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