[PATCH] ext3: Add "-o bh" option
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / Documentation / kernel-parameters.txt
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0ee9d71f 1 Kernel Parameters
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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
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20This document may not be entirely up to date and comprehensive. The command
21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22module. Loadable modules, after being loaded into the running kernel, also
23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24parameters may be changed at runtime by the command
25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
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27The parameters listed below are only valid if certain kernel build options were
28enabled and if respective hardware is present. The text in square brackets at
29the beginning of each description states the restrictions within which a
30parameter is applicable:
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31
32 ACPI ACPI support is enabled.
33 ALSA ALSA sound support is enabled.
34 APIC APIC support is enabled.
35 APM Advanced Power Management support is enabled.
36 AX25 Appropriate AX.25 support is enabled.
37 CD Appropriate CD support is enabled.
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38 DEVFS devfs support is enabled.
39 DRM Direct Rendering Management support is enabled.
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40 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
45 IA-32 IA-32 aka i386 architecture is enabled.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
41e2e8be 48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
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49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
309e57df 60 MSI Message Signaled Interrupts (PCI).
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61 MTD MTD support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
78 Documentation/scsi/.
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
a9913044 83 SWSUSP Software suspend is enabled.
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84 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
95
96In addition, the following text indicates that the option:
97
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
101
102Parameters denoted with BOOT are actually interpreted by the boot
103loader, and have no meaning to the kernel directly.
104Do not modify the syntax of boot loader parameters without extreme
105need or coordination with <Documentation/i386/boot.txt>.
106
107Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
108a trailing = on the name of any parameter states that that parameter will
109be entered as an environment variable, whereas its absence indicates that
110it will appear as a kernel argument readable via /proc/cmdline by programs
111running once the system is up.
112
113 53c7xx= [HW,SCSI] Amiga SCSI controllers
114 See header of drivers/scsi/53c7xx.c.
115 See also Documentation/scsi/ncr53c7xx.txt.
116
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117 acpi= [HW,ACPI] Advanced Configuration and Power Interface
118 Format: { force | off | ht | strict | noirq }
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119 force -- enable ACPI if default was off
120 off -- disable ACPI if default was on
121 noirq -- do not use ACPI for IRQ routing
122 ht -- run only enough ACPI to enable Hyper Threading
a9913044 123 strict -- Be less tolerant of platforms that are not
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124 strictly ACPI specification compliant.
125
126 See also Documentation/pm.txt, pci=noacpi
127
128 acpi_sleep= [HW,ACPI] Sleep options
129 Format: { s3_bios, s3_mode }
130 See Documentation/power/video.txt
a9913044 131
1da177e4 132 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 133 Format: { level | edge | high | low }
1da177e4 134
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135 acpi_irq_balance [HW,ACPI]
136 ACPI will balance active IRQs
137 default in APIC mode
1da177e4 138
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139 acpi_irq_nobalance [HW,ACPI]
140 ACPI will not move active IRQs (default)
141 default in PIC mode
1da177e4 142
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143 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
144 use by PCI
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145 Format: <irq>,<irq>...
146
a9913044 147 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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148 Format: <irq>,<irq>...
149
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150 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
151 Format: To spoof as Windows 98: ="Microsoft Windows"
152
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153 acpi_osi= [HW,ACPI] empty param disables _OSI
154
155 acpi_serialize [HW,ACPI] force serialization of AML methods
156
157 acpi_skip_timer_override [HW,ACPI]
158 Recognize and ignore IRQ0/pin2 Interrupt Override.
159 For broken nForce2 BIOS resulting in XT-PIC timer.
160
161 acpi_dbg_layer= [HW,ACPI]
162 Format: <int>
a9913044 163 Each bit of the <int> indicates an ACPI debug layer,
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164 1: enable, 0: disable. It is useful for boot time
165 debugging. After system has booted up, it can be set
166 via /proc/acpi/debug_layer.
167
168 acpi_dbg_level= [HW,ACPI]
169 Format: <int>
a9913044 170 Each bit of the <int> indicates an ACPI debug level,
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171 1: enable, 0: disable. It is useful for boot time
172 debugging. After system has booted up, it can be set
173 via /proc/acpi/debug_level.
174
175 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
176
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177 acpi_generic_hotkey [HW,ACPI]
178 Allow consolidated generic hotkey driver to
a9913044 179 override platform specific driver.
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180 See also Documentation/acpi-hotkey.txt.
181
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182 enable_timer_pin_1 [i386,x86-64]
183 Enable PIN 1 of APIC timer
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184 Can be useful to work around chipset bugs
185 (in particular on some ATI chipsets).
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186 The kernel tries to set a reasonable default.
187
188 disable_timer_pin_1 [i386,x86-64]
189 Disable PIN 1 of APIC timer
190 Can be useful to work around chipset bugs.
191
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192 ad1816= [HW,OSS]
193 Format: <io>,<irq>,<dma>,<dma2>
194 See also Documentation/sound/oss/AD1816.
195
196 ad1848= [HW,OSS]
197 Format: <io>,<irq>,<dma>,<dma2>,<type>
198
199 adlib= [HW,OSS]
200 Format: <io>
a9913044 201
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202 advansys= [HW,SCSI]
203 See header of drivers/scsi/advansys.c.
204
205 advwdt= [HW,WDT] Advantech WDT
206 Format: <iostart>,<iostop>
207
208 aedsp16= [HW,OSS] Audio Excel DSP 16
209 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
210 See also header of sound/oss/aedsp16.c.
a9913044 211
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212 aha152x= [HW,SCSI]
213 See Documentation/scsi/aha152x.txt.
214
215 aha1542= [HW,SCSI]
216 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
217
218 aic7xxx= [HW,SCSI]
219 See Documentation/scsi/aic7xxx.txt.
220
221 aic79xx= [HW,SCSI]
222 See Documentation/scsi/aic79xx.txt.
223
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224 amijoy.map= [HW,JOY] Amiga joystick support
225 Map of devices attached to JOY0DAT and JOY1DAT
226 Format: <a>,<b>
227 See also Documentation/kernel/input/joystick.txt
228
229 analog.map= [HW,JOY] Analog joystick and gamepad support
230 Specifies type or capabilities of an analog joystick
231 connected to one of 16 gameports
232 Format: <type1>,<type2>,..<type16>
233
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234 apc= [HW,SPARC]
235 Power management functions (SPARCstation-4/5 + deriv.)
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236 Format: noidle
237 Disable APC CPU standby support. SPARCstation-Fox does
238 not play well with APC CPU idle - disable it if you have
239 APC and your system crashes randomly.
240
a9913044 241 apic= [APIC,i386] Change the output verbosity whilst booting
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242 Format: { quiet (default) | verbose | debug }
243 Change the amount of debugging information output
244 when initialising the APIC and IO-APIC components.
a9913044 245
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246 apm= [APM] Advanced Power Management
247 See header of arch/i386/kernel/apm.c.
248
249 applicom= [HW]
250 Format: <mem>,<irq>
a9913044 251
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252 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
253 Format: <io>,<irq>,<nodeID>
254
255 ataflop= [HW,M68k]
256
257 atarimouse= [HW,MOUSE] Atari Mouse
258
259 atascsi= [HW,SCSI] Atari SCSI
260
261 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
262 EzKey and similar keyboards
263
264 atkbd.reset= [HW] Reset keyboard during initialization
265
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266 atkbd.set= [HW] Select keyboard code set
267 Format: <int> (2 = AT (default), 3 = PS/2)
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268
269 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
270 keyboards
271
272 atkbd.softraw= [HW] Choose between synthetic and real raw mode
273 Format: <bool> (0 = real, 1 = synthetic (default))
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274
275 atkbd.softrepeat= [HW]
276 Use software keyboard repeat
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277
278 autotest [IA64]
279
280 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
281 Format: <io>,<memsize>,<isapnp>
a9913044 282
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283 aztcd= [HW,CD] Aztech CD268 CDROM driver
284 Format: <io>,0x79 (?)
285
286 baycom_epp= [HW,AX25]
287 Format: <io>,<mode>
a9913044 288
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289 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
290 Format: <io>,<mode>
291 See header of drivers/net/hamradio/baycom_par.c.
292
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293 baycom_ser_fdx= [HW,AX25]
294 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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295 Format: <io>,<irq>,<mode>[,<baud>]
296 See header of drivers/net/hamradio/baycom_ser_fdx.c.
297
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298 baycom_ser_hdx= [HW,AX25]
299 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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300 Format: <io>,<irq>,<mode>
301 See header of drivers/net/hamradio/baycom_ser_hdx.c.
302
303 blkmtd_device= [HW,MTD]
304 blkmtd_erasesz=
305 blkmtd_ro=
306 blkmtd_bs=
307 blkmtd_count=
308
309 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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310 bttv.radio= Most important insmod options are available as
311 kernel args too.
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312 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
313 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
314
315 BusLogic= [HW,SCSI]
316 See drivers/scsi/BusLogic.c, comment before function
317 BusLogic_ParseDriverOptions().
318
319 c101= [NET] Moxa C101 synchronous serial card
320
321 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
322 Sometimes CPU hardware bugs make them report the cache
323 size incorrectly. The kernel will attempt work arounds
324 to fix known problems, but for some CPUs it is not
325 possible to determine what the correct size should be.
326 This option provides an override for these situations.
327
328 cdu31a= [HW,CD]
329 Format: <io>,<irq>[,PAS]
330 See header of drivers/cdrom/cdu31a.c.
331
332 chandev= [HW,NET] Generic channel device initialisation
333
334 checkreqprot [SELINUX] Set initial checkreqprot flag value.
335 Format: { "0" | "1" }
336 See security/selinux/Kconfig help text.
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337 0 -- check protection applied by kernel (includes
338 any implied execute protection).
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339 1 -- check protection requested by application.
340 Default value is set via a kernel config option.
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341 Value can be changed at runtime via
342 /selinux/checkreqprot.
343
344 clock= [BUGS=IA-32,HW] gettimeofday timesource override.
1da177e4 345 Forces specified timesource (if avaliable) to be used
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346 when calculating gettimeofday(). If specicified
347 timesource is not avalible, it defaults to PIT.
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348 Format: { pit | tsc | cyclone | pmtmr }
349
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350 disable_8254_timer
351 enable_8254_timer
352 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
353 over the 8254 in addition to over the IO-APIC. The
354 kernel tries to set a sensible default.
355
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356 hpet= [IA-32,HPET] option to disable HPET and use PIT.
357 Format: disable
358
359 cm206= [HW,CD]
360 Format: { auto | [<io>,][<irq>] }
361
362 com20020= [HW,NET] ARCnet - COM20020 chipset
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363 Format:
364 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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365
366 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
367 Format: <io>[,<irq>]
368
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369 com90xx= [HW,NET]
370 ARCnet - COM90xx chipset (memory-mapped buffers)
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371 Format: <io>[,<irq>[,<memstart>]]
372
373 condev= [HW,S390] console device
374 conmode=
a9913044 375
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376 console= [KNL] Output console device and options.
377
378 tty<n> Use the virtual console device <n>.
379
380 ttyS<n>[,options]
f1a1c2dc 381 ttyUSB0[,options]
1da177e4 382 Use the specified serial port. The options are of
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383 the form "bbbbpnf", where "bbbb" is the baud rate,
384 "p" is parity ("n", "o", or "e"), "n" is number of
385 bits, and "f" is flow control ("r" for RTS or
386 omit it). Default is "9600n8".
387
388 See Documentation/serial-console.txt for more
389 information. See
390 Documentation/networking/netconsole.txt for an
391 alternative.
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392
393 uart,io,<addr>[,options]
394 uart,mmio,<addr>[,options]
395 Start an early, polled-mode console on the 8250/16550
396 UART at the specified I/O port or MMIO address,
397 switching to the matching ttyS device later. The
398 options are the same as for ttyS, above.
399
400 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
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401 Format:
402 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
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403
404 cpia_pp= [HW,PPT]
405 Format: { parport<nr> | auto | none }
406
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407 crashkernel=nn[KMG]@ss[KMG]
408 [KNL] Reserve a chunk of physical memory to
409 hold a kernel to switch to with kexec on panic.
410
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411 cs4232= [HW,OSS]
412 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
413
414 cs89x0_dma= [HW,NET]
415 Format: <dma>
416
417 cs89x0_media= [HW,NET]
418 Format: { rj45 | aui | bnc }
a9913044 419
1da177e4 420 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
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421
422 dasd= [HW,NET]
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423 See header of drivers/s390/block/dasd_devmap.c.
424
425 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
426 (one device per port)
427 Format: <port#>,<type>
428 See also Documentation/input/joystick-parport.txt
429
430 debug [KNL] Enable kernel debugging (events log level).
431
432 decnet= [HW,NET]
433 Format: <area>[,<node>]
434 See also Documentation/networking/decnet.txt.
435
436 devfs= [DEVFS]
437 See Documentation/filesystems/devfs/boot-options.
438
439 dhash_entries= [KNL]
440 Set number of hash buckets for dentry cache.
a9913044 441
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442 digi= [HW,SERIAL]
443 IO parameters + enable/disable command.
444
445 digiepca= [HW,SERIAL]
446 See drivers/char/README.epca and
447 Documentation/digiepca.txt.
448
449 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
450 support available.
451 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
452
453 dmasound= [HW,OSS] Sound subsystem buffers
454
455 dscc4.setup= [NET]
456
457 dtc3181e= [HW,SCSI]
458
a9913044 459 earlyprintk= [IA-32,X86-64]
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460 earlyprintk=vga
461 earlyprintk=serial[,ttySn[,baudrate]]
462
a9913044 463 Append ",keep" to not disable it when the real console
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464 takes over.
465
466 Only vga or serial at a time, not both.
467
468 Currently only ttyS0 and ttyS1 are supported.
469
470 Interaction with the standard serial driver is not
471 very good.
472
473 The VGA output is eventually overwritten by the real
474 console.
475
476 eata= [HW,SCSI]
477
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478 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
479 Format: <int>
480 0: polling mode
481 non-0: interrupt mode (default)
482
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483 eda= [HW,PS2]
484
485 edb= [HW,PS2]
486
487 edd= [EDD]
488 Format: {"of[f]" | "sk[ipmbr]"}
489 See comment in arch/i386/boot/edd.S
490
a9913044 491 eicon= [HW,ISDN]
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492 Format: <id>,<membase>,<irq>
493
494 eisa_irq_edge= [PARISC,HW]
495 See header of drivers/parisc/eisa.c.
496
497 elanfreq= [IA-32]
498 See comment before function elanfreq_setup() in
499 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
500
501 elevator= [IOSCHED]
16ab3adf 502 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
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503 See Documentation/block/as-iosched.txt and
504 Documentation/block/deadline-iosched.txt for details.
505
aac04b32 506 elfcorehdr= [IA-32, X86_64]
a9913044 507 Specifies physical address of start of kernel core
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508 image elf header. Generally kexec loader will
509 pass this option to capture kernel.
510 See Documentation/kdump/kdump.txt for details.
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511
512 enforcing [SELINUX] Set initial enforcing status.
513 Format: {"0" | "1"}
514 See security/selinux/Kconfig help text.
515 0 -- permissive (log only, no denials).
516 1 -- enforcing (deny and log).
517 Default value is 0.
518 Value can be changed at runtime via /selinux/enforce.
519
520 es1370= [HW,OSS]
521 Format: <lineout>[,<micbias>]
522 See also header of sound/oss/es1370.c.
523
524 es1371= [HW,OSS]
525 Format: <spdif>,[<nomix>,[<amplifier>]]
526 See also header of sound/oss/es1371.c.
a9913044 527
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528 ether= [HW,NET] Ethernet cards parameters
529 This option is obsoleted by the "netdev=" option, which
530 has equivalent usage. See its documentation for details.
531
532 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
533 Format: <io>[,<irq>]
534
535 fd_mcs= [HW,SCSI]
536 See header of drivers/scsi/fd_mcs.c.
537
538 fdomain= [HW,SCSI]
539 See header of drivers/scsi/fdomain.c.
540
541 floppy= [HW]
542 See Documentation/floppy.txt.
543
544 ftape= [HW] Floppy Tape subsystem debugging options.
545 See Documentation/ftape.txt.
546
547 gamecon.map[2|3]=
548 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
549 support via parallel port (up to 5 devices per port)
550 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
551 See also Documentation/input/joystick-parport.txt
552
553 gamma= [HW,DRM]
554
555 gdth= [HW,SCSI]
556 See header of drivers/scsi/gdth.c.
557
558 gpt [EFI] Forces disk with valid GPT signature but
559 invalid Protective MBR to be treated as GPT.
560
561 gscd= [HW,CD]
562 Format: <io>
563
564 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
565
566 gus= [HW,OSS]
567 Format: <io>,<irq>,<dma>,<dma16>
a9913044 568
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569 gvp11= [HW,SCSI]
570
571 hashdist= [KNL,NUMA] Large hashes allocated during boot
572 are distributed across NUMA nodes. Defaults on
573 for IA-64, off otherwise.
a9913044 574 Format: 0 | 1 (for off | on)
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575
576 hcl= [IA-64] SGI's Hardware Graph compatibility layer
577
578 hd= [EIDE] (E)IDE hard drive subsystem geometry
579 Format: <cyl>,<head>,<sect>
580
581 hd?= [HW] (E)IDE subsystem
582 hd?lun= See Documentation/ide.txt.
583
584 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
585 size of <nn>. This works even on boxes that have no
586 highmem otherwise. This also works to reduce highmem
587 size on bigger boxes.
588
589 hisax= [HW,ISDN]
590 See Documentation/isdn/README.HiSax.
591
592 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
593
594 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
595
596 i8042.direct [HW] Put keyboard port into non-translated mode
597 i8042.dumbkbd [HW] Pretend that controlled can only read data from
598 keyboard and can not control its state
599 (Don't attempt to blink the leds)
600 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 601 i8042.nokbd [HW] Don't check/create keyboard port
1da177e4
LT
602 i8042.nomux [HW] Don't check presence of an active multiplexing
603 controller
604 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
605 controllers
606 i8042.panicblink=
607 [HW] Frequency with which keyboard LEDs should blink
608 when kernel panics (default is 0.5 sec)
609 i8042.reset [HW] Reset the controller during init and cleanup
610 i8042.unlock [HW] Unlock (ignore) the keylock
611
612 i810= [HW,DRM]
613
e70c9d5e
DT
614 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
615 indicates that the driver is running on unsupported
616 hardware.
1da177e4
LT
617 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
618 does not match list of supported models.
619 i8k.power_status
620 [HW] Report power status in /proc/i8k
621 (disabled by default)
622 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
623 capability is set.
624
625 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
626 See Documentation/mca.txt.
627
628 icn= [HW,ISDN]
629 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
630
631 ide= [HW] (E)IDE subsystem
632 Format: ide=nodma or ide=doubler or ide=reverse
633 See Documentation/ide.txt.
634
635 ide?= [HW] (E)IDE subsystem
636 Format: ide?=noprobe or chipset specific parameters.
637 See Documentation/ide.txt.
a9913044 638
1da177e4
LT
639 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
640 See Documentation/ide.txt.
641
642 idle= [HW]
643 Format: idle=poll or idle=halt
a9913044 644
1da177e4
LT
645 ihash_entries= [KNL]
646 Set number of hash buckets for inode cache.
647
648 in2000= [HW,SCSI]
649 See header of drivers/scsi/in2000.c.
650
651 init= [KNL]
652 Format: <full_path>
653 Run specified binary instead of /sbin/init as init
654 process.
655
656 initcall_debug [KNL] Trace initcalls as they are executed. Useful
657 for working out where the kernel is dying during
658 startup.
659
660 initrd= [BOOT] Specify the location of the initial ramdisk
661
662 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
663 Format: <irq>
664
2bd0fa3b
JB
665 combined_mode= [HW] control which driver uses IDE ports in combined
666 mode: legacy IDE driver, libata, or both
667 (in the libata case, libata.atapi_enabled=1 may be
668 useful as well). Note that using the ide or libata
669 options may affect your device naming (e.g. by
670 changing hdc to sdb).
671 Format: combined (default), ide, or libata
672
1da177e4
LT
673 inttest= [IA64]
674
675 io7= [HW] IO7 for Marvel based alpha systems
676 See comment before marvel_specify_io7 in
677 arch/alpha/kernel/core_marvel.c.
678
679 ip= [IP_PNP]
680 See Documentation/nfsroot.txt.
681
682 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
683 See comment before ip2_setup() in drivers/char/ip2.c.
684
685 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
686 See header of drivers/scsi/ips.c.
687
200803df
AC
688 irqfixup [HW]
689 When an interrupt is not handled search all handlers
690 for it. Intended to get systems with badly broken
691 firmware running.
692
693 irqpoll [HW]
694 When an interrupt is not handled search all handlers
695 for it. Also check all handlers each timer
696 interrupt. Intended to get systems with badly broken
697 firmware running.
698
1da177e4 699 isapnp= [ISAPNP]
a9913044 700 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
701
702 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
703 Format: <cpu number>,...,<cpu number>
704 This option can be used to specify one or more CPUs
705 to isolate from the general SMP balancing and scheduling
706 algorithms. The only way to move a process onto or off
707 an "isolated" CPU is via the CPU affinity syscalls.
708 <cpu number> begins at 0 and the maximum value is
709 "number of CPUs in system - 1".
710
711 This option is the preferred way to isolate CPUs. The
a9913044
RD
712 alternative -- manually setting the CPU mask of all
713 tasks in the system -- can cause problems and
714 suboptimal load balancer performance.
1da177e4
LT
715
716 isp16= [HW,CD]
717 Format: <io>,<irq>,<dma>,<setup>
718
a9913044 719 iucv= [HW,NET]
1da177e4
LT
720
721 js= [HW,JOY] Analog joystick
722 See Documentation/input/joystick.txt.
723
724 keepinitrd [HW,ARM]
725
a9913044 726 kstack=N [IA-32,X86-64] Print N words from the kernel stack
1da177e4
LT
727 in oops dumps.
728
729 l2cr= [PPC]
730
a9913044
RD
731 lapic [IA-32,APIC] Enable the local APIC even if BIOS
732 disabled it.
1da177e4
LT
733
734 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
735 Format: addr:<io>,irq:<irq>
736
a9913044
RD
737 llsc*= [IA64] See function print_params() in
738 arch/ia64/sn/kernel/llsc4.c.
1da177e4
LT
739
740 load_ramdisk= [RAM] List of ramdisks to load from floppy
741 See Documentation/ramdisk.txt.
742
a6b25b67
RD
743 lockd.nlm_grace_period=P [NFS] Assign grace period.
744 Format: <integer>
1da177e4 745
a6b25b67
RD
746 lockd.nlm_tcpport=N [NFS] Assign TCP port.
747 Format: <integer>
748
749 lockd.nlm_timeout=T [NFS] Assign timeout value.
750 Format: <integer>
751
752 lockd.nlm_udpport=M [NFS] Assign UDP port.
753 Format: <integer>
1da177e4
LT
754
755 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
756 Format: <irq>
757
758 loglevel= All Kernel Messages with a loglevel smaller than the
759 console loglevel will be printed to the console. It can
760 also be changed with klogd or other programs. The
761 loglevels are defined as follows:
762
763 0 (KERN_EMERG) system is unusable
764 1 (KERN_ALERT) action must be taken immediately
765 2 (KERN_CRIT) critical conditions
766 3 (KERN_ERR) error conditions
767 4 (KERN_WARNING) warning conditions
768 5 (KERN_NOTICE) normal but significant condition
769 6 (KERN_INFO) informational
770 7 (KERN_DEBUG) debug-level messages
771
772 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
773 Format: { n | nk | nM }
774 n must be a power of two. The default size
775 is set in the kernel config file.
1da177e4
LT
776
777 lp=0 [LP] Specify parallel ports to use, e.g,
778 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
779 lp=reset first parallel port). 'lp=0' disables the
780 lp=auto printer driver. 'lp=reset' (which can be
781 specified in addition to the ports) causes
782 attached printers to be reset. Using
783 lp=port1,port2,... specifies the parallel ports
784 to associate lp devices with, starting with
785 lp0. A port specification may be 'none' to skip
786 that lp device, or a parport name such as
787 'parport0'. Specifying 'lp=auto' instead of a
788 port specification list means that device IDs
789 from each port should be examined, to see if
790 an IEEE 1284-compliant printer is attached; if
791 so, the driver will manage that printer.
792 See also header of drivers/char/lp.c.
793
794 lpj=n [KNL]
795 Sets loops_per_jiffy to given constant, thus avoiding
796 time-consuming boot-time autodetection (up to 250 ms per
797 CPU). 0 enables autodetection (default). To determine
798 the correct value for your kernel, boot with normal
799 autodetection and see what value is printed. Note that
800 on SMP systems the preset will be applied to all CPUs,
801 which is likely to cause problems if your CPUs need
802 significantly divergent settings. An incorrect value
803 will cause delays in the kernel to be wrong, leading to
804 unpredictable I/O errors and other breakage. Although
805 unlikely, in the extreme case this might damage your
806 hardware.
807
808 ltpc= [NET]
809 Format: <io>,<irq>,<dma>
810
a9913044
RD
811 mac5380= [HW,SCSI] Format:
812 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 813
a9913044
RD
814 mac53c9x= [HW,SCSI] Format:
815 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 816
a9913044
RD
817 machvec= [IA64] Force the use of a particular machine-vector
818 (machvec) in a generic kernel.
819 Example: machvec=hpzx1_swiotlb
1da177e4 820
a9913044
RD
821 mad16= [HW,OSS] Format:
822 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
1da177e4
LT
823
824 maui= [HW,OSS]
825 Format: <io>,<irq>
a9913044
RD
826
827 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
828 be mounted
829 Format: <1-256>
830
831 maxcpus= [SMP] Maximum number of processors that an SMP kernel
832 should make use of
833
2b2c3750
BP
834 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
835 equal to this physical address is ignored.
836
a9913044 837 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
838 Should be between 1 and 2^32-1.
839
840 max_report_luns=
a9913044 841 [SCSI] Maximum number of LUNs received.
1da177e4
LT
842 Should be between 1 and 16384.
843
844 mca-pentium [BUGS=IA-32]
845
846 mcatest= [IA-64]
847
848 mcd= [HW,CD]
849 Format: <port>,<irq>,<mitsumi_bug_93_wait>
850
851 mcdx= [HW,CD]
852
853 mce [IA-32] Machine Check Exception
854
855 md= [HW] RAID subsystems devices and level
856 See Documentation/md.txt.
a9913044 857
1da177e4
LT
858 mdacon= [MDA]
859 Format: <first>,<last>
860 Specifies range of consoles to be captured by the MDA.
a9913044 861
1da177e4
LT
862 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
863 Amount of memory to be used when the kernel is not able
864 to see the whole system memory or for test.
865 [IA-32] Use together with memmap= to avoid physical
866 address space collisions. Without memmap= PCI devices
867 could be placed at addresses belonging to unused RAM.
868
869 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
870 memory.
871
69cda7b1 872 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
1da177e4
LT
873 E820 memory map, as specified by the user.
874 Such memmap=exactmap lines can be constructed based on
875 BIOS output or other requirements. See the memmap=nn@ss
876 option description.
877
878 memmap=nn[KMG]@ss[KMG]
879 [KNL] Force usage of a specific region of memory
880 Region of memory to be used, from ss to ss+nn.
881
882 memmap=nn[KMG]#ss[KMG]
883 [KNL,ACPI] Mark specific memory as ACPI data.
884 Region of memory to be used, from ss to ss+nn.
885
886 memmap=nn[KMG]$ss[KMG]
887 [KNL,ACPI] Mark specific memory as reserved.
888 Region of memory to be used, from ss to ss+nn.
889
890 meye.*= [HW] Set MotionEye Camera parameters
891 See Documentation/video4linux/meye.txt.
892
893 mga= [HW,DRM]
894
198e2f18
AM
895 migration_cost=
896 [KNL,SMP] debug: override scheduler migration costs
897 Format: <level-1-usecs>,<level-2-usecs>,...
898 This debugging option can be used to override the
899 default scheduler migration cost matrix. The numbers
900 are indexed by 'CPU domain distance'.
901 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
902 box will set up an intra-core migration cost of
903 1 msec, an inter-core migration cost of 2 msecs,
904 and an inter-node migration cost of 3 msecs.
905
906 WARNING: using the wrong values here can break
907 scheduler performance, so it's only for scheduler
908 development purposes, not production environments.
909
910 migration_debug=
911 [KNL,SMP] migration cost auto-detect verbosity
912 Format=<0|1|2>
913 If a system's migration matrix reported at bootup
914 seems erroneous then this option can be used to
915 increase verbosity of the detection process.
916 We default to 0 (no extra messages), 1 will print
917 some more information, and 2 will be really
918 verbose (probably only useful if you also have a
919 serial console attached to the system).
920
921 migration_factor=
922 [KNL,SMP] multiply/divide migration costs by a factor
923 Format=<percent>
924 This debug option can be used to proportionally
925 increase or decrease the auto-detected migration
926 costs for all entries of the migration matrix.
927 E.g. migration_factor=150 will increase migration
928 costs by 50%. (and thus the scheduler will be less
929 eager migrating cache-hot tasks)
930 migration_factor=80 will decrease migration costs
931 by 20%. (thus the scheduler will be more eager to
932 migrate tasks)
933
934 WARNING: using the wrong values here can break
935 scheduler performance, so it's only for scheduler
936 development purposes, not production environments.
937
1da177e4
LT
938 mousedev.tap_time=
939 [MOUSE] Maximum time between finger touching and
940 leaving touchpad surface for touch to be considered
941 a tap and be reported as a left button click (for
942 touchpads working in absolute mode only).
943 Format: <msecs>
944 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
945 reporting absolute coordinates, such as tablets
946 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
947 reporting absolute coordinates, such as tablets
948
949 mpu401= [HW,OSS]
950 Format: <io>,<irq>
951
952 MTD_Partition= [MTD]
953 Format: <name>,<region-number>,<size>,<offset>
954
a9913044
RD
955 MTD_Region= [MTD] Format:
956 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
957
958 mtdparts= [MTD]
959 See drivers/mtd/cmdline.c.
960
961 mtouchusb.raw_coordinates=
a9913044
RD
962 [HW] Make the MicroTouch USB driver use raw coordinates
963 ('y', default) or cooked coordinates ('n')
1da177e4
LT
964
965 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
966
967 NCR_D700= [HW,SCSI]
968 See header of drivers/scsi/NCR_D700.c.
969
970 ncr5380= [HW,SCSI]
971
972 ncr53c400= [HW,SCSI]
973
974 ncr53c400a= [HW,SCSI]
975
976 ncr53c406a= [HW,SCSI]
977
978 ncr53c8xx= [HW,SCSI]
979
980 netdev= [NET] Network devices parameters
981 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
982 Note that mem_start is often overloaded to mean
983 something different and driver-specific.
a9913044
RD
984 This usage is only documented in each driver source
985 file if at all.
986
1da177e4
LT
987 nfsaddrs= [NFS]
988 See Documentation/nfsroot.txt.
989
990 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
991 See Documentation/nfsroot.txt.
992
a72b4422
TM
993 nfs.callback_tcpport=
994 [NFS] set the TCP port on which the NFSv4 callback
995 channel should listen.
996
58df095b
TM
997 nfs.idmap_cache_timeout=
998 [NFS] set the maximum lifetime for idmapper cache
999 entries.
1000
1da177e4
LT
1001 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1002
1003 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1004 emulation library even if a 387 maths coprocessor
1005 is present.
1006
a9913044
RD
1007 noalign [KNL,ARM]
1008
1da177e4
LT
1009 noapic [SMP,APIC] Tells the kernel to not make use of any
1010 IOAPICs that may be present in the system.
1011
1012 noasync [HW,M68K] Disables async and sync negotiation for
1013 all devices.
1014
1015 nobats [PPC] Do not use BATs for mapping kernel lowmem
1016 on "Classic" PPC cores.
1017
1018 nocache [ARM]
a9913044 1019
1da177e4
LT
1020 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1021
1022 noexec [IA-64]
1023
a9913044 1024 noexec [IA-32,X86-64]
1da177e4
LT
1025 noexec=on: enable non-executable mappings (default)
1026 noexec=off: disable nn-executable mappings
1027
4f886511
CE
1028 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1029 register save and restore. The kernel will only save
1030 legacy floating-point registers on task switch.
1da177e4
LT
1031
1032 nohlt [BUGS=ARM]
a9913044 1033
1da177e4
LT
1034 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1035 instruction doesn't work correctly and not to
1036 use it.
1037
1038 nohalt [IA-64] Tells the kernel not to use the power saving
1039 function PAL_HALT_LIGHT when idle. This increases
1040 power-consumption. On the positive side, it reduces
1041 interrupt wake-up latency, which may improve performance
1042 in certain environments such as networked servers or
1043 real-time systems.
1044
1045 noirqdebug [IA-32] Disables the code which attempts to detect and
1046 disable unhandled interrupt sources.
1047
1048 noisapnp [ISAPNP] Disables ISA PnP code.
1049
1050 noinitrd [RAM] Tells the kernel not to load any configured
1051 initial RAM disk.
1052
1053 nointroute [IA-64]
1054
1055 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1056
1057 noltlbs [PPC] Do not use large page/tlb entries for kernel
1058 lowmem mapping on PPC40x.
1059
312f1f01
H
1060 nomca [IA-64] Disable machine check abort handling
1061
abe37e5a
H
1062 nomce [IA-32] Machine Check Exception
1063
1da177e4
LT
1064 noresidual [PPC] Don't use residual data on PReP machines.
1065
a9913044
RD
1066 noresume [SWSUSP] Disables resume and restores original swap
1067 space.
1068
1da177e4
LT
1069 no-scroll [VGA] Disables scrollback.
1070 This is required for the Braillex ib80-piezo Braille
1071 reader made by F.H. Papenmeier (Germany).
1072
1073 nosbagart [IA-64]
1074
4f886511
CE
1075 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1076
1da177e4
LT
1077 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1078
1079 nosync [HW,M68K] Disables sync negotiation for all devices.
1080
1081 notsc [BUGS=IA-32] Disable Time Stamp Counter
1082
1083 nousb [USB] Disable the USB subsystem
1084
1085 nowb [ARM]
a9913044 1086
a61c2d78
DJ
1087 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1088
1da177e4
LT
1089 opl3= [HW,OSS]
1090 Format: <io>
1091
1092 opl3sa= [HW,OSS]
1093 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1094
a9913044
RD
1095 opl3sa2= [HW,OSS] Format:
1096 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1097
1da177e4
LT
1098 oprofile.timer= [HW]
1099 Use timer interrupt instead of performance counters
1100
1101 optcd= [HW,CD]
1102 Format: <io>
1103
1104 osst= [HW,SCSI] SCSI Tape Driver
1105 Format: <buffer_size>,<write_threshold>
1106 See also Documentation/scsi/st.txt.
1107
1108 panic= [KNL] Kernel behaviour on panic
1109 Format: <timeout>
1110
1111 parkbd.port= [HW] Parallel port number the keyboard adapter is
1112 connected to, default is 0.
1113 Format: <parport#>
1114 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1115 0 for XT, 1 for AT (default is AT).
a9913044
RD
1116 Format: <mode>
1117
1118 parport= [HW,PPT] Specify parallel ports. 0 disables.
1119 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1120 Use 'auto' to force the driver to use any
1121 IRQ/DMA settings detected (the default is to
1122 ignore detected IRQ/DMA settings because of
1123 possible conflicts). You can specify the base
1124 address, IRQ, and DMA settings; IRQ and DMA
1125 should be numbers, or 'auto' (for using detected
1126 settings on that particular port), or 'nofifo'
1127 (to avoid using a FIFO even if it is detected).
1128 Parallel ports are assigned in the order they
1129 are specified on the command line, starting
1130 with parport0.
1131
1132 parport_init_mode= [HW,PPT]
1133 Configure VIA parallel port to operate in
1134 a specific mode. This is necessary on Pegasos
1135 computer where firmware has no options for setting
1136 up parallel port mode and sets it to spp.
1137 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1138 Format: [spp|ps2|epp|ecp|ecpepp]
1139
a9913044
RD
1140 pas2= [HW,OSS] Format:
1141 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1142
1da177e4
LT
1143 pas16= [HW,SCSI]
1144 See header of drivers/scsi/pas16.c.
1145
dd287796
AM
1146 pause_on_oops=
1147 Halt all CPUs after the first oops has been printed for
1148 the specified number of seconds. This is to be used if
1149 your oopses keep scrolling off the screen.
1150
1da177e4
LT
1151 pcbit= [HW,ISDN]
1152
1153 pcd. [PARIDE]
1154 See header of drivers/block/paride/pcd.c.
1155 See also Documentation/paride.txt.
1156
a9913044
RD
1157 pci=option[,option...] [PCI] various PCI subsystem options:
1158 off [IA-32] don't probe for the PCI bus
1159 bios [IA-32] force use of PCI BIOS, don't access
1160 the hardware directly. Use this if your machine
1161 has a non-standard PCI host bridge.
1162 nobios [IA-32] disallow use of PCI BIOS, only direct
1163 hardware access methods are allowed. Use this
1164 if you experience crashes upon bootup and you
1165 suspect they are caused by the BIOS.
1166 conf1 [IA-32] Force use of PCI Configuration
1167 Mechanism 1.
1168 conf2 [IA-32] Force use of PCI Configuration
1169 Mechanism 2.
61be6d66
BH
1170 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1171 Configuration
309e57df
MW
1172 nomsi [MSI] If the PCI_MSI kernel config parameter is
1173 enabled, this kernel boot option can be used to
1174 disable the use of MSI interrupts system-wide.
a9913044
RD
1175 nosort [IA-32] Don't sort PCI devices according to
1176 order given by the PCI BIOS. This sorting is
1177 done to get a device order compatible with
1178 older kernels.
1179 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1180 routing table. These calls are known to be buggy
1181 on several machines and they hang the machine
1182 when used, but on other computers it's the only
1183 way to get the interrupt routing table. Try
1184 this option if the kernel is unable to allocate
1185 IRQs or discover secondary PCI buses on your
1186 motherboard.
1187 rom [IA-32] Assign address space to expansion ROMs.
1188 Use with caution as certain devices share
1189 address decoders between ROMs and other
1190 resources.
1191 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1192 assigned automatically to PCI devices. You can
1193 make the kernel exclude IRQs of your ISA cards
1194 this way.
120bb424 1195 pirqaddr=0xAAAAA [IA-32] Specify the physical address
a9913044
RD
1196 of the PIRQ table (normally generated
1197 by the BIOS) if it is outside the
1198 F0000h-100000h range.
1199 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1200 useful if the kernel is unable to find your
1201 secondary buses and you want to tell it
1202 explicitly which ones they are.
1203 assign-busses [IA-32] Always assign all PCI bus
1204 numbers ourselves, overriding
1205 whatever the firmware may have done.
1206 usepirqmask [IA-32] Honor the possible IRQ mask stored
1207 in the BIOS $PIR table. This is needed on
1208 some systems with broken BIOSes, notably
1209 some HP Pavilion N5400 and Omnibook XE3
1210 notebooks. This will have no effect if ACPI
1211 IRQ routing is enabled.
1212 noacpi [IA-32] Do not use ACPI for IRQ routing
1213 or for PCI scanning.
1214 routeirq Do IRQ routing for all PCI devices.
1215 This is normally done in pci_enable_device(),
1216 so this option is a temporary workaround
1217 for broken drivers that don't call it.
1218 firmware [ARM] Do not re-enumerate the bus but instead
1219 just use the configuration from the
1220 bootloader. This is currently used on
1221 IXP2000 systems where the bus has to be
1222 configured a certain way for adjunct CPUs.
1da177e4
LT
1223
1224 pcmv= [HW,PCMCIA] BadgePAD 4
1225
1226 pd. [PARIDE]
1227 See Documentation/paride.txt.
1228
1229 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1230 boot time.
1231 Format: { 0 | 1 }
1232 See arch/parisc/kernel/pdc_chassis.c
1233
1234 pf. [PARIDE]
1235 See Documentation/paride.txt.
1236
1237 pg. [PARIDE]
1238 See Documentation/paride.txt.
1239
1240 pirq= [SMP,APIC] Manual mp-table setup
1241 See Documentation/i386/IO-APIC.txt.
1242
1243 plip= [PPT,NET] Parallel port network link
1244 Format: { parport<nr> | timid | 0 }
1245 See also Documentation/parport.txt.
1246
1247 pnpacpi= [ACPI]
1248 { off }
1249
1250 pnpbios= [ISAPNP]
1251 { on | off | curr | res | no-curr | no-res }
1252
1253 pnp_reserve_irq=
1254 [ISAPNP] Exclude IRQs for the autoconfiguration
1255
1256 pnp_reserve_dma=
1257 [ISAPNP] Exclude DMAs for the autoconfiguration
1258
1259 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1260 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1261
1262 pnp_reserve_mem=
a9913044
RD
1263 [ISAPNP] Exclude memory regions for the
1264 autoconfiguration.
1da177e4
LT
1265 Ranges are in pairs (memory base and size).
1266
1267 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1268 Format: [schedule,]<number>
1269 Param: "schedule" - profile schedule points.
1270 Param: <number> - step/bucket size as a power of 2 for
1271 statistical time based profiling.
1da177e4 1272
a9913044 1273 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1274 Limit processor to maximum C-state
1275 max_cstate=9 overrides any DMI blacklist limit.
1276
41c0d868
LB
1277 processor.nocst [HW,ACPI]
1278 Ignore the _CST method to determine C-states,
1279 instead using the legacy FADT method
1280
1da177e4
LT
1281 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1282 before loading.
1283 See Documentation/ramdisk.txt.
1284
a9913044
RD
1285 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1286 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1287 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1288 per second.
a9913044
RD
1289 psmouse.resetafter= [HW,MOUSE]
1290 Try to reset the device after so many bad packets
1da177e4
LT
1291 (0 = never).
1292 psmouse.resolution=
1293 [HW,MOUSE] Set desired mouse resolution, in dpi.
1294 psmouse.smartscroll=
a9913044 1295 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1296 0 = disabled, 1 = enabled (default).
1297
1298 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1299 Format:
1300 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1301
1302 pt. [PARIDE]
1303 See Documentation/paride.txt.
1304
1305 quiet= [KNL] Disable log messages
a9913044 1306
1da177e4
LT
1307 r128= [HW,DRM]
1308
1309 raid= [HW,RAID]
1310 See Documentation/md.txt.
1311
1312 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1313 See Documentation/ramdisk.txt.
1314
a9913044 1315 ramdisk_blocksize= [RAM]
1da177e4 1316 See Documentation/ramdisk.txt.
a9913044 1317
1da177e4
LT
1318 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1319 New name for the ramdisk parameter.
1320 See Documentation/ramdisk.txt.
1321
21a1ea9e
DS
1322 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1323 RCU callbacks to process in one batch.
1324
1325 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1326 RCU callbacks over which batch limiting is disabled.
1327
1328 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1329 RCU callbacks below which batch limiting is re-enabled.
1330
1331 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1332 RCU callbacks to queued before forcing reschedule
1333 on all cpus.
1334
ffdfc409
OJ
1335 rdinit= [KNL]
1336 Format: <full_path>
1337 Run specified binary instead of /init from the ramdisk,
1338 used for early userspace startup. See initrd.
1339
1da177e4
LT
1340 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1341 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1342 See arch/*/kernel/reboot.c.
1343
1344 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1345
a9913044
RD
1346 resume= [SWSUSP]
1347 Specify the partition device for software suspend
1da177e4
LT
1348
1349 rhash_entries= [KNL,NET]
1350 Set number of hash buckets for route cache
1351
1352 riscom8= [HW,SERIAL]
1353 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1354
1355 ro [KNL] Mount root device read-only on boot
1356
1357 root= [KNL] Root filesystem
1358
1359 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1360 mount the root filesystem
1361
1362 rootflags= [KNL] Set root filesystem mount option string
1363
1364 rootfstype= [KNL] Set root filesystem type
1365
1366 rw [KNL] Mount root device read-write on boot
1367
1368 S [KNL] Run init in single mode
1369
1370 sa1100ir [NET]
1371 See drivers/net/irda/sa1100_ir.c.
1372
1373 sb= [HW,OSS]
1374 Format: <io>,<irq>,<dma>,<dma2>
1375
1376 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1377
1da177e4
LT
1378 sbpcd= [HW,CD] Soundblaster CD adapter
1379 Format: <io>,<type>
1380 See a comment before function sbpcd_setup() in
1381 drivers/cdrom/sbpcd.c.
1382
1383 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1384 Format: <io>[,<timeout>[,<isapnp>]]
1385
1386 scsi_debug_*= [SCSI]
1387 See drivers/scsi/scsi_debug.c.
1388
1389 scsi_default_dev_flags=
1390 [SCSI] SCSI default device flags
1391 Format: <integer>
1392
1393 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1394 Format: <vendor>:<model>:<flags>
1395 (flags are integer value)
1396
1397 scsi_logging= [SCSI]
1398
1399 selinux [SELINUX] Disable or enable SELinux at boot time.
1400 Format: { "0" | "1" }
1401 See security/selinux/Kconfig help text.
1402 0 -- disable.
1403 1 -- enable.
1404 Default value is set via kernel config option.
1405 If enabled at boot time, /selinux/disable can be used
1406 later to disable prior to initial policy load.
1407
4e5ab4cb
JM
1408 selinux_compat_net =
1409 [SELINUX] Set initial selinux_compat_net flag value.
1410 Format: { "0" | "1" }
1411 0 -- use new secmark-based packet controls
1412 1 -- use legacy packet controls
1413 Default value is 0 (preferred).
1414 Value can be changed at runtime via
1415 /selinux/compat_net.
1416
1da177e4
LT
1417 serialnumber [BUGS=IA-32]
1418
a9913044
RD
1419 sg_def_reserved_size= [SCSI]
1420
1da177e4
LT
1421 sgalaxy= [HW,OSS]
1422 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1423
1424 shapers= [NET]
1425 Maximal number of shapers.
a9913044 1426
1da177e4
LT
1427 sim710= [SCSI,HW]
1428 See header of drivers/scsi/sim710.c.
1429
1430 simeth= [IA-64]
1431 simscsi=
a9913044 1432
1da177e4
LT
1433 sjcd= [HW,CD]
1434 Format: <io>,<irq>,<dma>
1435 See header of drivers/cdrom/sjcd.c.
1436
1437 slram= [HW,MTD]
1438
1439 smart2= [HW]
1440 Format: <io1>[,<io2>[,...,<io8>]]
1441
1442 snd-ad1816a= [HW,ALSA]
1443
1444 snd-ad1848= [HW,ALSA]
1445
1446 snd-ali5451= [HW,ALSA]
1447
1448 snd-als100= [HW,ALSA]
1449
1450 snd-als4000= [HW,ALSA]
1451
1452 snd-azt2320= [HW,ALSA]
1453
1454 snd-cmi8330= [HW,ALSA]
1455
1456 snd-cmipci= [HW,ALSA]
1457
1458 snd-cs4231= [HW,ALSA]
1459
1460 snd-cs4232= [HW,ALSA]
1461
1462 snd-cs4236= [HW,ALSA]
1463
1464 snd-cs4281= [HW,ALSA]
1465
1466 snd-cs46xx= [HW,ALSA]
1467
1468 snd-dt019x= [HW,ALSA]
1469
1470 snd-dummy= [HW,ALSA]
1471
1472 snd-emu10k1= [HW,ALSA]
1473
1474 snd-ens1370= [HW,ALSA]
1475
1476 snd-ens1371= [HW,ALSA]
1477
1478 snd-es968= [HW,ALSA]
1479
1480 snd-es1688= [HW,ALSA]
1481
1482 snd-es18xx= [HW,ALSA]
1483
1484 snd-es1938= [HW,ALSA]
1485
1486 snd-es1968= [HW,ALSA]
1487
1488 snd-fm801= [HW,ALSA]
1489
1490 snd-gusclassic= [HW,ALSA]
1491
1492 snd-gusextreme= [HW,ALSA]
1493
1494 snd-gusmax= [HW,ALSA]
1495
1496 snd-hdsp= [HW,ALSA]
1497
1498 snd-ice1712= [HW,ALSA]
1499
1500 snd-intel8x0= [HW,ALSA]
1501
1502 snd-interwave= [HW,ALSA]
1503
1504 snd-interwave-stb=
1505 [HW,ALSA]
1506
1507 snd-korg1212= [HW,ALSA]
1508
1509 snd-maestro3= [HW,ALSA]
1510
1511 snd-mpu401= [HW,ALSA]
1512
1513 snd-mtpav= [HW,ALSA]
1514
1515 snd-nm256= [HW,ALSA]
1516
1517 snd-opl3sa2= [HW,ALSA]
1518
1519 snd-opti92x-ad1848=
1520 [HW,ALSA]
1521
1522 snd-opti92x-cs4231=
1523 [HW,ALSA]
1524
1525 snd-opti93x= [HW,ALSA]
1526
1527 snd-pmac= [HW,ALSA]
1528
1529 snd-rme32= [HW,ALSA]
1530
1531 snd-rme96= [HW,ALSA]
1532
1533 snd-rme9652= [HW,ALSA]
1534
1535 snd-sb8= [HW,ALSA]
1536
1537 snd-sb16= [HW,ALSA]
1538
1539 snd-sbawe= [HW,ALSA]
1540
1541 snd-serial= [HW,ALSA]
1542
1543 snd-sgalaxy= [HW,ALSA]
1544
1545 snd-sonicvibes= [HW,ALSA]
1546
1547 snd-sun-amd7930=
1548 [HW,ALSA]
1549
1550 snd-sun-cs4231= [HW,ALSA]
1551
1552 snd-trident= [HW,ALSA]
1553
1554 snd-usb-audio= [HW,ALSA,USB]
1555
1556 snd-via82xx= [HW,ALSA]
1557
1558 snd-virmidi= [HW,ALSA]
1559
1560 snd-wavefront= [HW,ALSA]
1561
1562 snd-ymfpci= [HW,ALSA]
a9913044 1563
1da177e4
LT
1564 sonicvibes= [HW,OSS]
1565 Format: <reverb>
a9913044 1566
1da177e4
LT
1567 sonycd535= [HW,CD]
1568 Format: <io>[,<irq>]
1569
1570 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1571 See Documentation/sonypi.txt
1572
1573 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1574 See Documentation/specialix.txt.
1575
1576 spia_io_base= [HW,MTD]
1577 spia_fio_base=
1578 spia_pedr=
1579 spia_peddr=
1580
1581 sscape= [HW,OSS]
1582 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 1583
1da177e4
LT
1584 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1585 See Documentation/scsi/st.txt.
1586
1587 st0x= [HW,SCSI]
1588 See header of drivers/scsi/seagate.c.
1589
1590 sti= [PARISC,HW]
1591 Format: <num>
1592 Set the STI (builtin display/keyboard on the HP-PARISC
1593 machines) console (graphic card) which should be used
1594 as the initial boot-console.
1595 See also comment in drivers/video/console/sticore.c.
1596
1597 sti_font= [HW]
1598 See comment in drivers/video/console/sticore.c.
1599
1600 stifb= [HW]
1601 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1602
1da177e4 1603 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 1604
1da177e4
LT
1605 switches= [HW,M68k]
1606
1607 sym53c416= [HW,SCSI]
1608 See header of drivers/scsi/sym53c416.c.
1609
1610 t128= [HW,SCSI]
1611 See header of drivers/scsi/t128.c.
1612
1613 tdfx= [HW,DRM]
1614
1615 thash_entries= [KNL,NET]
1616 Set number of hash buckets for TCP connection
1617
1618 time Show timing data prefixed to each printk message line
1619
1620 tipar.timeout= [HW,PPT]
1621 Set communications timeout in tenths of a second
1622 (default 15).
1623
1624 tipar.delay= [HW,PPT]
1625 Set inter-bit delay in microseconds (default 10).
1626
1627 tmc8xx= [HW,SCSI]
1628 See header of drivers/scsi/seagate.c.
1629
1630 tmscsim= [HW,SCSI]
1631 See comment before function dc390_setup() in
1632 drivers/scsi/tmscsim.c.
1633
1634 tp720= [HW,PS2]
1635
1636 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
1637 Format:
1638 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1639
1da177e4
LT
1640 tsdev.xres= [TS] Horizontal screen resolution.
1641 tsdev.yres= [TS] Vertical screen resolution.
1642
a9913044
RD
1643 turbografx.map[2|3]= [HW,JOY]
1644 TurboGraFX parallel port interface
1645 Format:
1646 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
1647 See also Documentation/input/joystick-parport.txt
1648
1649 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1650 See header of drivers/scsi/u14-34f.c.
1651
1652 uart401= [HW,OSS]
1653 Format: <io>,<irq>
1654
1655 uart6850= [HW,OSS]
1656 Format: <io>,<irq>
1657
1da177e4
LT
1658 usbhid.mousepoll=
1659 [USBHID] The interval which mice are to be polled at.
a9913044 1660
1da177e4
LT
1661 video= [FB] Frame buffer configuration
1662 See Documentation/fb/modedb.txt.
1663
1664 vga= [BOOT,IA-32] Select a particular video mode
a9913044
RD
1665 See Documentation/i386/boot.txt and
1666 Documentation/svga.txt.
1da177e4
LT
1667 Use vga=ask for menu.
1668 This is actually a boot loader parameter; the value is
1669 passed to the kernel using a special protocol.
1670
a9913044 1671 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
1672 size of <nn>. This can be used to increase the
1673 minimum size (128MB on x86). It can also be used to
1674 decrease the size and leave more room for directly
1675 mapped kernel RAM.
1676
1677 vmhalt= [KNL,S390]
1678
a9913044
RD
1679 vmpoff= [KNL,S390]
1680
1da177e4
LT
1681 waveartist= [HW,OSS]
1682 Format: <io>,<irq>,<dma>,<dma2>
a9913044 1683
1da177e4
LT
1684 wd33c93= [HW,SCSI]
1685 See header of drivers/scsi/wd33c93.c.
1686
1687 wd7000= [HW,SCSI]
1688 See header of drivers/scsi/wd7000.c.
1689
1690 wdt= [WDT] Watchdog
1691 See Documentation/watchdog/watchdog.txt.
1692
1693 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1694 xd_geo= See header of drivers/block/xd.c.
1695
1696 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
1697 Format:
1698 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 1699
a62eaf15
AK
1700 norandmaps Don't use address space randomization
1701 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1702
1da177e4 1703
a9913044 1704______________________________________________________________________
1da177e4
LT
1705
1706TODO:
1707
1708 Add documentation for ALSA options.
1709 Add more DRM drivers.