kernel-parameters.txt 48 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. 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. 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. NFS Appropriate NFS support is enabled.
  57. OSS OSS sound support is enabled.
  58. PARIDE The ParIDE subsystem is enabled.
  59. PARISC The PA-RISC architecture is enabled.
  60. PCI PCI bus support is enabled.
  61. PCMCIA The PCMCIA subsystem is enabled.
  62. PNP Plug & Play support is enabled.
  63. PPC PowerPC architecture is enabled.
  64. PPT Parallel port support is enabled.
  65. PS2 Appropriate PS/2 support is enabled.
  66. RAM RAM disk support is enabled.
  67. S390 S390 architecture is enabled.
  68. SCSI Appropriate SCSI support is enabled.
  69. A lot of drivers has their options described inside of
  70. Documentation/scsi/.
  71. SELINUX SELinux support is enabled.
  72. SERIAL Serial support is enabled.
  73. SMP The kernel is an SMP kernel.
  74. SPARC Sparc architecture is enabled.
  75. SWSUSP Software suspend is enabled.
  76. TS Appropriate touchscreen support is enabled.
  77. USB USB support is enabled.
  78. USBHID USB Human Interface Device support is enabled.
  79. V4L Video For Linux support is enabled.
  80. VGA The VGA console has been enabled.
  81. VT Virtual terminal support is enabled.
  82. WDT Watchdog support is enabled.
  83. XT IBM PC/XT MFM hard disk support is enabled.
  84. X86-64 X86-64 architecture is enabled.
  85. More X86-64 boot options can be found in
  86. Documentation/x86_64/boot-options.txt .
  87. In addition, the following text indicates that the option:
  88. BUGS= Relates to possible processor bugs on the said processor.
  89. KNL Is a kernel start-up parameter.
  90. BOOT Is a boot loader parameter.
  91. Parameters denoted with BOOT are actually interpreted by the boot
  92. loader, and have no meaning to the kernel directly.
  93. Do not modify the syntax of boot loader parameters without extreme
  94. need or coordination with <Documentation/i386/boot.txt>.
  95. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  96. a trailing = on the name of any parameter states that that parameter will
  97. be entered as an environment variable, whereas its absence indicates that
  98. it will appear as a kernel argument readable via /proc/cmdline by programs
  99. running once the system is up.
  100. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  101. See header of drivers/scsi/53c7xx.c.
  102. See also Documentation/scsi/ncr53c7xx.txt.
  103. acpi= [HW,ACPI] Advanced Configuration and Power Interface
  104. Format: { force | off | ht | strict | noirq }
  105. force -- enable ACPI if default was off
  106. off -- disable ACPI if default was on
  107. noirq -- do not use ACPI for IRQ routing
  108. ht -- run only enough ACPI to enable Hyper Threading
  109. strict -- Be less tolerant of platforms that are not
  110. strictly ACPI specification compliant.
  111. See also Documentation/pm.txt, pci=noacpi
  112. acpi_sleep= [HW,ACPI] Sleep options
  113. Format: { s3_bios, s3_mode }
  114. See Documentation/power/video.txt
  115. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  116. Format: { level | edge | high | low }
  117. acpi_irq_balance [HW,ACPI]
  118. ACPI will balance active IRQs
  119. default in APIC mode
  120. acpi_irq_nobalance [HW,ACPI]
  121. ACPI will not move active IRQs (default)
  122. default in PIC mode
  123. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  124. use by PCI
  125. Format: <irq>,<irq>...
  126. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  127. Format: <irq>,<irq>...
  128. acpi_osi= [HW,ACPI] empty param disables _OSI
  129. acpi_serialize [HW,ACPI] force serialization of AML methods
  130. acpi_skip_timer_override [HW,ACPI]
  131. Recognize and ignore IRQ0/pin2 Interrupt Override.
  132. For broken nForce2 BIOS resulting in XT-PIC timer.
  133. acpi_dbg_layer= [HW,ACPI]
  134. Format: <int>
  135. Each bit of the <int> indicates an ACPI debug layer,
  136. 1: enable, 0: disable. It is useful for boot time
  137. debugging. After system has booted up, it can be set
  138. via /proc/acpi/debug_layer.
  139. acpi_dbg_level= [HW,ACPI]
  140. Format: <int>
  141. Each bit of the <int> indicates an ACPI debug level,
  142. 1: enable, 0: disable. It is useful for boot time
  143. debugging. After system has booted up, it can be set
  144. via /proc/acpi/debug_level.
  145. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  146. acpi_generic_hotkey [HW,ACPI]
  147. Allow consolidated generic hotkey driver to
  148. override platform specific driver.
  149. See also Documentation/acpi-hotkey.txt.
  150. enable_timer_pin_1 [i386,x86-64]
  151. Enable PIN 1 of APIC timer
  152. Can be useful to work around chipset bugs
  153. (in particular on some ATI chipsets).
  154. The kernel tries to set a reasonable default.
  155. disable_timer_pin_1 [i386,x86-64]
  156. Disable PIN 1 of APIC timer
  157. Can be useful to work around chipset bugs.
  158. ad1816= [HW,OSS]
  159. Format: <io>,<irq>,<dma>,<dma2>
  160. See also Documentation/sound/oss/AD1816.
  161. ad1848= [HW,OSS]
  162. Format: <io>,<irq>,<dma>,<dma2>,<type>
  163. adlib= [HW,OSS]
  164. Format: <io>
  165. advansys= [HW,SCSI]
  166. See header of drivers/scsi/advansys.c.
  167. advwdt= [HW,WDT] Advantech WDT
  168. Format: <iostart>,<iostop>
  169. aedsp16= [HW,OSS] Audio Excel DSP 16
  170. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  171. See also header of sound/oss/aedsp16.c.
  172. aha152x= [HW,SCSI]
  173. See Documentation/scsi/aha152x.txt.
  174. aha1542= [HW,SCSI]
  175. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  176. aic7xxx= [HW,SCSI]
  177. See Documentation/scsi/aic7xxx.txt.
  178. aic79xx= [HW,SCSI]
  179. See Documentation/scsi/aic79xx.txt.
  180. amijoy.map= [HW,JOY] Amiga joystick support
  181. Map of devices attached to JOY0DAT and JOY1DAT
  182. Format: <a>,<b>
  183. See also Documentation/kernel/input/joystick.txt
  184. analog.map= [HW,JOY] Analog joystick and gamepad support
  185. Specifies type or capabilities of an analog joystick
  186. connected to one of 16 gameports
  187. Format: <type1>,<type2>,..<type16>
  188. apc= [HW,SPARC]
  189. Power management functions (SPARCstation-4/5 + deriv.)
  190. Format: noidle
  191. Disable APC CPU standby support. SPARCstation-Fox does
  192. not play well with APC CPU idle - disable it if you have
  193. APC and your system crashes randomly.
  194. apic= [APIC,i386] Change the output verbosity whilst booting
  195. Format: { quiet (default) | verbose | debug }
  196. Change the amount of debugging information output
  197. when initialising the APIC and IO-APIC components.
  198. apm= [APM] Advanced Power Management
  199. See header of arch/i386/kernel/apm.c.
  200. applicom= [HW]
  201. Format: <mem>,<irq>
  202. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  203. Format: <io>,<irq>,<nodeID>
  204. ataflop= [HW,M68k]
  205. atarimouse= [HW,MOUSE] Atari Mouse
  206. atascsi= [HW,SCSI] Atari SCSI
  207. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  208. EzKey and similar keyboards
  209. atkbd.reset= [HW] Reset keyboard during initialization
  210. atkbd.set= [HW] Select keyboard code set
  211. Format: <int> (2 = AT (default), 3 = PS/2)
  212. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  213. keyboards
  214. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  215. Format: <bool> (0 = real, 1 = synthetic (default))
  216. atkbd.softrepeat= [HW]
  217. Use software keyboard repeat
  218. autotest [IA64]
  219. awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
  220. Format: <io>,<memsize>,<isapnp>
  221. aztcd= [HW,CD] Aztech CD268 CDROM driver
  222. Format: <io>,0x79 (?)
  223. baycom_epp= [HW,AX25]
  224. Format: <io>,<mode>
  225. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  226. Format: <io>,<mode>
  227. See header of drivers/net/hamradio/baycom_par.c.
  228. baycom_ser_fdx= [HW,AX25]
  229. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  230. Format: <io>,<irq>,<mode>[,<baud>]
  231. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  232. baycom_ser_hdx= [HW,AX25]
  233. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  234. Format: <io>,<irq>,<mode>
  235. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  236. blkmtd_device= [HW,MTD]
  237. blkmtd_erasesz=
  238. blkmtd_ro=
  239. blkmtd_bs=
  240. blkmtd_count=
  241. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  242. bttv.radio= Most important insmod options are available as
  243. kernel args too.
  244. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  245. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  246. BusLogic= [HW,SCSI]
  247. See drivers/scsi/BusLogic.c, comment before function
  248. BusLogic_ParseDriverOptions().
  249. c101= [NET] Moxa C101 synchronous serial card
  250. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  251. Sometimes CPU hardware bugs make them report the cache
  252. size incorrectly. The kernel will attempt work arounds
  253. to fix known problems, but for some CPUs it is not
  254. possible to determine what the correct size should be.
  255. This option provides an override for these situations.
  256. cdu31a= [HW,CD]
  257. Format: <io>,<irq>[,PAS]
  258. See header of drivers/cdrom/cdu31a.c.
  259. chandev= [HW,NET] Generic channel device initialisation
  260. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  261. Format: { "0" | "1" }
  262. See security/selinux/Kconfig help text.
  263. 0 -- check protection applied by kernel (includes
  264. any implied execute protection).
  265. 1 -- check protection requested by application.
  266. Default value is set via a kernel config option.
  267. Value can be changed at runtime via
  268. /selinux/checkreqprot.
  269. clock= [BUGS=IA-32,HW] gettimeofday timesource override.
  270. Forces specified timesource (if avaliable) to be used
  271. when calculating gettimeofday(). If specicified
  272. timesource is not avalible, it defaults to PIT.
  273. Format: { pit | tsc | cyclone | pmtmr }
  274. disable_8254_timer
  275. enable_8254_timer
  276. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  277. over the 8254 in addition to over the IO-APIC. The
  278. kernel tries to set a sensible default.
  279. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  280. Format: disable
  281. cm206= [HW,CD]
  282. Format: { auto | [<io>,][<irq>] }
  283. com20020= [HW,NET] ARCnet - COM20020 chipset
  284. Format:
  285. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  286. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  287. Format: <io>[,<irq>]
  288. com90xx= [HW,NET]
  289. ARCnet - COM90xx chipset (memory-mapped buffers)
  290. Format: <io>[,<irq>[,<memstart>]]
  291. condev= [HW,S390] console device
  292. conmode=
  293. console= [KNL] Output console device and options.
  294. tty<n> Use the virtual console device <n>.
  295. ttyS<n>[,options]
  296. ttyUSB0[,options]
  297. Use the specified serial port. The options are of
  298. the form "bbbbpnf", where "bbbb" is the baud rate,
  299. "p" is parity ("n", "o", or "e"), "n" is number of
  300. bits, and "f" is flow control ("r" for RTS or
  301. omit it). Default is "9600n8".
  302. See Documentation/serial-console.txt for more
  303. information. See
  304. Documentation/networking/netconsole.txt for an
  305. alternative.
  306. uart,io,<addr>[,options]
  307. uart,mmio,<addr>[,options]
  308. Start an early, polled-mode console on the 8250/16550
  309. UART at the specified I/O port or MMIO address,
  310. switching to the matching ttyS device later. The
  311. options are the same as for ttyS, above.
  312. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  313. Format:
  314. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  315. cpia_pp= [HW,PPT]
  316. Format: { parport<nr> | auto | none }
  317. crashkernel=nn[KMG]@ss[KMG]
  318. [KNL] Reserve a chunk of physical memory to
  319. hold a kernel to switch to with kexec on panic.
  320. cs4232= [HW,OSS]
  321. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  322. cs89x0_dma= [HW,NET]
  323. Format: <dma>
  324. cs89x0_media= [HW,NET]
  325. Format: { rj45 | aui | bnc }
  326. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  327. dasd= [HW,NET]
  328. See header of drivers/s390/block/dasd_devmap.c.
  329. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  330. (one device per port)
  331. Format: <port#>,<type>
  332. See also Documentation/input/joystick-parport.txt
  333. debug [KNL] Enable kernel debugging (events log level).
  334. decnet= [HW,NET]
  335. Format: <area>[,<node>]
  336. See also Documentation/networking/decnet.txt.
  337. devfs= [DEVFS]
  338. See Documentation/filesystems/devfs/boot-options.
  339. dhash_entries= [KNL]
  340. Set number of hash buckets for dentry cache.
  341. digi= [HW,SERIAL]
  342. IO parameters + enable/disable command.
  343. digiepca= [HW,SERIAL]
  344. See drivers/char/README.epca and
  345. Documentation/digiepca.txt.
  346. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  347. support available.
  348. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  349. dmasound= [HW,OSS] Sound subsystem buffers
  350. dscc4.setup= [NET]
  351. dtc3181e= [HW,SCSI]
  352. earlyprintk= [IA-32,X86-64]
  353. earlyprintk=vga
  354. earlyprintk=serial[,ttySn[,baudrate]]
  355. Append ",keep" to not disable it when the real console
  356. takes over.
  357. Only vga or serial at a time, not both.
  358. Currently only ttyS0 and ttyS1 are supported.
  359. Interaction with the standard serial driver is not
  360. very good.
  361. The VGA output is eventually overwritten by the real
  362. console.
  363. eata= [HW,SCSI]
  364. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  365. Format: <int>
  366. 0: polling mode
  367. non-0: interrupt mode (default)
  368. eda= [HW,PS2]
  369. edb= [HW,PS2]
  370. edd= [EDD]
  371. Format: {"of[f]" | "sk[ipmbr]"}
  372. See comment in arch/i386/boot/edd.S
  373. eicon= [HW,ISDN]
  374. Format: <id>,<membase>,<irq>
  375. eisa_irq_edge= [PARISC,HW]
  376. See header of drivers/parisc/eisa.c.
  377. elanfreq= [IA-32]
  378. See comment before function elanfreq_setup() in
  379. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  380. elevator= [IOSCHED]
  381. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  382. See Documentation/block/as-iosched.txt and
  383. Documentation/block/deadline-iosched.txt for details.
  384. elfcorehdr= [IA-32, X86_64]
  385. Specifies physical address of start of kernel core
  386. image elf header. Generally kexec loader will
  387. pass this option to capture kernel.
  388. See Documentation/kdump/kdump.txt for details.
  389. enforcing [SELINUX] Set initial enforcing status.
  390. Format: {"0" | "1"}
  391. See security/selinux/Kconfig help text.
  392. 0 -- permissive (log only, no denials).
  393. 1 -- enforcing (deny and log).
  394. Default value is 0.
  395. Value can be changed at runtime via /selinux/enforce.
  396. es1370= [HW,OSS]
  397. Format: <lineout>[,<micbias>]
  398. See also header of sound/oss/es1370.c.
  399. es1371= [HW,OSS]
  400. Format: <spdif>,[<nomix>,[<amplifier>]]
  401. See also header of sound/oss/es1371.c.
  402. ether= [HW,NET] Ethernet cards parameters
  403. This option is obsoleted by the "netdev=" option, which
  404. has equivalent usage. See its documentation for details.
  405. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  406. Format: <io>[,<irq>]
  407. fd_mcs= [HW,SCSI]
  408. See header of drivers/scsi/fd_mcs.c.
  409. fdomain= [HW,SCSI]
  410. See header of drivers/scsi/fdomain.c.
  411. floppy= [HW]
  412. See Documentation/floppy.txt.
  413. ftape= [HW] Floppy Tape subsystem debugging options.
  414. See Documentation/ftape.txt.
  415. gamecon.map[2|3]=
  416. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  417. support via parallel port (up to 5 devices per port)
  418. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  419. See also Documentation/input/joystick-parport.txt
  420. gamma= [HW,DRM]
  421. gdth= [HW,SCSI]
  422. See header of drivers/scsi/gdth.c.
  423. gpt [EFI] Forces disk with valid GPT signature but
  424. invalid Protective MBR to be treated as GPT.
  425. gscd= [HW,CD]
  426. Format: <io>
  427. gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
  428. gus= [HW,OSS]
  429. Format: <io>,<irq>,<dma>,<dma16>
  430. gvp11= [HW,SCSI]
  431. hashdist= [KNL,NUMA] Large hashes allocated during boot
  432. are distributed across NUMA nodes. Defaults on
  433. for IA-64, off otherwise.
  434. Format: 0 | 1 (for off | on)
  435. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  436. hd= [EIDE] (E)IDE hard drive subsystem geometry
  437. Format: <cyl>,<head>,<sect>
  438. hd?= [HW] (E)IDE subsystem
  439. hd?lun= See Documentation/ide.txt.
  440. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  441. size of <nn>. This works even on boxes that have no
  442. highmem otherwise. This also works to reduce highmem
  443. size on bigger boxes.
  444. hisax= [HW,ISDN]
  445. See Documentation/isdn/README.HiSax.
  446. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  447. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  448. i8042.direct [HW] Put keyboard port into non-translated mode
  449. i8042.dumbkbd [HW] Pretend that controlled can only read data from
  450. keyboard and can not control its state
  451. (Don't attempt to blink the leds)
  452. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  453. i8042.nokbd [HW] Don't check/create keyboard port
  454. i8042.nomux [HW] Don't check presence of an active multiplexing
  455. controller
  456. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  457. controllers
  458. i8042.panicblink=
  459. [HW] Frequency with which keyboard LEDs should blink
  460. when kernel panics (default is 0.5 sec)
  461. i8042.reset [HW] Reset the controller during init and cleanup
  462. i8042.unlock [HW] Unlock (ignore) the keylock
  463. i810= [HW,DRM]
  464. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  465. indicates that the driver is running on unsupported
  466. hardware.
  467. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  468. does not match list of supported models.
  469. i8k.power_status
  470. [HW] Report power status in /proc/i8k
  471. (disabled by default)
  472. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  473. capability is set.
  474. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  475. See Documentation/mca.txt.
  476. icn= [HW,ISDN]
  477. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  478. ide= [HW] (E)IDE subsystem
  479. Format: ide=nodma or ide=doubler or ide=reverse
  480. See Documentation/ide.txt.
  481. ide?= [HW] (E)IDE subsystem
  482. Format: ide?=noprobe or chipset specific parameters.
  483. See Documentation/ide.txt.
  484. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  485. See Documentation/ide.txt.
  486. idle= [HW]
  487. Format: idle=poll or idle=halt
  488. ihash_entries= [KNL]
  489. Set number of hash buckets for inode cache.
  490. in2000= [HW,SCSI]
  491. See header of drivers/scsi/in2000.c.
  492. init= [KNL]
  493. Format: <full_path>
  494. Run specified binary instead of /sbin/init as init
  495. process.
  496. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  497. for working out where the kernel is dying during
  498. startup.
  499. initrd= [BOOT] Specify the location of the initial ramdisk
  500. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  501. Format: <irq>
  502. combined_mode= [HW] control which driver uses IDE ports in combined
  503. mode: legacy IDE driver, libata, or both
  504. (in the libata case, libata.atapi_enabled=1 may be
  505. useful as well). Note that using the ide or libata
  506. options may affect your device naming (e.g. by
  507. changing hdc to sdb).
  508. Format: combined (default), ide, or libata
  509. inttest= [IA64]
  510. io7= [HW] IO7 for Marvel based alpha systems
  511. See comment before marvel_specify_io7 in
  512. arch/alpha/kernel/core_marvel.c.
  513. ip= [IP_PNP]
  514. See Documentation/nfsroot.txt.
  515. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  516. See comment before ip2_setup() in drivers/char/ip2.c.
  517. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  518. See header of drivers/scsi/ips.c.
  519. irqfixup [HW]
  520. When an interrupt is not handled search all handlers
  521. for it. Intended to get systems with badly broken
  522. firmware running.
  523. irqpoll [HW]
  524. When an interrupt is not handled search all handlers
  525. for it. Also check all handlers each timer
  526. interrupt. Intended to get systems with badly broken
  527. firmware running.
  528. isapnp= [ISAPNP]
  529. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  530. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  531. Format: <cpu number>,...,<cpu number>
  532. This option can be used to specify one or more CPUs
  533. to isolate from the general SMP balancing and scheduling
  534. algorithms. The only way to move a process onto or off
  535. an "isolated" CPU is via the CPU affinity syscalls.
  536. <cpu number> begins at 0 and the maximum value is
  537. "number of CPUs in system - 1".
  538. This option is the preferred way to isolate CPUs. The
  539. alternative -- manually setting the CPU mask of all
  540. tasks in the system -- can cause problems and
  541. suboptimal load balancer performance.
  542. isp16= [HW,CD]
  543. Format: <io>,<irq>,<dma>,<setup>
  544. iucv= [HW,NET]
  545. js= [HW,JOY] Analog joystick
  546. See Documentation/input/joystick.txt.
  547. keepinitrd [HW,ARM]
  548. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  549. in oops dumps.
  550. l2cr= [PPC]
  551. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  552. disabled it.
  553. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  554. Format: addr:<io>,irq:<irq>
  555. llsc*= [IA64] See function print_params() in
  556. arch/ia64/sn/kernel/llsc4.c.
  557. load_ramdisk= [RAM] List of ramdisks to load from floppy
  558. See Documentation/ramdisk.txt.
  559. lockd.nlm_grace_period=P [NFS] Assign grace period.
  560. Format: <integer>
  561. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  562. Format: <integer>
  563. lockd.nlm_timeout=T [NFS] Assign timeout value.
  564. Format: <integer>
  565. lockd.nlm_udpport=M [NFS] Assign UDP port.
  566. Format: <integer>
  567. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  568. Format: <irq>
  569. loglevel= All Kernel Messages with a loglevel smaller than the
  570. console loglevel will be printed to the console. It can
  571. also be changed with klogd or other programs. The
  572. loglevels are defined as follows:
  573. 0 (KERN_EMERG) system is unusable
  574. 1 (KERN_ALERT) action must be taken immediately
  575. 2 (KERN_CRIT) critical conditions
  576. 3 (KERN_ERR) error conditions
  577. 4 (KERN_WARNING) warning conditions
  578. 5 (KERN_NOTICE) normal but significant condition
  579. 6 (KERN_INFO) informational
  580. 7 (KERN_DEBUG) debug-level messages
  581. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  582. Format: { n | nk | nM }
  583. n must be a power of two. The default size
  584. is set in the kernel config file.
  585. lp=0 [LP] Specify parallel ports to use, e.g,
  586. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  587. lp=reset first parallel port). 'lp=0' disables the
  588. lp=auto printer driver. 'lp=reset' (which can be
  589. specified in addition to the ports) causes
  590. attached printers to be reset. Using
  591. lp=port1,port2,... specifies the parallel ports
  592. to associate lp devices with, starting with
  593. lp0. A port specification may be 'none' to skip
  594. that lp device, or a parport name such as
  595. 'parport0'. Specifying 'lp=auto' instead of a
  596. port specification list means that device IDs
  597. from each port should be examined, to see if
  598. an IEEE 1284-compliant printer is attached; if
  599. so, the driver will manage that printer.
  600. See also header of drivers/char/lp.c.
  601. lpj=n [KNL]
  602. Sets loops_per_jiffy to given constant, thus avoiding
  603. time-consuming boot-time autodetection (up to 250 ms per
  604. CPU). 0 enables autodetection (default). To determine
  605. the correct value for your kernel, boot with normal
  606. autodetection and see what value is printed. Note that
  607. on SMP systems the preset will be applied to all CPUs,
  608. which is likely to cause problems if your CPUs need
  609. significantly divergent settings. An incorrect value
  610. will cause delays in the kernel to be wrong, leading to
  611. unpredictable I/O errors and other breakage. Although
  612. unlikely, in the extreme case this might damage your
  613. hardware.
  614. ltpc= [NET]
  615. Format: <io>,<irq>,<dma>
  616. mac5380= [HW,SCSI] Format:
  617. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  618. mac53c9x= [HW,SCSI] Format:
  619. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  620. machvec= [IA64] Force the use of a particular machine-vector
  621. (machvec) in a generic kernel.
  622. Example: machvec=hpzx1_swiotlb
  623. mad16= [HW,OSS] Format:
  624. <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
  625. maui= [HW,OSS]
  626. Format: <io>,<irq>
  627. max_loop= [LOOP] Maximum number of loopback devices that can
  628. be mounted
  629. Format: <1-256>
  630. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  631. should make use of
  632. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  633. equal to this physical address is ignored.
  634. max_luns= [SCSI] Maximum number of LUNs to probe.
  635. Should be between 1 and 2^32-1.
  636. max_report_luns=
  637. [SCSI] Maximum number of LUNs received.
  638. Should be between 1 and 16384.
  639. mca-pentium [BUGS=IA-32]
  640. mcatest= [IA-64]
  641. mcd= [HW,CD]
  642. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  643. mcdx= [HW,CD]
  644. mce [IA-32] Machine Check Exception
  645. md= [HW] RAID subsystems devices and level
  646. See Documentation/md.txt.
  647. mdacon= [MDA]
  648. Format: <first>,<last>
  649. Specifies range of consoles to be captured by the MDA.
  650. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  651. Amount of memory to be used when the kernel is not able
  652. to see the whole system memory or for test.
  653. [IA-32] Use together with memmap= to avoid physical
  654. address space collisions. Without memmap= PCI devices
  655. could be placed at addresses belonging to unused RAM.
  656. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  657. memory.
  658. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  659. E820 memory map, as specified by the user.
  660. Such memmap=exactmap lines can be constructed based on
  661. BIOS output or other requirements. See the memmap=nn@ss
  662. option description.
  663. memmap=nn[KMG]@ss[KMG]
  664. [KNL] Force usage of a specific region of memory
  665. Region of memory to be used, from ss to ss+nn.
  666. memmap=nn[KMG]#ss[KMG]
  667. [KNL,ACPI] Mark specific memory as ACPI data.
  668. Region of memory to be used, from ss to ss+nn.
  669. memmap=nn[KMG]$ss[KMG]
  670. [KNL,ACPI] Mark specific memory as reserved.
  671. Region of memory to be used, from ss to ss+nn.
  672. meye.*= [HW] Set MotionEye Camera parameters
  673. See Documentation/video4linux/meye.txt.
  674. mga= [HW,DRM]
  675. migration_cost=
  676. [KNL,SMP] debug: override scheduler migration costs
  677. Format: <level-1-usecs>,<level-2-usecs>,...
  678. This debugging option can be used to override the
  679. default scheduler migration cost matrix. The numbers
  680. are indexed by 'CPU domain distance'.
  681. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  682. box will set up an intra-core migration cost of
  683. 1 msec, an inter-core migration cost of 2 msecs,
  684. and an inter-node migration cost of 3 msecs.
  685. WARNING: using the wrong values here can break
  686. scheduler performance, so it's only for scheduler
  687. development purposes, not production environments.
  688. migration_debug=
  689. [KNL,SMP] migration cost auto-detect verbosity
  690. Format=<0|1|2>
  691. If a system's migration matrix reported at bootup
  692. seems erroneous then this option can be used to
  693. increase verbosity of the detection process.
  694. We default to 0 (no extra messages), 1 will print
  695. some more information, and 2 will be really
  696. verbose (probably only useful if you also have a
  697. serial console attached to the system).
  698. migration_factor=
  699. [KNL,SMP] multiply/divide migration costs by a factor
  700. Format=<percent>
  701. This debug option can be used to proportionally
  702. increase or decrease the auto-detected migration
  703. costs for all entries of the migration matrix.
  704. E.g. migration_factor=150 will increase migration
  705. costs by 50%. (and thus the scheduler will be less
  706. eager migrating cache-hot tasks)
  707. migration_factor=80 will decrease migration costs
  708. by 20%. (thus the scheduler will be more eager to
  709. migrate tasks)
  710. WARNING: using the wrong values here can break
  711. scheduler performance, so it's only for scheduler
  712. development purposes, not production environments.
  713. mousedev.tap_time=
  714. [MOUSE] Maximum time between finger touching and
  715. leaving touchpad surface for touch to be considered
  716. a tap and be reported as a left button click (for
  717. touchpads working in absolute mode only).
  718. Format: <msecs>
  719. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  720. reporting absolute coordinates, such as tablets
  721. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  722. reporting absolute coordinates, such as tablets
  723. mpu401= [HW,OSS]
  724. Format: <io>,<irq>
  725. MTD_Partition= [MTD]
  726. Format: <name>,<region-number>,<size>,<offset>
  727. MTD_Region= [MTD] Format:
  728. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  729. mtdparts= [MTD]
  730. See drivers/mtd/cmdline.c.
  731. mtouchusb.raw_coordinates=
  732. [HW] Make the MicroTouch USB driver use raw coordinates
  733. ('y', default) or cooked coordinates ('n')
  734. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  735. NCR_D700= [HW,SCSI]
  736. See header of drivers/scsi/NCR_D700.c.
  737. ncr5380= [HW,SCSI]
  738. ncr53c400= [HW,SCSI]
  739. ncr53c400a= [HW,SCSI]
  740. ncr53c406a= [HW,SCSI]
  741. ncr53c8xx= [HW,SCSI]
  742. netdev= [NET] Network devices parameters
  743. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  744. Note that mem_start is often overloaded to mean
  745. something different and driver-specific.
  746. This usage is only documented in each driver source
  747. file if at all.
  748. nfsaddrs= [NFS]
  749. See Documentation/nfsroot.txt.
  750. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  751. See Documentation/nfsroot.txt.
  752. nfs.callback_tcpport=
  753. [NFS] set the TCP port on which the NFSv4 callback
  754. channel should listen.
  755. nfs.idmap_cache_timeout=
  756. [NFS] set the maximum lifetime for idmapper cache
  757. entries.
  758. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  759. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  760. emulation library even if a 387 maths coprocessor
  761. is present.
  762. noalign [KNL,ARM]
  763. noapic [SMP,APIC] Tells the kernel to not make use of any
  764. IOAPICs that may be present in the system.
  765. noasync [HW,M68K] Disables async and sync negotiation for
  766. all devices.
  767. nobats [PPC] Do not use BATs for mapping kernel lowmem
  768. on "Classic" PPC cores.
  769. nocache [ARM]
  770. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  771. noexec [IA-64]
  772. noexec [IA-32,X86-64]
  773. noexec=on: enable non-executable mappings (default)
  774. noexec=off: disable nn-executable mappings
  775. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  776. register save and restore. The kernel will only save
  777. legacy floating-point registers on task switch.
  778. nohlt [BUGS=ARM]
  779. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  780. instruction doesn't work correctly and not to
  781. use it.
  782. nohalt [IA-64] Tells the kernel not to use the power saving
  783. function PAL_HALT_LIGHT when idle. This increases
  784. power-consumption. On the positive side, it reduces
  785. interrupt wake-up latency, which may improve performance
  786. in certain environments such as networked servers or
  787. real-time systems.
  788. noirqdebug [IA-32] Disables the code which attempts to detect and
  789. disable unhandled interrupt sources.
  790. noisapnp [ISAPNP] Disables ISA PnP code.
  791. noinitrd [RAM] Tells the kernel not to load any configured
  792. initial RAM disk.
  793. nointroute [IA-64]
  794. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  795. noltlbs [PPC] Do not use large page/tlb entries for kernel
  796. lowmem mapping on PPC40x.
  797. nomca [IA-64] Disable machine check abort handling
  798. nomce [IA-32] Machine Check Exception
  799. noresidual [PPC] Don't use residual data on PReP machines.
  800. noresume [SWSUSP] Disables resume and restores original swap
  801. space.
  802. no-scroll [VGA] Disables scrollback.
  803. This is required for the Braillex ib80-piezo Braille
  804. reader made by F.H. Papenmeier (Germany).
  805. nosbagart [IA-64]
  806. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  807. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  808. nosync [HW,M68K] Disables sync negotiation for all devices.
  809. notsc [BUGS=IA-32] Disable Time Stamp Counter
  810. nousb [USB] Disable the USB subsystem
  811. nowb [ARM]
  812. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  813. opl3= [HW,OSS]
  814. Format: <io>
  815. opl3sa= [HW,OSS]
  816. Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
  817. opl3sa2= [HW,OSS] Format:
  818. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  819. oprofile.timer= [HW]
  820. Use timer interrupt instead of performance counters
  821. optcd= [HW,CD]
  822. Format: <io>
  823. osst= [HW,SCSI] SCSI Tape Driver
  824. Format: <buffer_size>,<write_threshold>
  825. See also Documentation/scsi/st.txt.
  826. panic= [KNL] Kernel behaviour on panic
  827. Format: <timeout>
  828. parkbd.port= [HW] Parallel port number the keyboard adapter is
  829. connected to, default is 0.
  830. Format: <parport#>
  831. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  832. 0 for XT, 1 for AT (default is AT).
  833. Format: <mode>
  834. parport= [HW,PPT] Specify parallel ports. 0 disables.
  835. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  836. Use 'auto' to force the driver to use any
  837. IRQ/DMA settings detected (the default is to
  838. ignore detected IRQ/DMA settings because of
  839. possible conflicts). You can specify the base
  840. address, IRQ, and DMA settings; IRQ and DMA
  841. should be numbers, or 'auto' (for using detected
  842. settings on that particular port), or 'nofifo'
  843. (to avoid using a FIFO even if it is detected).
  844. Parallel ports are assigned in the order they
  845. are specified on the command line, starting
  846. with parport0.
  847. parport_init_mode= [HW,PPT]
  848. Configure VIA parallel port to operate in
  849. a specific mode. This is necessary on Pegasos
  850. computer where firmware has no options for setting
  851. up parallel port mode and sets it to spp.
  852. Currently this function knows 686a and 8231 chips.
  853. Format: [spp|ps2|epp|ecp|ecpepp]
  854. pas2= [HW,OSS] Format:
  855. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  856. pas16= [HW,SCSI]
  857. See header of drivers/scsi/pas16.c.
  858. pause_on_oops=
  859. Halt all CPUs after the first oops has been printed for
  860. the specified number of seconds. This is to be used if
  861. your oopses keep scrolling off the screen.
  862. pcbit= [HW,ISDN]
  863. pcd. [PARIDE]
  864. See header of drivers/block/paride/pcd.c.
  865. See also Documentation/paride.txt.
  866. pci=option[,option...] [PCI] various PCI subsystem options:
  867. off [IA-32] don't probe for the PCI bus
  868. bios [IA-32] force use of PCI BIOS, don't access
  869. the hardware directly. Use this if your machine
  870. has a non-standard PCI host bridge.
  871. nobios [IA-32] disallow use of PCI BIOS, only direct
  872. hardware access methods are allowed. Use this
  873. if you experience crashes upon bootup and you
  874. suspect they are caused by the BIOS.
  875. conf1 [IA-32] Force use of PCI Configuration
  876. Mechanism 1.
  877. conf2 [IA-32] Force use of PCI Configuration
  878. Mechanism 2.
  879. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  880. Configuration
  881. nomsi [MSI] If the PCI_MSI kernel config parameter is
  882. enabled, this kernel boot option can be used to
  883. disable the use of MSI interrupts system-wide.
  884. nosort [IA-32] Don't sort PCI devices according to
  885. order given by the PCI BIOS. This sorting is
  886. done to get a device order compatible with
  887. older kernels.
  888. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  889. routing table. These calls are known to be buggy
  890. on several machines and they hang the machine
  891. when used, but on other computers it's the only
  892. way to get the interrupt routing table. Try
  893. this option if the kernel is unable to allocate
  894. IRQs or discover secondary PCI buses on your
  895. motherboard.
  896. rom [IA-32] Assign address space to expansion ROMs.
  897. Use with caution as certain devices share
  898. address decoders between ROMs and other
  899. resources.
  900. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  901. assigned automatically to PCI devices. You can
  902. make the kernel exclude IRQs of your ISA cards
  903. this way.
  904. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  905. of the PIRQ table (normally generated
  906. by the BIOS) if it is outside the
  907. F0000h-100000h range.
  908. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  909. useful if the kernel is unable to find your
  910. secondary buses and you want to tell it
  911. explicitly which ones they are.
  912. assign-busses [IA-32] Always assign all PCI bus
  913. numbers ourselves, overriding
  914. whatever the firmware may have done.
  915. usepirqmask [IA-32] Honor the possible IRQ mask stored
  916. in the BIOS $PIR table. This is needed on
  917. some systems with broken BIOSes, notably
  918. some HP Pavilion N5400 and Omnibook XE3
  919. notebooks. This will have no effect if ACPI
  920. IRQ routing is enabled.
  921. noacpi [IA-32] Do not use ACPI for IRQ routing
  922. or for PCI scanning.
  923. routeirq Do IRQ routing for all PCI devices.
  924. This is normally done in pci_enable_device(),
  925. so this option is a temporary workaround
  926. for broken drivers that don't call it.
  927. firmware [ARM] Do not re-enumerate the bus but instead
  928. just use the configuration from the
  929. bootloader. This is currently used on
  930. IXP2000 systems where the bus has to be
  931. configured a certain way for adjunct CPUs.
  932. pcmv= [HW,PCMCIA] BadgePAD 4
  933. pd. [PARIDE]
  934. See Documentation/paride.txt.
  935. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  936. boot time.
  937. Format: { 0 | 1 }
  938. See arch/parisc/kernel/pdc_chassis.c
  939. pf. [PARIDE]
  940. See Documentation/paride.txt.
  941. pg. [PARIDE]
  942. See Documentation/paride.txt.
  943. pirq= [SMP,APIC] Manual mp-table setup
  944. See Documentation/i386/IO-APIC.txt.
  945. plip= [PPT,NET] Parallel port network link
  946. Format: { parport<nr> | timid | 0 }
  947. See also Documentation/parport.txt.
  948. pnpacpi= [ACPI]
  949. { off }
  950. pnpbios= [ISAPNP]
  951. { on | off | curr | res | no-curr | no-res }
  952. pnp_reserve_irq=
  953. [ISAPNP] Exclude IRQs for the autoconfiguration
  954. pnp_reserve_dma=
  955. [ISAPNP] Exclude DMAs for the autoconfiguration
  956. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  957. Ranges are in pairs (I/O port base and size).
  958. pnp_reserve_mem=
  959. [ISAPNP] Exclude memory regions for the
  960. autoconfiguration.
  961. Ranges are in pairs (memory base and size).
  962. profile= [KNL] Enable kernel profiling via /proc/profile
  963. Format: [schedule,]<number>
  964. Param: "schedule" - profile schedule points.
  965. Param: <number> - step/bucket size as a power of 2 for
  966. statistical time based profiling.
  967. processor.max_cstate= [HW,ACPI]
  968. Limit processor to maximum C-state
  969. max_cstate=9 overrides any DMI blacklist limit.
  970. processor.nocst [HW,ACPI]
  971. Ignore the _CST method to determine C-states,
  972. instead using the legacy FADT method
  973. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  974. before loading.
  975. See Documentation/ramdisk.txt.
  976. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  977. probe for; one of (bare|imps|exps|lifebook|any).
  978. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  979. per second.
  980. psmouse.resetafter= [HW,MOUSE]
  981. Try to reset the device after so many bad packets
  982. (0 = never).
  983. psmouse.resolution=
  984. [HW,MOUSE] Set desired mouse resolution, in dpi.
  985. psmouse.smartscroll=
  986. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  987. 0 = disabled, 1 = enabled (default).
  988. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  989. Format:
  990. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  991. pt. [PARIDE]
  992. See Documentation/paride.txt.
  993. quiet= [KNL] Disable log messages
  994. r128= [HW,DRM]
  995. raid= [HW,RAID]
  996. See Documentation/md.txt.
  997. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  998. See Documentation/ramdisk.txt.
  999. ramdisk_blocksize= [RAM]
  1000. See Documentation/ramdisk.txt.
  1001. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  1002. New name for the ramdisk parameter.
  1003. See Documentation/ramdisk.txt.
  1004. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  1005. RCU callbacks to process in one batch.
  1006. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  1007. RCU callbacks over which batch limiting is disabled.
  1008. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  1009. RCU callbacks below which batch limiting is re-enabled.
  1010. rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
  1011. RCU callbacks to queued before forcing reschedule
  1012. on all cpus.
  1013. rdinit= [KNL]
  1014. Format: <full_path>
  1015. Run specified binary instead of /init from the ramdisk,
  1016. used for early userspace startup. See initrd.
  1017. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  1018. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  1019. See arch/*/kernel/reboot.c.
  1020. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1021. resume= [SWSUSP]
  1022. Specify the partition device for software suspend
  1023. rhash_entries= [KNL,NET]
  1024. Set number of hash buckets for route cache
  1025. riscom8= [HW,SERIAL]
  1026. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1027. ro [KNL] Mount root device read-only on boot
  1028. root= [KNL] Root filesystem
  1029. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1030. mount the root filesystem
  1031. rootflags= [KNL] Set root filesystem mount option string
  1032. rootfstype= [KNL] Set root filesystem type
  1033. rw [KNL] Mount root device read-write on boot
  1034. S [KNL] Run init in single mode
  1035. sa1100ir [NET]
  1036. See drivers/net/irda/sa1100_ir.c.
  1037. sb= [HW,OSS]
  1038. Format: <io>,<irq>,<dma>,<dma2>
  1039. sbni= [NET] Granch SBNI12 leased line adapter
  1040. sbpcd= [HW,CD] Soundblaster CD adapter
  1041. Format: <io>,<type>
  1042. See a comment before function sbpcd_setup() in
  1043. drivers/cdrom/sbpcd.c.
  1044. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1045. Format: <io>[,<timeout>[,<isapnp>]]
  1046. scsi_debug_*= [SCSI]
  1047. See drivers/scsi/scsi_debug.c.
  1048. scsi_default_dev_flags=
  1049. [SCSI] SCSI default device flags
  1050. Format: <integer>
  1051. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1052. Format: <vendor>:<model>:<flags>
  1053. (flags are integer value)
  1054. scsi_logging= [SCSI]
  1055. selinux [SELINUX] Disable or enable SELinux at boot time.
  1056. Format: { "0" | "1" }
  1057. See security/selinux/Kconfig help text.
  1058. 0 -- disable.
  1059. 1 -- enable.
  1060. Default value is set via kernel config option.
  1061. If enabled at boot time, /selinux/disable can be used
  1062. later to disable prior to initial policy load.
  1063. serialnumber [BUGS=IA-32]
  1064. sg_def_reserved_size= [SCSI]
  1065. sgalaxy= [HW,OSS]
  1066. Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
  1067. shapers= [NET]
  1068. Maximal number of shapers.
  1069. sim710= [SCSI,HW]
  1070. See header of drivers/scsi/sim710.c.
  1071. simeth= [IA-64]
  1072. simscsi=
  1073. sjcd= [HW,CD]
  1074. Format: <io>,<irq>,<dma>
  1075. See header of drivers/cdrom/sjcd.c.
  1076. slram= [HW,MTD]
  1077. smart2= [HW]
  1078. Format: <io1>[,<io2>[,...,<io8>]]
  1079. snd-ad1816a= [HW,ALSA]
  1080. snd-ad1848= [HW,ALSA]
  1081. snd-ali5451= [HW,ALSA]
  1082. snd-als100= [HW,ALSA]
  1083. snd-als4000= [HW,ALSA]
  1084. snd-azt2320= [HW,ALSA]
  1085. snd-cmi8330= [HW,ALSA]
  1086. snd-cmipci= [HW,ALSA]
  1087. snd-cs4231= [HW,ALSA]
  1088. snd-cs4232= [HW,ALSA]
  1089. snd-cs4236= [HW,ALSA]
  1090. snd-cs4281= [HW,ALSA]
  1091. snd-cs46xx= [HW,ALSA]
  1092. snd-dt019x= [HW,ALSA]
  1093. snd-dummy= [HW,ALSA]
  1094. snd-emu10k1= [HW,ALSA]
  1095. snd-ens1370= [HW,ALSA]
  1096. snd-ens1371= [HW,ALSA]
  1097. snd-es968= [HW,ALSA]
  1098. snd-es1688= [HW,ALSA]
  1099. snd-es18xx= [HW,ALSA]
  1100. snd-es1938= [HW,ALSA]
  1101. snd-es1968= [HW,ALSA]
  1102. snd-fm801= [HW,ALSA]
  1103. snd-gusclassic= [HW,ALSA]
  1104. snd-gusextreme= [HW,ALSA]
  1105. snd-gusmax= [HW,ALSA]
  1106. snd-hdsp= [HW,ALSA]
  1107. snd-ice1712= [HW,ALSA]
  1108. snd-intel8x0= [HW,ALSA]
  1109. snd-interwave= [HW,ALSA]
  1110. snd-interwave-stb=
  1111. [HW,ALSA]
  1112. snd-korg1212= [HW,ALSA]
  1113. snd-maestro3= [HW,ALSA]
  1114. snd-mpu401= [HW,ALSA]
  1115. snd-mtpav= [HW,ALSA]
  1116. snd-nm256= [HW,ALSA]
  1117. snd-opl3sa2= [HW,ALSA]
  1118. snd-opti92x-ad1848=
  1119. [HW,ALSA]
  1120. snd-opti92x-cs4231=
  1121. [HW,ALSA]
  1122. snd-opti93x= [HW,ALSA]
  1123. snd-pmac= [HW,ALSA]
  1124. snd-rme32= [HW,ALSA]
  1125. snd-rme96= [HW,ALSA]
  1126. snd-rme9652= [HW,ALSA]
  1127. snd-sb8= [HW,ALSA]
  1128. snd-sb16= [HW,ALSA]
  1129. snd-sbawe= [HW,ALSA]
  1130. snd-serial= [HW,ALSA]
  1131. snd-sgalaxy= [HW,ALSA]
  1132. snd-sonicvibes= [HW,ALSA]
  1133. snd-sun-amd7930=
  1134. [HW,ALSA]
  1135. snd-sun-cs4231= [HW,ALSA]
  1136. snd-trident= [HW,ALSA]
  1137. snd-usb-audio= [HW,ALSA,USB]
  1138. snd-via82xx= [HW,ALSA]
  1139. snd-virmidi= [HW,ALSA]
  1140. snd-wavefront= [HW,ALSA]
  1141. snd-ymfpci= [HW,ALSA]
  1142. sonicvibes= [HW,OSS]
  1143. Format: <reverb>
  1144. sonycd535= [HW,CD]
  1145. Format: <io>[,<irq>]
  1146. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1147. See Documentation/sonypi.txt
  1148. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1149. See Documentation/specialix.txt.
  1150. spia_io_base= [HW,MTD]
  1151. spia_fio_base=
  1152. spia_pedr=
  1153. spia_peddr=
  1154. sscape= [HW,OSS]
  1155. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1156. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1157. See Documentation/scsi/st.txt.
  1158. st0x= [HW,SCSI]
  1159. See header of drivers/scsi/seagate.c.
  1160. sti= [PARISC,HW]
  1161. Format: <num>
  1162. Set the STI (builtin display/keyboard on the HP-PARISC
  1163. machines) console (graphic card) which should be used
  1164. as the initial boot-console.
  1165. See also comment in drivers/video/console/sticore.c.
  1166. sti_font= [HW]
  1167. See comment in drivers/video/console/sticore.c.
  1168. stifb= [HW]
  1169. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1170. swiotlb= [IA-64] Number of I/O TLB slabs
  1171. switches= [HW,M68k]
  1172. sym53c416= [HW,SCSI]
  1173. See header of drivers/scsi/sym53c416.c.
  1174. t128= [HW,SCSI]
  1175. See header of drivers/scsi/t128.c.
  1176. tdfx= [HW,DRM]
  1177. thash_entries= [KNL,NET]
  1178. Set number of hash buckets for TCP connection
  1179. time Show timing data prefixed to each printk message line
  1180. tipar.timeout= [HW,PPT]
  1181. Set communications timeout in tenths of a second
  1182. (default 15).
  1183. tipar.delay= [HW,PPT]
  1184. Set inter-bit delay in microseconds (default 10).
  1185. tmc8xx= [HW,SCSI]
  1186. See header of drivers/scsi/seagate.c.
  1187. tmscsim= [HW,SCSI]
  1188. See comment before function dc390_setup() in
  1189. drivers/scsi/tmscsim.c.
  1190. tp720= [HW,PS2]
  1191. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1192. Format:
  1193. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1194. tsdev.xres= [TS] Horizontal screen resolution.
  1195. tsdev.yres= [TS] Vertical screen resolution.
  1196. turbografx.map[2|3]= [HW,JOY]
  1197. TurboGraFX parallel port interface
  1198. Format:
  1199. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1200. See also Documentation/input/joystick-parport.txt
  1201. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1202. See header of drivers/scsi/u14-34f.c.
  1203. uart401= [HW,OSS]
  1204. Format: <io>,<irq>
  1205. uart6850= [HW,OSS]
  1206. Format: <io>,<irq>
  1207. usbhid.mousepoll=
  1208. [USBHID] The interval which mice are to be polled at.
  1209. video= [FB] Frame buffer configuration
  1210. See Documentation/fb/modedb.txt.
  1211. vga= [BOOT,IA-32] Select a particular video mode
  1212. See Documentation/i386/boot.txt and
  1213. Documentation/svga.txt.
  1214. Use vga=ask for menu.
  1215. This is actually a boot loader parameter; the value is
  1216. passed to the kernel using a special protocol.
  1217. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1218. size of <nn>. This can be used to increase the
  1219. minimum size (128MB on x86). It can also be used to
  1220. decrease the size and leave more room for directly
  1221. mapped kernel RAM.
  1222. vmhalt= [KNL,S390]
  1223. vmpoff= [KNL,S390]
  1224. waveartist= [HW,OSS]
  1225. Format: <io>,<irq>,<dma>,<dma2>
  1226. wd33c93= [HW,SCSI]
  1227. See header of drivers/scsi/wd33c93.c.
  1228. wd7000= [HW,SCSI]
  1229. See header of drivers/scsi/wd7000.c.
  1230. wdt= [WDT] Watchdog
  1231. See Documentation/watchdog/watchdog.txt.
  1232. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1233. xd_geo= See header of drivers/block/xd.c.
  1234. xirc2ps_cs= [NET,PCMCIA]
  1235. Format:
  1236. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1237. norandmaps Don't use address space randomization
  1238. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1239. ______________________________________________________________________
  1240. TODO:
  1241. Add documentation for ALSA options.
  1242. Add more DRM drivers.