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1February 2003 Kernel Parameters v2.5.59
2 ~~~~~~~~~~~~~~~~~
3
4The following is a consolidated list of the kernel parameters as implemented
5(mostly) by the __setup() macro and sorted into English Dictionary order
6(defined as ignoring all punctuation and sorting digits before letters in a
7case insensitive manner), and with descriptions where known.
8
9Module parameters for loadable modules are specified only as the
10parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14Module parameters for modules that are built into the kernel image
15are specified on the kernel command line with the module name plus
16'.' plus parameter name, with '=' and value if appropriate, such as:
17
18 usbcore.blinkenlights=1
19
a9913044 20The text in square brackets at the beginning of the description states the
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21restrictions on the kernel for the said kernel parameter to be valid. The
22restrictions referred to are that the relevant option is valid if:
23
24 ACPI ACPI support is enabled.
25 ALSA ALSA sound support is enabled.
26 APIC APIC support is enabled.
27 APM Advanced Power Management support is enabled.
28 AX25 Appropriate AX.25 support is enabled.
29 CD Appropriate CD support is enabled.
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30 DEVFS devfs support is enabled.
31 DRM Direct Rendering Management support is enabled.
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32 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
33 EFI EFI Partitioning (GPT) is enabled
34 EIDE EIDE/ATAPI support is enabled.
35 FB The frame buffer device is enabled.
36 HW Appropriate hardware is enabled.
37 IA-32 IA-32 aka i386 architecture is enabled.
38 IA-64 IA-64 architecture is enabled.
39 IOSCHED More than one I/O scheduler is enabled.
41e2e8be 40 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
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41 ISAPNP ISA PnP code is enabled.
42 ISDN Appropriate ISDN support is enabled.
43 JOY Appropriate joystick support is enabled.
44 LP Printer support is enabled.
45 LOOP Loopback device support is enabled.
46 M68k M68k architecture is enabled.
47 These options have more detailed description inside of
48 Documentation/m68k/kernel-options.txt.
49 MCA MCA bus support is enabled.
50 MDA MDA console support is enabled.
51 MOUSE Appropriate mouse support is enabled.
309e57df 52 MSI Message Signaled Interrupts (PCI).
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53 MTD MTD support is enabled.
54 NET Appropriate network support is enabled.
55 NUMA NUMA support is enabled.
56 NFS Appropriate NFS support is enabled.
57 OSS OSS sound support is enabled.
58 PARIDE The ParIDE subsystem is enabled.
59 PARISC The PA-RISC architecture is enabled.
60 PCI PCI bus support is enabled.
61 PCMCIA The PCMCIA subsystem is enabled.
62 PNP Plug & Play support is enabled.
63 PPC PowerPC architecture is enabled.
64 PPT Parallel port support is enabled.
65 PS2 Appropriate PS/2 support is enabled.
66 RAM RAM disk support is enabled.
67 S390 S390 architecture is enabled.
68 SCSI Appropriate SCSI support is enabled.
69 A lot of drivers has their options described inside of
70 Documentation/scsi/.
71 SELINUX SELinux support is enabled.
72 SERIAL Serial support is enabled.
73 SMP The kernel is an SMP kernel.
74 SPARC Sparc architecture is enabled.
a9913044 75 SWSUSP Software suspend is enabled.
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76 TS Appropriate touchscreen support is enabled.
77 USB USB support is enabled.
78 USBHID USB Human Interface Device support is enabled.
79 V4L Video For Linux support is enabled.
80 VGA The VGA console has been enabled.
81 VT Virtual terminal support is enabled.
82 WDT Watchdog support is enabled.
83 XT IBM PC/XT MFM hard disk support is enabled.
84 X86-64 X86-64 architecture is enabled.
85 More X86-64 boot options can be found in
86 Documentation/x86_64/boot-options.txt .
87
88In addition, the following text indicates that the option:
89
90 BUGS= Relates to possible processor bugs on the said processor.
91 KNL Is a kernel start-up parameter.
92 BOOT Is a boot loader parameter.
93
94Parameters denoted with BOOT are actually interpreted by the boot
95loader, and have no meaning to the kernel directly.
96Do not modify the syntax of boot loader parameters without extreme
97need or coordination with <Documentation/i386/boot.txt>.
98
99Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
100a trailing = on the name of any parameter states that that parameter will
101be entered as an environment variable, whereas its absence indicates that
102it will appear as a kernel argument readable via /proc/cmdline by programs
103running once the system is up.
104
105 53c7xx= [HW,SCSI] Amiga SCSI controllers
106 See header of drivers/scsi/53c7xx.c.
107 See also Documentation/scsi/ncr53c7xx.txt.
108
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109 acpi= [HW,ACPI] Advanced Configuration and Power Interface
110 Format: { force | off | ht | strict | noirq }
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111 force -- enable ACPI if default was off
112 off -- disable ACPI if default was on
113 noirq -- do not use ACPI for IRQ routing
114 ht -- run only enough ACPI to enable Hyper Threading
a9913044 115 strict -- Be less tolerant of platforms that are not
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116 strictly ACPI specification compliant.
117
118 See also Documentation/pm.txt, pci=noacpi
119
120 acpi_sleep= [HW,ACPI] Sleep options
121 Format: { s3_bios, s3_mode }
122 See Documentation/power/video.txt
a9913044 123
1da177e4 124 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 125 Format: { level | edge | high | low }
1da177e4 126
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127 acpi_irq_balance [HW,ACPI]
128 ACPI will balance active IRQs
129 default in APIC mode
1da177e4 130
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131 acpi_irq_nobalance [HW,ACPI]
132 ACPI will not move active IRQs (default)
133 default in PIC mode
1da177e4 134
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135 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
136 use by PCI
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137 Format: <irq>,<irq>...
138
a9913044 139 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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140 Format: <irq>,<irq>...
141
142 acpi_osi= [HW,ACPI] empty param disables _OSI
143
144 acpi_serialize [HW,ACPI] force serialization of AML methods
145
146 acpi_skip_timer_override [HW,ACPI]
147 Recognize and ignore IRQ0/pin2 Interrupt Override.
148 For broken nForce2 BIOS resulting in XT-PIC timer.
149
150 acpi_dbg_layer= [HW,ACPI]
151 Format: <int>
a9913044 152 Each bit of the <int> indicates an ACPI debug layer,
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153 1: enable, 0: disable. It is useful for boot time
154 debugging. After system has booted up, it can be set
155 via /proc/acpi/debug_layer.
156
157 acpi_dbg_level= [HW,ACPI]
158 Format: <int>
a9913044 159 Each bit of the <int> indicates an ACPI debug level,
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160 1: enable, 0: disable. It is useful for boot time
161 debugging. After system has booted up, it can be set
162 via /proc/acpi/debug_level.
163
164 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
165
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166 acpi_generic_hotkey [HW,ACPI]
167 Allow consolidated generic hotkey driver to
a9913044 168 override platform specific driver.
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169 See also Documentation/acpi-hotkey.txt.
170
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171 enable_timer_pin_1 [i386,x86-64]
172 Enable PIN 1 of APIC timer
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173 Can be useful to work around chipset bugs
174 (in particular on some ATI chipsets).
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175 The kernel tries to set a reasonable default.
176
177 disable_timer_pin_1 [i386,x86-64]
178 Disable PIN 1 of APIC timer
179 Can be useful to work around chipset bugs.
180
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181 ad1816= [HW,OSS]
182 Format: <io>,<irq>,<dma>,<dma2>
183 See also Documentation/sound/oss/AD1816.
184
185 ad1848= [HW,OSS]
186 Format: <io>,<irq>,<dma>,<dma2>,<type>
187
188 adlib= [HW,OSS]
189 Format: <io>
a9913044 190
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191 advansys= [HW,SCSI]
192 See header of drivers/scsi/advansys.c.
193
194 advwdt= [HW,WDT] Advantech WDT
195 Format: <iostart>,<iostop>
196
197 aedsp16= [HW,OSS] Audio Excel DSP 16
198 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
199 See also header of sound/oss/aedsp16.c.
a9913044 200
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201 aha152x= [HW,SCSI]
202 See Documentation/scsi/aha152x.txt.
203
204 aha1542= [HW,SCSI]
205 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
206
207 aic7xxx= [HW,SCSI]
208 See Documentation/scsi/aic7xxx.txt.
209
210 aic79xx= [HW,SCSI]
211 See Documentation/scsi/aic79xx.txt.
212
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213 amijoy.map= [HW,JOY] Amiga joystick support
214 Map of devices attached to JOY0DAT and JOY1DAT
215 Format: <a>,<b>
216 See also Documentation/kernel/input/joystick.txt
217
218 analog.map= [HW,JOY] Analog joystick and gamepad support
219 Specifies type or capabilities of an analog joystick
220 connected to one of 16 gameports
221 Format: <type1>,<type2>,..<type16>
222
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223 apc= [HW,SPARC]
224 Power management functions (SPARCstation-4/5 + deriv.)
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225 Format: noidle
226 Disable APC CPU standby support. SPARCstation-Fox does
227 not play well with APC CPU idle - disable it if you have
228 APC and your system crashes randomly.
229
a9913044 230 apic= [APIC,i386] Change the output verbosity whilst booting
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231 Format: { quiet (default) | verbose | debug }
232 Change the amount of debugging information output
233 when initialising the APIC and IO-APIC components.
a9913044 234
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235 apm= [APM] Advanced Power Management
236 See header of arch/i386/kernel/apm.c.
237
238 applicom= [HW]
239 Format: <mem>,<irq>
a9913044 240
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241 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
242 Format: <io>,<irq>,<nodeID>
243
244 ataflop= [HW,M68k]
245
246 atarimouse= [HW,MOUSE] Atari Mouse
247
248 atascsi= [HW,SCSI] Atari SCSI
249
250 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
251 EzKey and similar keyboards
252
253 atkbd.reset= [HW] Reset keyboard during initialization
254
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255 atkbd.set= [HW] Select keyboard code set
256 Format: <int> (2 = AT (default), 3 = PS/2)
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257
258 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
259 keyboards
260
261 atkbd.softraw= [HW] Choose between synthetic and real raw mode
262 Format: <bool> (0 = real, 1 = synthetic (default))
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263
264 atkbd.softrepeat= [HW]
265 Use software keyboard repeat
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266
267 autotest [IA64]
268
269 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
270 Format: <io>,<memsize>,<isapnp>
a9913044 271
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272 aztcd= [HW,CD] Aztech CD268 CDROM driver
273 Format: <io>,0x79 (?)
274
275 baycom_epp= [HW,AX25]
276 Format: <io>,<mode>
a9913044 277
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278 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
279 Format: <io>,<mode>
280 See header of drivers/net/hamradio/baycom_par.c.
281
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282 baycom_ser_fdx= [HW,AX25]
283 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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284 Format: <io>,<irq>,<mode>[,<baud>]
285 See header of drivers/net/hamradio/baycom_ser_fdx.c.
286
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287 baycom_ser_hdx= [HW,AX25]
288 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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289 Format: <io>,<irq>,<mode>
290 See header of drivers/net/hamradio/baycom_ser_hdx.c.
291
292 blkmtd_device= [HW,MTD]
293 blkmtd_erasesz=
294 blkmtd_ro=
295 blkmtd_bs=
296 blkmtd_count=
297
298 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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299 bttv.radio= Most important insmod options are available as
300 kernel args too.
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301 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
302 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
303
304 BusLogic= [HW,SCSI]
305 See drivers/scsi/BusLogic.c, comment before function
306 BusLogic_ParseDriverOptions().
307
308 c101= [NET] Moxa C101 synchronous serial card
309
310 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
311 Sometimes CPU hardware bugs make them report the cache
312 size incorrectly. The kernel will attempt work arounds
313 to fix known problems, but for some CPUs it is not
314 possible to determine what the correct size should be.
315 This option provides an override for these situations.
316
317 cdu31a= [HW,CD]
318 Format: <io>,<irq>[,PAS]
319 See header of drivers/cdrom/cdu31a.c.
320
321 chandev= [HW,NET] Generic channel device initialisation
322
323 checkreqprot [SELINUX] Set initial checkreqprot flag value.
324 Format: { "0" | "1" }
325 See security/selinux/Kconfig help text.
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326 0 -- check protection applied by kernel (includes
327 any implied execute protection).
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328 1 -- check protection requested by application.
329 Default value is set via a kernel config option.
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330 Value can be changed at runtime via
331 /selinux/checkreqprot.
332
333 clock= [BUGS=IA-32,HW] gettimeofday timesource override.
1da177e4 334 Forces specified timesource (if avaliable) to be used
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335 when calculating gettimeofday(). If specicified
336 timesource is not avalible, it defaults to PIT.
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337 Format: { pit | tsc | cyclone | pmtmr }
338
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339 disable_8254_timer
340 enable_8254_timer
341 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
342 over the 8254 in addition to over the IO-APIC. The
343 kernel tries to set a sensible default.
344
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345 hpet= [IA-32,HPET] option to disable HPET and use PIT.
346 Format: disable
347
348 cm206= [HW,CD]
349 Format: { auto | [<io>,][<irq>] }
350
351 com20020= [HW,NET] ARCnet - COM20020 chipset
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352 Format:
353 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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354
355 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
356 Format: <io>[,<irq>]
357
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358 com90xx= [HW,NET]
359 ARCnet - COM90xx chipset (memory-mapped buffers)
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360 Format: <io>[,<irq>[,<memstart>]]
361
362 condev= [HW,S390] console device
363 conmode=
a9913044 364
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365 console= [KNL] Output console device and options.
366
367 tty<n> Use the virtual console device <n>.
368
369 ttyS<n>[,options]
370 Use the specified serial port. The options are of
371 the form "bbbbpn", where "bbbb" is the baud rate,
372 "p" is parity ("n", "o", or "e"), and "n" is bits.
373 Default is "9600n8".
374
375 See also Documentation/serial-console.txt.
376
377 uart,io,<addr>[,options]
378 uart,mmio,<addr>[,options]
379 Start an early, polled-mode console on the 8250/16550
380 UART at the specified I/O port or MMIO address,
381 switching to the matching ttyS device later. The
382 options are the same as for ttyS, above.
383
384 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
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385 Format:
386 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
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387
388 cpia_pp= [HW,PPT]
389 Format: { parport<nr> | auto | none }
390
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391 crashkernel=nn[KMG]@ss[KMG]
392 [KNL] Reserve a chunk of physical memory to
393 hold a kernel to switch to with kexec on panic.
394
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395 cs4232= [HW,OSS]
396 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
397
398 cs89x0_dma= [HW,NET]
399 Format: <dma>
400
401 cs89x0_media= [HW,NET]
402 Format: { rj45 | aui | bnc }
a9913044 403
1da177e4 404 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
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405
406 dasd= [HW,NET]
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407 See header of drivers/s390/block/dasd_devmap.c.
408
409 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
410 (one device per port)
411 Format: <port#>,<type>
412 See also Documentation/input/joystick-parport.txt
413
414 debug [KNL] Enable kernel debugging (events log level).
415
416 decnet= [HW,NET]
417 Format: <area>[,<node>]
418 See also Documentation/networking/decnet.txt.
419
420 devfs= [DEVFS]
421 See Documentation/filesystems/devfs/boot-options.
422
423 dhash_entries= [KNL]
424 Set number of hash buckets for dentry cache.
a9913044 425
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426 digi= [HW,SERIAL]
427 IO parameters + enable/disable command.
428
429 digiepca= [HW,SERIAL]
430 See drivers/char/README.epca and
431 Documentation/digiepca.txt.
432
433 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
434 support available.
435 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
436
437 dmasound= [HW,OSS] Sound subsystem buffers
438
439 dscc4.setup= [NET]
440
441 dtc3181e= [HW,SCSI]
442
a9913044 443 earlyprintk= [IA-32,X86-64]
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444 earlyprintk=vga
445 earlyprintk=serial[,ttySn[,baudrate]]
446
a9913044 447 Append ",keep" to not disable it when the real console
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448 takes over.
449
450 Only vga or serial at a time, not both.
451
452 Currently only ttyS0 and ttyS1 are supported.
453
454 Interaction with the standard serial driver is not
455 very good.
456
457 The VGA output is eventually overwritten by the real
458 console.
459
460 eata= [HW,SCSI]
461
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462 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
463 Format: <int>
464 0: polling mode
465 non-0: interrupt mode (default)
466
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467 eda= [HW,PS2]
468
469 edb= [HW,PS2]
470
471 edd= [EDD]
472 Format: {"of[f]" | "sk[ipmbr]"}
473 See comment in arch/i386/boot/edd.S
474
a9913044 475 eicon= [HW,ISDN]
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476 Format: <id>,<membase>,<irq>
477
478 eisa_irq_edge= [PARISC,HW]
479 See header of drivers/parisc/eisa.c.
480
481 elanfreq= [IA-32]
482 See comment before function elanfreq_setup() in
483 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
484
485 elevator= [IOSCHED]
16ab3adf 486 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
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487 See Documentation/block/as-iosched.txt and
488 Documentation/block/deadline-iosched.txt for details.
489
aac04b32 490 elfcorehdr= [IA-32, X86_64]
a9913044 491 Specifies physical address of start of kernel core
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492 image elf header. Generally kexec loader will
493 pass this option to capture kernel.
494 See Documentation/kdump/kdump.txt for details.
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495
496 enforcing [SELINUX] Set initial enforcing status.
497 Format: {"0" | "1"}
498 See security/selinux/Kconfig help text.
499 0 -- permissive (log only, no denials).
500 1 -- enforcing (deny and log).
501 Default value is 0.
502 Value can be changed at runtime via /selinux/enforce.
503
504 es1370= [HW,OSS]
505 Format: <lineout>[,<micbias>]
506 See also header of sound/oss/es1370.c.
507
508 es1371= [HW,OSS]
509 Format: <spdif>,[<nomix>,[<amplifier>]]
510 See also header of sound/oss/es1371.c.
a9913044 511
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512 ether= [HW,NET] Ethernet cards parameters
513 This option is obsoleted by the "netdev=" option, which
514 has equivalent usage. See its documentation for details.
515
516 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
517 Format: <io>[,<irq>]
518
519 fd_mcs= [HW,SCSI]
520 See header of drivers/scsi/fd_mcs.c.
521
522 fdomain= [HW,SCSI]
523 See header of drivers/scsi/fdomain.c.
524
525 floppy= [HW]
526 See Documentation/floppy.txt.
527
528 ftape= [HW] Floppy Tape subsystem debugging options.
529 See Documentation/ftape.txt.
530
531 gamecon.map[2|3]=
532 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
533 support via parallel port (up to 5 devices per port)
534 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
535 See also Documentation/input/joystick-parport.txt
536
537 gamma= [HW,DRM]
538
539 gdth= [HW,SCSI]
540 See header of drivers/scsi/gdth.c.
541
542 gpt [EFI] Forces disk with valid GPT signature but
543 invalid Protective MBR to be treated as GPT.
544
545 gscd= [HW,CD]
546 Format: <io>
547
548 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
549
550 gus= [HW,OSS]
551 Format: <io>,<irq>,<dma>,<dma16>
a9913044 552
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553 gvp11= [HW,SCSI]
554
555 hashdist= [KNL,NUMA] Large hashes allocated during boot
556 are distributed across NUMA nodes. Defaults on
557 for IA-64, off otherwise.
a9913044 558 Format: 0 | 1 (for off | on)
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559
560 hcl= [IA-64] SGI's Hardware Graph compatibility layer
561
562 hd= [EIDE] (E)IDE hard drive subsystem geometry
563 Format: <cyl>,<head>,<sect>
564
565 hd?= [HW] (E)IDE subsystem
566 hd?lun= See Documentation/ide.txt.
567
568 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
569 size of <nn>. This works even on boxes that have no
570 highmem otherwise. This also works to reduce highmem
571 size on bigger boxes.
572
573 hisax= [HW,ISDN]
574 See Documentation/isdn/README.HiSax.
575
576 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
577
578 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
579
580 i8042.direct [HW] Put keyboard port into non-translated mode
581 i8042.dumbkbd [HW] Pretend that controlled can only read data from
582 keyboard and can not control its state
583 (Don't attempt to blink the leds)
584 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 585 i8042.nokbd [HW] Don't check/create keyboard port
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586 i8042.nomux [HW] Don't check presence of an active multiplexing
587 controller
588 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
589 controllers
590 i8042.panicblink=
591 [HW] Frequency with which keyboard LEDs should blink
592 when kernel panics (default is 0.5 sec)
593 i8042.reset [HW] Reset the controller during init and cleanup
594 i8042.unlock [HW] Unlock (ignore) the keylock
595
596 i810= [HW,DRM]
597
e70c9d5e
DT
598 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
599 indicates that the driver is running on unsupported
600 hardware.
1da177e4
LT
601 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
602 does not match list of supported models.
603 i8k.power_status
604 [HW] Report power status in /proc/i8k
605 (disabled by default)
606 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
607 capability is set.
608
609 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
610 See Documentation/mca.txt.
611
612 icn= [HW,ISDN]
613 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
614
615 ide= [HW] (E)IDE subsystem
616 Format: ide=nodma or ide=doubler or ide=reverse
617 See Documentation/ide.txt.
618
619 ide?= [HW] (E)IDE subsystem
620 Format: ide?=noprobe or chipset specific parameters.
621 See Documentation/ide.txt.
a9913044 622
1da177e4
LT
623 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
624 See Documentation/ide.txt.
625
626 idle= [HW]
627 Format: idle=poll or idle=halt
a9913044 628
1da177e4
LT
629 ihash_entries= [KNL]
630 Set number of hash buckets for inode cache.
631
632 in2000= [HW,SCSI]
633 See header of drivers/scsi/in2000.c.
634
635 init= [KNL]
636 Format: <full_path>
637 Run specified binary instead of /sbin/init as init
638 process.
639
640 initcall_debug [KNL] Trace initcalls as they are executed. Useful
641 for working out where the kernel is dying during
642 startup.
643
644 initrd= [BOOT] Specify the location of the initial ramdisk
645
646 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
647 Format: <irq>
648
2bd0fa3b
JB
649 combined_mode= [HW] control which driver uses IDE ports in combined
650 mode: legacy IDE driver, libata, or both
651 (in the libata case, libata.atapi_enabled=1 may be
652 useful as well). Note that using the ide or libata
653 options may affect your device naming (e.g. by
654 changing hdc to sdb).
655 Format: combined (default), ide, or libata
656
1da177e4
LT
657 inttest= [IA64]
658
659 io7= [HW] IO7 for Marvel based alpha systems
660 See comment before marvel_specify_io7 in
661 arch/alpha/kernel/core_marvel.c.
662
663 ip= [IP_PNP]
664 See Documentation/nfsroot.txt.
665
666 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
667 See comment before ip2_setup() in drivers/char/ip2.c.
668
669 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
670 See header of drivers/scsi/ips.c.
671
200803df
AC
672 irqfixup [HW]
673 When an interrupt is not handled search all handlers
674 for it. Intended to get systems with badly broken
675 firmware running.
676
677 irqpoll [HW]
678 When an interrupt is not handled search all handlers
679 for it. Also check all handlers each timer
680 interrupt. Intended to get systems with badly broken
681 firmware running.
682
1da177e4 683 isapnp= [ISAPNP]
a9913044 684 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
685
686 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
687 Format: <cpu number>,...,<cpu number>
688 This option can be used to specify one or more CPUs
689 to isolate from the general SMP balancing and scheduling
690 algorithms. The only way to move a process onto or off
691 an "isolated" CPU is via the CPU affinity syscalls.
692 <cpu number> begins at 0 and the maximum value is
693 "number of CPUs in system - 1".
694
695 This option is the preferred way to isolate CPUs. The
a9913044
RD
696 alternative -- manually setting the CPU mask of all
697 tasks in the system -- can cause problems and
698 suboptimal load balancer performance.
1da177e4
LT
699
700 isp16= [HW,CD]
701 Format: <io>,<irq>,<dma>,<setup>
702
a9913044 703 iucv= [HW,NET]
1da177e4
LT
704
705 js= [HW,JOY] Analog joystick
706 See Documentation/input/joystick.txt.
707
708 keepinitrd [HW,ARM]
709
a9913044 710 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
711 in oops dumps.
712
713 l2cr= [PPC]
714
a9913044
RD
715 lapic [IA-32,APIC] Enable the local APIC even if BIOS
716 disabled it.
1da177e4
LT
717
718 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
719 Format: addr:<io>,irq:<irq>
720
a9913044
RD
721 llsc*= [IA64] See function print_params() in
722 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
723
724 load_ramdisk= [RAM] List of ramdisks to load from floppy
725 See Documentation/ramdisk.txt.
726
a6b25b67
RD
727 lockd.nlm_grace_period=P [NFS] Assign grace period.
728 Format: <integer>
1da177e4 729
a6b25b67
RD
730 lockd.nlm_tcpport=N [NFS] Assign TCP port.
731 Format: <integer>
732
733 lockd.nlm_timeout=T [NFS] Assign timeout value.
734 Format: <integer>
735
736 lockd.nlm_udpport=M [NFS] Assign UDP port.
737 Format: <integer>
1da177e4
LT
738
739 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
740 Format: <irq>
741
742 loglevel= All Kernel Messages with a loglevel smaller than the
743 console loglevel will be printed to the console. It can
744 also be changed with klogd or other programs. The
745 loglevels are defined as follows:
746
747 0 (KERN_EMERG) system is unusable
748 1 (KERN_ALERT) action must be taken immediately
749 2 (KERN_CRIT) critical conditions
750 3 (KERN_ERR) error conditions
751 4 (KERN_WARNING) warning conditions
752 5 (KERN_NOTICE) normal but significant condition
753 6 (KERN_INFO) informational
754 7 (KERN_DEBUG) debug-level messages
755
756 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
757 Format: { n | nk | nM }
758 n must be a power of two. The default size
759 is set in the kernel config file.
1da177e4
LT
760
761 lp=0 [LP] Specify parallel ports to use, e.g,
762 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
763 lp=reset first parallel port). 'lp=0' disables the
764 lp=auto printer driver. 'lp=reset' (which can be
765 specified in addition to the ports) causes
766 attached printers to be reset. Using
767 lp=port1,port2,... specifies the parallel ports
768 to associate lp devices with, starting with
769 lp0. A port specification may be 'none' to skip
770 that lp device, or a parport name such as
771 'parport0'. Specifying 'lp=auto' instead of a
772 port specification list means that device IDs
773 from each port should be examined, to see if
774 an IEEE 1284-compliant printer is attached; if
775 so, the driver will manage that printer.
776 See also header of drivers/char/lp.c.
777
778 lpj=n [KNL]
779 Sets loops_per_jiffy to given constant, thus avoiding
780 time-consuming boot-time autodetection (up to 250 ms per
781 CPU). 0 enables autodetection (default). To determine
782 the correct value for your kernel, boot with normal
783 autodetection and see what value is printed. Note that
784 on SMP systems the preset will be applied to all CPUs,
785 which is likely to cause problems if your CPUs need
786 significantly divergent settings. An incorrect value
787 will cause delays in the kernel to be wrong, leading to
788 unpredictable I/O errors and other breakage. Although
789 unlikely, in the extreme case this might damage your
790 hardware.
791
792 ltpc= [NET]
793 Format: <io>,<irq>,<dma>
794
a9913044
RD
795 mac5380= [HW,SCSI] Format:
796 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 797
a9913044
RD
798 mac53c9x= [HW,SCSI] Format:
799 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 800
a9913044
RD
801 machvec= [IA64] Force the use of a particular machine-vector
802 (machvec) in a generic kernel.
803 Example: machvec=hpzx1_swiotlb
1da177e4 804
a9913044
RD
805 mad16= [HW,OSS] Format:
806 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
807
808 maui= [HW,OSS]
809 Format: <io>,<irq>
a9913044
RD
810
811 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
812 be mounted
813 Format: <1-256>
814
815 maxcpus= [SMP] Maximum number of processors that an SMP kernel
816 should make use of
817
2b2c3750
BP
818 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
819 equal to this physical address is ignored.
820
a9913044 821 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
822 Should be between 1 and 2^32-1.
823
824 max_report_luns=
a9913044 825 [SCSI] Maximum number of LUNs received.
1da177e4
LT
826 Should be between 1 and 16384.
827
828 mca-pentium [BUGS=IA-32]
829
830 mcatest= [IA-64]
831
832 mcd= [HW,CD]
833 Format: <port>,<irq>,<mitsumi_bug_93_wait>
834
835 mcdx= [HW,CD]
836
837 mce [IA-32] Machine Check Exception
838
839 md= [HW] RAID subsystems devices and level
840 See Documentation/md.txt.
a9913044 841
1da177e4
LT
842 mdacon= [MDA]
843 Format: <first>,<last>
844 Specifies range of consoles to be captured by the MDA.
a9913044 845
1da177e4
LT
846 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
847 Amount of memory to be used when the kernel is not able
848 to see the whole system memory or for test.
849 [IA-32] Use together with memmap= to avoid physical
850 address space collisions. Without memmap= PCI devices
851 could be placed at addresses belonging to unused RAM.
852
853 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
854 memory.
855
69cda7b1 856 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
857 E820 memory map, as specified by the user.
858 Such memmap=exactmap lines can be constructed based on
859 BIOS output or other requirements. See the memmap=nn@ss
860 option description.
861
862 memmap=nn[KMG]@ss[KMG]
863 [KNL] Force usage of a specific region of memory
864 Region of memory to be used, from ss to ss+nn.
865
866 memmap=nn[KMG]#ss[KMG]
867 [KNL,ACPI] Mark specific memory as ACPI data.
868 Region of memory to be used, from ss to ss+nn.
869
870 memmap=nn[KMG]$ss[KMG]
871 [KNL,ACPI] Mark specific memory as reserved.
872 Region of memory to be used, from ss to ss+nn.
873
874 meye.*= [HW] Set MotionEye Camera parameters
875 See Documentation/video4linux/meye.txt.
876
877 mga= [HW,DRM]
878
198e2f18 879 migration_cost=
880 [KNL,SMP] debug: override scheduler migration costs
881 Format: <level-1-usecs>,<level-2-usecs>,...
882 This debugging option can be used to override the
883 default scheduler migration cost matrix. The numbers
884 are indexed by 'CPU domain distance'.
885 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
886 box will set up an intra-core migration cost of
887 1 msec, an inter-core migration cost of 2 msecs,
888 and an inter-node migration cost of 3 msecs.
889
890 WARNING: using the wrong values here can break
891 scheduler performance, so it's only for scheduler
892 development purposes, not production environments.
893
894 migration_debug=
895 [KNL,SMP] migration cost auto-detect verbosity
896 Format=<0|1|2>
897 If a system's migration matrix reported at bootup
898 seems erroneous then this option can be used to
899 increase verbosity of the detection process.
900 We default to 0 (no extra messages), 1 will print
901 some more information, and 2 will be really
902 verbose (probably only useful if you also have a
903 serial console attached to the system).
904
905 migration_factor=
906 [KNL,SMP] multiply/divide migration costs by a factor
907 Format=<percent>
908 This debug option can be used to proportionally
909 increase or decrease the auto-detected migration
910 costs for all entries of the migration matrix.
911 E.g. migration_factor=150 will increase migration
912 costs by 50%. (and thus the scheduler will be less
913 eager migrating cache-hot tasks)
914 migration_factor=80 will decrease migration costs
915 by 20%. (thus the scheduler will be more eager to
916 migrate tasks)
917
918 WARNING: using the wrong values here can break
919 scheduler performance, so it's only for scheduler
920 development purposes, not production environments.
921
1da177e4
LT
922 mousedev.tap_time=
923 [MOUSE] Maximum time between finger touching and
924 leaving touchpad surface for touch to be considered
925 a tap and be reported as a left button click (for
926 touchpads working in absolute mode only).
927 Format: <msecs>
928 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
929 reporting absolute coordinates, such as tablets
930 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
931 reporting absolute coordinates, such as tablets
932
933 mpu401= [HW,OSS]
934 Format: <io>,<irq>
935
936 MTD_Partition= [MTD]
937 Format: <name>,<region-number>,<size>,<offset>
938
a9913044
RD
939 MTD_Region= [MTD] Format:
940 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
941
942 mtdparts= [MTD]
943 See drivers/mtd/cmdline.c.
944
945 mtouchusb.raw_coordinates=
a9913044
RD
946 [HW] Make the MicroTouch USB driver use raw coordinates
947 ('y', default) or cooked coordinates ('n')
1da177e4
LT
948
949 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
950
951 NCR_D700= [HW,SCSI]
952 See header of drivers/scsi/NCR_D700.c.
953
954 ncr5380= [HW,SCSI]
955
956 ncr53c400= [HW,SCSI]
957
958 ncr53c400a= [HW,SCSI]
959
960 ncr53c406a= [HW,SCSI]
961
962 ncr53c8xx= [HW,SCSI]
963
964 netdev= [NET] Network devices parameters
965 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
966 Note that mem_start is often overloaded to mean
967 something different and driver-specific.
a9913044
RD
968 This usage is only documented in each driver source
969 file if at all.
970
1da177e4
LT
971 nfsaddrs= [NFS]
972 See Documentation/nfsroot.txt.
973
974 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
975 See Documentation/nfsroot.txt.
976
a72b4422
TM
977 nfs.callback_tcpport=
978 [NFS] set the TCP port on which the NFSv4 callback
979 channel should listen.
980
58df095b
TM
981 nfs.idmap_cache_timeout=
982 [NFS] set the maximum lifetime for idmapper cache
983 entries.
984
1da177e4
LT
985 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
986
987 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
988 emulation library even if a 387 maths coprocessor
989 is present.
990
a9913044
RD
991 noalign [KNL,ARM]
992
1da177e4
LT
993 noapic [SMP,APIC] Tells the kernel to not make use of any
994 IOAPICs that may be present in the system.
995
996 noasync [HW,M68K] Disables async and sync negotiation for
997 all devices.
998
999 nobats [PPC] Do not use BATs for mapping kernel lowmem
1000 on "Classic" PPC cores.
1001
1002 nocache [ARM]
a9913044 1003
1da177e4
LT
1004 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1005
1006 noexec [IA-64]
1007
a9913044 1008 noexec [IA-32,X86-64]
1da177e4
LT
1009 noexec=on: enable non-executable mappings (default)
1010 noexec=off: disable nn-executable mappings
1011
4f886511
CE
1012 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1013 register save and restore. The kernel will only save
1014 legacy floating-point registers on task switch.
1da177e4
LT
1015
1016 nohlt [BUGS=ARM]
a9913044 1017
1da177e4
LT
1018 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1019 instruction doesn't work correctly and not to
1020 use it.
1021
1022 nohalt [IA-64] Tells the kernel not to use the power saving
1023 function PAL_HALT_LIGHT when idle. This increases
1024 power-consumption. On the positive side, it reduces
1025 interrupt wake-up latency, which may improve performance
1026 in certain environments such as networked servers or
1027 real-time systems.
1028
1029 noirqdebug [IA-32] Disables the code which attempts to detect and
1030 disable unhandled interrupt sources.
1031
1032 noisapnp [ISAPNP] Disables ISA PnP code.
1033
1034 noinitrd [RAM] Tells the kernel not to load any configured
1035 initial RAM disk.
1036
1037 nointroute [IA-64]
1038
1039 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1040
1041 noltlbs [PPC] Do not use large page/tlb entries for kernel
1042 lowmem mapping on PPC40x.
1043
1044 nomce [IA-32] Machine Check Exception
1045
312f1f01
H
1046 nomca [IA-64] Disable machine check abort handling
1047
1da177e4
LT
1048 noresidual [PPC] Don't use residual data on PReP machines.
1049
a9913044
RD
1050 noresume [SWSUSP] Disables resume and restores original swap
1051 space.
1052
1da177e4
LT
1053 no-scroll [VGA] Disables scrollback.
1054 This is required for the Braillex ib80-piezo Braille
1055 reader made by F.H. Papenmeier (Germany).
1056
1057 nosbagart [IA-64]
1058
4f886511
CE
1059 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1060
1da177e4
LT
1061 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1062
1063 nosync [HW,M68K] Disables sync negotiation for all devices.
1064
1065 notsc [BUGS=IA-32] Disable Time Stamp Counter
1066
1067 nousb [USB] Disable the USB subsystem
1068
1069 nowb [ARM]
a9913044 1070
a61c2d78
DJ
1071 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1072
1da177e4
LT
1073 opl3= [HW,OSS]
1074 Format: <io>
1075
1076 opl3sa= [HW,OSS]
1077 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1078
a9913044
RD
1079 opl3sa2= [HW,OSS] Format:
1080 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1081
1da177e4
LT
1082 oprofile.timer= [HW]
1083 Use timer interrupt instead of performance counters
1084
1085 optcd= [HW,CD]
1086 Format: <io>
1087
1088 osst= [HW,SCSI] SCSI Tape Driver
1089 Format: <buffer_size>,<write_threshold>
1090 See also Documentation/scsi/st.txt.
1091
1092 panic= [KNL] Kernel behaviour on panic
1093 Format: <timeout>
1094
1095 parkbd.port= [HW] Parallel port number the keyboard adapter is
1096 connected to, default is 0.
1097 Format: <parport#>
1098 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1099 0 for XT, 1 for AT (default is AT).
a9913044
RD
1100 Format: <mode>
1101
1102 parport= [HW,PPT] Specify parallel ports. 0 disables.
1103 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1104 Use 'auto' to force the driver to use any
1105 IRQ/DMA settings detected (the default is to
1106 ignore detected IRQ/DMA settings because of
1107 possible conflicts). You can specify the base
1108 address, IRQ, and DMA settings; IRQ and DMA
1109 should be numbers, or 'auto' (for using detected
1110 settings on that particular port), or 'nofifo'
1111 (to avoid using a FIFO even if it is detected).
1112 Parallel ports are assigned in the order they
1113 are specified on the command line, starting
1114 with parport0.
1115
1116 parport_init_mode= [HW,PPT]
1117 Configure VIA parallel port to operate in
1118 a specific mode. This is necessary on Pegasos
1119 computer where firmware has no options for setting
1120 up parallel port mode and sets it to spp.
1121 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1122 Format: [spp|ps2|epp|ecp|ecpepp]
1123
a9913044
RD
1124 pas2= [HW,OSS] Format:
1125 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1126
1da177e4
LT
1127 pas16= [HW,SCSI]
1128 See header of drivers/scsi/pas16.c.
1129
dd287796
AM
1130 pause_on_oops=
1131 Halt all CPUs after the first oops has been printed for
1132 the specified number of seconds. This is to be used if
1133 your oopses keep scrolling off the screen.
1134
1da177e4
LT
1135 pcbit= [HW,ISDN]
1136
1137 pcd. [PARIDE]
1138 See header of drivers/block/paride/pcd.c.
1139 See also Documentation/paride.txt.
1140
a9913044
RD
1141 pci=option[,option...] [PCI] various PCI subsystem options:
1142 off [IA-32] don't probe for the PCI bus
1143 bios [IA-32] force use of PCI BIOS, don't access
1144 the hardware directly. Use this if your machine
1145 has a non-standard PCI host bridge.
1146 nobios [IA-32] disallow use of PCI BIOS, only direct
1147 hardware access methods are allowed. Use this
1148 if you experience crashes upon bootup and you
1149 suspect they are caused by the BIOS.
1150 conf1 [IA-32] Force use of PCI Configuration
1151 Mechanism 1.
1152 conf2 [IA-32] Force use of PCI Configuration
1153 Mechanism 2.
61be6d66
BH
1154 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1155 Configuration
309e57df
MW
1156 nomsi [MSI] If the PCI_MSI kernel config parameter is
1157 enabled, this kernel boot option can be used to
1158 disable the use of MSI interrupts system-wide.
a9913044
RD
1159 nosort [IA-32] Don't sort PCI devices according to
1160 order given by the PCI BIOS. This sorting is
1161 done to get a device order compatible with
1162 older kernels.
1163 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1164 routing table. These calls are known to be buggy
1165 on several machines and they hang the machine
1166 when used, but on other computers it's the only
1167 way to get the interrupt routing table. Try
1168 this option if the kernel is unable to allocate
1169 IRQs or discover secondary PCI buses on your
1170 motherboard.
1171 rom [IA-32] Assign address space to expansion ROMs.
1172 Use with caution as certain devices share
1173 address decoders between ROMs and other
1174 resources.
1175 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1176 assigned automatically to PCI devices. You can
1177 make the kernel exclude IRQs of your ISA cards
1178 this way.
120bb424 1179 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1180 of the PIRQ table (normally generated
1181 by the BIOS) if it is outside the
1182 F0000h-100000h range.
1183 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1184 useful if the kernel is unable to find your
1185 secondary buses and you want to tell it
1186 explicitly which ones they are.
1187 assign-busses [IA-32] Always assign all PCI bus
1188 numbers ourselves, overriding
1189 whatever the firmware may have done.
1190 usepirqmask [IA-32] Honor the possible IRQ mask stored
1191 in the BIOS $PIR table. This is needed on
1192 some systems with broken BIOSes, notably
1193 some HP Pavilion N5400 and Omnibook XE3
1194 notebooks. This will have no effect if ACPI
1195 IRQ routing is enabled.
1196 noacpi [IA-32] Do not use ACPI for IRQ routing
1197 or for PCI scanning.
1198 routeirq Do IRQ routing for all PCI devices.
1199 This is normally done in pci_enable_device(),
1200 so this option is a temporary workaround
1201 for broken drivers that don't call it.
1202 firmware [ARM] Do not re-enumerate the bus but instead
1203 just use the configuration from the
1204 bootloader. This is currently used on
1205 IXP2000 systems where the bus has to be
1206 configured a certain way for adjunct CPUs.
1da177e4
LT
1207
1208 pcmv= [HW,PCMCIA] BadgePAD 4
1209
1210 pd. [PARIDE]
1211 See Documentation/paride.txt.
1212
1213 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1214 boot time.
1215 Format: { 0 | 1 }
1216 See arch/parisc/kernel/pdc_chassis.c
1217
1218 pf. [PARIDE]
1219 See Documentation/paride.txt.
1220
1221 pg. [PARIDE]
1222 See Documentation/paride.txt.
1223
1224 pirq= [SMP,APIC] Manual mp-table setup
1225 See Documentation/i386/IO-APIC.txt.
1226
1227 plip= [PPT,NET] Parallel port network link
1228 Format: { parport<nr> | timid | 0 }
1229 See also Documentation/parport.txt.
1230
1231 pnpacpi= [ACPI]
1232 { off }
1233
1234 pnpbios= [ISAPNP]
1235 { on | off | curr | res | no-curr | no-res }
1236
1237 pnp_reserve_irq=
1238 [ISAPNP] Exclude IRQs for the autoconfiguration
1239
1240 pnp_reserve_dma=
1241 [ISAPNP] Exclude DMAs for the autoconfiguration
1242
1243 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1244 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1245
1246 pnp_reserve_mem=
a9913044
RD
1247 [ISAPNP] Exclude memory regions for the
1248 autoconfiguration.
1da177e4
LT
1249 Ranges are in pairs (memory base and size).
1250
1251 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1252 Format: [schedule,]<number>
1253 Param: "schedule" - profile schedule points.
1254 Param: <number> - step/bucket size as a power of 2 for
1255 statistical time based profiling.
1da177e4 1256
a9913044 1257 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1258 Limit processor to maximum C-state
1259 max_cstate=9 overrides any DMI blacklist limit.
1260
41c0d868
LB
1261 processor.nocst [HW,ACPI]
1262 Ignore the _CST method to determine C-states,
1263 instead using the legacy FADT method
1264
1da177e4
LT
1265 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1266 before loading.
1267 See Documentation/ramdisk.txt.
1268
a9913044
RD
1269 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1270 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1271 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1272 per second.
a9913044
RD
1273 psmouse.resetafter= [HW,MOUSE]
1274 Try to reset the device after so many bad packets
1da177e4
LT
1275 (0 = never).
1276 psmouse.resolution=
1277 [HW,MOUSE] Set desired mouse resolution, in dpi.
1278 psmouse.smartscroll=
a9913044 1279 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1280 0 = disabled, 1 = enabled (default).
1281
1282 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1283 Format:
1284 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1285
1286 pt. [PARIDE]
1287 See Documentation/paride.txt.
1288
1289 quiet= [KNL] Disable log messages
a9913044 1290
1da177e4
LT
1291 r128= [HW,DRM]
1292
1293 raid= [HW,RAID]
1294 See Documentation/md.txt.
1295
1296 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1297 See Documentation/ramdisk.txt.
1298
a9913044 1299 ramdisk_blocksize= [RAM]
1da177e4 1300 See Documentation/ramdisk.txt.
a9913044 1301
1da177e4
LT
1302 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1303 New name for the ramdisk parameter.
1304 See Documentation/ramdisk.txt.
1305
21a1ea9e
DS
1306 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1307 RCU callbacks to process in one batch.
1308
1309 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1310 RCU callbacks over which batch limiting is disabled.
1311
1312 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1313 RCU callbacks below which batch limiting is re-enabled.
1314
1315 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1316 RCU callbacks to queued before forcing reschedule
1317 on all cpus.
1318
ffdfc409
OJ
1319 rdinit= [KNL]
1320 Format: <full_path>
1321 Run specified binary instead of /init from the ramdisk,
1322 used for early userspace startup. See initrd.
1323
1da177e4
LT
1324 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1325 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1326 See arch/*/kernel/reboot.c.
1327
1328 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1329
a9913044
RD
1330 resume= [SWSUSP]
1331 Specify the partition device for software suspend
1da177e4
LT
1332
1333 rhash_entries= [KNL,NET]
1334 Set number of hash buckets for route cache
1335
1336 riscom8= [HW,SERIAL]
1337 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1338
1339 ro [KNL] Mount root device read-only on boot
1340
1341 root= [KNL] Root filesystem
1342
1343 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1344 mount the root filesystem
1345
1346 rootflags= [KNL] Set root filesystem mount option string
1347
1348 rootfstype= [KNL] Set root filesystem type
1349
1350 rw [KNL] Mount root device read-write on boot
1351
1352 S [KNL] Run init in single mode
1353
1354 sa1100ir [NET]
1355 See drivers/net/irda/sa1100_ir.c.
1356
1357 sb= [HW,OSS]
1358 Format: <io>,<irq>,<dma>,<dma2>
1359
1360 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1361
1da177e4
LT
1362 sbpcd= [HW,CD] Soundblaster CD adapter
1363 Format: <io>,<type>
1364 See a comment before function sbpcd_setup() in
1365 drivers/cdrom/sbpcd.c.
1366
1367 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1368 Format: <io>[,<timeout>[,<isapnp>]]
1369
1370 scsi_debug_*= [SCSI]
1371 See drivers/scsi/scsi_debug.c.
1372
1373 scsi_default_dev_flags=
1374 [SCSI] SCSI default device flags
1375 Format: <integer>
1376
1377 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1378 Format: <vendor>:<model>:<flags>
1379 (flags are integer value)
1380
1381 scsi_logging= [SCSI]
1382
1383 selinux [SELINUX] Disable or enable SELinux at boot time.
1384 Format: { "0" | "1" }
1385 See security/selinux/Kconfig help text.
1386 0 -- disable.
1387 1 -- enable.
1388 Default value is set via kernel config option.
1389 If enabled at boot time, /selinux/disable can be used
1390 later to disable prior to initial policy load.
1391
1392 serialnumber [BUGS=IA-32]
1393
a9913044
RD
1394 sg_def_reserved_size= [SCSI]
1395
1da177e4
LT
1396 sgalaxy= [HW,OSS]
1397 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1398
1399 shapers= [NET]
1400 Maximal number of shapers.
a9913044 1401
1da177e4
LT
1402 sim710= [SCSI,HW]
1403 See header of drivers/scsi/sim710.c.
1404
1405 simeth= [IA-64]
1406 simscsi=
a9913044 1407
1da177e4
LT
1408 sjcd= [HW,CD]
1409 Format: <io>,<irq>,<dma>
1410 See header of drivers/cdrom/sjcd.c.
1411
1412 slram= [HW,MTD]
1413
1414 smart2= [HW]
1415 Format: <io1>[,<io2>[,...,<io8>]]
1416
1417 snd-ad1816a= [HW,ALSA]
1418
1419 snd-ad1848= [HW,ALSA]
1420
1421 snd-ali5451= [HW,ALSA]
1422
1423 snd-als100= [HW,ALSA]
1424
1425 snd-als4000= [HW,ALSA]
1426
1427 snd-azt2320= [HW,ALSA]
1428
1429 snd-cmi8330= [HW,ALSA]
1430
1431 snd-cmipci= [HW,ALSA]
1432
1433 snd-cs4231= [HW,ALSA]
1434
1435 snd-cs4232= [HW,ALSA]
1436
1437 snd-cs4236= [HW,ALSA]
1438
1439 snd-cs4281= [HW,ALSA]
1440
1441 snd-cs46xx= [HW,ALSA]
1442
1443 snd-dt019x= [HW,ALSA]
1444
1445 snd-dummy= [HW,ALSA]
1446
1447 snd-emu10k1= [HW,ALSA]
1448
1449 snd-ens1370= [HW,ALSA]
1450
1451 snd-ens1371= [HW,ALSA]
1452
1453 snd-es968= [HW,ALSA]
1454
1455 snd-es1688= [HW,ALSA]
1456
1457 snd-es18xx= [HW,ALSA]
1458
1459 snd-es1938= [HW,ALSA]
1460
1461 snd-es1968= [HW,ALSA]
1462
1463 snd-fm801= [HW,ALSA]
1464
1465 snd-gusclassic= [HW,ALSA]
1466
1467 snd-gusextreme= [HW,ALSA]
1468
1469 snd-gusmax= [HW,ALSA]
1470
1471 snd-hdsp= [HW,ALSA]
1472
1473 snd-ice1712= [HW,ALSA]
1474
1475 snd-intel8x0= [HW,ALSA]
1476
1477 snd-interwave= [HW,ALSA]
1478
1479 snd-interwave-stb=
1480 [HW,ALSA]
1481
1482 snd-korg1212= [HW,ALSA]
1483
1484 snd-maestro3= [HW,ALSA]
1485
1486 snd-mpu401= [HW,ALSA]
1487
1488 snd-mtpav= [HW,ALSA]
1489
1490 snd-nm256= [HW,ALSA]
1491
1492 snd-opl3sa2= [HW,ALSA]
1493
1494 snd-opti92x-ad1848=
1495 [HW,ALSA]
1496
1497 snd-opti92x-cs4231=
1498 [HW,ALSA]
1499
1500 snd-opti93x= [HW,ALSA]
1501
1502 snd-pmac= [HW,ALSA]
1503
1504 snd-rme32= [HW,ALSA]
1505
1506 snd-rme96= [HW,ALSA]
1507
1508 snd-rme9652= [HW,ALSA]
1509
1510 snd-sb8= [HW,ALSA]
1511
1512 snd-sb16= [HW,ALSA]
1513
1514 snd-sbawe= [HW,ALSA]
1515
1516 snd-serial= [HW,ALSA]
1517
1518 snd-sgalaxy= [HW,ALSA]
1519
1520 snd-sonicvibes= [HW,ALSA]
1521
1522 snd-sun-amd7930=
1523 [HW,ALSA]
1524
1525 snd-sun-cs4231= [HW,ALSA]
1526
1527 snd-trident= [HW,ALSA]
1528
1529 snd-usb-audio= [HW,ALSA,USB]
1530
1531 snd-via82xx= [HW,ALSA]
1532
1533 snd-virmidi= [HW,ALSA]
1534
1535 snd-wavefront= [HW,ALSA]
1536
1537 snd-ymfpci= [HW,ALSA]
a9913044 1538
1da177e4
LT
1539 sonicvibes= [HW,OSS]
1540 Format: <reverb>
a9913044 1541
1da177e4
LT
1542 sonycd535= [HW,CD]
1543 Format: <io>[,<irq>]
1544
1545 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1546 See Documentation/sonypi.txt
1547
1548 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1549 See Documentation/specialix.txt.
1550
1551 spia_io_base= [HW,MTD]
1552 spia_fio_base=
1553 spia_pedr=
1554 spia_peddr=
1555
1556 sscape= [HW,OSS]
1557 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1558
1da177e4
LT
1559 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1560 See Documentation/scsi/st.txt.
1561
1562 st0x= [HW,SCSI]
1563 See header of drivers/scsi/seagate.c.
1564
1565 sti= [PARISC,HW]
1566 Format: <num>
1567 Set the STI (builtin display/keyboard on the HP-PARISC
1568 machines) console (graphic card) which should be used
1569 as the initial boot-console.
1570 See also comment in drivers/video/console/sticore.c.
1571
1572 sti_font= [HW]
1573 See comment in drivers/video/console/sticore.c.
1574
1575 stifb= [HW]
1576 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1577
1da177e4 1578 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1579
1da177e4
LT
1580 switches= [HW,M68k]
1581
1582 sym53c416= [HW,SCSI]
1583 See header of drivers/scsi/sym53c416.c.
1584
1585 t128= [HW,SCSI]
1586 See header of drivers/scsi/t128.c.
1587
1588 tdfx= [HW,DRM]
1589
1590 thash_entries= [KNL,NET]
1591 Set number of hash buckets for TCP connection
1592
1593 time Show timing data prefixed to each printk message line
1594
1595 tipar.timeout= [HW,PPT]
1596 Set communications timeout in tenths of a second
1597 (default 15).
1598
1599 tipar.delay= [HW,PPT]
1600 Set inter-bit delay in microseconds (default 10).
1601
1602 tmc8xx= [HW,SCSI]
1603 See header of drivers/scsi/seagate.c.
1604
1605 tmscsim= [HW,SCSI]
1606 See comment before function dc390_setup() in
1607 drivers/scsi/tmscsim.c.
1608
1609 tp720= [HW,PS2]
1610
1611 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1612 Format:
1613 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1614
1da177e4
LT
1615 tsdev.xres= [TS] Horizontal screen resolution.
1616 tsdev.yres= [TS] Vertical screen resolution.
1617
a9913044
RD
1618 turbografx.map[2|3]= [HW,JOY]
1619 TurboGraFX parallel port interface
1620 Format:
1621 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1622 See also Documentation/input/joystick-parport.txt
1623
1624 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1625 See header of drivers/scsi/u14-34f.c.
1626
1627 uart401= [HW,OSS]
1628 Format: <io>,<irq>
1629
1630 uart6850= [HW,OSS]
1631 Format: <io>,<irq>
1632
1da177e4
LT
1633 usbhid.mousepoll=
1634 [USBHID] The interval which mice are to be polled at.
a9913044 1635
1da177e4
LT
1636 video= [FB] Frame buffer configuration
1637 See Documentation/fb/modedb.txt.
1638
1639 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1640 See Documentation/i386/boot.txt and
1641 Documentation/svga.txt.
1da177e4
LT
1642 Use vga=ask for menu.
1643 This is actually a boot loader parameter; the value is
1644 passed to the kernel using a special protocol.
1645
a9913044 1646 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1647 size of <nn>. This can be used to increase the
1648 minimum size (128MB on x86). It can also be used to
1649 decrease the size and leave more room for directly
1650 mapped kernel RAM.
1651
1652 vmhalt= [KNL,S390]
1653
a9913044
RD
1654 vmpoff= [KNL,S390]
1655
1da177e4
LT
1656 waveartist= [HW,OSS]
1657 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1658
1da177e4
LT
1659 wd33c93= [HW,SCSI]
1660 See header of drivers/scsi/wd33c93.c.
1661
1662 wd7000= [HW,SCSI]
1663 See header of drivers/scsi/wd7000.c.
1664
1665 wdt= [WDT] Watchdog
1666 See Documentation/watchdog/watchdog.txt.
1667
1668 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1669 xd_geo= See header of drivers/block/xd.c.
1670
1671 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1672 Format:
1673 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 1674
a62eaf15
AK
1675 norandmaps Don't use address space randomization
1676 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1677
1da177e4 1678
a9913044 1679______________________________________________________________________
1da177e4
LT
1680Changelog:
1681
a9913044 16822000-06-?? Mr. Unknown
1da177e4 1683 The last known update (for 2.4.0) - the changelog was not kept before.
1da177e4 1684
a9913044
RD
16852002-11-24 Petr Baudis <pasky@ucw.cz>
1686 Randy Dunlap <randy.dunlap@verizon.net>
1da177e4
LT
1687 Update for 2.5.49, description for most of the options introduced,
1688 references to other documentation (C files, READMEs, ..), added S390,
1689 PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1690 reformatting.
a9913044
RD
1691
16922005-10-19 Randy Dunlap <rdunlap@xenotime.net>
1693 Lots of typos, whitespace, some reformatting.
1da177e4
LT
1694
1695TODO:
1696
1697 Add documentation for ALSA options.
1698 Add more DRM drivers.