kernel-parameters.txt 59 KB

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  1. Kernel Parameters
  2. ~~~~~~~~~~~~~~~~~
  3. The following is a consolidated list of the kernel parameters as implemented
  4. (mostly) by the __setup() macro and sorted into English Dictionary order
  5. (defined as ignoring all punctuation and sorting digits before letters in a
  6. case insensitive manner), and with descriptions where known.
  7. Module parameters for loadable modules are specified only as the
  8. parameter name with optional '=' and value as appropriate, such as:
  9. modprobe usbcore blinkenlights=1
  10. Module parameters for modules that are built into the kernel image
  11. are specified on the kernel command line with the module name plus
  12. '.' plus parameter name, with '=' and value if appropriate, such as:
  13. usbcore.blinkenlights=1
  14. This document may not be entirely up to date and comprehensive. The command
  15. "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
  16. module. Loadable modules, after being loaded into the running kernel, also
  17. reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
  18. parameters may be changed at runtime by the command
  19. "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
  20. The parameters listed below are only valid if certain kernel build options were
  21. enabled and if respective hardware is present. The text in square brackets at
  22. the beginning of each description states the restrictions within which a
  23. parameter is applicable:
  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. DRM Direct Rendering Management support is enabled.
  31. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  32. EFI EFI Partitioning (GPT) is enabled
  33. EIDE EIDE/ATAPI support is enabled.
  34. FB The frame buffer device is enabled.
  35. HW Appropriate hardware is enabled.
  36. IA-32 IA-32 aka i386 architecture is enabled.
  37. IA-64 IA-64 architecture is enabled.
  38. IOSCHED More than one I/O scheduler is enabled.
  39. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  40. ISAPNP ISA PnP code is enabled.
  41. ISDN Appropriate ISDN support is enabled.
  42. JOY Appropriate joystick support is enabled.
  43. LIBATA Libata driver 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. MSI Message Signaled Interrupts (PCI).
  53. MTD MTD support is enabled.
  54. NET Appropriate network support is enabled.
  55. NUMA NUMA support is enabled.
  56. GENERIC_TIME The generic timeofday code is enabled.
  57. NFS Appropriate NFS support is enabled.
  58. OSS OSS sound support is enabled.
  59. PV_OPS A paravirtualized kernel
  60. PARIDE The ParIDE subsystem is enabled.
  61. PARISC The PA-RISC architecture is enabled.
  62. PCI PCI bus support is enabled.
  63. PCMCIA The PCMCIA subsystem is enabled.
  64. PNP Plug & Play support is enabled.
  65. PPC PowerPC architecture is enabled.
  66. PPT Parallel port support is enabled.
  67. PS2 Appropriate PS/2 support is enabled.
  68. RAM RAM disk support is enabled.
  69. S390 S390 architecture is enabled.
  70. SCSI Appropriate SCSI support is enabled.
  71. A lot of drivers has their options described inside of
  72. Documentation/scsi/.
  73. SELINUX SELinux support is enabled.
  74. SERIAL Serial support is enabled.
  75. SH SuperH architecture is enabled.
  76. SMP The kernel is an SMP kernel.
  77. SPARC Sparc architecture is enabled.
  78. SWSUSP Software suspend is enabled.
  79. TS Appropriate touchscreen support is enabled.
  80. USB USB support is enabled.
  81. USBHID USB Human Interface Device support is enabled.
  82. V4L Video For Linux support is enabled.
  83. VGA The VGA console has been enabled.
  84. VT Virtual terminal support is enabled.
  85. WDT Watchdog support is enabled.
  86. XT IBM PC/XT MFM hard disk support is enabled.
  87. X86-64 X86-64 architecture is enabled.
  88. More X86-64 boot options can be found in
  89. Documentation/x86_64/boot-options.txt .
  90. In addition, the following text indicates that the option:
  91. BUGS= Relates to possible processor bugs on the said processor.
  92. KNL Is a kernel start-up parameter.
  93. BOOT Is a boot loader parameter.
  94. Parameters denoted with BOOT are actually interpreted by the boot
  95. loader, and have no meaning to the kernel directly.
  96. Do not modify the syntax of boot loader parameters without extreme
  97. need or coordination with <Documentation/i386/boot.txt>.
  98. There are also arch-specific kernel-parameters not documented here.
  99. See for example <Documentation/x86_64/boot-options.txt>.
  100. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  101. a trailing = on the name of any parameter states that that parameter will
  102. be entered as an environment variable, whereas its absence indicates that
  103. it will appear as a kernel argument readable via /proc/cmdline by programs
  104. running once the system is up.
  105. The number of kernel parameters is not limited, but the length of the
  106. complete command line (parameters including spaces etc.) is limited to
  107. a fixed number of characters. This limit depends on the architecture
  108. and is between 256 and 4096 characters. It is defined in the file
  109. ./include/asm/setup.h as COMMAND_LINE_SIZE.
  110. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  111. See header of drivers/scsi/53c7xx.c.
  112. See also Documentation/scsi/ncr53c7xx.txt.
  113. acpi= [HW,ACPI,X86-64,i386]
  114. Advanced Configuration and Power Interface
  115. Format: { force | off | ht | strict | noirq }
  116. force -- enable ACPI if default was off
  117. off -- disable ACPI if default was on
  118. noirq -- do not use ACPI for IRQ routing
  119. ht -- run only enough ACPI to enable Hyper Threading
  120. strict -- Be less tolerant of platforms that are not
  121. strictly ACPI specification compliant.
  122. See also Documentation/pm.txt, pci=noacpi
  123. acpi_apic_instance= [ACPI, IOAPIC]
  124. Format: <int>
  125. 2: use 2nd APIC table, if available
  126. 1,0: use 1st APIC table
  127. default: 0
  128. acpi_sleep= [HW,ACPI] Sleep options
  129. Format: { s3_bios, s3_mode }
  130. See Documentation/power/video.txt
  131. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  132. Format: { level | edge | high | low }
  133. acpi_irq_balance [HW,ACPI]
  134. ACPI will balance active IRQs
  135. default in APIC mode
  136. acpi_irq_nobalance [HW,ACPI]
  137. ACPI will not move active IRQs (default)
  138. default in PIC mode
  139. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  140. use by PCI
  141. Format: <irq>,<irq>...
  142. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  143. Format: <irq>,<irq>...
  144. acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
  145. Format: To spoof as Windows 98: ="Microsoft Windows"
  146. acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
  147. acpi_osi="string1" # add string1 -- only one string
  148. acpi_osi="!string2" # remove built-in string2
  149. acpi_osi= # disable all strings
  150. acpi_serialize [HW,ACPI] force serialization of AML methods
  151. acpi_skip_timer_override [HW,ACPI]
  152. Recognize and ignore IRQ0/pin2 Interrupt Override.
  153. For broken nForce2 BIOS resulting in XT-PIC timer.
  154. acpi_use_timer_override [HW,ACPI}
  155. Use timer override. For some broken Nvidia NF5 boards
  156. that require a timer override, but don't have
  157. HPET
  158. acpi.debug_layer= [HW,ACPI]
  159. Format: <int>
  160. Each bit of the <int> indicates an ACPI debug layer,
  161. 1: enable, 0: disable. It is useful for boot time
  162. debugging. After system has booted up, it can be set
  163. via /sys/module/acpi/parameters/debug_layer.
  164. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  165. Available bits (add the numbers together) to enable debug output
  166. for specific parts of the ACPI subsystem:
  167. 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
  168. 0x10 namespace 0x20 parser 0x40 dispatcher
  169. 0x80 executer 0x100 resources 0x200 acpica debugger
  170. 0x400 os services 0x800 acpica disassembler.
  171. The number can be in decimal or prefixed with 0x in hex.
  172. Warning: Many of these options can produce a lot of
  173. output and make your system unusable. Be very careful.
  174. acpi.debug_level= [HW,ACPI]
  175. Format: <int>
  176. Each bit of the <int> indicates an ACPI debug level,
  177. 1: enable, 0: disable. It is useful for boot time
  178. debugging. After system has booted up, it can be set
  179. via /sys/module/acpi/parameters/debug_level.
  180. CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
  181. Available bits (add the numbers together) to enable different
  182. debug output levels of the ACPI subsystem:
  183. 0x01 error 0x02 warn 0x04 init 0x08 debug object
  184. 0x10 info 0x20 init names 0x40 parse 0x80 load
  185. 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
  186. 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
  187. 0x10000 resources 0x20000 user requests 0x40000 package.
  188. The number can be in decimal or prefixed with 0x in hex.
  189. Warning: Many of these options can produce a lot of
  190. output and make your system unusable. Be very careful.
  191. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  192. acpi_generic_hotkey [HW,ACPI]
  193. Allow consolidated generic hotkey driver to
  194. override platform specific driver.
  195. See also Documentation/acpi-hotkey.txt.
  196. acpi_pm_good [IA-32,X86-64]
  197. Override the pmtimer bug detection: force the kernel
  198. to assume that this machine's pmtimer latches its value
  199. and always returns good values.
  200. enable_timer_pin_1 [i386,x86-64]
  201. Enable PIN 1 of APIC timer
  202. Can be useful to work around chipset bugs
  203. (in particular on some ATI chipsets).
  204. The kernel tries to set a reasonable default.
  205. disable_timer_pin_1 [i386,x86-64]
  206. Disable PIN 1 of APIC timer
  207. Can be useful to work around chipset bugs.
  208. ad1816= [HW,OSS]
  209. Format: <io>,<irq>,<dma>,<dma2>
  210. See also Documentation/sound/oss/AD1816.
  211. ad1848= [HW,OSS]
  212. Format: <io>,<irq>,<dma>,<dma2>,<type>
  213. adlib= [HW,OSS]
  214. Format: <io>
  215. advansys= [HW,SCSI]
  216. See header of drivers/scsi/advansys.c.
  217. advwdt= [HW,WDT] Advantech WDT
  218. Format: <iostart>,<iostop>
  219. aedsp16= [HW,OSS] Audio Excel DSP 16
  220. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  221. See also header of sound/oss/aedsp16.c.
  222. aha152x= [HW,SCSI]
  223. See Documentation/scsi/aha152x.txt.
  224. aha1542= [HW,SCSI]
  225. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  226. aic7xxx= [HW,SCSI]
  227. See Documentation/scsi/aic7xxx.txt.
  228. aic79xx= [HW,SCSI]
  229. See Documentation/scsi/aic79xx.txt.
  230. amijoy.map= [HW,JOY] Amiga joystick support
  231. Map of devices attached to JOY0DAT and JOY1DAT
  232. Format: <a>,<b>
  233. See also Documentation/kernel/input/joystick.txt
  234. analog.map= [HW,JOY] Analog joystick and gamepad support
  235. Specifies type or capabilities of an analog joystick
  236. connected to one of 16 gameports
  237. Format: <type1>,<type2>,..<type16>
  238. apc= [HW,SPARC]
  239. Power management functions (SPARCstation-4/5 + deriv.)
  240. Format: noidle
  241. Disable APC CPU standby support. SPARCstation-Fox does
  242. not play well with APC CPU idle - disable it if you have
  243. APC and your system crashes randomly.
  244. apic= [APIC,i386] Change the output verbosity whilst booting
  245. Format: { quiet (default) | verbose | debug }
  246. Change the amount of debugging information output
  247. when initialising the APIC and IO-APIC components.
  248. apm= [APM] Advanced Power Management
  249. See header of arch/i386/kernel/apm.c.
  250. applicom= [HW]
  251. Format: <mem>,<irq>
  252. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  253. Format: <io>,<irq>,<nodeID>
  254. ataflop= [HW,M68k]
  255. atarimouse= [HW,MOUSE] Atari Mouse
  256. atascsi= [HW,SCSI] Atari SCSI
  257. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  258. EzKey and similar keyboards
  259. atkbd.reset= [HW] Reset keyboard during initialization
  260. atkbd.set= [HW] Select keyboard code set
  261. Format: <int> (2 = AT (default), 3 = PS/2)
  262. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  263. keyboards
  264. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  265. Format: <bool> (0 = real, 1 = synthetic (default))
  266. atkbd.softrepeat= [HW]
  267. Use software keyboard repeat
  268. autotest [IA64]
  269. aztcd= [HW,CD] Aztech CD268 CDROM driver
  270. Format: <io>,0x79 (?)
  271. baycom_epp= [HW,AX25]
  272. Format: <io>,<mode>
  273. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  274. Format: <io>,<mode>
  275. See header of drivers/net/hamradio/baycom_par.c.
  276. baycom_ser_fdx= [HW,AX25]
  277. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  278. Format: <io>,<irq>,<mode>[,<baud>]
  279. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  280. baycom_ser_hdx= [HW,AX25]
  281. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  282. Format: <io>,<irq>,<mode>
  283. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  284. blkmtd_device= [HW,MTD]
  285. blkmtd_erasesz=
  286. blkmtd_ro=
  287. blkmtd_bs=
  288. blkmtd_count=
  289. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  290. bttv.radio= Most important insmod options are available as
  291. kernel args too.
  292. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  293. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  294. BusLogic= [HW,SCSI]
  295. See drivers/scsi/BusLogic.c, comment before function
  296. BusLogic_ParseDriverOptions().
  297. c101= [NET] Moxa C101 synchronous serial card
  298. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  299. Sometimes CPU hardware bugs make them report the cache
  300. size incorrectly. The kernel will attempt work arounds
  301. to fix known problems, but for some CPUs it is not
  302. possible to determine what the correct size should be.
  303. This option provides an override for these situations.
  304. cdu31a= [HW,CD]
  305. Format: <io>,<irq>[,PAS]
  306. See header of drivers/cdrom/cdu31a.c.
  307. chandev= [HW,NET] Generic channel device initialisation
  308. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  309. Format: { "0" | "1" }
  310. See security/selinux/Kconfig help text.
  311. 0 -- check protection applied by kernel (includes
  312. 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
  316. /selinux/checkreqprot.
  317. clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
  318. [Deprecated]
  319. Forces specified clocksource (if available) to be used
  320. when calculating gettimeofday(). If specified
  321. clocksource is not available, it defaults to PIT.
  322. Format: { pit | tsc | cyclone | pmtmr }
  323. clocksource= [GENERIC_TIME] Override the default clocksource
  324. Format: <string>
  325. Override the default clocksource and use the clocksource
  326. with the name specified.
  327. Some clocksource names to choose from, depending on
  328. the platform:
  329. [all] jiffies (this is the base, fallback clocksource)
  330. [ACPI] acpi_pm
  331. [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
  332. pxa_timer,timer3,32k_counter,timer0_1
  333. [AVR32] avr32
  334. [IA-32] pit,hpet,tsc,vmi-timer;
  335. scx200_hrt on Geode; cyclone on IBM x440
  336. [MIPS] MIPS
  337. [PARISC] cr16
  338. [S390] tod
  339. [SH] SuperH
  340. [SPARC64] tick
  341. [X86-64] hpet,tsc
  342. code_bytes [IA32] How many bytes of object code to print in an
  343. oops report.
  344. Range: 0 - 8192
  345. Default: 64
  346. disable_8254_timer
  347. enable_8254_timer
  348. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  349. over the 8254 in addition to over the IO-APIC. The
  350. kernel tries to set a sensible default.
  351. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  352. Format: disable
  353. cm206= [HW,CD]
  354. Format: { auto | [<io>,][<irq>] }
  355. com20020= [HW,NET] ARCnet - COM20020 chipset
  356. Format:
  357. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  358. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  359. Format: <io>[,<irq>]
  360. com90xx= [HW,NET]
  361. ARCnet - COM90xx chipset (memory-mapped buffers)
  362. Format: <io>[,<irq>[,<memstart>]]
  363. condev= [HW,S390] console device
  364. conmode=
  365. console= [KNL] Output console device and options.
  366. tty<n> Use the virtual console device <n>.
  367. ttyS<n>[,options]
  368. ttyUSB0[,options]
  369. Use the specified serial port. The options are of
  370. the form "bbbbpnf", where "bbbb" is the baud rate,
  371. "p" is parity ("n", "o", or "e"), "n" is number of
  372. bits, and "f" is flow control ("r" for RTS or
  373. omit it). Default is "9600n8".
  374. See Documentation/serial-console.txt for more
  375. information. See
  376. Documentation/networking/netconsole.txt for an
  377. alternative.
  378. uart,io,<addr>[,options]
  379. uart,mmio,<addr>[,options]
  380. Start an early, polled-mode console on the 8250/16550
  381. UART at the specified I/O port or MMIO address,
  382. switching to the matching ttyS device later. The
  383. options are the same as for ttyS, above.
  384. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  385. Format:
  386. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  387. cpia_pp= [HW,PPT]
  388. Format: { parport<nr> | auto | none }
  389. crashkernel=nn[KMG]@ss[KMG]
  390. [KNL] Reserve a chunk of physical memory to
  391. hold a kernel to switch to with kexec on panic.
  392. cs4232= [HW,OSS]
  393. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  394. cs89x0_dma= [HW,NET]
  395. Format: <dma>
  396. cs89x0_media= [HW,NET]
  397. Format: { rj45 | aui | bnc }
  398. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  399. dasd= [HW,NET]
  400. See header of drivers/s390/block/dasd_devmap.c.
  401. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  402. (one device per port)
  403. Format: <port#>,<type>
  404. See also Documentation/input/joystick-parport.txt
  405. debug [KNL] Enable kernel debugging (events log level).
  406. debug_locks_verbose=
  407. [KNL] verbose self-tests
  408. Format=<0|1>
  409. Print debugging info while doing the locking API
  410. self-tests.
  411. We default to 0 (no extra messages), setting it to
  412. 1 will print _a lot_ more information - normally
  413. only useful to kernel developers.
  414. decnet= [HW,NET]
  415. Format: <area>[,<node>]
  416. See also Documentation/networking/decnet.txt.
  417. default_blu= [VT]
  418. Format: <blue0>,<blue1>,<blue2>,...,<blue15>
  419. Change the default blue palette of the console.
  420. This is a 16-member array composed of values
  421. ranging from 0-255.
  422. default_grn= [VT]
  423. Format: <green0>,<green1>,<green2>,...,<green15>
  424. Change the default green palette of the console.
  425. This is a 16-member array composed of values
  426. ranging from 0-255.
  427. default_red= [VT]
  428. Format: <red0>,<red1>,<red2>,...,<red15>
  429. Change the default red palette of the console.
  430. This is a 16-member array composed of values
  431. ranging from 0-255.
  432. default_utf8= [VT]
  433. Format=<0|1>
  434. Set system-wide default UTF-8 mode for all tty's.
  435. Default is 0 and by setting to 1, it enables UTF-8
  436. mode for all newly opened or allocated terminals.
  437. dhash_entries= [KNL]
  438. Set number of hash buckets for dentry cache.
  439. digi= [HW,SERIAL]
  440. IO parameters + enable/disable command.
  441. digiepca= [HW,SERIAL]
  442. See drivers/char/README.epca and
  443. Documentation/digiepca.txt.
  444. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  445. support available.
  446. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  447. dmasound= [HW,OSS] Sound subsystem buffers
  448. dscc4.setup= [NET]
  449. dtc3181e= [HW,SCSI]
  450. earlyprintk= [IA-32,X86-64,SH]
  451. earlyprintk=vga
  452. earlyprintk=serial[,ttySn[,baudrate]]
  453. Append ",keep" to not disable it when the real console
  454. takes over.
  455. Only vga or serial at a time, not both.
  456. Currently only ttyS0 and ttyS1 are supported.
  457. Interaction with the standard serial driver is not
  458. very good.
  459. The VGA output is eventually overwritten by the real
  460. console.
  461. eata= [HW,SCSI]
  462. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  463. Format: <int>
  464. 0: polling mode
  465. non-0: interrupt mode (default)
  466. eda= [HW,PS2]
  467. edb= [HW,PS2]
  468. edd= [EDD]
  469. Format: {"of[f]" | "sk[ipmbr]"}
  470. See comment in arch/i386/boot/edd.S
  471. eicon= [HW,ISDN]
  472. Format: <id>,<membase>,<irq>
  473. eisa_irq_edge= [PARISC,HW]
  474. See header of drivers/parisc/eisa.c.
  475. elanfreq= [IA-32]
  476. See comment before function elanfreq_setup() in
  477. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  478. elevator= [IOSCHED]
  479. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  480. See Documentation/block/as-iosched.txt and
  481. Documentation/block/deadline-iosched.txt for details.
  482. elfcorehdr= [IA-32, X86_64]
  483. Specifies physical address of start of kernel core
  484. image elf header. Generally kexec loader will
  485. pass this option to capture kernel.
  486. See Documentation/kdump/kdump.txt for details.
  487. enforcing [SELINUX] Set initial enforcing status.
  488. Format: {"0" | "1"}
  489. See security/selinux/Kconfig help text.
  490. 0 -- permissive (log only, no denials).
  491. 1 -- enforcing (deny and log).
  492. Default value is 0.
  493. Value can be changed at runtime via /selinux/enforce.
  494. es1371= [HW,OSS]
  495. Format: <spdif>,[<nomix>,[<amplifier>]]
  496. See also header of sound/oss/es1371.c.
  497. ether= [HW,NET] Ethernet cards parameters
  498. This option is obsoleted by the "netdev=" option, which
  499. has equivalent usage. See its documentation for details.
  500. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  501. Format: <io>[,<irq>]
  502. failslab=
  503. fail_page_alloc=
  504. fail_make_request=[KNL]
  505. General fault injection mechanism.
  506. Format: <interval>,<probability>,<space>,<times>
  507. See also /Documentation/fault-injection/.
  508. fd_mcs= [HW,SCSI]
  509. See header of drivers/scsi/fd_mcs.c.
  510. fdomain= [HW,SCSI]
  511. See header of drivers/scsi/fdomain.c.
  512. floppy= [HW]
  513. See Documentation/floppy.txt.
  514. gamecon.map[2|3]=
  515. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  516. support via parallel port (up to 5 devices per port)
  517. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  518. See also Documentation/input/joystick-parport.txt
  519. gamma= [HW,DRM]
  520. gdth= [HW,SCSI]
  521. See header of drivers/scsi/gdth.c.
  522. gpt [EFI] Forces disk with valid GPT signature but
  523. invalid Protective MBR to be treated as GPT.
  524. gscd= [HW,CD]
  525. Format: <io>
  526. gvp11= [HW,SCSI]
  527. hashdist= [KNL,NUMA] Large hashes allocated during boot
  528. are distributed across NUMA nodes. Defaults on
  529. for IA-64, off otherwise.
  530. Format: 0 | 1 (for off | on)
  531. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  532. hd= [EIDE] (E)IDE hard drive subsystem geometry
  533. Format: <cyl>,<head>,<sect>
  534. hd?= [HW] (E)IDE subsystem
  535. hd?lun= See Documentation/ide.txt.
  536. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  537. size of <nn>. This works even on boxes that have no
  538. highmem otherwise. This also works to reduce highmem
  539. size on bigger boxes.
  540. highres= [KNL] Enable/disable high resolution timer mode.
  541. Valid parameters: "on", "off"
  542. Default: "on"
  543. hisax= [HW,ISDN]
  544. See Documentation/isdn/README.HiSax.
  545. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  546. i8042.direct [HW] Put keyboard port into non-translated mode
  547. i8042.dumbkbd [HW] Pretend that controller can only read data from
  548. keyboard and cannot control its state
  549. (Don't attempt to blink the leds)
  550. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  551. i8042.nokbd [HW] Don't check/create keyboard port
  552. i8042.nomux [HW] Don't check presence of an active multiplexing
  553. controller
  554. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  555. controllers
  556. i8042.panicblink=
  557. [HW] Frequency with which keyboard LEDs should blink
  558. when kernel panics (default is 0.5 sec)
  559. i8042.reset [HW] Reset the controller during init and cleanup
  560. i8042.unlock [HW] Unlock (ignore) the keylock
  561. i810= [HW,DRM]
  562. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  563. indicates that the driver is running on unsupported
  564. hardware.
  565. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  566. does not match list of supported models.
  567. i8k.power_status
  568. [HW] Report power status in /proc/i8k
  569. (disabled by default)
  570. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  571. capability is set.
  572. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  573. See Documentation/mca.txt.
  574. icn= [HW,ISDN]
  575. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  576. ide= [HW] (E)IDE subsystem
  577. Format: ide=nodma or ide=doubler or ide=reverse
  578. See Documentation/ide.txt.
  579. ide?= [HW] (E)IDE subsystem
  580. Format: ide?=noprobe or chipset specific parameters.
  581. See Documentation/ide.txt.
  582. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  583. See Documentation/ide.txt.
  584. idle= [X86]
  585. Format: idle=poll or idle=mwait
  586. Poll forces a polling idle loop that can slightly improves the performance
  587. of waking up a idle CPU, but will use a lot of power and make the system
  588. run hot. Not recommended.
  589. idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
  590. to not use it because it doesn't save as much power as a normal idle
  591. loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
  592. as idle=poll.
  593. ignore_loglevel [KNL]
  594. Ignore loglevel setting - this will print /all/
  595. kernel messages to the console. Useful for debugging.
  596. ihash_entries= [KNL]
  597. Set number of hash buckets for inode cache.
  598. in2000= [HW,SCSI]
  599. See header of drivers/scsi/in2000.c.
  600. init= [KNL]
  601. Format: <full_path>
  602. Run specified binary instead of /sbin/init as init
  603. process.
  604. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  605. for working out where the kernel is dying during
  606. startup.
  607. initrd= [BOOT] Specify the location of the initial ramdisk
  608. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  609. Format: <irq>
  610. inttest= [IA64]
  611. io7= [HW] IO7 for Marvel based alpha systems
  612. See comment before marvel_specify_io7 in
  613. arch/alpha/kernel/core_marvel.c.
  614. ip= [IP_PNP]
  615. See Documentation/nfsroot.txt.
  616. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  617. See comment before ip2_setup() in drivers/char/ip2.c.
  618. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  619. See header of drivers/scsi/ips.c.
  620. ports= [IP_VS_FTP] IPVS ftp helper module
  621. Default is 21.
  622. Up to 8 (IP_VS_APP_MAX_PORTS) ports
  623. may be specified.
  624. Format: <port>,<port>....
  625. irqfixup [HW]
  626. When an interrupt is not handled search all handlers
  627. for it. Intended to get systems with badly broken
  628. firmware running.
  629. irqpoll [HW]
  630. When an interrupt is not handled search all handlers
  631. for it. Also check all handlers each timer
  632. interrupt. Intended to get systems with badly broken
  633. firmware running.
  634. isapnp= [ISAPNP]
  635. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  636. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  637. Format:
  638. <cpu number>,...,<cpu number>
  639. or
  640. <cpu number>-<cpu number> (must be a positive range in ascending order)
  641. or a mixture
  642. <cpu number>,...,<cpu number>-<cpu number>
  643. This option can be used to specify one or more CPUs
  644. to isolate from the general SMP balancing and scheduling
  645. algorithms. The only way to move a process onto or off
  646. an "isolated" CPU is via the CPU affinity syscalls.
  647. <cpu number> begins at 0 and the maximum value is
  648. "number of CPUs in system - 1".
  649. This option is the preferred way to isolate CPUs. The
  650. alternative -- manually setting the CPU mask of all
  651. tasks in the system -- can cause problems and
  652. suboptimal load balancer performance.
  653. isp16= [HW,CD]
  654. Format: <io>,<irq>,<dma>,<setup>
  655. iucv= [HW,NET]
  656. js= [HW,JOY] Analog joystick
  657. See Documentation/input/joystick.txt.
  658. keepinitrd [HW,ARM]
  659. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  660. in oops dumps.
  661. l2cr= [PPC]
  662. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  663. disabled it.
  664. lapic_timer_c2_ok [IA-32,x86-64,APIC] trust the local apic timer in
  665. C2 power state.
  666. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  667. Format: addr:<io>,irq:<irq>
  668. legacy_serial.force [HW,IA-32,X86-64]
  669. Probe for COM ports at legacy addresses even
  670. if PNPBIOS or ACPI should describe them. This
  671. is for working around firmware defects.
  672. llsc*= [IA64] See function print_params() in
  673. arch/ia64/sn/kernel/llsc4.c.
  674. load_ramdisk= [RAM] List of ramdisks to load from floppy
  675. See Documentation/ramdisk.txt.
  676. lockd.nlm_grace_period=P [NFS] Assign grace period.
  677. Format: <integer>
  678. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  679. Format: <integer>
  680. lockd.nlm_timeout=T [NFS] Assign timeout value.
  681. Format: <integer>
  682. lockd.nlm_udpport=M [NFS] Assign UDP port.
  683. Format: <integer>
  684. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  685. Format: <irq>
  686. loglevel= All Kernel Messages with a loglevel smaller than the
  687. console loglevel will be printed to the console. It can
  688. also be changed with klogd or other programs. The
  689. loglevels are defined as follows:
  690. 0 (KERN_EMERG) system is unusable
  691. 1 (KERN_ALERT) action must be taken immediately
  692. 2 (KERN_CRIT) critical conditions
  693. 3 (KERN_ERR) error conditions
  694. 4 (KERN_WARNING) warning conditions
  695. 5 (KERN_NOTICE) normal but significant condition
  696. 6 (KERN_INFO) informational
  697. 7 (KERN_DEBUG) debug-level messages
  698. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  699. Format: { n | nk | nM }
  700. n must be a power of two. The default size
  701. is set in the kernel config file.
  702. lp=0 [LP] Specify parallel ports to use, e.g,
  703. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  704. lp=reset first parallel port). 'lp=0' disables the
  705. lp=auto printer driver. 'lp=reset' (which can be
  706. specified in addition to the ports) causes
  707. attached printers to be reset. Using
  708. lp=port1,port2,... specifies the parallel ports
  709. to associate lp devices with, starting with
  710. lp0. A port specification may be 'none' to skip
  711. that lp device, or a parport name such as
  712. 'parport0'. Specifying 'lp=auto' instead of a
  713. port specification list means that device IDs
  714. from each port should be examined, to see if
  715. an IEEE 1284-compliant printer is attached; if
  716. so, the driver will manage that printer.
  717. See also header of drivers/char/lp.c.
  718. lpj=n [KNL]
  719. Sets loops_per_jiffy to given constant, thus avoiding
  720. time-consuming boot-time autodetection (up to 250 ms per
  721. CPU). 0 enables autodetection (default). To determine
  722. the correct value for your kernel, boot with normal
  723. autodetection and see what value is printed. Note that
  724. on SMP systems the preset will be applied to all CPUs,
  725. which is likely to cause problems if your CPUs need
  726. significantly divergent settings. An incorrect value
  727. will cause delays in the kernel to be wrong, leading to
  728. unpredictable I/O errors and other breakage. Although
  729. unlikely, in the extreme case this might damage your
  730. hardware.
  731. ltpc= [NET]
  732. Format: <io>,<irq>,<dma>
  733. mac5380= [HW,SCSI] Format:
  734. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  735. mac53c9x= [HW,SCSI] Format:
  736. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  737. machvec= [IA64] Force the use of a particular machine-vector
  738. (machvec) in a generic kernel.
  739. Example: machvec=hpzx1_swiotlb
  740. max_loop= [LOOP] Maximum number of loopback devices that can
  741. be mounted
  742. Format: <1-256>
  743. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  744. should make use of.
  745. Using "nosmp" or "maxcpus=0" will disable SMP
  746. entirely (the MPS table probe still happens, though).
  747. A command-line option of "maxcpus=<NUM>", where <NUM>
  748. is an integer greater than 0, limits the maximum number
  749. of CPUs activated in SMP mode to <NUM>.
  750. Using "maxcpus=1" on an SMP kernel is the trivial
  751. case of an SMP kernel with only one CPU.
  752. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  753. equal to this physical address is ignored.
  754. max_luns= [SCSI] Maximum number of LUNs to probe.
  755. Should be between 1 and 2^32-1.
  756. max_report_luns=
  757. [SCSI] Maximum number of LUNs received.
  758. Should be between 1 and 16384.
  759. mca-pentium [BUGS=IA-32]
  760. mcatest= [IA-64]
  761. mcd= [HW,CD]
  762. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  763. mcdx= [HW,CD]
  764. mce [IA-32] Machine Check Exception
  765. md= [HW] RAID subsystems devices and level
  766. See Documentation/md.txt.
  767. mdacon= [MDA]
  768. Format: <first>,<last>
  769. Specifies range of consoles to be captured by the MDA.
  770. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  771. Amount of memory to be used when the kernel is not able
  772. to see the whole system memory or for test.
  773. [IA-32] Use together with memmap= to avoid physical
  774. address space collisions. Without memmap= PCI devices
  775. could be placed at addresses belonging to unused RAM.
  776. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  777. memory.
  778. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  779. E820 memory map, as specified by the user.
  780. Such memmap=exactmap lines can be constructed based on
  781. BIOS output or other requirements. See the memmap=nn@ss
  782. option description.
  783. memmap=nn[KMG]@ss[KMG]
  784. [KNL] Force usage of a specific region of memory
  785. Region of memory to be used, from ss to ss+nn.
  786. memmap=nn[KMG]#ss[KMG]
  787. [KNL,ACPI] Mark specific memory as ACPI data.
  788. Region of memory to be used, from ss to ss+nn.
  789. memmap=nn[KMG]$ss[KMG]
  790. [KNL,ACPI] Mark specific memory as reserved.
  791. Region of memory to be used, from ss to ss+nn.
  792. meye.*= [HW] Set MotionEye Camera parameters
  793. See Documentation/video4linux/meye.txt.
  794. mga= [HW,DRM]
  795. migration_cost=
  796. [KNL,SMP] debug: override scheduler migration costs
  797. Format: <level-1-usecs>,<level-2-usecs>,...
  798. This debugging option can be used to override the
  799. default scheduler migration cost matrix. The numbers
  800. are indexed by 'CPU domain distance'.
  801. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  802. box will set up an intra-core migration cost of
  803. 1 msec, an inter-core migration cost of 2 msecs,
  804. and an inter-node migration cost of 3 msecs.
  805. WARNING: using the wrong values here can break
  806. scheduler performance, so it's only for scheduler
  807. development purposes, not production environments.
  808. migration_debug=
  809. [KNL,SMP] migration cost auto-detect verbosity
  810. Format=<0|1|2>
  811. If a system's migration matrix reported at bootup
  812. seems erroneous then this option can be used to
  813. increase verbosity of the detection process.
  814. We default to 0 (no extra messages), 1 will print
  815. some more information, and 2 will be really
  816. verbose (probably only useful if you also have a
  817. serial console attached to the system).
  818. migration_factor=
  819. [KNL,SMP] multiply/divide migration costs by a factor
  820. Format=<percent>
  821. This debug option can be used to proportionally
  822. increase or decrease the auto-detected migration
  823. costs for all entries of the migration matrix.
  824. E.g. migration_factor=150 will increase migration
  825. costs by 50%. (and thus the scheduler will be less
  826. eager migrating cache-hot tasks)
  827. migration_factor=80 will decrease migration costs
  828. by 20%. (thus the scheduler will be more eager to
  829. migrate tasks)
  830. WARNING: using the wrong values here can break
  831. scheduler performance, so it's only for scheduler
  832. development purposes, not production environments.
  833. mousedev.tap_time=
  834. [MOUSE] Maximum time between finger touching and
  835. leaving touchpad surface for touch to be considered
  836. a tap and be reported as a left button click (for
  837. touchpads working in absolute mode only).
  838. Format: <msecs>
  839. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  840. reporting absolute coordinates, such as tablets
  841. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  842. reporting absolute coordinates, such as tablets
  843. mpu401= [HW,OSS]
  844. Format: <io>,<irq>
  845. MTD_Partition= [MTD]
  846. Format: <name>,<region-number>,<size>,<offset>
  847. MTD_Region= [MTD] Format:
  848. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  849. mtdparts= [MTD]
  850. See drivers/mtd/cmdline.c.
  851. mtouchusb.raw_coordinates=
  852. [HW] Make the MicroTouch USB driver use raw coordinates
  853. ('y', default) or cooked coordinates ('n')
  854. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  855. NCR_D700= [HW,SCSI]
  856. See header of drivers/scsi/NCR_D700.c.
  857. ncr5380= [HW,SCSI]
  858. ncr53c400= [HW,SCSI]
  859. ncr53c400a= [HW,SCSI]
  860. ncr53c406a= [HW,SCSI]
  861. ncr53c8xx= [HW,SCSI]
  862. netdev= [NET] Network devices parameters
  863. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  864. Note that mem_start is often overloaded to mean
  865. something different and driver-specific.
  866. This usage is only documented in each driver source
  867. file if at all.
  868. nfsaddrs= [NFS]
  869. See Documentation/nfsroot.txt.
  870. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  871. See Documentation/nfsroot.txt.
  872. nfs.callback_tcpport=
  873. [NFS] set the TCP port on which the NFSv4 callback
  874. channel should listen.
  875. nfs.idmap_cache_timeout=
  876. [NFS] set the maximum lifetime for idmapper cache
  877. entries.
  878. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  879. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  880. emulation library even if a 387 maths coprocessor
  881. is present.
  882. noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
  883. when set.
  884. Format: <int>
  885. noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
  886. caches in the slab allocator. Saves per-node memory,
  887. but will impact performance.
  888. noalign [KNL,ARM]
  889. noapic [SMP,APIC] Tells the kernel to not make use of any
  890. IOAPICs that may be present in the system.
  891. noasync [HW,M68K] Disables async and sync negotiation for
  892. all devices.
  893. nobats [PPC] Do not use BATs for mapping kernel lowmem
  894. on "Classic" PPC cores.
  895. nocache [ARM]
  896. nodelayacct [KNL] Disable per-task delay accounting
  897. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  898. noexec [IA-64]
  899. noexec [IA-32,X86-64]
  900. noexec=on: enable non-executable mappings (default)
  901. noexec=off: disable nn-executable mappings
  902. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  903. register save and restore. The kernel will only save
  904. legacy floating-point registers on task switch.
  905. nohlt [BUGS=ARM]
  906. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  907. instruction doesn't work correctly and not to
  908. use it.
  909. nohalt [IA-64] Tells the kernel not to use the power saving
  910. function PAL_HALT_LIGHT when idle. This increases
  911. power-consumption. On the positive side, it reduces
  912. interrupt wake-up latency, which may improve performance
  913. in certain environments such as networked servers or
  914. real-time systems.
  915. nohz= [KNL] Boottime enable/disable dynamic ticks
  916. Valid arguments: on, off
  917. Default: on
  918. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  919. noirqdebug [IA-32] Disables the code which attempts to detect and
  920. disable unhandled interrupt sources.
  921. no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
  922. broken timer IRQ sources.
  923. noisapnp [ISAPNP] Disables ISA PnP code.
  924. noinitrd [RAM] Tells the kernel not to load any configured
  925. initial RAM disk.
  926. nointroute [IA-64]
  927. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  928. nolapic_timer [IA-32,APIC] Do not use the local APIC timer.
  929. noltlbs [PPC] Do not use large page/tlb entries for kernel
  930. lowmem mapping on PPC40x.
  931. nomca [IA-64] Disable machine check abort handling
  932. nomce [IA-32] Machine Check Exception
  933. noreplace-paravirt [IA-32,PV_OPS] Don't patch paravirt_ops
  934. noreplace-smp [IA-32,SMP] Don't replace SMP instructions
  935. with UP alternatives
  936. noresidual [PPC] Don't use residual data on PReP machines.
  937. noresume [SWSUSP] Disables resume and restores original swap
  938. space.
  939. no-scroll [VGA] Disables scrollback.
  940. This is required for the Braillex ib80-piezo Braille
  941. reader made by F.H. Papenmeier (Germany).
  942. nosbagart [IA-64]
  943. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  944. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  945. nosync [HW,M68K] Disables sync negotiation for all devices.
  946. notsc [BUGS=IA-32] Disable Time Stamp Counter
  947. nousb [USB] Disable the USB subsystem
  948. nowb [ARM]
  949. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  950. opl3= [HW,OSS]
  951. Format: <io>
  952. opl3sa2= [HW,OSS] Format:
  953. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  954. oprofile.timer= [HW]
  955. Use timer interrupt instead of performance counters
  956. optcd= [HW,CD]
  957. Format: <io>
  958. osst= [HW,SCSI] SCSI Tape Driver
  959. Format: <buffer_size>,<write_threshold>
  960. See also Documentation/scsi/st.txt.
  961. panic= [KNL] Kernel behaviour on panic
  962. Format: <timeout>
  963. parkbd.port= [HW] Parallel port number the keyboard adapter is
  964. connected to, default is 0.
  965. Format: <parport#>
  966. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  967. 0 for XT, 1 for AT (default is AT).
  968. Format: <mode>
  969. parport= [HW,PPT] Specify parallel ports. 0 disables.
  970. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  971. Use 'auto' to force the driver to use any
  972. IRQ/DMA settings detected (the default is to
  973. ignore detected IRQ/DMA settings because of
  974. possible conflicts). You can specify the base
  975. address, IRQ, and DMA settings; IRQ and DMA
  976. should be numbers, or 'auto' (for using detected
  977. settings on that particular port), or 'nofifo'
  978. (to avoid using a FIFO even if it is detected).
  979. Parallel ports are assigned in the order they
  980. are specified on the command line, starting
  981. with parport0.
  982. parport_init_mode= [HW,PPT]
  983. Configure VIA parallel port to operate in
  984. a specific mode. This is necessary on Pegasos
  985. computer where firmware has no options for setting
  986. up parallel port mode and sets it to spp.
  987. Currently this function knows 686a and 8231 chips.
  988. Format: [spp|ps2|epp|ecp|ecpepp]
  989. pas2= [HW,OSS] Format:
  990. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  991. pas16= [HW,SCSI]
  992. See header of drivers/scsi/pas16.c.
  993. pause_on_oops=
  994. Halt all CPUs after the first oops has been printed for
  995. the specified number of seconds. This is to be used if
  996. your oopses keep scrolling off the screen.
  997. pcbit= [HW,ISDN]
  998. pcd. [PARIDE]
  999. See header of drivers/block/paride/pcd.c.
  1000. See also Documentation/paride.txt.
  1001. pci=option[,option...] [PCI] various PCI subsystem options:
  1002. off [IA-32] don't probe for the PCI bus
  1003. bios [IA-32] force use of PCI BIOS, don't access
  1004. the hardware directly. Use this if your machine
  1005. has a non-standard PCI host bridge.
  1006. nobios [IA-32] disallow use of PCI BIOS, only direct
  1007. hardware access methods are allowed. Use this
  1008. if you experience crashes upon bootup and you
  1009. suspect they are caused by the BIOS.
  1010. conf1 [IA-32] Force use of PCI Configuration
  1011. Mechanism 1.
  1012. conf2 [IA-32] Force use of PCI Configuration
  1013. Mechanism 2.
  1014. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  1015. Configuration
  1016. nomsi [MSI] If the PCI_MSI kernel config parameter is
  1017. enabled, this kernel boot option can be used to
  1018. disable the use of MSI interrupts system-wide.
  1019. nosort [IA-32] Don't sort PCI devices according to
  1020. order given by the PCI BIOS. This sorting is
  1021. done to get a device order compatible with
  1022. older kernels.
  1023. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  1024. routing table. These calls are known to be buggy
  1025. on several machines and they hang the machine
  1026. when used, but on other computers it's the only
  1027. way to get the interrupt routing table. Try
  1028. this option if the kernel is unable to allocate
  1029. IRQs or discover secondary PCI buses on your
  1030. motherboard.
  1031. rom [IA-32] Assign address space to expansion ROMs.
  1032. Use with caution as certain devices share
  1033. address decoders between ROMs and other
  1034. resources.
  1035. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  1036. assigned automatically to PCI devices. You can
  1037. make the kernel exclude IRQs of your ISA cards
  1038. this way.
  1039. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  1040. of the PIRQ table (normally generated
  1041. by the BIOS) if it is outside the
  1042. F0000h-100000h range.
  1043. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  1044. useful if the kernel is unable to find your
  1045. secondary buses and you want to tell it
  1046. explicitly which ones they are.
  1047. assign-busses [IA-32] Always assign all PCI bus
  1048. numbers ourselves, overriding
  1049. whatever the firmware may have done.
  1050. usepirqmask [IA-32] Honor the possible IRQ mask stored
  1051. in the BIOS $PIR table. This is needed on
  1052. some systems with broken BIOSes, notably
  1053. some HP Pavilion N5400 and Omnibook XE3
  1054. notebooks. This will have no effect if ACPI
  1055. IRQ routing is enabled.
  1056. noacpi [IA-32] Do not use ACPI for IRQ routing
  1057. or for PCI scanning.
  1058. routeirq Do IRQ routing for all PCI devices.
  1059. This is normally done in pci_enable_device(),
  1060. so this option is a temporary workaround
  1061. for broken drivers that don't call it.
  1062. firmware [ARM] Do not re-enumerate the bus but instead
  1063. just use the configuration from the
  1064. bootloader. This is currently used on
  1065. IXP2000 systems where the bus has to be
  1066. configured a certain way for adjunct CPUs.
  1067. noearly [X86] Don't do any early type 1 scanning.
  1068. This might help on some broken boards which
  1069. machine check when some devices' config space
  1070. is read. But various workarounds are disabled
  1071. and some IOMMU drivers will not work.
  1072. bfsort Sort PCI devices into breadth-first order.
  1073. This sorting is done to get a device
  1074. order compatible with older (<= 2.4) kernels.
  1075. nobfsort Don't sort PCI devices into breadth-first order.
  1076. cbiosize=nn[KMG] The fixed amount of bus space which is
  1077. reserved for the CardBus bridge's IO window.
  1078. The default value is 256 bytes.
  1079. cbmemsize=nn[KMG] The fixed amount of bus space which is
  1080. reserved for the CardBus bridge's memory
  1081. window. The default value is 64 megabytes.
  1082. pcmv= [HW,PCMCIA] BadgePAD 4
  1083. pd. [PARIDE]
  1084. See Documentation/paride.txt.
  1085. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  1086. boot time.
  1087. Format: { 0 | 1 }
  1088. See arch/parisc/kernel/pdc_chassis.c
  1089. pf. [PARIDE]
  1090. See Documentation/paride.txt.
  1091. pg. [PARIDE]
  1092. See Documentation/paride.txt.
  1093. pirq= [SMP,APIC] Manual mp-table setup
  1094. See Documentation/i386/IO-APIC.txt.
  1095. plip= [PPT,NET] Parallel port network link
  1096. Format: { parport<nr> | timid | 0 }
  1097. See also Documentation/parport.txt.
  1098. pnpacpi= [ACPI]
  1099. { off }
  1100. pnpbios= [ISAPNP]
  1101. { on | off | curr | res | no-curr | no-res }
  1102. pnp_reserve_irq=
  1103. [ISAPNP] Exclude IRQs for the autoconfiguration
  1104. pnp_reserve_dma=
  1105. [ISAPNP] Exclude DMAs for the autoconfiguration
  1106. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  1107. Ranges are in pairs (I/O port base and size).
  1108. pnp_reserve_mem=
  1109. [ISAPNP] Exclude memory regions for the
  1110. autoconfiguration.
  1111. Ranges are in pairs (memory base and size).
  1112. profile= [KNL] Enable kernel profiling via /proc/profile
  1113. Format: [schedule,]<number>
  1114. Param: "schedule" - profile schedule points.
  1115. Param: <number> - step/bucket size as a power of 2 for
  1116. statistical time based profiling.
  1117. Param: "sleep" - profile D-state sleeping (millisecs)
  1118. processor.max_cstate= [HW,ACPI]
  1119. Limit processor to maximum C-state
  1120. max_cstate=9 overrides any DMI blacklist limit.
  1121. processor.nocst [HW,ACPI]
  1122. Ignore the _CST method to determine C-states,
  1123. instead using the legacy FADT method
  1124. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  1125. before loading.
  1126. See Documentation/ramdisk.txt.
  1127. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  1128. probe for; one of (bare|imps|exps|lifebook|any).
  1129. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  1130. per second.
  1131. psmouse.resetafter= [HW,MOUSE]
  1132. Try to reset the device after so many bad packets
  1133. (0 = never).
  1134. psmouse.resolution=
  1135. [HW,MOUSE] Set desired mouse resolution, in dpi.
  1136. psmouse.smartscroll=
  1137. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  1138. 0 = disabled, 1 = enabled (default).
  1139. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  1140. Format:
  1141. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  1142. pt. [PARIDE]
  1143. See Documentation/paride.txt.
  1144. quiet [KNL] Disable most log messages
  1145. r128= [HW,DRM]
  1146. raid= [HW,RAID]
  1147. See Documentation/md.txt.
  1148. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  1149. See Documentation/ramdisk.txt.
  1150. ramdisk_blocksize= [RAM]
  1151. See Documentation/ramdisk.txt.
  1152. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1153. New name for the ramdisk parameter.
  1154. See Documentation/ramdisk.txt.
  1155. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1156. RCU callbacks to process in one batch.
  1157. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1158. RCU callbacks over which batch limiting is disabled.
  1159. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1160. RCU callbacks below which batch limiting is re-enabled.
  1161. rdinit= [KNL]
  1162. Format: <full_path>
  1163. Run specified binary instead of /init from the ramdisk,
  1164. used for early userspace startup. See initrd.
  1165. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1166. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1167. See arch/*/kernel/reboot.c or arch/*/kernel/process.c
  1168. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1169. reservetop= [IA-32]
  1170. Format: nn[KMG]
  1171. Reserves a hole at the top of the kernel virtual
  1172. address space.
  1173. reset_devices [KNL] Force drivers to reset the underlying device
  1174. during initialization.
  1175. resume= [SWSUSP]
  1176. Specify the partition device for software suspend
  1177. resume_offset= [SWSUSP]
  1178. Specify the offset from the beginning of the partition
  1179. given by "resume=" at which the swap header is located,
  1180. in <PAGE_SIZE> units (needed only for swap files).
  1181. See Documentation/power/swsusp-and-swap-files.txt
  1182. retain_initrd [RAM] Keep initrd memory after extraction
  1183. rhash_entries= [KNL,NET]
  1184. Set number of hash buckets for route cache
  1185. riscom8= [HW,SERIAL]
  1186. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1187. ro [KNL] Mount root device read-only on boot
  1188. root= [KNL] Root filesystem
  1189. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1190. mount the root filesystem
  1191. rootflags= [KNL] Set root filesystem mount option string
  1192. rootfstype= [KNL] Set root filesystem type
  1193. rw [KNL] Mount root device read-write on boot
  1194. S [KNL] Run init in single mode
  1195. sa1100ir [NET]
  1196. See drivers/net/irda/sa1100_ir.c.
  1197. sb= [HW,OSS]
  1198. Format: <io>,<irq>,<dma>,<dma2>
  1199. sbni= [NET] Granch SBNI12 leased line adapter
  1200. sbpcd= [HW,CD] Soundblaster CD adapter
  1201. Format: <io>,<type>
  1202. See a comment before function sbpcd_setup() in
  1203. drivers/cdrom/sbpcd.c.
  1204. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1205. Format: <io>[,<timeout>[,<isapnp>]]
  1206. scsi_debug_*= [SCSI]
  1207. See drivers/scsi/scsi_debug.c.
  1208. scsi_default_dev_flags=
  1209. [SCSI] SCSI default device flags
  1210. Format: <integer>
  1211. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1212. Format: <vendor>:<model>:<flags>
  1213. (flags are integer value)
  1214. scsi_logging= [SCSI]
  1215. scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
  1216. discovered. async scans them in kernel threads,
  1217. allowing boot to proceed. none ignores them, expecting
  1218. user space to do the scan.
  1219. selinux [SELINUX] Disable or enable SELinux at boot time.
  1220. Format: { "0" | "1" }
  1221. See security/selinux/Kconfig help text.
  1222. 0 -- disable.
  1223. 1 -- enable.
  1224. Default value is set via kernel config option.
  1225. If enabled at boot time, /selinux/disable can be used
  1226. later to disable prior to initial policy load.
  1227. selinux_compat_net =
  1228. [SELINUX] Set initial selinux_compat_net flag value.
  1229. Format: { "0" | "1" }
  1230. 0 -- use new secmark-based packet controls
  1231. 1 -- use legacy packet controls
  1232. Default value is 0 (preferred).
  1233. Value can be changed at runtime via
  1234. /selinux/compat_net.
  1235. serialnumber [BUGS=IA-32]
  1236. sg_def_reserved_size= [SCSI]
  1237. shapers= [NET]
  1238. Maximal number of shapers.
  1239. sim710= [SCSI,HW]
  1240. See header of drivers/scsi/sim710.c.
  1241. simeth= [IA-64]
  1242. simscsi=
  1243. sjcd= [HW,CD]
  1244. Format: <io>,<irq>,<dma>
  1245. See header of drivers/cdrom/sjcd.c.
  1246. slram= [HW,MTD]
  1247. slub_debug [MM, SLUB]
  1248. Enabling slub_debug allows one to determine the culprit
  1249. if slab objects become corrupted. Enabling slub_debug
  1250. creates guard zones around objects and poisons objects
  1251. when not in use. Also tracks the last alloc / free.
  1252. For more information see Documentation/vm/slub.txt.
  1253. slub_max_order= [MM, SLUB]
  1254. Determines the maximum allowed order for slabs. Setting
  1255. this too high may cause fragmentation.
  1256. For more information see Documentation/vm/slub.txt.
  1257. slub_min_objects= [MM, SLUB]
  1258. The minimum objects per slab. SLUB will increase the
  1259. slab order up to slub_max_order to generate a
  1260. sufficiently big slab to satisfy the number of objects.
  1261. The higher the number of objects the smaller the overhead
  1262. of tracking slabs.
  1263. For more information see Documentation/vm/slub.txt.
  1264. slub_min_order= [MM, SLUB]
  1265. Determines the mininum page order for slabs. Must be
  1266. lower than slub_max_order
  1267. For more information see Documentation/vm/slub.txt.
  1268. slub_nomerge [MM, SLUB]
  1269. Disable merging of slabs of similar size. May be
  1270. necessary if there is some reason to distinguish
  1271. allocs to different slabs.
  1272. For more information see Documentation/vm/slub.txt.
  1273. smart2= [HW]
  1274. Format: <io1>[,<io2>[,...,<io8>]]
  1275. smp-alt-once [IA-32,SMP] On a hotplug CPU system, only
  1276. attempt to substitute SMP alternatives once at boot.
  1277. smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
  1278. smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
  1279. smsc-ircc2.ircc_sir= [HW] SIR base I/O port
  1280. smsc-ircc2.ircc_fir= [HW] FIR base I/O port
  1281. smsc-ircc2.ircc_irq= [HW] IRQ line
  1282. smsc-ircc2.ircc_dma= [HW] DMA channel
  1283. smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
  1284. 0: Toshiba Satellite 1800 (GP data pin select)
  1285. 1: Fast pin select (default)
  1286. 2: ATC IRMode
  1287. snd-ad1816a= [HW,ALSA]
  1288. snd-ad1848= [HW,ALSA]
  1289. snd-ali5451= [HW,ALSA]
  1290. snd-als100= [HW,ALSA]
  1291. snd-als4000= [HW,ALSA]
  1292. snd-azt2320= [HW,ALSA]
  1293. snd-cmi8330= [HW,ALSA]
  1294. snd-cmipci= [HW,ALSA]
  1295. snd-cs4231= [HW,ALSA]
  1296. snd-cs4232= [HW,ALSA]
  1297. snd-cs4236= [HW,ALSA]
  1298. snd-cs4281= [HW,ALSA]
  1299. snd-cs46xx= [HW,ALSA]
  1300. snd-dt019x= [HW,ALSA]
  1301. snd-dummy= [HW,ALSA]
  1302. snd-emu10k1= [HW,ALSA]
  1303. snd-ens1370= [HW,ALSA]
  1304. snd-ens1371= [HW,ALSA]
  1305. snd-es968= [HW,ALSA]
  1306. snd-es1688= [HW,ALSA]
  1307. snd-es18xx= [HW,ALSA]
  1308. snd-es1938= [HW,ALSA]
  1309. snd-es1968= [HW,ALSA]
  1310. snd-fm801= [HW,ALSA]
  1311. snd-gusclassic= [HW,ALSA]
  1312. snd-gusextreme= [HW,ALSA]
  1313. snd-gusmax= [HW,ALSA]
  1314. snd-hdsp= [HW,ALSA]
  1315. snd-ice1712= [HW,ALSA]
  1316. snd-intel8x0= [HW,ALSA]
  1317. snd-interwave= [HW,ALSA]
  1318. snd-interwave-stb=
  1319. [HW,ALSA]
  1320. snd-korg1212= [HW,ALSA]
  1321. snd-maestro3= [HW,ALSA]
  1322. snd-mpu401= [HW,ALSA]
  1323. snd-mtpav= [HW,ALSA]
  1324. snd-nm256= [HW,ALSA]
  1325. snd-opl3sa2= [HW,ALSA]
  1326. snd-opti92x-ad1848=
  1327. [HW,ALSA]
  1328. snd-opti92x-cs4231=
  1329. [HW,ALSA]
  1330. snd-opti93x= [HW,ALSA]
  1331. snd-pmac= [HW,ALSA]
  1332. snd-rme32= [HW,ALSA]
  1333. snd-rme96= [HW,ALSA]
  1334. snd-rme9652= [HW,ALSA]
  1335. snd-sb8= [HW,ALSA]
  1336. snd-sb16= [HW,ALSA]
  1337. snd-sbawe= [HW,ALSA]
  1338. snd-serial= [HW,ALSA]
  1339. snd-sgalaxy= [HW,ALSA]
  1340. snd-sonicvibes= [HW,ALSA]
  1341. snd-sun-amd7930=
  1342. [HW,ALSA]
  1343. snd-sun-cs4231= [HW,ALSA]
  1344. snd-trident= [HW,ALSA]
  1345. snd-usb-audio= [HW,ALSA,USB]
  1346. snd-via82xx= [HW,ALSA]
  1347. snd-virmidi= [HW,ALSA]
  1348. snd-wavefront= [HW,ALSA]
  1349. snd-ymfpci= [HW,ALSA]
  1350. sonycd535= [HW,CD]
  1351. Format: <io>[,<irq>]
  1352. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1353. See Documentation/sonypi.txt
  1354. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1355. See Documentation/specialix.txt.
  1356. spia_io_base= [HW,MTD]
  1357. spia_fio_base=
  1358. spia_pedr=
  1359. spia_peddr=
  1360. sscape= [HW,OSS]
  1361. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1362. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1363. See Documentation/scsi/st.txt.
  1364. st0x= [HW,SCSI]
  1365. See header of drivers/scsi/seagate.c.
  1366. sti= [PARISC,HW]
  1367. Format: <num>
  1368. Set the STI (builtin display/keyboard on the HP-PARISC
  1369. machines) console (graphic card) which should be used
  1370. as the initial boot-console.
  1371. See also comment in drivers/video/console/sticore.c.
  1372. sti_font= [HW]
  1373. See comment in drivers/video/console/sticore.c.
  1374. stifb= [HW]
  1375. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1376. sunrpc.pool_mode=
  1377. [NFS]
  1378. Control how the NFS server code allocates CPUs to
  1379. service thread pools. Depending on how many NICs
  1380. you have and where their interrupts are bound, this
  1381. option will affect which CPUs will do NFS serving.
  1382. Note: this parameter cannot be changed while the
  1383. NFS server is running.
  1384. auto the server chooses an appropriate mode
  1385. automatically using heuristics
  1386. global a single global pool contains all CPUs
  1387. percpu one pool for each CPU
  1388. pernode one pool for each NUMA node (equivalent
  1389. to global on non-NUMA machines)
  1390. swiotlb= [IA-64] Number of I/O TLB slabs
  1391. switches= [HW,M68k]
  1392. sym53c416= [HW,SCSI]
  1393. See header of drivers/scsi/sym53c416.c.
  1394. sysrq_always_enabled
  1395. [KNL]
  1396. Ignore sysrq setting - this boot parameter will
  1397. neutralize any effect of /proc/sys/kernel/sysrq.
  1398. Useful for debugging.
  1399. t128= [HW,SCSI]
  1400. See header of drivers/scsi/t128.c.
  1401. tdfx= [HW,DRM]
  1402. thash_entries= [KNL,NET]
  1403. Set number of hash buckets for TCP connection
  1404. time Show timing data prefixed to each printk message line
  1405. tipar.timeout= [HW,PPT]
  1406. Set communications timeout in tenths of a second
  1407. (default 15).
  1408. tipar.delay= [HW,PPT]
  1409. Set inter-bit delay in microseconds (default 10).
  1410. tmc8xx= [HW,SCSI]
  1411. See header of drivers/scsi/seagate.c.
  1412. tmscsim= [HW,SCSI]
  1413. See comment before function dc390_setup() in
  1414. drivers/scsi/tmscsim.c.
  1415. tp720= [HW,PS2]
  1416. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1417. Format:
  1418. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1419. tsdev.xres= [TS] Horizontal screen resolution.
  1420. tsdev.yres= [TS] Vertical screen resolution.
  1421. turbografx.map[2|3]= [HW,JOY]
  1422. TurboGraFX parallel port interface
  1423. Format:
  1424. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1425. See also Documentation/input/joystick-parport.txt
  1426. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1427. See header of drivers/scsi/u14-34f.c.
  1428. uart401= [HW,OSS]
  1429. Format: <io>,<irq>
  1430. uart6850= [HW,OSS]
  1431. Format: <io>,<irq>
  1432. uhci-hcd.ignore_oc=
  1433. [USB] Ignore overcurrent events (default N).
  1434. Some badly-designed motherboards generate lots of
  1435. bogus events, for ports that aren't wired to
  1436. anything. Set this parameter to avoid log spamming.
  1437. Note that genuine overcurrent events won't be
  1438. reported either.
  1439. usbcore.autosuspend=
  1440. [USB] The autosuspend time delay (in seconds) used
  1441. for newly-detected USB devices (default 2). This
  1442. is the time required before an idle device will be
  1443. autosuspended. Devices for which the delay is set
  1444. to a negative value won't be autosuspended at all.
  1445. usbhid.mousepoll=
  1446. [USBHID] The interval which mice are to be polled at.
  1447. vdso= [IA-32,SH]
  1448. vdso=2: enable compat VDSO (default with COMPAT_VDSO)
  1449. vdso=1: enable VDSO (default)
  1450. vdso=0: disable VDSO mapping
  1451. video= [FB] Frame buffer configuration
  1452. See Documentation/fb/modedb.txt.
  1453. vga= [BOOT,IA-32] Select a particular video mode
  1454. See Documentation/i386/boot.txt and
  1455. Documentation/svga.txt.
  1456. Use vga=ask for menu.
  1457. This is actually a boot loader parameter; the value is
  1458. passed to the kernel using a special protocol.
  1459. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1460. size of <nn>. This can be used to increase the
  1461. minimum size (128MB on x86). It can also be used to
  1462. decrease the size and leave more room for directly
  1463. mapped kernel RAM.
  1464. vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
  1465. Format: <command>
  1466. vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
  1467. Format: <command>
  1468. vmpoff= [KNL,S390] Perform z/VM CP command after power off.
  1469. Format: <command>
  1470. waveartist= [HW,OSS]
  1471. Format: <io>,<irq>,<dma>,<dma2>
  1472. wd33c93= [HW,SCSI]
  1473. See header of drivers/scsi/wd33c93.c.
  1474. wd7000= [HW,SCSI]
  1475. See header of drivers/scsi/wd7000.c.
  1476. wdt= [WDT] Watchdog
  1477. See Documentation/watchdog/watchdog.txt.
  1478. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1479. xd_geo= See header of drivers/block/xd.c.
  1480. xirc2ps_cs= [NET,PCMCIA]
  1481. Format:
  1482. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1483. norandmaps Don't use address space randomization
  1484. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1485. unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
  1486. This is useful to get more information why
  1487. you got a "dwarf2 unwinder stuck"
  1488. ______________________________________________________________________
  1489. TODO:
  1490. Add documentation for ALSA options.
  1491. Add more DRM drivers.