
 216
 217         analog.map=     [HW,JOY] Analog joystick and gamepad support
 218                         Specifies type or capabilities of an analog joystick
 219                         connected to one of 16 gameports
 220                         Format: <type1>,<type2>,..<type16>
 221
 222         apc=            [HW,SPARC] Power management functions (SPARCstation-4/5 + deriv.)
 223                         Format: noidle
 224                         Disable APC CPU standby support. SPARCstation-Fox does
 225                         not play well with APC CPU idle - disable it if you have
 226                         APC and your system crashes randomly.
 227
 228         apic=           [APIC,i386] Change the output verbosity  whilst booting
 229                         Format: { quiet (default) | verbose | debug }
 230                         Change the amount of debugging information output
 231                         when initialising the APIC and IO-APIC components.
 232
 233         apm=            [APM] Advanced Power Management
 234                         See header of arch/i386/kernel/apm.c.
 235
 236         applicom=       [HW]
 237                         Format: <mem>,<irq>
 238
 239         arcrimi=        [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
 240                         Format: <io>,<irq>,<nodeID>
 241
 242         ataflop=        [HW,M68k]
 243
 244         atarimouse=     [HW,MOUSE] Atari Mouse
 245
 246         atascsi=        [HW,SCSI] Atari SCSI
 247
 248         atkbd.extra=    [HW] Enable extra LEDs and keys on IBM RapidAccess,
 249                         EzKey and similar keyboards
 250
 251         atkbd.reset=    [HW] Reset keyboard during initialization
 252
 253         atkbd.set=      [HW] Select keyboard code set
 254                         Format: <int> (2 = AT (default) 3 = PS/2)
 255
 256         atkbd.scroll=   [HW] Enable scroll wheel on MS Office and similar
 257                         keyboards
 258
 259         atkbd.softraw=  [HW] Choose between synthetic and real raw mode
 260                         Format: <bool> (0 = real, 1 = synthetic (default))
 261
 262         atkbd.softrepeat=
 263                         [HW] Use software keyboard repeat
 264
 265         autotest        [IA64]
 266
 267         awe=            [HW,OSS] AWE32/SB32/AWE64 wave table synth
 268                         Format: <io>,<memsize>,<isapnp>
 269
 270         aztcd=          [HW,CD] Aztech CD268 CDROM driver
 271                         Format: <io>,0x79 (?)
 272
 273         baycom_epp=     [HW,AX25]
 274                         Format: <io>,<mode>
 275
 276         baycom_par=     [HW,AX25] BayCom Parallel Port AX.25 Modem
 277                         Format: <io>,<mode>
 278                         See header of drivers/net/hamradio/baycom_par.c.
 279
 280         baycom_ser_fdx= [HW,AX25] BayCom Serial Port AX.25 Modem (Full Duplex Mode)
 281                         Format: <io>,<irq>,<mode>[,<baud>]
 282                         See header of drivers/net/hamradio/baycom_ser_fdx.c.
 283
 284         baycom_ser_hdx= [HW,AX25] BayCom Serial Port AX.25 Modem (Half Duplex Mode)
 285                         Format: <io>,<irq>,<mode>
 286                         See header of drivers/net/hamradio/baycom_ser_hdx.c.
 287
 288         blkmtd_device=  [HW,MTD]
 289         blkmtd_erasesz=
 290         blkmtd_ro=
 291         blkmtd_bs=
 292         blkmtd_count=
 293
 294         bttv.card=      [HW,V4L] bttv (bt848 + bt878 based grabber cards)
 295         bttv.radio=     Most important insmod options are available as kernel args too.
 296         bttv.pll=       See Documentation/video4linux/bttv/Insmod-options
 297         bttv.tuner=     and Documentation/video4linux/bttv/CARDLIST
 298
 299         BusLogic=       [HW,SCSI]
 300                         See drivers/scsi/BusLogic.c, comment before function
 301                         BusLogic_ParseDriverOptions().
 302
 303         c101=           [NET] Moxa C101 synchronous serial card
 304
 305         cachesize=      [BUGS=IA-32] Override level 2 CPU cache size detection.
 306                         Sometimes CPU hardware bugs make them report the cache
 307                         size incorrectly. The kernel will attempt work arounds
 308                         to fix known problems, but for some CPUs it is not
 309                         possible to determine what the correct size should be.
 310                         This option provides an override for these situations.
 311
 312         cdu31a=         [HW,CD]
 313                         Format: <io>,<irq>[,PAS]
 314                         See header of drivers/cdrom/cdu31a.c.
 315
 316         chandev=        [HW,NET] Generic channel device initialisation
 317
 318         checkreqprot    [SELINUX] Set initial checkreqprot flag value.
 319                         Format: { "0" | "1" }
 320                         See security/selinux/Kconfig help text.
 321                         0 -- check protection applied by kernel (includes any implied execute protection).
 322                         1 -- check protection requested by application.
 323                         Default value is set via a kernel config option.
 324                         Value can be changed at runtime via /selinux/checkreqprot.
 325
 326         clock=          [BUGS=IA-32, HW] gettimeofday timesource override.
 327                         Forces specified timesource (if avaliable) to be used
 328                         when calculating gettimeofday(). If specicified timesource
 329                         is not avalible, it defaults to PIT.
 330                         Format: { pit | tsc | cyclone | pmtmr }
 331
 332         hpet=           [IA-32,HPET] option to disable HPET and use PIT.
 333                         Format: disable
 334
 335         cm206=          [HW,CD]
 336                         Format: { auto | [<io>,][<irq>] }
 337
 338         com20020=       [HW,NET] ARCnet - COM20020 chipset
 339                         Format: <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
 340
 341         com90io=        [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
 342                         Format: <io>[,<irq>]
 343
 344         com90xx=        [HW,NET] ARCnet - COM90xx chipset (memory-mapped buffers)
 345                         Format: <io>[,<irq>[,<memstart>]]
 346
 347         condev=         [HW,S390] console device
 348         conmode=
 349
 350         console=        [KNL] Output console device and options.
 351
 352                 tty<n>  Use the virtual console device <n>.
 353
 354                 ttyS<n>[,options]
 355                         Use the specified serial port.  The options are of
 356                         the form "bbbbpn", where "bbbb" is the baud rate,
 357                         "p" is parity ("n", "o", or "e"), and "n" is bits.
 358                         Default is "9600n8".
 359
 360                         See also Documentation/serial-console.txt.
 361
 362                 uart,io,<addr>[,options]
 363                 uart,mmio,<addr>[,options]
 364                         Start an early, polled-mode console on the 8250/16550
 365                         UART at the specified I/O port or MMIO address,
 366                         switching to the matching ttyS device later.  The
 367                         options are the same as for ttyS, above.
 368
 369         cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
 370                         Format: <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
 371
 372         cpia_pp=        [HW,PPT]
 373                         Format: { parport<nr> | auto | none }
 374
 375         crashkernel=nn[KMG]@ss[KMG]
 376                         [KNL] Reserve a chunk of physical memory to
 377                         hold a kernel to switch to with kexec on panic.
 378
 379         cs4232=         [HW,OSS]
 380                         Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
 381
 382         cs89x0_dma=     [HW,NET]
 383                         Format: <dma>
 384
 385         cs89x0_media=   [HW,NET]
 386                         Format: { rj45 | aui | bnc }
 387
 388         cyclades=       [HW,SERIAL] Cyclades multi-serial port adapter.
 389
 390         dasd=           [HW,NET]
 391                         See header of drivers/s390/block/dasd_devmap.c.
 392
 393         db9.dev[2|3]=   [HW,JOY] Multisystem joystick support via parallel port
 394                         (one device per port)
 395                         Format: <port#>,<type>
 396                         See also Documentation/input/joystick-parport.txt
 397
 398         debug           [KNL] Enable kernel debugging (events log level).
 399
 400         decnet=         [HW,NET]
 401                         Format: <area>[,<node>]
 402                         See also Documentation/networking/decnet.txt.
 403
 404         devfs=          [DEVFS]
 405                         See Documentation/filesystems/devfs/boot-options.
 406
 407         dhash_entries=  [KNL]
 408                         Set number of hash buckets for dentry cache.
 409
 410         digi=           [HW,SERIAL]
 411                         IO parameters + enable/disable command.
 412
 413         digiepca=       [HW,SERIAL]
 414                         See drivers/char/README.epca and
 415                         Documentation/digiepca.txt.
 416
 417         dmascc=         [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
 418                         support available.
 419                         Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
 420
 421         dmasound=       [HW,OSS] Sound subsystem buffers
 422
 423         dscc4.setup=    [NET]
 424
 425         dtc3181e=       [HW,SCSI]
 426
 427         earlyprintk=    [IA-32, X86-64]
 428                         earlyprintk=vga
 429                         earlyprintk=serial[,ttySn[,baudrate]]
 430
 431                         Append ,keep to not disable it when the real console
 432                         takes over.
 433
 434                         Only vga or serial at a time, not both.
 435
 436                         Currently only ttyS0 and ttyS1 are supported.
 437
 438                         Interaction with the standard serial driver is not
 439                         very good.
 440
 441                         The VGA output is eventually overwritten by the real
 442                         console.
 443
 444         eata=           [HW,SCSI]
 445
 446         eda=            [HW,PS2]
 447
 448         edb=            [HW,PS2]
 449
 450         edd=            [EDD]
 451                         Format: {"of[f]" | "sk[ipmbr]"}
 452                         See comment in arch/i386/boot/edd.S
 453
 454         eicon=          [HW,ISDN]
 455                         Format: <id>,<membase>,<irq>
 456
 457         eisa_irq_edge=  [PARISC,HW]
 458                         See header of drivers/parisc/eisa.c.
 459
 460         elanfreq=       [IA-32]
 461                         See comment before function elanfreq_setup() in
 462                         arch/i386/kernel/cpu/cpufreq/elanfreq.c.
 463
 464         elevator=       [IOSCHED]
 465                         Format: {"as"|"cfq"|"deadline"|"noop"}
 466                         See Documentation/block/as-iosched.txt
 467                         and Documentation/block/deadline-iosched.txt for details.
 468         elfcorehdr=     [IA-32]
 469                         Specifies physical address of start of kernel core image
 470                         elf header.
 471                         See Documentation/kdump.txt for details.
 472
 473         enforcing       [SELINUX] Set initial enforcing status.
 474                         Format: {"0" | "1"}
 475                         See security/selinux/Kconfig help text.
 476                         0 -- permissive (log only, no denials).
 477                         1 -- enforcing (deny and log).
 478                         Default value is 0.
 479                         Value can be changed at runtime via /selinux/enforce.
 480
 481         es1370=         [HW,OSS]
 482                         Format: <lineout>[,<micbias>]
 483                         See also header of sound/oss/es1370.c.
 484
 485         es1371=         [HW,OSS]
 486                         Format: <spdif>,[<nomix>,[<amplifier>]]
 487                         See also header of sound/oss/es1371.c.
 488
 489         ether=          [HW,NET] Ethernet cards parameters
 490                         This option is obsoleted by the "netdev=" option, which
 491                         has equivalent usage. See its documentation for details.
 492
 493         eurwdt=         [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
 494                         Format: <io>[,<irq>]
 495
 496         fd_mcs=         [HW,SCSI]
 497                         See header of drivers/scsi/fd_mcs.c.
 498
 499         fdomain=        [HW,SCSI]
 500                         See header of drivers/scsi/fdomain.c.
 501
 502         floppy=         [HW]
 503                         See Documentation/floppy.txt.
 504
 505         ftape=          [HW] Floppy Tape subsystem debugging options.
 506                         See Documentation/ftape.txt.
 507
 508         gamecon.map[2|3]=
 509                         [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
 510                         support via parallel port (up to 5 devices per port)
 511                         Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
 512                         See also Documentation/input/joystick-parport.txt
 513
 514         gamma=          [HW,DRM]
 515
 516         gdth=           [HW,SCSI]
 517                         See header of drivers/scsi/gdth.c.
 518
 519         gpt             [EFI] Forces disk with valid GPT signature but
 520                         invalid Protective MBR to be treated as GPT.
 521
 522         gscd=           [HW,CD]
 523                         Format: <io>
 524
 525         gt96100eth=     [NET] MIPS GT96100 Advanced Communication Controller
 526
 527         gus=            [HW,OSS]
 528                         Format: <io>,<irq>,<dma>,<dma16>
 529
 530         gvp11=          [HW,SCSI]
 531
 532         hashdist=       [KNL,NUMA] Large hashes allocated during boot
 533                         are distributed across NUMA nodes.  Defaults on
 534                         for IA-64, off otherwise.
 535
 536         hcl=            [IA-64] SGI's Hardware Graph compatibility layer
 537
 538         hd=             [EIDE] (E)IDE hard drive subsystem geometry
 539                         Format: <cyl>,<head>,<sect>
 540
 541         hd?=            [HW] (E)IDE subsystem
 542         hd?lun=         See Documentation/ide.txt.
 543
 544         highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
 545                         size of <nn>. This works even on boxes that have no
 546                         highmem otherwise. This also works to reduce highmem
 547                         size on bigger boxes.
 548
 549         hisax=          [HW,ISDN]
 550                         See Documentation/isdn/README.HiSax.
 551
 552         hugepages=      [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
 553
 554         noirqbalance    [IA-32,SMP,KNL] Disable kernel irq balancing
 555
 556         i8042.direct    [HW] Put keyboard port into non-translated mode
 557         i8042.dumbkbd   [HW] Pretend that controlled can only read data from
 558                              keyboard and can not control its state
 559                              (Don't attempt to blink the leds)
 560         i8042.noaux     [HW] Don't check for auxiliary (== mouse) port
 561         i8042.nokbd     [HW] Don't check/create keyboard port
 562         i8042.nomux     [HW] Don't check presence of an active multiplexing
 563                              controller
 564         i8042.nopnp     [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
 565                              controllers
 566         i8042.panicblink=
 567                         [HW] Frequency with which keyboard LEDs should blink
 568                              when kernel panics (default is 0.5 sec)
 569         i8042.reset     [HW] Reset the controller during init and cleanup
 570         i8042.unlock    [HW] Unlock (ignore) the keylock
 571
 572         i810=           [HW,DRM]
 573
 574         i8k.ignore_dmi  [HW] Continue probing hardware even if DMI data
 575                         indicates that the driver is running on unsupported
 576                         hardware.
 577         i8k.force       [HW] Activate i8k driver even if SMM BIOS signature
 578                         does not match list of supported models.
 579         i8k.power_status
 580                         [HW] Report power status in /proc/i8k
 581                         (disabled by default)
 582         i8k.restricted  [HW] Allow controlling fans only if SYS_ADMIN
 583                         capability is set.
 584
 585         ibmmcascsi=     [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
 586                         See Documentation/mca.txt.
 587
 588         icn=            [HW,ISDN]
 589                         Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
 590
 591         ide=            [HW] (E)IDE subsystem
 592                         Format: ide=nodma or ide=doubler or ide=reverse
 593                         See Documentation/ide.txt.
 594
 595         ide?=           [HW] (E)IDE subsystem
 596                         Format: ide?=noprobe or chipset specific parameters.
 597                         See Documentation/ide.txt.
 598
 599         idebus=         [HW] (E)IDE subsystem - VLB/PCI bus speed
 600                         See Documentation/ide.txt.
 601
 602         idle=           [HW]
 603                         Format: idle=poll or idle=halt
 604
 605         ihash_entries=  [KNL]
 606                         Set number of hash buckets for inode cache.
 607
 608         in2000=         [HW,SCSI]
 609                         See header of drivers/scsi/in2000.c.
 610
 611         init=           [KNL]
 612                         Format: <full_path>
 613                         Run specified binary instead of /sbin/init as init
 614                         process.
 615
 616         initcall_debug  [KNL] Trace initcalls as they are executed.  Useful
 617                         for working out where the kernel is dying during
 618                         startup.
 619
 620         initrd=         [BOOT] Specify the location of the initial ramdisk
 621
 622         inport.irq=     [HW] Inport (ATI XL and Microsoft) busmouse driver
 623                         Format: <irq>
 624
 625         inttest=        [IA64]
 626
 627         io7=            [HW] IO7 for Marvel based alpha systems
 628                         See comment before marvel_specify_io7 in
 629                         arch/alpha/kernel/core_marvel.c.
 630
 631         ip=             [IP_PNP]
 632                         See Documentation/nfsroot.txt.
 633
 634         ip2=            [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
 635                         See comment before ip2_setup() in drivers/char/ip2.c.
 636
 637         ips=            [HW,SCSI] Adaptec / IBM ServeRAID controller
 638                         See header of drivers/scsi/ips.c.
 639
 640         irqfixup        [HW]
 641                         When an interrupt is not handled search all handlers
 642                         for it. Intended to get systems with badly broken
 643                         firmware running.
 644
 645         irqpoll         [HW]
 646                         When an interrupt is not handled search all handlers
 647                         for it. Also check all handlers each timer
 648                         interrupt. Intended to get systems with badly broken
 649                         firmware running.
 650
 651         isapnp=         [ISAPNP]
 652                         Format: <RDP>, <reset>, <pci_scan>, <verbosity>
 653
 654         isolcpus=       [KNL,SMP] Isolate CPUs from the general scheduler.
 655                         Format: <cpu number>,...,<cpu number>
 656                         This option can be used to specify one or more CPUs
 657                         to isolate from the general SMP balancing and scheduling
 658                         algorithms. The only way to move a process onto or off
 659                         an "isolated" CPU is via the CPU affinity syscalls.
 660                         <cpu number> begins at 0 and the maximum value is
 661                         "number of CPUs in system - 1".
 662
 663                         This option is the preferred way to isolate CPUs. The
 664                         alternative - manually setting the CPU mask of all tasks
 665                         in the system can cause problems and suboptimal load
 666                         balancer performance.
 667
 668         isp16=          [HW,CD]
 669                         Format: <io>,<irq>,<dma>,<setup>
 670
 671         iucv=           [HW,NET]
 672
 673         js=             [HW,JOY] Analog joystick
 674                         See Documentation/input/joystick.txt.
 675
 676         keepinitrd      [HW,ARM]
 677
 678         kstack=N        [IA-32, X86-64] Print N words from the kernel stack
 679                         in oops dumps.
 680
 681         l2cr=           [PPC]
 682
 683         lapic           [IA-32,APIC] Enable the local APIC even if BIOS disabled it.
 684
 685         lasi=           [HW,SCSI] PARISC LASI driver for the 53c700 chip
 686                         Format: addr:<io>,irq:<irq>
 687
 688         llsc*=          [IA64]
 689                         See function print_params() in arch/ia64/sn/kernel/llsc4.c.
 690
 691         load_ramdisk=   [RAM] List of ramdisks to load from floppy
 692                         See Documentation/ramdisk.txt.
 693
 694         lockd.udpport=  [NFS]
 695
 696         lockd.tcpport=  [NFS]
 697
 698         logibm.irq=     [HW,MOUSE] Logitech Bus Mouse Driver
 699                         Format: <irq>
 700
 701         loglevel=       All Kernel Messages with a loglevel smaller than the
 702                         console loglevel will be printed to the console. It can
 703                         also be changed with klogd or other programs. The
 704                         loglevels are defined as follows:
 705
 706                         0 (KERN_EMERG)          system is unusable
 707                         1 (KERN_ALERT)          action must be taken immediately
 708                         2 (KERN_CRIT)           critical conditions
 709                         3 (KERN_ERR)            error conditions
 710                         4 (KERN_WARNING)        warning conditions
 711                         5 (KERN_NOTICE)         normal but significant condition
 712                         6 (KERN_INFO)           informational
 713                         7 (KERN_DEBUG)          debug-level messages
 714
 715         log_buf_len=n   Sets the size of the printk ring buffer, in bytes.
 716                         Format is n, nk, nM.  n must be a power of two.  The
 717                         default is set in kernel config.
 718
 719         lp=0            [LP]    Specify parallel ports to use, e.g,
 720         lp=port[,port...]       lp=none,parport0 (lp0 not configured, lp1 uses
 721         lp=reset                first parallel port). 'lp=0' disables the
 722         lp=auto                 printer driver. 'lp=reset' (which can be
 723                                 specified in addition to the ports) causes
 724                                 attached printers to be reset. Using
 725                                 lp=port1,port2,... specifies the parallel ports
 726                                 to associate lp devices with, starting with
 727                                 lp0. A port specification may be 'none' to skip
 728                                 that lp device, or a parport name such as
 729                                 'parport0'. Specifying 'lp=auto' instead of a
 730                                 port specification list means that device IDs
 731                                 from each port should be examined, to see if
 732                                 an IEEE 1284-compliant printer is attached; if
 733                                 so, the driver will manage that printer.
 734                                 See also header of drivers/char/lp.c.
 735
 736         lpj=n           [KNL]
 737                         Sets loops_per_jiffy to given constant, thus avoiding
 738                         time-consuming boot-time autodetection (up to 250 ms per
 739                         CPU). 0 enables autodetection (default). To determine
 740                         the correct value for your kernel, boot with normal
 741                         autodetection and see what value is printed. Note that
 742                         on SMP systems the preset will be applied to all CPUs,
 743                         which is likely to cause problems if your CPUs need
 744                         significantly divergent settings. An incorrect value
 745                         will cause delays in the kernel to be wrong, leading to
 746                         unpredictable I/O errors and other breakage. Although
 747                         unlikely, in the extreme case this might damage your
 748                         hardware.
 749
 750         ltpc=           [NET]
 751                         Format: <io>,<irq>,<dma>
 752
 753         mac5380=        [HW,SCSI]
 754                         Format: <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 755
 756         mac53c9x=       [HW,SCSI]
 757                         Format: <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 758
 759         machvec=        [IA64]
 760                         Force the use of a particular machine-vector (machvec) in a generic
 761                         kernel.  Example: machvec=hpzx1_swiotlb
 762
 763         mad16=          [HW,OSS]
 764                         Format: <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
 765
 766         maui=           [HW,OSS]
 767                         Format: <io>,<irq>
 768
 769         max_loop=       [LOOP] Maximum number of loopback devices that can
 770                         be mounted
 771                         Format: <1-256>
 772
 773         maxcpus=        [SMP] Maximum number of processors that an SMP kernel
 774                         should make use of
 775
 776         max_addr=[KMG]  [KNL,BOOT,ia64] All physical memory greater than or
 777                         equal to this physical address is ignored.
 778
 779         max_luns=       [SCSI] Maximum number of LUNs to probe
 780                         Should be between 1 and 2^32-1.
 781
 782         max_report_luns=
 783                         [SCSI] Maximum number of LUNs received
 784                         Should be between 1 and 16384.
 785
 786         mca-pentium     [BUGS=IA-32]
 787
 788         mcatest=        [IA-64]
 789
 790         mcd=            [HW,CD]
 791                         Format: <port>,<irq>,<mitsumi_bug_93_wait>
 792
 793         mcdx=           [HW,CD]
 794
 795         mce             [IA-32] Machine Check Exception
 796
 797         md=             [HW] RAID subsystems devices and level
 798                         See Documentation/md.txt.
 799
 800         mdacon=         [MDA]
 801                         Format: <first>,<last>
 802                         Specifies range of consoles to be captured by the MDA.
 803
 804         mem=nn[KMG]     [KNL,BOOT] Force usage of a specific amount of memory
 805                         Amount of memory to be used when the kernel is not able
 806                         to see the whole system memory or for test.
 807                         [IA-32] Use together with memmap= to avoid physical
 808                         address space collisions. Without memmap= PCI devices
 809                         could be placed at addresses belonging to unused RAM.
 810
 811         mem=nopentium   [BUGS=IA-32] Disable usage of 4MB pages for kernel
 812                         memory.
 813
 814         memmap=exactmap [KNL,IA-32] Enable setting of an exact
 815                         E820 memory map, as specified by the user.
 816                         Such memmap=exactmap lines can be constructed based on
 817                         BIOS output or other requirements. See the memmap=nn@ss
 818                         option description.
 819
 820         memmap=nn[KMG]@ss[KMG]
 821                         [KNL] Force usage of a specific region of memory
 822                         Region of memory to be used, from ss to ss+nn.
 823
 824         memmap=nn[KMG]#ss[KMG]
 825                         [KNL,ACPI] Mark specific memory as ACPI data.
 826                         Region of memory to be used, from ss to ss+nn.
 827
 828         memmap=nn[KMG]$ss[KMG]
 829                         [KNL,ACPI] Mark specific memory as reserved.
 830                         Region of memory to be used, from ss to ss+nn.
 831
 832         meye.*=         [HW] Set MotionEye Camera parameters
 833                         See Documentation/video4linux/meye.txt.
 834
 835         mga=            [HW,DRM]
 836
 837         mousedev.tap_time=
 838                         [MOUSE] Maximum time between finger touching and
 839                         leaving touchpad surface for touch to be considered
 840                         a tap and be reported as a left button click (for
 841                         touchpads working in absolute mode only).
 842                         Format: <msecs>
 843         mousedev.xres=  [MOUSE] Horizontal screen resolution, used for devices
 844                         reporting absolute coordinates, such as tablets
 845         mousedev.yres=  [MOUSE] Vertical screen resolution, used for devices
 846                         reporting absolute coordinates, such as tablets
 847
 848         mpu401=         [HW,OSS]
 849                         Format: <io>,<irq>
 850
 851         MTD_Partition=  [MTD]
 852                         Format: <name>,<region-number>,<size>,<offset>
 853
 854         MTD_Region=     [MTD]
 855                         Format: <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
 856
 857         mtdparts=       [MTD]
 858                         See drivers/mtd/cmdline.c.
 859
 860         mtouchusb.raw_coordinates=
 861                         [HW] Make the MicroTouch USB driver use raw coordinates ('y', default)
 862                         or cooked coordinates ('n')
 863
 864         n2=             [NET] SDL Inc. RISCom/N2 synchronous serial card
 865
 866         NCR_D700=       [HW,SCSI]
 867                         See header of drivers/scsi/NCR_D700.c.
 868
 869         ncr5380=        [HW,SCSI]
 870
 871         ncr53c400=      [HW,SCSI]
 872
 873         ncr53c400a=     [HW,SCSI]
 874
 875         ncr53c406a=     [HW,SCSI]
 876
 877         ncr53c8xx=      [HW,SCSI]
 878
 879         netdev=         [NET] Network devices parameters
 880                         Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
 881                         Note that mem_start is often overloaded to mean
 882                         something different and driver-specific.
 883
 884         nfsaddrs=       [NFS]
 885                         See Documentation/nfsroot.txt.
 886
 887         nfsroot=        [NFS] nfs root filesystem for disk-less boxes.
 888                         See Documentation/nfsroot.txt.
 889
 890         nmi_watchdog=   [KNL,BUGS=IA-32] Debugging features for SMP kernels
 891
 892         no387           [BUGS=IA-32] Tells the kernel to use the 387 maths
 893                         emulation library even if a 387 maths coprocessor
 894                         is present.
 895
 896         noalign         [KNL,ARM]
 897
 898         noapic          [SMP,APIC] Tells the kernel to not make use of any
 899                         IOAPICs that may be present in the system.
 900
 901         noasync         [HW,M68K] Disables async and sync negotiation for
 902                         all devices.
 903
 904         nobats          [PPC] Do not use BATs for mapping kernel lowmem
 905                         on "Classic" PPC cores.
 906
 907         nocache         [ARM]
 908
 909         nodisconnect    [HW,SCSI,M68K] Disables SCSI disconnects.
 910
 911         noexec          [IA-64]
 912
 913         noexec          [IA-32, X86-64]
 914                         noexec=on: enable non-executable mappings (default)
 915                         noexec=off: disable nn-executable mappings
 916
 917         nofxsr          [BUGS=IA-32]
 918
 919         nohlt           [BUGS=ARM]
 920
 921         no-hlt          [BUGS=IA-32] Tells the kernel that the hlt
 922                         instruction doesn't work correctly and not to
 923                         use it.
 924
 925         nohalt          [IA-64] Tells the kernel not to use the power saving
 926                         function PAL_HALT_LIGHT when idle. This increases
 927                         power-consumption. On the positive side, it reduces
 928                         interrupt wake-up latency, which may improve performance
 929                         in certain environments such as networked servers or
 930                         real-time systems.
 931
 932         noirqdebug      [IA-32] Disables the code which attempts to detect and
 933                         disable unhandled interrupt sources.
 934
 935         noisapnp        [ISAPNP] Disables ISA PnP code.
 936
 937         noinitrd        [RAM] Tells the kernel not to load any configured
 938                         initial RAM disk.
 939
 940         nointroute      [IA-64]
 941
 942         nolapic         [IA-32,APIC] Do not enable or use the local APIC.
 943
 944         noltlbs         [PPC] Do not use large page/tlb entries for kernel
 945                         lowmem mapping on PPC40x.
 946
 947         nomce           [IA-32] Machine Check Exception
 948
 949         noresidual      [PPC] Don't use residual data on PReP machines.
 950
 951         noresume        [SWSUSP] Disables resume and restore original swap space.
 952
 953         no-scroll       [VGA] Disables scrollback.
 954                         This is required for the Braillex ib80-piezo Braille
 955                         reader made by F.H. Papenmeier (Germany).
 956
 957         nosbagart       [IA-64]
 958
 959         nosmp           [SMP] Tells an SMP kernel to act as a UP kernel.
 960
 961         nosync          [HW,M68K] Disables sync negotiation for all devices.
 962
 963         notsc           [BUGS=IA-32] Disable Time Stamp Counter
 964
 965         nousb           [USB] Disable the USB subsystem
 966
 967         nowb            [ARM]
 968
 969         opl3=           [HW,OSS]
 970                         Format: <io>
 971
 972         opl3sa=         [HW,OSS]
 973                         Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
 974
 975         opl3sa2=        [HW,OSS]
 976                         Format: <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
 977
 978         oprofile.timer= [HW]
 979                         Use timer interrupt instead of performance counters
 980
 981         optcd=          [HW,CD]
 982                         Format: <io>
 983
 984         osst=           [HW,SCSI] SCSI Tape Driver
 985                         Format: <buffer_size>,<write_threshold>
 986                         See also Documentation/scsi/st.txt.
 987
 988         panic=          [KNL] Kernel behaviour on panic
 989                         Format: <timeout>
 990
 991         parkbd.port=    [HW] Parallel port number the keyboard adapter is
 992                         connected to, default is 0.
 993                         Format: <parport#>
 994         parkbd.mode=    [HW] Parallel port keyboard adapter mode of operation,
 995                         0 for XT, 1 for AT (default is AT).
 996                         Format: <mode>
 997
 998         parport=0       [HW,PPT]        Specify parallel ports. 0 disables.
 999         parport=auto                    Use 'auto' to force the driver to use
1000         parport=0xBBB[,IRQ[,DMA]]       any IRQ/DMA settings detected (the
1001                                         default is to ignore detected IRQ/DMA
1002                                         settings because of possible
1003                                         conflicts). You can specify the base
1004                                         address, IRQ, and DMA settings; IRQ and
1005                                         DMA should be numbers, or 'auto' (for
1006                                         using detected settings on that
1007                                         particular port), or 'nofifo' (to avoid
1008                                         using a FIFO even if it is detected).
1009                                         Parallel ports are assigned in the
1010                                         order they are specified on the command
1011                                         line, starting with parport0.
1012
1013         parport_init_mode=
1014                         [HW,PPT]        Configure VIA parallel port to
1015                                         operate in specific mode. This is
1016                                         necessary on Pegasos computer where
1017                                         firmware has no options for setting up
1018                                         parallel port mode and sets it to
1019                                         spp. Currently this function knows
1020                                         686a and 8231 chips.
1021                         Format: [spp|ps2|epp|ecp|ecpepp]
1022
1023         pas2=           [HW,OSS]
1024                         Format: <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1025
1026         pas16=          [HW,SCSI]
1027                         See header of drivers/scsi/pas16.c.
1028
1029         pcbit=          [HW,ISDN]
1030
1031         pcd.            [PARIDE]
1032                         See header of drivers/block/paride/pcd.c.
1033                         See also Documentation/paride.txt.
1034
1035         pci=option[,option...]          [PCI] various PCI subsystem options:
1036                 off                     [IA-32] don't probe for the PCI bus
1037                 bios                    [IA-32] force use of PCI BIOS, don't access
1038                                         the hardware directly. Use this if your machine
1039                                         has a non-standard PCI host bridge.
1040                 nobios                  [IA-32] disallow use of PCI BIOS, only direct
1041                                         hardware access methods are allowed. Use this
1042                                         if you experience crashes upon bootup and you
1043                                         suspect they are caused by the BIOS.
1044                 conf1                   [IA-32] Force use of PCI Configuration Mechanism 1.
1045                 conf2                   [IA-32] Force use of PCI Configuration Mechanism 2.
1046                 nosort                  [IA-32] Don't sort PCI devices according to
1047                                         order given by the PCI BIOS. This sorting is done
1048                                         to get a device order compatible with older kernels.
1049                 biosirq                 [IA-32] Use PCI BIOS calls to get the interrupt
1050                                         routing table. These calls are known to be buggy
1051                                         on several machines and they hang the machine when used,
1052                                         but on other computers it's the only way to get the
1053                                         interrupt routing table. Try this option if the kernel
1054                                         is unable to allocate IRQs or discover secondary PCI
1055                                         buses on your motherboard.
1056                 rom                     [IA-32] Assign address space to expansion ROMs.
1057                                         Use with caution as certain devices share address
1058                                         decoders between ROMs and other resources.
1059                 irqmask=0xMMMM          [IA-32] Set a bit mask of IRQs allowed to be assigned
1060                                         automatically to PCI devices. You can make the kernel
1061                                         exclude IRQs of your ISA cards this way.
1062                 pirqaddr=0xAAAAA        [IA-32] Specify the physical address
1063                                         of the PIRQ table (normally generated
1064                                         by the BIOS) if it is outside the
1065                                         F0000h-100000h range.
1066                 lastbus=N               [IA-32] Scan all buses till bus #N. Can be useful
1067                                         if the kernel is unable to find your secondary buses
1068                                         and you want to tell it explicitly which ones they are.
1069                 assign-busses           [IA-32] Always assign all PCI bus
1070                                         numbers ourselves, overriding
1071                                         whatever the firmware may have
1072                                         done.
1073                 usepirqmask             [IA-32] Honor the possible IRQ mask
1074                                         stored in the BIOS $PIR table. This is
1075                                         needed on some systems with broken
1076                                         BIOSes, notably some HP Pavilion N5400
1077                                         and Omnibook XE3 notebooks. This will
1078                                         have no effect if ACPI IRQ routing is
1079                                         enabled.
1080                 noacpi                  [IA-32] Do not use ACPI for IRQ routing
1081                                         or for PCI scanning.
1082                 routeirq                Do IRQ routing for all PCI devices.
1083                                         This is normally done in pci_enable_device(),
1084                                         so this option is a temporary workaround
1085                                         for broken drivers that don't call it.
1086
1087                 firmware                [ARM] Do not re-enumerate the bus but
1088                                         instead just use the configuration
1089                                         from the bootloader. This is currently
1090                                         used on IXP2000 systems where the
1091                                         bus has to be configured a certain way
1092                                         for adjunct CPUs.
1093
1094         pcmv=           [HW,PCMCIA] BadgePAD 4
1095
1096         pd.             [PARIDE]
1097                         See Documentation/paride.txt.
1098
1099         pdcchassis=     [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1100                         boot time.
1101                         Format: { 0 | 1 }
1102                         See arch/parisc/kernel/pdc_chassis.c
1103
1104         pf.             [PARIDE]
1105                         See Documentation/paride.txt.
1106
1107         pg.             [PARIDE]
1108                         See Documentation/paride.txt.
1109
1110         pirq=           [SMP,APIC] Manual mp-table setup
1111                         See Documentation/i386/IO-APIC.txt.
1112
1113         plip=           [PPT,NET] Parallel port network link
1114                         Format: { parport<nr> | timid | 0 }
1115                         See also Documentation/parport.txt.
1116
1117         pnpacpi=        [ACPI]
1118                         { off }
1119
1120         pnpbios=        [ISAPNP]
1121                         { on | off | curr | res | no-curr | no-res }
1122
1123         pnp_reserve_irq=
1124                         [ISAPNP] Exclude IRQs for the autoconfiguration
1125
1126         pnp_reserve_dma=
1127                         [ISAPNP] Exclude DMAs for the autoconfiguration
1128
1129         pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1130                         Ranges are in pairs (I/O port base and size).
1131
1132         pnp_reserve_mem=
1133                         [ISAPNP] Exclude memory regions for the autoconfiguration
1134                         Ranges are in pairs (memory base and size).
1135
1136         profile=        [KNL] Enable kernel profiling via /proc/profile
1137                         { schedule | <number> }
1138                         (param: schedule - profile schedule points}
1139                         (param: profile step/bucket size as a power of 2 for
1140                                 statistical time based profiling)
1141
1142         processor.max_cstate=   [HW, ACPI]
1143                         Limit processor to maximum C-state
1144                         max_cstate=9 overrides any DMI blacklist limit.
1145
1146         prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1147                         before loading.
1148                         See Documentation/ramdisk.txt.
1149
1150         psmouse.proto=  [HW,MOUSE] Highest PS2 mouse protocol extension to
1151                         probe for (bare|imps|exps|lifebook|any).
1152         psmouse.rate=   [HW,MOUSE] Set desired mouse report rate, in reports
1153                         per second.
1154         psmouse.resetafter=
1155                         [HW,MOUSE] Try to reset the device after so many bad packets
1156                         (0 = never).
1157         psmouse.resolution=
1158                         [HW,MOUSE] Set desired mouse resolution, in dpi.
1159         psmouse.smartscroll=
1160                         [HW,MOUSE] Controls Logitech smartscroll autorepeat,
1161                         0 = disabled, 1 = enabled (default).
1162
1163         pss=            [HW,OSS] Personal Sound System (ECHO ESC614)
1164                         Format: <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1165
1166         pt.             [PARIDE]
1167                         See Documentation/paride.txt.
1168
1169         quiet=          [KNL] Disable log messages
1170
1171         r128=           [HW,DRM]
1172
1173         raid=           [HW,RAID]
1174                         See Documentation/md.txt.
1175
1176         ramdisk=        [RAM] Sizes of RAM disks in kilobytes [deprecated]
1177                         See Documentation/ramdisk.txt.
1178
1179         ramdisk_blocksize=
1180                         [RAM]
1181                         See Documentation/ramdisk.txt.
1182
1183         ramdisk_size=   [RAM] Sizes of RAM disks in kilobytes
1184                         New name for the ramdisk parameter.
1185                         See Documentation/ramdisk.txt.
1186
1187         rdinit=         [KNL]
1188                         Format: <full_path>
1189                         Run specified binary instead of /init from the ramdisk,
1190                         used for early userspace startup. See initrd.
1191
1192         reboot=         [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1193                         Format: <reboot_mode>[,<reboot_mode2>[,...]]
1194                         See arch/*/kernel/reboot.c.
1195
1196         reserve=        [KNL,BUGS] Force the kernel to ignore some iomem area
1197
1198         resume=         [SWSUSP] Specify the partition device for software suspension
1199
1200         rhash_entries=  [KNL,NET]
1201                         Set number of hash buckets for route cache
1202
1203         riscom8=        [HW,SERIAL]
1204                         Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1205
1206         ro              [KNL] Mount root device read-only on boot
1207
1208         root=           [KNL] Root filesystem
1209
1210         rootdelay=      [KNL] Delay (in seconds) to pause before attempting to
1211                         mount the root filesystem
1212
1213         rootflags=      [KNL] Set root filesystem mount option string
1214
1215         rootfstype=     [KNL] Set root filesystem type
1216
1217         rw              [KNL] Mount root device read-write on boot
1218
1219         S               [KNL] Run init in single mode
1220
1221         sa1100ir        [NET]
1222                         See drivers/net/irda/sa1100_ir.c.
1223
1224         sb=             [HW,OSS]
1225                         Format: <io>,<irq>,<dma>,<dma2>
1226
1227         sbni=           [NET] Granch SBNI12 leased line adapter
1228
1229         sbpcd=          [HW,CD] Soundblaster CD adapter
1230                         Format: <io>,<type>
1231                         See a comment before function sbpcd_setup() in
1232                         drivers/cdrom/sbpcd.c.
1233
1234         sc1200wdt=      [HW,WDT] SC1200 WDT (watchdog) driver
1235                         Format: <io>[,<timeout>[,<isapnp>]]
1236
1237         scsi_debug_*=   [SCSI]
1238                         See drivers/scsi/scsi_debug.c.
1239
1240         scsi_default_dev_flags=
1241                         [SCSI] SCSI default device flags
1242                         Format: <integer>
1243
1244         scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1245                         Format: <vendor>:<model>:<flags>
1246                         (flags are integer value)
1247
1248         scsi_logging=   [SCSI]
1249
1250         selinux         [SELINUX] Disable or enable SELinux at boot time.
1251                         Format: { "0" | "1" }
1252                         See security/selinux/Kconfig help text.
1253                         0 -- disable.
1254                         1 -- enable.
1255                         Default value is set via kernel config option.
1256                         If enabled at boot time, /selinux/disable can be used
1257                         later to disable prior to initial policy load.
1258
1259         serialnumber    [BUGS=IA-32]
1260
1261         sg_def_reserved_size=
1262                         [SCSI]
1263
1264         sgalaxy=        [HW,OSS]
1265                         Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1266
1267         shapers=        [NET]
1268                         Maximal number of shapers.
1269
1270         sim710=         [SCSI,HW]
1271                         See header of drivers/scsi/sim710.c.
1272
1273         simeth=         [IA-64]
1274         simscsi=
1275
1276         sjcd=           [HW,CD]
1277                         Format: <io>,<irq>,<dma>
1278                         See header of drivers/cdrom/sjcd.c.
1279
1280         slram=          [HW,MTD]
1281
1282         smart2=         [HW]
1283                         Format: <io1>[,<io2>[,...,<io8>]]
1284
1285         snd-ad1816a=    [HW,ALSA]
1286
1287         snd-ad1848=     [HW,ALSA]
1288
1289         snd-ali5451=    [HW,ALSA]
1290
1291         snd-als100=     [HW,ALSA]
1292
1293         snd-als4000=    [HW,ALSA]
1294
1295         snd-azt2320=    [HW,ALSA]
1296
1297         snd-cmi8330=    [HW,ALSA]
1298
1299         snd-cmipci=     [HW,ALSA]
1300
1301         snd-cs4231=     [HW,ALSA]
1302
1303         snd-cs4232=     [HW,ALSA]
1304
1305         snd-cs4236=     [HW,ALSA]
1306
1307         snd-cs4281=     [HW,ALSA]
1308
1309         snd-cs46xx=     [HW,ALSA]
1310
1311         snd-dt019x=     [HW,ALSA]
1312
1313         snd-dummy=      [HW,ALSA]
1314
1315         snd-emu10k1=    [HW,ALSA]
1316
1317         snd-ens1370=    [HW,ALSA]
1318
1319         snd-ens1371=    [HW,ALSA]
1320
1321         snd-es968=      [HW,ALSA]
1322
1323         snd-es1688=     [HW,ALSA]
1324
1325         snd-es18xx=     [HW,ALSA]
1326
1327         snd-es1938=     [HW,ALSA]
1328
1329         snd-es1968=     [HW,ALSA]
1330
1331         snd-fm801=      [HW,ALSA]
1332
1333         snd-gusclassic= [HW,ALSA]
1334
1335         snd-gusextreme= [HW,ALSA]
1336
1337         snd-gusmax=     [HW,ALSA]
1338
1339         snd-hdsp=       [HW,ALSA]
1340
1341         snd-ice1712=    [HW,ALSA]
1342
1343         snd-intel8x0=   [HW,ALSA]
1344
1345         snd-interwave=  [HW,ALSA]
1346
1347         snd-interwave-stb=
1348                         [HW,ALSA]
1349
1350         snd-korg1212=   [HW,ALSA]
1351
1352         snd-maestro3=   [HW,ALSA]
1353
1354         snd-mpu401=     [HW,ALSA]
1355
1356         snd-mtpav=      [HW,ALSA]
1357
1358         snd-nm256=      [HW,ALSA]
1359
1360         snd-opl3sa2=    [HW,ALSA]
1361
1362         snd-opti92x-ad1848=
1363                         [HW,ALSA]
1364
1365         snd-opti92x-cs4231=
1366                         [HW,ALSA]
1367
1368         snd-opti93x=    [HW,ALSA]
1369
1370         snd-pmac=       [HW,ALSA]
1371
1372         snd-rme32=      [HW,ALSA]
1373
1374         snd-rme96=      [HW,ALSA]
1375
1376         snd-rme9652=    [HW,ALSA]
1377
1378         snd-sb8=        [HW,ALSA]
1379
1380         snd-sb16=       [HW,ALSA]
1381
1382         snd-sbawe=      [HW,ALSA]
1383
1384         snd-serial=     [HW,ALSA]
1385
1386         snd-sgalaxy=    [HW,ALSA]
1387
1388         snd-sonicvibes= [HW,ALSA]
1389
1390         snd-sun-amd7930=
1391                         [HW,ALSA]
1392
1393         snd-sun-cs4231= [HW,ALSA]
1394
1395         snd-trident=    [HW,ALSA]
1396
1397         snd-usb-audio=  [HW,ALSA,USB]
1398
1399         snd-via82xx=    [HW,ALSA]
1400
1401         snd-virmidi=    [HW,ALSA]
1402
1403         snd-wavefront=  [HW,ALSA]
1404
1405         snd-ymfpci=     [HW,ALSA]
1406
1407         sonicvibes=     [HW,OSS]
1408                         Format: <reverb>
1409
1410         sonycd535=      [HW,CD]
1411                         Format: <io>[,<irq>]
1412
1413         sonypi.*=       [HW] Sony Programmable I/O Control Device driver
1414                         See Documentation/sonypi.txt
1415
1416         specialix=      [HW,SERIAL] Specialix multi-serial port adapter
1417                         See Documentation/specialix.txt.
1418
1419         spia_io_base=   [HW,MTD]
1420         spia_fio_base=
1421         spia_pedr=
1422         spia_peddr=
1423
1424         sscape=         [HW,OSS]
1425                         Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1426
1427         st=             [HW,SCSI] SCSI tape parameters (buffers, etc.)
1428                         See Documentation/scsi/st.txt.
1429
1430         st0x=           [HW,SCSI]
1431                         See header of drivers/scsi/seagate.c.
1432
1433         sti=            [PARISC,HW]
1434                         Format: <num>
1435                         Set the STI (builtin display/keyboard on the HP-PARISC
1436                         machines) console (graphic card) which should be used
1437                         as the initial boot-console.
1438                         See also comment in drivers/video/console/sticore.c.
1439
1440         sti_font=       [HW]
1441                         See comment in drivers/video/console/sticore.c.
1442
1443         stifb=          [HW]
1444                         Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1445
1446         stram_swap=     [HW,M68k]
1447
1448         swiotlb=        [IA-64] Number of I/O TLB slabs
1449
1450         switches=       [HW,M68k]
1451
1452         sym53c416=      [HW,SCSI]
1453                         See header of drivers/scsi/sym53c416.c.
1454
1455         t128=           [HW,SCSI]
1456                         See header of drivers/scsi/t128.c.
1457
1458         tdfx=           [HW,DRM]
1459
1460         thash_entries=  [KNL,NET]
1461                         Set number of hash buckets for TCP connection
1462
1463         time            Show timing data prefixed to each printk message line
1464
1465         tipar.timeout=  [HW,PPT]
1466                         Set communications timeout in tenths of a second
1467                         (default 15).
1468
1469         tipar.delay=    [HW,PPT]
1470                         Set inter-bit delay in microseconds (default 10).
1471
1472         tmc8xx=         [HW,SCSI]
1473                         See header of drivers/scsi/seagate.c.
1474
1475         tmscsim=        [HW,SCSI]
1476                         See comment before function dc390_setup() in
1477                         drivers/scsi/tmscsim.c.
1478
1479         tp720=          [HW,PS2]
1480
1481         trix=           [HW,OSS] MediaTrix AudioTrix Pro
1482                         Format: <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1483
1484         tsdev.xres=     [TS] Horizontal screen resolution.
1485         tsdev.yres=     [TS] Vertical screen resolution.
1486
1487         turbografx.map[2|3]=
1488                         [HW,JOY] TurboGraFX parallel port interface
1489                         Format: <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1490                         See also Documentation/input/joystick-parport.txt
1491
1492         u14-34f=        [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1493                         See header of drivers/scsi/u14-34f.c.
1494
1495         uart401=        [HW,OSS]
1496                         Format: <io>,<irq>
1497
1498         uart6850=       [HW,OSS]
1499                         Format: <io>,<irq>
1500
1501         usb-handoff     [HW] Enable early USB BIOS -> OS handoff
1502
1503         usbhid.mousepoll=
1504                         [USBHID] The interval which mice are to be polled at.
1505
1506         video=          [FB] Frame buffer configuration
1507                         See Documentation/fb/modedb.txt.
1508
1509         vga=            [BOOT,IA-32] Select a particular video mode
1510                         See Documentation/i386/boot.txt and Documentation/svga.txt.
1511                         Use vga=ask for menu.
1512                         This is actually a boot loader parameter; the value is
1513                         passed to the kernel using a special protocol.
1514
1515         vmalloc=nn[KMG] [KNL,BOOT] forces the vmalloc area to have an exact
1516                         size of <nn>. This can be used to increase the
1517                         minimum size (128MB on x86). It can also be used to
1518                         decrease the size and leave more room for directly
1519                         mapped kernel RAM.
1520
1521         vmhalt=         [KNL,S390]
1522
1523         vmpoff=         [KNL,S390]
1524
1525         waveartist=     [HW,OSS]
1526                         Format: <io>,<irq>,<dma>,<dma2>
1527
1528         wd33c93=        [HW,SCSI]
1529                         See header of drivers/scsi/wd33c93.c.
1530
1531         wd7000=         [HW,SCSI]
1532                         See header of drivers/scsi/wd7000.c.
1533
1534         wdt=            [WDT] Watchdog
1535                         See Documentation/watchdog/watchdog.txt.
1536
1537         xd=             [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1538         xd_geo=         See header of drivers/block/xd.c.
1539
1540         xirc2ps_cs=     [NET,PCMCIA]
1541                         Format: <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1542
1543
1544
1545 Changelog:
1546
1547         The last known update (for 2.4.0) - the changelog was not kept before.
1548         2000-06-??      Mr. Unknown
1549
1550         Update for 2.5.49, description for most of the options introduced,
1551         references to other documentation (C files, READMEs, ..), added S390,
1552         PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1553         reformatting.
1554         2002-11-24      Petr Baudis <pasky@ucw.cz>
1555                         Randy Dunlap <randy.dunlap@verizon.net>
1556
1557 TODO:
1558
1559         Add documentation for ALSA options.
1560         Add more DRM drivers.