kernel-parameters.txt 48 KB

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  1. February 2003 Kernel Parameters v2.5.59
  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. The text in square brackets at the beginning of the description states the
  15. restrictions on the kernel for the said kernel parameter to be valid. The
  16. restrictions referred to are that the relevant option is valid if:
  17. ACPI ACPI support is enabled.
  18. ALSA ALSA sound support is enabled.
  19. APIC APIC support is enabled.
  20. APM Advanced Power Management support is enabled.
  21. AX25 Appropriate AX.25 support is enabled.
  22. CD Appropriate CD support is enabled.
  23. DEVFS devfs support is enabled.
  24. DRM Direct Rendering Management support is enabled.
  25. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
  26. EFI EFI Partitioning (GPT) is enabled
  27. EIDE EIDE/ATAPI support is enabled.
  28. FB The frame buffer device is enabled.
  29. HW Appropriate hardware is enabled.
  30. IA-32 IA-32 aka i386 architecture is enabled.
  31. IA-64 IA-64 architecture is enabled.
  32. IOSCHED More than one I/O scheduler is enabled.
  33. IP_PNP IP DHCP, BOOTP, or RARP is enabled.
  34. ISAPNP ISA PnP code is enabled.
  35. ISDN Appropriate ISDN support is enabled.
  36. JOY Appropriate joystick support is enabled.
  37. LP Printer support is enabled.
  38. LOOP Loopback device support is enabled.
  39. M68k M68k architecture is enabled.
  40. These options have more detailed description inside of
  41. Documentation/m68k/kernel-options.txt.
  42. MCA MCA bus support is enabled.
  43. MDA MDA console support is enabled.
  44. MOUSE Appropriate mouse support is enabled.
  45. MTD MTD support is enabled.
  46. NET Appropriate network support is enabled.
  47. NUMA NUMA support is enabled.
  48. NFS Appropriate NFS support is enabled.
  49. OSS OSS sound support is enabled.
  50. PARIDE The ParIDE subsystem is enabled.
  51. PARISC The PA-RISC architecture is enabled.
  52. PCI PCI bus support is enabled.
  53. PCMCIA The PCMCIA subsystem is enabled.
  54. PNP Plug & Play support is enabled.
  55. PPC PowerPC architecture is enabled.
  56. PPT Parallel port support is enabled.
  57. PS2 Appropriate PS/2 support is enabled.
  58. RAM RAM disk support is enabled.
  59. S390 S390 architecture is enabled.
  60. SCSI Appropriate SCSI support is enabled.
  61. A lot of drivers has their options described inside of
  62. Documentation/scsi/.
  63. SELINUX SELinux support is enabled.
  64. SERIAL Serial support is enabled.
  65. SMP The kernel is an SMP kernel.
  66. SPARC Sparc architecture is enabled.
  67. SWSUSP Software suspend is enabled.
  68. TS Appropriate touchscreen support is enabled.
  69. USB USB support is enabled.
  70. USBHID USB Human Interface Device support is enabled.
  71. V4L Video For Linux support is enabled.
  72. VGA The VGA console has been enabled.
  73. VT Virtual terminal support is enabled.
  74. WDT Watchdog support is enabled.
  75. XT IBM PC/XT MFM hard disk support is enabled.
  76. X86-64 X86-64 architecture is enabled.
  77. More X86-64 boot options can be found in
  78. Documentation/x86_64/boot-options.txt .
  79. In addition, the following text indicates that the option:
  80. BUGS= Relates to possible processor bugs on the said processor.
  81. KNL Is a kernel start-up parameter.
  82. BOOT Is a boot loader parameter.
  83. Parameters denoted with BOOT are actually interpreted by the boot
  84. loader, and have no meaning to the kernel directly.
  85. Do not modify the syntax of boot loader parameters without extreme
  86. need or coordination with <Documentation/i386/boot.txt>.
  87. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
  88. a trailing = on the name of any parameter states that that parameter will
  89. be entered as an environment variable, whereas its absence indicates that
  90. it will appear as a kernel argument readable via /proc/cmdline by programs
  91. running once the system is up.
  92. 53c7xx= [HW,SCSI] Amiga SCSI controllers
  93. See header of drivers/scsi/53c7xx.c.
  94. See also Documentation/scsi/ncr53c7xx.txt.
  95. acpi= [HW,ACPI] Advanced Configuration and Power Interface
  96. Format: { force | off | ht | strict | noirq }
  97. force -- enable ACPI if default was off
  98. off -- disable ACPI if default was on
  99. noirq -- do not use ACPI for IRQ routing
  100. ht -- run only enough ACPI to enable Hyper Threading
  101. strict -- Be less tolerant of platforms that are not
  102. strictly ACPI specification compliant.
  103. See also Documentation/pm.txt, pci=noacpi
  104. acpi_sleep= [HW,ACPI] Sleep options
  105. Format: { s3_bios, s3_mode }
  106. See Documentation/power/video.txt
  107. acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
  108. Format: { level | edge | high | low }
  109. acpi_irq_balance [HW,ACPI]
  110. ACPI will balance active IRQs
  111. default in APIC mode
  112. acpi_irq_nobalance [HW,ACPI]
  113. ACPI will not move active IRQs (default)
  114. default in PIC mode
  115. acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
  116. use by PCI
  117. Format: <irq>,<irq>...
  118. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
  119. Format: <irq>,<irq>...
  120. acpi_osi= [HW,ACPI] empty param disables _OSI
  121. acpi_serialize [HW,ACPI] force serialization of AML methods
  122. acpi_skip_timer_override [HW,ACPI]
  123. Recognize and ignore IRQ0/pin2 Interrupt Override.
  124. For broken nForce2 BIOS resulting in XT-PIC timer.
  125. acpi_dbg_layer= [HW,ACPI]
  126. Format: <int>
  127. Each bit of the <int> indicates an ACPI debug layer,
  128. 1: enable, 0: disable. It is useful for boot time
  129. debugging. After system has booted up, it can be set
  130. via /proc/acpi/debug_layer.
  131. acpi_dbg_level= [HW,ACPI]
  132. Format: <int>
  133. Each bit of the <int> indicates an ACPI debug level,
  134. 1: enable, 0: disable. It is useful for boot time
  135. debugging. After system has booted up, it can be set
  136. via /proc/acpi/debug_level.
  137. acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
  138. acpi_generic_hotkey [HW,ACPI]
  139. Allow consolidated generic hotkey driver to
  140. override platform specific driver.
  141. See also Documentation/acpi-hotkey.txt.
  142. enable_timer_pin_1 [i386,x86-64]
  143. Enable PIN 1 of APIC timer
  144. Can be useful to work around chipset bugs
  145. (in particular on some ATI chipsets).
  146. The kernel tries to set a reasonable default.
  147. disable_timer_pin_1 [i386,x86-64]
  148. Disable PIN 1 of APIC timer
  149. Can be useful to work around chipset bugs.
  150. ad1816= [HW,OSS]
  151. Format: <io>,<irq>,<dma>,<dma2>
  152. See also Documentation/sound/oss/AD1816.
  153. ad1848= [HW,OSS]
  154. Format: <io>,<irq>,<dma>,<dma2>,<type>
  155. adlib= [HW,OSS]
  156. Format: <io>
  157. advansys= [HW,SCSI]
  158. See header of drivers/scsi/advansys.c.
  159. advwdt= [HW,WDT] Advantech WDT
  160. Format: <iostart>,<iostop>
  161. aedsp16= [HW,OSS] Audio Excel DSP 16
  162. Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
  163. See also header of sound/oss/aedsp16.c.
  164. aha152x= [HW,SCSI]
  165. See Documentation/scsi/aha152x.txt.
  166. aha1542= [HW,SCSI]
  167. Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
  168. aic7xxx= [HW,SCSI]
  169. See Documentation/scsi/aic7xxx.txt.
  170. aic79xx= [HW,SCSI]
  171. See Documentation/scsi/aic79xx.txt.
  172. amijoy.map= [HW,JOY] Amiga joystick support
  173. Map of devices attached to JOY0DAT and JOY1DAT
  174. Format: <a>,<b>
  175. See also Documentation/kernel/input/joystick.txt
  176. analog.map= [HW,JOY] Analog joystick and gamepad support
  177. Specifies type or capabilities of an analog joystick
  178. connected to one of 16 gameports
  179. Format: <type1>,<type2>,..<type16>
  180. apc= [HW,SPARC]
  181. Power management functions (SPARCstation-4/5 + deriv.)
  182. Format: noidle
  183. Disable APC CPU standby support. SPARCstation-Fox does
  184. not play well with APC CPU idle - disable it if you have
  185. APC and your system crashes randomly.
  186. apic= [APIC,i386] Change the output verbosity whilst booting
  187. Format: { quiet (default) | verbose | debug }
  188. Change the amount of debugging information output
  189. when initialising the APIC and IO-APIC components.
  190. apm= [APM] Advanced Power Management
  191. See header of arch/i386/kernel/apm.c.
  192. applicom= [HW]
  193. Format: <mem>,<irq>
  194. arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
  195. Format: <io>,<irq>,<nodeID>
  196. ataflop= [HW,M68k]
  197. atarimouse= [HW,MOUSE] Atari Mouse
  198. atascsi= [HW,SCSI] Atari SCSI
  199. atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
  200. EzKey and similar keyboards
  201. atkbd.reset= [HW] Reset keyboard during initialization
  202. atkbd.set= [HW] Select keyboard code set
  203. Format: <int> (2 = AT (default), 3 = PS/2)
  204. atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
  205. keyboards
  206. atkbd.softraw= [HW] Choose between synthetic and real raw mode
  207. Format: <bool> (0 = real, 1 = synthetic (default))
  208. atkbd.softrepeat= [HW]
  209. Use software keyboard repeat
  210. autotest [IA64]
  211. awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
  212. Format: <io>,<memsize>,<isapnp>
  213. aztcd= [HW,CD] Aztech CD268 CDROM driver
  214. Format: <io>,0x79 (?)
  215. baycom_epp= [HW,AX25]
  216. Format: <io>,<mode>
  217. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
  218. Format: <io>,<mode>
  219. See header of drivers/net/hamradio/baycom_par.c.
  220. baycom_ser_fdx= [HW,AX25]
  221. BayCom Serial Port AX.25 Modem (Full Duplex Mode)
  222. Format: <io>,<irq>,<mode>[,<baud>]
  223. See header of drivers/net/hamradio/baycom_ser_fdx.c.
  224. baycom_ser_hdx= [HW,AX25]
  225. BayCom Serial Port AX.25 Modem (Half Duplex Mode)
  226. Format: <io>,<irq>,<mode>
  227. See header of drivers/net/hamradio/baycom_ser_hdx.c.
  228. blkmtd_device= [HW,MTD]
  229. blkmtd_erasesz=
  230. blkmtd_ro=
  231. blkmtd_bs=
  232. blkmtd_count=
  233. bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
  234. bttv.radio= Most important insmod options are available as
  235. kernel args too.
  236. bttv.pll= See Documentation/video4linux/bttv/Insmod-options
  237. bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
  238. BusLogic= [HW,SCSI]
  239. See drivers/scsi/BusLogic.c, comment before function
  240. BusLogic_ParseDriverOptions().
  241. c101= [NET] Moxa C101 synchronous serial card
  242. cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
  243. Sometimes CPU hardware bugs make them report the cache
  244. size incorrectly. The kernel will attempt work arounds
  245. to fix known problems, but for some CPUs it is not
  246. possible to determine what the correct size should be.
  247. This option provides an override for these situations.
  248. cdu31a= [HW,CD]
  249. Format: <io>,<irq>[,PAS]
  250. See header of drivers/cdrom/cdu31a.c.
  251. chandev= [HW,NET] Generic channel device initialisation
  252. checkreqprot [SELINUX] Set initial checkreqprot flag value.
  253. Format: { "0" | "1" }
  254. See security/selinux/Kconfig help text.
  255. 0 -- check protection applied by kernel (includes
  256. any implied execute protection).
  257. 1 -- check protection requested by application.
  258. Default value is set via a kernel config option.
  259. Value can be changed at runtime via
  260. /selinux/checkreqprot.
  261. clock= [BUGS=IA-32,HW] gettimeofday timesource override.
  262. Forces specified timesource (if avaliable) to be used
  263. when calculating gettimeofday(). If specicified
  264. timesource is not avalible, it defaults to PIT.
  265. Format: { pit | tsc | cyclone | pmtmr }
  266. disable_8254_timer
  267. enable_8254_timer
  268. [IA32/X86_64] Disable/Enable interrupt 0 timer routing
  269. over the 8254 in addition to over the IO-APIC. The
  270. kernel tries to set a sensible default.
  271. hpet= [IA-32,HPET] option to disable HPET and use PIT.
  272. Format: disable
  273. cm206= [HW,CD]
  274. Format: { auto | [<io>,][<irq>] }
  275. com20020= [HW,NET] ARCnet - COM20020 chipset
  276. Format:
  277. <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
  278. com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
  279. Format: <io>[,<irq>]
  280. com90xx= [HW,NET]
  281. ARCnet - COM90xx chipset (memory-mapped buffers)
  282. Format: <io>[,<irq>[,<memstart>]]
  283. condev= [HW,S390] console device
  284. conmode=
  285. console= [KNL] Output console device and options.
  286. tty<n> Use the virtual console device <n>.
  287. ttyS<n>[,options]
  288. Use the specified serial port. The options are of
  289. the form "bbbbpn", where "bbbb" is the baud rate,
  290. "p" is parity ("n", "o", or "e"), and "n" is bits.
  291. Default is "9600n8".
  292. See also Documentation/serial-console.txt.
  293. uart,io,<addr>[,options]
  294. uart,mmio,<addr>[,options]
  295. Start an early, polled-mode console on the 8250/16550
  296. UART at the specified I/O port or MMIO address,
  297. switching to the matching ttyS device later. The
  298. options are the same as for ttyS, above.
  299. cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
  300. Format:
  301. <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
  302. cpia_pp= [HW,PPT]
  303. Format: { parport<nr> | auto | none }
  304. crashkernel=nn[KMG]@ss[KMG]
  305. [KNL] Reserve a chunk of physical memory to
  306. hold a kernel to switch to with kexec on panic.
  307. cs4232= [HW,OSS]
  308. Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
  309. cs89x0_dma= [HW,NET]
  310. Format: <dma>
  311. cs89x0_media= [HW,NET]
  312. Format: { rj45 | aui | bnc }
  313. cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
  314. dasd= [HW,NET]
  315. See header of drivers/s390/block/dasd_devmap.c.
  316. db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
  317. (one device per port)
  318. Format: <port#>,<type>
  319. See also Documentation/input/joystick-parport.txt
  320. debug [KNL] Enable kernel debugging (events log level).
  321. decnet= [HW,NET]
  322. Format: <area>[,<node>]
  323. See also Documentation/networking/decnet.txt.
  324. devfs= [DEVFS]
  325. See Documentation/filesystems/devfs/boot-options.
  326. dhash_entries= [KNL]
  327. Set number of hash buckets for dentry cache.
  328. digi= [HW,SERIAL]
  329. IO parameters + enable/disable command.
  330. digiepca= [HW,SERIAL]
  331. See drivers/char/README.epca and
  332. Documentation/digiepca.txt.
  333. dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
  334. support available.
  335. Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
  336. dmasound= [HW,OSS] Sound subsystem buffers
  337. dscc4.setup= [NET]
  338. dtc3181e= [HW,SCSI]
  339. earlyprintk= [IA-32,X86-64]
  340. earlyprintk=vga
  341. earlyprintk=serial[,ttySn[,baudrate]]
  342. Append ",keep" to not disable it when the real console
  343. takes over.
  344. Only vga or serial at a time, not both.
  345. Currently only ttyS0 and ttyS1 are supported.
  346. Interaction with the standard serial driver is not
  347. very good.
  348. The VGA output is eventually overwritten by the real
  349. console.
  350. eata= [HW,SCSI]
  351. ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
  352. Format: <int>
  353. 0: polling mode
  354. non-0: interrupt mode (default)
  355. eda= [HW,PS2]
  356. edb= [HW,PS2]
  357. edd= [EDD]
  358. Format: {"of[f]" | "sk[ipmbr]"}
  359. See comment in arch/i386/boot/edd.S
  360. eicon= [HW,ISDN]
  361. Format: <id>,<membase>,<irq>
  362. eisa_irq_edge= [PARISC,HW]
  363. See header of drivers/parisc/eisa.c.
  364. elanfreq= [IA-32]
  365. See comment before function elanfreq_setup() in
  366. arch/i386/kernel/cpu/cpufreq/elanfreq.c.
  367. elevator= [IOSCHED]
  368. Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
  369. See Documentation/block/as-iosched.txt and
  370. Documentation/block/deadline-iosched.txt for details.
  371. elfcorehdr= [IA-32, X86_64]
  372. Specifies physical address of start of kernel core
  373. image elf header. Generally kexec loader will
  374. pass this option to capture kernel.
  375. See Documentation/kdump/kdump.txt for details.
  376. enforcing [SELINUX] Set initial enforcing status.
  377. Format: {"0" | "1"}
  378. See security/selinux/Kconfig help text.
  379. 0 -- permissive (log only, no denials).
  380. 1 -- enforcing (deny and log).
  381. Default value is 0.
  382. Value can be changed at runtime via /selinux/enforce.
  383. es1370= [HW,OSS]
  384. Format: <lineout>[,<micbias>]
  385. See also header of sound/oss/es1370.c.
  386. es1371= [HW,OSS]
  387. Format: <spdif>,[<nomix>,[<amplifier>]]
  388. See also header of sound/oss/es1371.c.
  389. ether= [HW,NET] Ethernet cards parameters
  390. This option is obsoleted by the "netdev=" option, which
  391. has equivalent usage. See its documentation for details.
  392. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
  393. Format: <io>[,<irq>]
  394. fd_mcs= [HW,SCSI]
  395. See header of drivers/scsi/fd_mcs.c.
  396. fdomain= [HW,SCSI]
  397. See header of drivers/scsi/fdomain.c.
  398. floppy= [HW]
  399. See Documentation/floppy.txt.
  400. ftape= [HW] Floppy Tape subsystem debugging options.
  401. See Documentation/ftape.txt.
  402. gamecon.map[2|3]=
  403. [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
  404. support via parallel port (up to 5 devices per port)
  405. Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
  406. See also Documentation/input/joystick-parport.txt
  407. gamma= [HW,DRM]
  408. gdth= [HW,SCSI]
  409. See header of drivers/scsi/gdth.c.
  410. gpt [EFI] Forces disk with valid GPT signature but
  411. invalid Protective MBR to be treated as GPT.
  412. gscd= [HW,CD]
  413. Format: <io>
  414. gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
  415. gus= [HW,OSS]
  416. Format: <io>,<irq>,<dma>,<dma16>
  417. gvp11= [HW,SCSI]
  418. hashdist= [KNL,NUMA] Large hashes allocated during boot
  419. are distributed across NUMA nodes. Defaults on
  420. for IA-64, off otherwise.
  421. Format: 0 | 1 (for off | on)
  422. hcl= [IA-64] SGI's Hardware Graph compatibility layer
  423. hd= [EIDE] (E)IDE hard drive subsystem geometry
  424. Format: <cyl>,<head>,<sect>
  425. hd?= [HW] (E)IDE subsystem
  426. hd?lun= See Documentation/ide.txt.
  427. highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
  428. size of <nn>. This works even on boxes that have no
  429. highmem otherwise. This also works to reduce highmem
  430. size on bigger boxes.
  431. hisax= [HW,ISDN]
  432. See Documentation/isdn/README.HiSax.
  433. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
  434. noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
  435. i8042.direct [HW] Put keyboard port into non-translated mode
  436. i8042.dumbkbd [HW] Pretend that controlled can only read data from
  437. keyboard and can not control its state
  438. (Don't attempt to blink the leds)
  439. i8042.noaux [HW] Don't check for auxiliary (== mouse) port
  440. i8042.nokbd [HW] Don't check/create keyboard port
  441. i8042.nomux [HW] Don't check presence of an active multiplexing
  442. controller
  443. i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
  444. controllers
  445. i8042.panicblink=
  446. [HW] Frequency with which keyboard LEDs should blink
  447. when kernel panics (default is 0.5 sec)
  448. i8042.reset [HW] Reset the controller during init and cleanup
  449. i8042.unlock [HW] Unlock (ignore) the keylock
  450. i810= [HW,DRM]
  451. i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
  452. indicates that the driver is running on unsupported
  453. hardware.
  454. i8k.force [HW] Activate i8k driver even if SMM BIOS signature
  455. does not match list of supported models.
  456. i8k.power_status
  457. [HW] Report power status in /proc/i8k
  458. (disabled by default)
  459. i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
  460. capability is set.
  461. ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
  462. See Documentation/mca.txt.
  463. icn= [HW,ISDN]
  464. Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
  465. ide= [HW] (E)IDE subsystem
  466. Format: ide=nodma or ide=doubler or ide=reverse
  467. See Documentation/ide.txt.
  468. ide?= [HW] (E)IDE subsystem
  469. Format: ide?=noprobe or chipset specific parameters.
  470. See Documentation/ide.txt.
  471. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
  472. See Documentation/ide.txt.
  473. idle= [HW]
  474. Format: idle=poll or idle=halt
  475. ihash_entries= [KNL]
  476. Set number of hash buckets for inode cache.
  477. in2000= [HW,SCSI]
  478. See header of drivers/scsi/in2000.c.
  479. init= [KNL]
  480. Format: <full_path>
  481. Run specified binary instead of /sbin/init as init
  482. process.
  483. initcall_debug [KNL] Trace initcalls as they are executed. Useful
  484. for working out where the kernel is dying during
  485. startup.
  486. initrd= [BOOT] Specify the location of the initial ramdisk
  487. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
  488. Format: <irq>
  489. combined_mode= [HW] control which driver uses IDE ports in combined
  490. mode: legacy IDE driver, libata, or both
  491. (in the libata case, libata.atapi_enabled=1 may be
  492. useful as well). Note that using the ide or libata
  493. options may affect your device naming (e.g. by
  494. changing hdc to sdb).
  495. Format: combined (default), ide, or libata
  496. inttest= [IA64]
  497. io7= [HW] IO7 for Marvel based alpha systems
  498. See comment before marvel_specify_io7 in
  499. arch/alpha/kernel/core_marvel.c.
  500. ip= [IP_PNP]
  501. See Documentation/nfsroot.txt.
  502. ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
  503. See comment before ip2_setup() in drivers/char/ip2.c.
  504. ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
  505. See header of drivers/scsi/ips.c.
  506. irqfixup [HW]
  507. When an interrupt is not handled search all handlers
  508. for it. Intended to get systems with badly broken
  509. firmware running.
  510. irqpoll [HW]
  511. When an interrupt is not handled search all handlers
  512. for it. Also check all handlers each timer
  513. interrupt. Intended to get systems with badly broken
  514. firmware running.
  515. isapnp= [ISAPNP]
  516. Format: <RDP>,<reset>,<pci_scan>,<verbosity>
  517. isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
  518. Format: <cpu number>,...,<cpu number>
  519. This option can be used to specify one or more CPUs
  520. to isolate from the general SMP balancing and scheduling
  521. algorithms. The only way to move a process onto or off
  522. an "isolated" CPU is via the CPU affinity syscalls.
  523. <cpu number> begins at 0 and the maximum value is
  524. "number of CPUs in system - 1".
  525. This option is the preferred way to isolate CPUs. The
  526. alternative -- manually setting the CPU mask of all
  527. tasks in the system -- can cause problems and
  528. suboptimal load balancer performance.
  529. isp16= [HW,CD]
  530. Format: <io>,<irq>,<dma>,<setup>
  531. iucv= [HW,NET]
  532. js= [HW,JOY] Analog joystick
  533. See Documentation/input/joystick.txt.
  534. keepinitrd [HW,ARM]
  535. kstack=N [IA-32,X86-64] Print N words from the kernel stack
  536. in oops dumps.
  537. l2cr= [PPC]
  538. lapic [IA-32,APIC] Enable the local APIC even if BIOS
  539. disabled it.
  540. lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
  541. Format: addr:<io>,irq:<irq>
  542. llsc*= [IA64] See function print_params() in
  543. arch/ia64/sn/kernel/llsc4.c.
  544. load_ramdisk= [RAM] List of ramdisks to load from floppy
  545. See Documentation/ramdisk.txt.
  546. lockd.nlm_grace_period=P [NFS] Assign grace period.
  547. Format: <integer>
  548. lockd.nlm_tcpport=N [NFS] Assign TCP port.
  549. Format: <integer>
  550. lockd.nlm_timeout=T [NFS] Assign timeout value.
  551. Format: <integer>
  552. lockd.nlm_udpport=M [NFS] Assign UDP port.
  553. Format: <integer>
  554. logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
  555. Format: <irq>
  556. loglevel= All Kernel Messages with a loglevel smaller than the
  557. console loglevel will be printed to the console. It can
  558. also be changed with klogd or other programs. The
  559. loglevels are defined as follows:
  560. 0 (KERN_EMERG) system is unusable
  561. 1 (KERN_ALERT) action must be taken immediately
  562. 2 (KERN_CRIT) critical conditions
  563. 3 (KERN_ERR) error conditions
  564. 4 (KERN_WARNING) warning conditions
  565. 5 (KERN_NOTICE) normal but significant condition
  566. 6 (KERN_INFO) informational
  567. 7 (KERN_DEBUG) debug-level messages
  568. log_buf_len=n Sets the size of the printk ring buffer, in bytes.
  569. Format: { n | nk | nM }
  570. n must be a power of two. The default size
  571. is set in the kernel config file.
  572. lp=0 [LP] Specify parallel ports to use, e.g,
  573. lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
  574. lp=reset first parallel port). 'lp=0' disables the
  575. lp=auto printer driver. 'lp=reset' (which can be
  576. specified in addition to the ports) causes
  577. attached printers to be reset. Using
  578. lp=port1,port2,... specifies the parallel ports
  579. to associate lp devices with, starting with
  580. lp0. A port specification may be 'none' to skip
  581. that lp device, or a parport name such as
  582. 'parport0'. Specifying 'lp=auto' instead of a
  583. port specification list means that device IDs
  584. from each port should be examined, to see if
  585. an IEEE 1284-compliant printer is attached; if
  586. so, the driver will manage that printer.
  587. See also header of drivers/char/lp.c.
  588. lpj=n [KNL]
  589. Sets loops_per_jiffy to given constant, thus avoiding
  590. time-consuming boot-time autodetection (up to 250 ms per
  591. CPU). 0 enables autodetection (default). To determine
  592. the correct value for your kernel, boot with normal
  593. autodetection and see what value is printed. Note that
  594. on SMP systems the preset will be applied to all CPUs,
  595. which is likely to cause problems if your CPUs need
  596. significantly divergent settings. An incorrect value
  597. will cause delays in the kernel to be wrong, leading to
  598. unpredictable I/O errors and other breakage. Although
  599. unlikely, in the extreme case this might damage your
  600. hardware.
  601. ltpc= [NET]
  602. Format: <io>,<irq>,<dma>
  603. mac5380= [HW,SCSI] Format:
  604. <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  605. mac53c9x= [HW,SCSI] Format:
  606. <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
  607. machvec= [IA64] Force the use of a particular machine-vector
  608. (machvec) in a generic kernel.
  609. Example: machvec=hpzx1_swiotlb
  610. mad16= [HW,OSS] Format:
  611. <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
  612. maui= [HW,OSS]
  613. Format: <io>,<irq>
  614. max_loop= [LOOP] Maximum number of loopback devices that can
  615. be mounted
  616. Format: <1-256>
  617. maxcpus= [SMP] Maximum number of processors that an SMP kernel
  618. should make use of
  619. max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
  620. equal to this physical address is ignored.
  621. max_luns= [SCSI] Maximum number of LUNs to probe.
  622. Should be between 1 and 2^32-1.
  623. max_report_luns=
  624. [SCSI] Maximum number of LUNs received.
  625. Should be between 1 and 16384.
  626. mca-pentium [BUGS=IA-32]
  627. mcatest= [IA-64]
  628. mcd= [HW,CD]
  629. Format: <port>,<irq>,<mitsumi_bug_93_wait>
  630. mcdx= [HW,CD]
  631. mce [IA-32] Machine Check Exception
  632. md= [HW] RAID subsystems devices and level
  633. See Documentation/md.txt.
  634. mdacon= [MDA]
  635. Format: <first>,<last>
  636. Specifies range of consoles to be captured by the MDA.
  637. mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
  638. Amount of memory to be used when the kernel is not able
  639. to see the whole system memory or for test.
  640. [IA-32] Use together with memmap= to avoid physical
  641. address space collisions. Without memmap= PCI devices
  642. could be placed at addresses belonging to unused RAM.
  643. mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
  644. memory.
  645. memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
  646. E820 memory map, as specified by the user.
  647. Such memmap=exactmap lines can be constructed based on
  648. BIOS output or other requirements. See the memmap=nn@ss
  649. option description.
  650. memmap=nn[KMG]@ss[KMG]
  651. [KNL] Force usage of a specific region of memory
  652. Region of memory to be used, from ss to ss+nn.
  653. memmap=nn[KMG]#ss[KMG]
  654. [KNL,ACPI] Mark specific memory as ACPI data.
  655. Region of memory to be used, from ss to ss+nn.
  656. memmap=nn[KMG]$ss[KMG]
  657. [KNL,ACPI] Mark specific memory as reserved.
  658. Region of memory to be used, from ss to ss+nn.
  659. meye.*= [HW] Set MotionEye Camera parameters
  660. See Documentation/video4linux/meye.txt.
  661. mga= [HW,DRM]
  662. migration_cost=
  663. [KNL,SMP] debug: override scheduler migration costs
  664. Format: <level-1-usecs>,<level-2-usecs>,...
  665. This debugging option can be used to override the
  666. default scheduler migration cost matrix. The numbers
  667. are indexed by 'CPU domain distance'.
  668. E.g. migration_cost=1000,2000,3000 on an SMT NUMA
  669. box will set up an intra-core migration cost of
  670. 1 msec, an inter-core migration cost of 2 msecs,
  671. and an inter-node migration cost of 3 msecs.
  672. WARNING: using the wrong values here can break
  673. scheduler performance, so it's only for scheduler
  674. development purposes, not production environments.
  675. migration_debug=
  676. [KNL,SMP] migration cost auto-detect verbosity
  677. Format=<0|1|2>
  678. If a system's migration matrix reported at bootup
  679. seems erroneous then this option can be used to
  680. increase verbosity of the detection process.
  681. We default to 0 (no extra messages), 1 will print
  682. some more information, and 2 will be really
  683. verbose (probably only useful if you also have a
  684. serial console attached to the system).
  685. migration_factor=
  686. [KNL,SMP] multiply/divide migration costs by a factor
  687. Format=<percent>
  688. This debug option can be used to proportionally
  689. increase or decrease the auto-detected migration
  690. costs for all entries of the migration matrix.
  691. E.g. migration_factor=150 will increase migration
  692. costs by 50%. (and thus the scheduler will be less
  693. eager migrating cache-hot tasks)
  694. migration_factor=80 will decrease migration costs
  695. by 20%. (thus the scheduler will be more eager to
  696. migrate tasks)
  697. WARNING: using the wrong values here can break
  698. scheduler performance, so it's only for scheduler
  699. development purposes, not production environments.
  700. mousedev.tap_time=
  701. [MOUSE] Maximum time between finger touching and
  702. leaving touchpad surface for touch to be considered
  703. a tap and be reported as a left button click (for
  704. touchpads working in absolute mode only).
  705. Format: <msecs>
  706. mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
  707. reporting absolute coordinates, such as tablets
  708. mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
  709. reporting absolute coordinates, such as tablets
  710. mpu401= [HW,OSS]
  711. Format: <io>,<irq>
  712. MTD_Partition= [MTD]
  713. Format: <name>,<region-number>,<size>,<offset>
  714. MTD_Region= [MTD] Format:
  715. <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
  716. mtdparts= [MTD]
  717. See drivers/mtd/cmdline.c.
  718. mtouchusb.raw_coordinates=
  719. [HW] Make the MicroTouch USB driver use raw coordinates
  720. ('y', default) or cooked coordinates ('n')
  721. n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
  722. NCR_D700= [HW,SCSI]
  723. See header of drivers/scsi/NCR_D700.c.
  724. ncr5380= [HW,SCSI]
  725. ncr53c400= [HW,SCSI]
  726. ncr53c400a= [HW,SCSI]
  727. ncr53c406a= [HW,SCSI]
  728. ncr53c8xx= [HW,SCSI]
  729. netdev= [NET] Network devices parameters
  730. Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
  731. Note that mem_start is often overloaded to mean
  732. something different and driver-specific.
  733. This usage is only documented in each driver source
  734. file if at all.
  735. nfsaddrs= [NFS]
  736. See Documentation/nfsroot.txt.
  737. nfsroot= [NFS] nfs root filesystem for disk-less boxes.
  738. See Documentation/nfsroot.txt.
  739. nfs.callback_tcpport=
  740. [NFS] set the TCP port on which the NFSv4 callback
  741. channel should listen.
  742. nfs.idmap_cache_timeout=
  743. [NFS] set the maximum lifetime for idmapper cache
  744. entries.
  745. nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
  746. no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
  747. emulation library even if a 387 maths coprocessor
  748. is present.
  749. noalign [KNL,ARM]
  750. noapic [SMP,APIC] Tells the kernel to not make use of any
  751. IOAPICs that may be present in the system.
  752. noasync [HW,M68K] Disables async and sync negotiation for
  753. all devices.
  754. nobats [PPC] Do not use BATs for mapping kernel lowmem
  755. on "Classic" PPC cores.
  756. nocache [ARM]
  757. nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
  758. noexec [IA-64]
  759. noexec [IA-32,X86-64]
  760. noexec=on: enable non-executable mappings (default)
  761. noexec=off: disable nn-executable mappings
  762. nofxsr [BUGS=IA-32] Disables x86 floating point extended
  763. register save and restore. The kernel will only save
  764. legacy floating-point registers on task switch.
  765. nohlt [BUGS=ARM]
  766. no-hlt [BUGS=IA-32] Tells the kernel that the hlt
  767. instruction doesn't work correctly and not to
  768. use it.
  769. nohalt [IA-64] Tells the kernel not to use the power saving
  770. function PAL_HALT_LIGHT when idle. This increases
  771. power-consumption. On the positive side, it reduces
  772. interrupt wake-up latency, which may improve performance
  773. in certain environments such as networked servers or
  774. real-time systems.
  775. noirqdebug [IA-32] Disables the code which attempts to detect and
  776. disable unhandled interrupt sources.
  777. noisapnp [ISAPNP] Disables ISA PnP code.
  778. noinitrd [RAM] Tells the kernel not to load any configured
  779. initial RAM disk.
  780. nointroute [IA-64]
  781. nolapic [IA-32,APIC] Do not enable or use the local APIC.
  782. noltlbs [PPC] Do not use large page/tlb entries for kernel
  783. lowmem mapping on PPC40x.
  784. nomce [IA-32] Machine Check Exception
  785. nomca [IA-64] Disable machine check abort handling
  786. noresidual [PPC] Don't use residual data on PReP machines.
  787. noresume [SWSUSP] Disables resume and restores original swap
  788. space.
  789. no-scroll [VGA] Disables scrollback.
  790. This is required for the Braillex ib80-piezo Braille
  791. reader made by F.H. Papenmeier (Germany).
  792. nosbagart [IA-64]
  793. nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
  794. nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
  795. nosync [HW,M68K] Disables sync negotiation for all devices.
  796. notsc [BUGS=IA-32] Disable Time Stamp Counter
  797. nousb [USB] Disable the USB subsystem
  798. nowb [ARM]
  799. nr_uarts= [SERIAL] maximum number of UARTs to be registered.
  800. opl3= [HW,OSS]
  801. Format: <io>
  802. opl3sa= [HW,OSS]
  803. Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
  804. opl3sa2= [HW,OSS] Format:
  805. <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
  806. oprofile.timer= [HW]
  807. Use timer interrupt instead of performance counters
  808. optcd= [HW,CD]
  809. Format: <io>
  810. osst= [HW,SCSI] SCSI Tape Driver
  811. Format: <buffer_size>,<write_threshold>
  812. See also Documentation/scsi/st.txt.
  813. panic= [KNL] Kernel behaviour on panic
  814. Format: <timeout>
  815. parkbd.port= [HW] Parallel port number the keyboard adapter is
  816. connected to, default is 0.
  817. Format: <parport#>
  818. parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
  819. 0 for XT, 1 for AT (default is AT).
  820. Format: <mode>
  821. parport= [HW,PPT] Specify parallel ports. 0 disables.
  822. Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
  823. Use 'auto' to force the driver to use any
  824. IRQ/DMA settings detected (the default is to
  825. ignore detected IRQ/DMA settings because of
  826. possible conflicts). You can specify the base
  827. address, IRQ, and DMA settings; IRQ and DMA
  828. should be numbers, or 'auto' (for using detected
  829. settings on that particular port), or 'nofifo'
  830. (to avoid using a FIFO even if it is detected).
  831. Parallel ports are assigned in the order they
  832. are specified on the command line, starting
  833. with parport0.
  834. parport_init_mode= [HW,PPT]
  835. Configure VIA parallel port to operate in
  836. a specific mode. This is necessary on Pegasos
  837. computer where firmware has no options for setting
  838. up parallel port mode and sets it to spp.
  839. Currently this function knows 686a and 8231 chips.
  840. Format: [spp|ps2|epp|ecp|ecpepp]
  841. pas2= [HW,OSS] Format:
  842. <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
  843. pas16= [HW,SCSI]
  844. See header of drivers/scsi/pas16.c.
  845. pcbit= [HW,ISDN]
  846. pcd. [PARIDE]
  847. See header of drivers/block/paride/pcd.c.
  848. See also Documentation/paride.txt.
  849. pci=option[,option...] [PCI] various PCI subsystem options:
  850. off [IA-32] don't probe for the PCI bus
  851. bios [IA-32] force use of PCI BIOS, don't access
  852. the hardware directly. Use this if your machine
  853. has a non-standard PCI host bridge.
  854. nobios [IA-32] disallow use of PCI BIOS, only direct
  855. hardware access methods are allowed. Use this
  856. if you experience crashes upon bootup and you
  857. suspect they are caused by the BIOS.
  858. conf1 [IA-32] Force use of PCI Configuration
  859. Mechanism 1.
  860. conf2 [IA-32] Force use of PCI Configuration
  861. Mechanism 2.
  862. nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
  863. Configuration
  864. nosort [IA-32] Don't sort PCI devices according to
  865. order given by the PCI BIOS. This sorting is
  866. done to get a device order compatible with
  867. older kernels.
  868. biosirq [IA-32] Use PCI BIOS calls to get the interrupt
  869. routing table. These calls are known to be buggy
  870. on several machines and they hang the machine
  871. when used, but on other computers it's the only
  872. way to get the interrupt routing table. Try
  873. this option if the kernel is unable to allocate
  874. IRQs or discover secondary PCI buses on your
  875. motherboard.
  876. rom [IA-32] Assign address space to expansion ROMs.
  877. Use with caution as certain devices share
  878. address decoders between ROMs and other
  879. resources.
  880. irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
  881. assigned automatically to PCI devices. You can
  882. make the kernel exclude IRQs of your ISA cards
  883. this way.
  884. pirqaddr=0xAAAAA [IA-32] Specify the physical address
  885. of the PIRQ table (normally generated
  886. by the BIOS) if it is outside the
  887. F0000h-100000h range.
  888. lastbus=N [IA-32] Scan all buses thru bus #N. Can be
  889. useful if the kernel is unable to find your
  890. secondary buses and you want to tell it
  891. explicitly which ones they are.
  892. assign-busses [IA-32] Always assign all PCI bus
  893. numbers ourselves, overriding
  894. whatever the firmware may have done.
  895. usepirqmask [IA-32] Honor the possible IRQ mask stored
  896. in the BIOS $PIR table. This is needed on
  897. some systems with broken BIOSes, notably
  898. some HP Pavilion N5400 and Omnibook XE3
  899. notebooks. This will have no effect if ACPI
  900. IRQ routing is enabled.
  901. noacpi [IA-32] Do not use ACPI for IRQ routing
  902. or for PCI scanning.
  903. routeirq Do IRQ routing for all PCI devices.
  904. This is normally done in pci_enable_device(),
  905. so this option is a temporary workaround
  906. for broken drivers that don't call it.
  907. firmware [ARM] Do not re-enumerate the bus but instead
  908. just use the configuration from the
  909. bootloader. This is currently used on
  910. IXP2000 systems where the bus has to be
  911. configured a certain way for adjunct CPUs.
  912. pcmv= [HW,PCMCIA] BadgePAD 4
  913. pd. [PARIDE]
  914. See Documentation/paride.txt.
  915. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
  916. boot time.
  917. Format: { 0 | 1 }
  918. See arch/parisc/kernel/pdc_chassis.c
  919. pf. [PARIDE]
  920. See Documentation/paride.txt.
  921. pg. [PARIDE]
  922. See Documentation/paride.txt.
  923. pirq= [SMP,APIC] Manual mp-table setup
  924. See Documentation/i386/IO-APIC.txt.
  925. plip= [PPT,NET] Parallel port network link
  926. Format: { parport<nr> | timid | 0 }
  927. See also Documentation/parport.txt.
  928. pnpacpi= [ACPI]
  929. { off }
  930. pnpbios= [ISAPNP]
  931. { on | off | curr | res | no-curr | no-res }
  932. pnp_reserve_irq=
  933. [ISAPNP] Exclude IRQs for the autoconfiguration
  934. pnp_reserve_dma=
  935. [ISAPNP] Exclude DMAs for the autoconfiguration
  936. pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
  937. Ranges are in pairs (I/O port base and size).
  938. pnp_reserve_mem=
  939. [ISAPNP] Exclude memory regions for the
  940. autoconfiguration.
  941. Ranges are in pairs (memory base and size).
  942. profile= [KNL] Enable kernel profiling via /proc/profile
  943. Format: [schedule,]<number>
  944. Param: "schedule" - profile schedule points.
  945. Param: <number> - step/bucket size as a power of 2 for
  946. statistical time based profiling.
  947. processor.max_cstate= [HW,ACPI]
  948. Limit processor to maximum C-state
  949. max_cstate=9 overrides any DMI blacklist limit.
  950. processor.nocst [HW,ACPI]
  951. Ignore the _CST method to determine C-states,
  952. instead using the legacy FADT method
  953. prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
  954. before loading.
  955. See Documentation/ramdisk.txt.
  956. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
  957. probe for; one of (bare|imps|exps|lifebook|any).
  958. psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
  959. per second.
  960. psmouse.resetafter= [HW,MOUSE]
  961. Try to reset the device after so many bad packets
  962. (0 = never).
  963. psmouse.resolution=
  964. [HW,MOUSE] Set desired mouse resolution, in dpi.
  965. psmouse.smartscroll=
  966. [HW,MOUSE] Controls Logitech smartscroll autorepeat.
  967. 0 = disabled, 1 = enabled (default).
  968. pss= [HW,OSS] Personal Sound System (ECHO ESC614)
  969. Format:
  970. <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
  971. pt. [PARIDE]
  972. See Documentation/paride.txt.
  973. quiet= [KNL] Disable log messages
  974. r128= [HW,DRM]
  975. raid= [HW,RAID]
  976. See Documentation/md.txt.
  977. ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
  978. See Documentation/ramdisk.txt.
  979. ramdisk_blocksize= [RAM]
  980. See Documentation/ramdisk.txt.
  981. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
  982. New name for the ramdisk parameter.
  983. See Documentation/ramdisk.txt.
  984. rcu.blimit= [KNL,BOOT] Set maximum number of finished
  985. RCU callbacks to process in one batch.
  986. rcu.qhimark= [KNL,BOOT] Set threshold of queued
  987. RCU callbacks over which batch limiting is disabled.
  988. rcu.qlowmark= [KNL,BOOT] Set threshold of queued
  989. RCU callbacks below which batch limiting is re-enabled.
  990. rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
  991. RCU callbacks to queued before forcing reschedule
  992. on all cpus.
  993. rdinit= [KNL]
  994. Format: <full_path>
  995. Run specified binary instead of /init from the ramdisk,
  996. used for early userspace startup. See initrd.
  997. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
  998. Format: <reboot_mode>[,<reboot_mode2>[,...]]
  999. See arch/*/kernel/reboot.c.
  1000. reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
  1001. resume= [SWSUSP]
  1002. Specify the partition device for software suspend
  1003. rhash_entries= [KNL,NET]
  1004. Set number of hash buckets for route cache
  1005. riscom8= [HW,SERIAL]
  1006. Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
  1007. ro [KNL] Mount root device read-only on boot
  1008. root= [KNL] Root filesystem
  1009. rootdelay= [KNL] Delay (in seconds) to pause before attempting to
  1010. mount the root filesystem
  1011. rootflags= [KNL] Set root filesystem mount option string
  1012. rootfstype= [KNL] Set root filesystem type
  1013. rw [KNL] Mount root device read-write on boot
  1014. S [KNL] Run init in single mode
  1015. sa1100ir [NET]
  1016. See drivers/net/irda/sa1100_ir.c.
  1017. sb= [HW,OSS]
  1018. Format: <io>,<irq>,<dma>,<dma2>
  1019. sbni= [NET] Granch SBNI12 leased line adapter
  1020. sbpcd= [HW,CD] Soundblaster CD adapter
  1021. Format: <io>,<type>
  1022. See a comment before function sbpcd_setup() in
  1023. drivers/cdrom/sbpcd.c.
  1024. sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
  1025. Format: <io>[,<timeout>[,<isapnp>]]
  1026. scsi_debug_*= [SCSI]
  1027. See drivers/scsi/scsi_debug.c.
  1028. scsi_default_dev_flags=
  1029. [SCSI] SCSI default device flags
  1030. Format: <integer>
  1031. scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
  1032. Format: <vendor>:<model>:<flags>
  1033. (flags are integer value)
  1034. scsi_logging= [SCSI]
  1035. selinux [SELINUX] Disable or enable SELinux at boot time.
  1036. Format: { "0" | "1" }
  1037. See security/selinux/Kconfig help text.
  1038. 0 -- disable.
  1039. 1 -- enable.
  1040. Default value is set via kernel config option.
  1041. If enabled at boot time, /selinux/disable can be used
  1042. later to disable prior to initial policy load.
  1043. serialnumber [BUGS=IA-32]
  1044. sg_def_reserved_size= [SCSI]
  1045. sgalaxy= [HW,OSS]
  1046. Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
  1047. shapers= [NET]
  1048. Maximal number of shapers.
  1049. sim710= [SCSI,HW]
  1050. See header of drivers/scsi/sim710.c.
  1051. simeth= [IA-64]
  1052. simscsi=
  1053. sjcd= [HW,CD]
  1054. Format: <io>,<irq>,<dma>
  1055. See header of drivers/cdrom/sjcd.c.
  1056. slram= [HW,MTD]
  1057. smart2= [HW]
  1058. Format: <io1>[,<io2>[,...,<io8>]]
  1059. snd-ad1816a= [HW,ALSA]
  1060. snd-ad1848= [HW,ALSA]
  1061. snd-ali5451= [HW,ALSA]
  1062. snd-als100= [HW,ALSA]
  1063. snd-als4000= [HW,ALSA]
  1064. snd-azt2320= [HW,ALSA]
  1065. snd-cmi8330= [HW,ALSA]
  1066. snd-cmipci= [HW,ALSA]
  1067. snd-cs4231= [HW,ALSA]
  1068. snd-cs4232= [HW,ALSA]
  1069. snd-cs4236= [HW,ALSA]
  1070. snd-cs4281= [HW,ALSA]
  1071. snd-cs46xx= [HW,ALSA]
  1072. snd-dt019x= [HW,ALSA]
  1073. snd-dummy= [HW,ALSA]
  1074. snd-emu10k1= [HW,ALSA]
  1075. snd-ens1370= [HW,ALSA]
  1076. snd-ens1371= [HW,ALSA]
  1077. snd-es968= [HW,ALSA]
  1078. snd-es1688= [HW,ALSA]
  1079. snd-es18xx= [HW,ALSA]
  1080. snd-es1938= [HW,ALSA]
  1081. snd-es1968= [HW,ALSA]
  1082. snd-fm801= [HW,ALSA]
  1083. snd-gusclassic= [HW,ALSA]
  1084. snd-gusextreme= [HW,ALSA]
  1085. snd-gusmax= [HW,ALSA]
  1086. snd-hdsp= [HW,ALSA]
  1087. snd-ice1712= [HW,ALSA]
  1088. snd-intel8x0= [HW,ALSA]
  1089. snd-interwave= [HW,ALSA]
  1090. snd-interwave-stb=
  1091. [HW,ALSA]
  1092. snd-korg1212= [HW,ALSA]
  1093. snd-maestro3= [HW,ALSA]
  1094. snd-mpu401= [HW,ALSA]
  1095. snd-mtpav= [HW,ALSA]
  1096. snd-nm256= [HW,ALSA]
  1097. snd-opl3sa2= [HW,ALSA]
  1098. snd-opti92x-ad1848=
  1099. [HW,ALSA]
  1100. snd-opti92x-cs4231=
  1101. [HW,ALSA]
  1102. snd-opti93x= [HW,ALSA]
  1103. snd-pmac= [HW,ALSA]
  1104. snd-rme32= [HW,ALSA]
  1105. snd-rme96= [HW,ALSA]
  1106. snd-rme9652= [HW,ALSA]
  1107. snd-sb8= [HW,ALSA]
  1108. snd-sb16= [HW,ALSA]
  1109. snd-sbawe= [HW,ALSA]
  1110. snd-serial= [HW,ALSA]
  1111. snd-sgalaxy= [HW,ALSA]
  1112. snd-sonicvibes= [HW,ALSA]
  1113. snd-sun-amd7930=
  1114. [HW,ALSA]
  1115. snd-sun-cs4231= [HW,ALSA]
  1116. snd-trident= [HW,ALSA]
  1117. snd-usb-audio= [HW,ALSA,USB]
  1118. snd-via82xx= [HW,ALSA]
  1119. snd-virmidi= [HW,ALSA]
  1120. snd-wavefront= [HW,ALSA]
  1121. snd-ymfpci= [HW,ALSA]
  1122. sonicvibes= [HW,OSS]
  1123. Format: <reverb>
  1124. sonycd535= [HW,CD]
  1125. Format: <io>[,<irq>]
  1126. sonypi.*= [HW] Sony Programmable I/O Control Device driver
  1127. See Documentation/sonypi.txt
  1128. specialix= [HW,SERIAL] Specialix multi-serial port adapter
  1129. See Documentation/specialix.txt.
  1130. spia_io_base= [HW,MTD]
  1131. spia_fio_base=
  1132. spia_pedr=
  1133. spia_peddr=
  1134. sscape= [HW,OSS]
  1135. Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
  1136. st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
  1137. See Documentation/scsi/st.txt.
  1138. st0x= [HW,SCSI]
  1139. See header of drivers/scsi/seagate.c.
  1140. sti= [PARISC,HW]
  1141. Format: <num>
  1142. Set the STI (builtin display/keyboard on the HP-PARISC
  1143. machines) console (graphic card) which should be used
  1144. as the initial boot-console.
  1145. See also comment in drivers/video/console/sticore.c.
  1146. sti_font= [HW]
  1147. See comment in drivers/video/console/sticore.c.
  1148. stifb= [HW]
  1149. Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
  1150. swiotlb= [IA-64] Number of I/O TLB slabs
  1151. switches= [HW,M68k]
  1152. sym53c416= [HW,SCSI]
  1153. See header of drivers/scsi/sym53c416.c.
  1154. t128= [HW,SCSI]
  1155. See header of drivers/scsi/t128.c.
  1156. tdfx= [HW,DRM]
  1157. thash_entries= [KNL,NET]
  1158. Set number of hash buckets for TCP connection
  1159. time Show timing data prefixed to each printk message line
  1160. tipar.timeout= [HW,PPT]
  1161. Set communications timeout in tenths of a second
  1162. (default 15).
  1163. tipar.delay= [HW,PPT]
  1164. Set inter-bit delay in microseconds (default 10).
  1165. tmc8xx= [HW,SCSI]
  1166. See header of drivers/scsi/seagate.c.
  1167. tmscsim= [HW,SCSI]
  1168. See comment before function dc390_setup() in
  1169. drivers/scsi/tmscsim.c.
  1170. tp720= [HW,PS2]
  1171. trix= [HW,OSS] MediaTrix AudioTrix Pro
  1172. Format:
  1173. <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
  1174. tsdev.xres= [TS] Horizontal screen resolution.
  1175. tsdev.yres= [TS] Vertical screen resolution.
  1176. turbografx.map[2|3]= [HW,JOY]
  1177. TurboGraFX parallel port interface
  1178. Format:
  1179. <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
  1180. See also Documentation/input/joystick-parport.txt
  1181. u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
  1182. See header of drivers/scsi/u14-34f.c.
  1183. uart401= [HW,OSS]
  1184. Format: <io>,<irq>
  1185. uart6850= [HW,OSS]
  1186. Format: <io>,<irq>
  1187. usbhid.mousepoll=
  1188. [USBHID] The interval which mice are to be polled at.
  1189. video= [FB] Frame buffer configuration
  1190. See Documentation/fb/modedb.txt.
  1191. vga= [BOOT,IA-32] Select a particular video mode
  1192. See Documentation/i386/boot.txt and
  1193. Documentation/svga.txt.
  1194. Use vga=ask for menu.
  1195. This is actually a boot loader parameter; the value is
  1196. passed to the kernel using a special protocol.
  1197. vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
  1198. size of <nn>. This can be used to increase the
  1199. minimum size (128MB on x86). It can also be used to
  1200. decrease the size and leave more room for directly
  1201. mapped kernel RAM.
  1202. vmhalt= [KNL,S390]
  1203. vmpoff= [KNL,S390]
  1204. waveartist= [HW,OSS]
  1205. Format: <io>,<irq>,<dma>,<dma2>
  1206. wd33c93= [HW,SCSI]
  1207. See header of drivers/scsi/wd33c93.c.
  1208. wd7000= [HW,SCSI]
  1209. See header of drivers/scsi/wd7000.c.
  1210. wdt= [WDT] Watchdog
  1211. See Documentation/watchdog/watchdog.txt.
  1212. xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
  1213. xd_geo= See header of drivers/block/xd.c.
  1214. xirc2ps_cs= [NET,PCMCIA]
  1215. Format:
  1216. <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
  1217. norandmaps Don't use address space randomization
  1218. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
  1219. ______________________________________________________________________
  1220. Changelog:
  1221. 2000-06-?? Mr. Unknown
  1222. The last known update (for 2.4.0) - the changelog was not kept before.
  1223. 2002-11-24 Petr Baudis <pasky@ucw.cz>
  1224. Randy Dunlap <randy.dunlap@verizon.net>
  1225. Update for 2.5.49, description for most of the options introduced,
  1226. references to other documentation (C files, READMEs, ..), added S390,
  1227. PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
  1228. reformatting.
  1229. 2005-10-19 Randy Dunlap <rdunlap@xenotime.net>
  1230. Lots of typos, whitespace, some reformatting.
  1231. TODO:
  1232. Add documentation for ALSA options.
  1233. Add more DRM drivers.