Commit | Line | Data |
---|---|---|
0ee9d71f | 1 | Kernel Parameters |
1da177e4 LT |
2 | ~~~~~~~~~~~~~~~~~ |
3 | ||
4 | The 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 | |
7 | case insensitive manner), and with descriptions where known. | |
8 | ||
9 | Module parameters for loadable modules are specified only as the | |
10 | parameter name with optional '=' and value as appropriate, such as: | |
11 | ||
12 | modprobe usbcore blinkenlights=1 | |
13 | ||
14 | Module parameters for modules that are built into the kernel image | |
15 | are 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 | ||
a901ebb9 SR |
20 | This document may not be entirely up to date and comprehensive. The command |
21 | "modinfo -p ${modulename}" shows a current list of all parameters of a loadable | |
22 | module. Loadable modules, after being loaded into the running kernel, also | |
23 | reveal their parameters in /sys/module/${modulename}/parameters/. Some of these | |
24 | parameters may be changed at runtime by the command | |
25 | "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". | |
26 | ||
6585fa8a SR |
27 | The parameters listed below are only valid if certain kernel build options were |
28 | enabled and if respective hardware is present. The text in square brackets at | |
29 | the beginning of each description states the restrictions within which a | |
30 | parameter is applicable: | |
1da177e4 LT |
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. | |
a9913044 | 37 | DRM Direct Rendering Management support is enabled. |
1da177e4 LT |
38 | EDD BIOS Enhanced Disk Drive Services (EDD) is enabled |
39 | EFI EFI Partitioning (GPT) is enabled | |
40 | EIDE EIDE/ATAPI support is enabled. | |
41 | FB The frame buffer device is enabled. | |
42 | HW Appropriate hardware is enabled. | |
43 | IA-32 IA-32 aka i386 architecture is enabled. | |
44 | IA-64 IA-64 architecture is enabled. | |
45 | IOSCHED More than one I/O scheduler is enabled. | |
41e2e8be | 46 | IP_PNP IP DHCP, BOOTP, or RARP is enabled. |
1da177e4 LT |
47 | ISAPNP ISA PnP code is enabled. |
48 | ISDN Appropriate ISDN support is enabled. | |
49 | JOY Appropriate joystick support is enabled. | |
11ef697b | 50 | LIBATA Libata driver is enabled |
1da177e4 LT |
51 | LP Printer support is enabled. |
52 | LOOP Loopback device support is enabled. | |
53 | M68k M68k architecture is enabled. | |
54 | These options have more detailed description inside of | |
55 | Documentation/m68k/kernel-options.txt. | |
56 | MCA MCA bus support is enabled. | |
57 | MDA MDA console support is enabled. | |
58 | MOUSE Appropriate mouse support is enabled. | |
309e57df | 59 | MSI Message Signaled Interrupts (PCI). |
1da177e4 LT |
60 | MTD MTD support is enabled. |
61 | NET Appropriate network support is enabled. | |
62 | NUMA NUMA support is enabled. | |
734efb46 | 63 | GENERIC_TIME The generic timeofday code is enabled. |
1da177e4 LT |
64 | NFS Appropriate NFS support is enabled. |
65 | OSS OSS sound support is enabled. | |
959b4fdf | 66 | PV_OPS A paravirtualized kernel |
1da177e4 LT |
67 | PARIDE The ParIDE subsystem is enabled. |
68 | PARISC The PA-RISC architecture is enabled. | |
69 | PCI PCI bus support is enabled. | |
70 | PCMCIA The PCMCIA subsystem is enabled. | |
71 | PNP Plug & Play support is enabled. | |
72 | PPC PowerPC architecture is enabled. | |
73 | PPT Parallel port support is enabled. | |
74 | PS2 Appropriate PS/2 support is enabled. | |
75 | RAM RAM disk support is enabled. | |
76 | S390 S390 architecture is enabled. | |
77 | SCSI Appropriate SCSI support is enabled. | |
78 | A lot of drivers has their options described inside of | |
79 | Documentation/scsi/. | |
80 | SELINUX SELinux support is enabled. | |
81 | SERIAL Serial support is enabled. | |
e523d93c | 82 | SH SuperH architecture is enabled. |
1da177e4 LT |
83 | SMP The kernel is an SMP kernel. |
84 | SPARC Sparc architecture is enabled. | |
a9913044 | 85 | SWSUSP Software suspend is enabled. |
1da177e4 LT |
86 | TS Appropriate touchscreen support is enabled. |
87 | USB USB support is enabled. | |
88 | USBHID USB Human Interface Device support is enabled. | |
89 | V4L Video For Linux support is enabled. | |
90 | VGA The VGA console has been enabled. | |
91 | VT Virtual terminal support is enabled. | |
92 | WDT Watchdog support is enabled. | |
93 | XT IBM PC/XT MFM hard disk support is enabled. | |
94 | X86-64 X86-64 architecture is enabled. | |
95 | More X86-64 boot options can be found in | |
96 | Documentation/x86_64/boot-options.txt . | |
97 | ||
98 | In addition, the following text indicates that the option: | |
99 | ||
100 | BUGS= Relates to possible processor bugs on the said processor. | |
101 | KNL Is a kernel start-up parameter. | |
102 | BOOT Is a boot loader parameter. | |
103 | ||
104 | Parameters denoted with BOOT are actually interpreted by the boot | |
105 | loader, and have no meaning to the kernel directly. | |
106 | Do not modify the syntax of boot loader parameters without extreme | |
107 | need or coordination with <Documentation/i386/boot.txt>. | |
108 | ||
5558870b KW |
109 | There are also arch-specific kernel-parameters not documented here. |
110 | See for example <Documentation/x86_64/boot-options.txt>. | |
111 | ||
1da177e4 LT |
112 | Note that ALL kernel parameters listed below are CASE SENSITIVE, and that |
113 | a trailing = on the name of any parameter states that that parameter will | |
114 | be entered as an environment variable, whereas its absence indicates that | |
115 | it will appear as a kernel argument readable via /proc/cmdline by programs | |
116 | running once the system is up. | |
117 | ||
9c4751fd | 118 | The number of kernel parameters is not limited, but the length of the |
119 | complete command line (parameters including spaces etc.) is limited to | |
120 | a fixed number of characters. This limit depends on the architecture | |
121 | and is between 256 and 4096 characters. It is defined in the file | |
122 | ./include/asm/setup.h as COMMAND_LINE_SIZE. | |
123 | ||
124 | ||
1da177e4 LT |
125 | 53c7xx= [HW,SCSI] Amiga SCSI controllers |
126 | See header of drivers/scsi/53c7xx.c. | |
127 | See also Documentation/scsi/ncr53c7xx.txt. | |
128 | ||
03d926f8 BW |
129 | acpi= [HW,ACPI,X86-64,i386] |
130 | Advanced Configuration and Power Interface | |
a9913044 | 131 | Format: { force | off | ht | strict | noirq } |
1da177e4 LT |
132 | force -- enable ACPI if default was off |
133 | off -- disable ACPI if default was on | |
134 | noirq -- do not use ACPI for IRQ routing | |
135 | ht -- run only enough ACPI to enable Hyper Threading | |
a9913044 | 136 | strict -- Be less tolerant of platforms that are not |
1da177e4 LT |
137 | strictly ACPI specification compliant. |
138 | ||
139 | See also Documentation/pm.txt, pci=noacpi | |
140 | ||
a1fdcc0d LB |
141 | acpi_apic_instance= [ACPI, IOAPIC] |
142 | Format: <int> | |
143 | 2: use 2nd APIC table, if available | |
144 | 1,0: use 1st APIC table | |
4e381a4f | 145 | default: 0 |
a1fdcc0d | 146 | |
1da177e4 LT |
147 | acpi_sleep= [HW,ACPI] Sleep options |
148 | Format: { s3_bios, s3_mode } | |
149 | See Documentation/power/video.txt | |
a9913044 | 150 | |
1da177e4 | 151 | acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode |
a9913044 | 152 | Format: { level | edge | high | low } |
1da177e4 | 153 | |
a9913044 RD |
154 | acpi_irq_balance [HW,ACPI] |
155 | ACPI will balance active IRQs | |
156 | default in APIC mode | |
1da177e4 | 157 | |
a9913044 RD |
158 | acpi_irq_nobalance [HW,ACPI] |
159 | ACPI will not move active IRQs (default) | |
160 | default in PIC mode | |
1da177e4 | 161 | |
a9913044 RD |
162 | acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for |
163 | use by PCI | |
1da177e4 LT |
164 | Format: <irq>,<irq>... |
165 | ||
a9913044 | 166 | acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA |
1da177e4 LT |
167 | Format: <irq>,<irq>... |
168 | ||
a1f9e65e LB |
169 | acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS |
170 | Format: To spoof as Windows 98: ="Microsoft Windows" | |
171 | ||
ae00d812 LB |
172 | acpi_osi= [HW,ACPI] Modify list of supported OS interface strings |
173 | acpi_osi="string1" # add string1 -- only one string | |
174 | acpi_osi="!string2" # remove built-in string2 | |
175 | acpi_osi= # disable all strings | |
1da177e4 LT |
176 | |
177 | acpi_serialize [HW,ACPI] force serialization of AML methods | |
178 | ||
179 | acpi_skip_timer_override [HW,ACPI] | |
180 | Recognize and ignore IRQ0/pin2 Interrupt Override. | |
181 | For broken nForce2 BIOS resulting in XT-PIC timer. | |
fa18f477 AK |
182 | acpi_use_timer_override [HW,ACPI} |
183 | Use timer override. For some broken Nvidia NF5 boards | |
184 | that require a timer override, but don't have | |
185 | HPET | |
1da177e4 | 186 | |
f989106c | 187 | acpi.debug_layer= [HW,ACPI] |
1da177e4 | 188 | Format: <int> |
a9913044 | 189 | Each bit of the <int> indicates an ACPI debug layer, |
1da177e4 LT |
190 | 1: enable, 0: disable. It is useful for boot time |
191 | debugging. After system has booted up, it can be set | |
f989106c ZR |
192 | via /sys/module/acpi/parameters/debug_layer. |
193 | CONFIG_ACPI_DEBUG must be enabled for this to produce any output. | |
194 | Available bits (add the numbers together) to enable debug output | |
195 | for specific parts of the ACPI subsystem: | |
196 | 0x01 utilities 0x02 hardware 0x04 events 0x08 tables | |
197 | 0x10 namespace 0x20 parser 0x40 dispatcher | |
198 | 0x80 executer 0x100 resources 0x200 acpica debugger | |
199 | 0x400 os services 0x800 acpica disassembler. | |
200 | The number can be in decimal or prefixed with 0x in hex. | |
201 | Warning: Many of these options can produce a lot of | |
202 | output and make your system unusable. Be very careful. | |
203 | ||
204 | acpi.debug_level= [HW,ACPI] | |
1da177e4 | 205 | Format: <int> |
a9913044 | 206 | Each bit of the <int> indicates an ACPI debug level, |
1da177e4 LT |
207 | 1: enable, 0: disable. It is useful for boot time |
208 | debugging. After system has booted up, it can be set | |
f989106c ZR |
209 | via /sys/module/acpi/parameters/debug_level. |
210 | CONFIG_ACPI_DEBUG must be enabled for this to produce any output. | |
211 | Available bits (add the numbers together) to enable different | |
212 | debug output levels of the ACPI subsystem: | |
213 | 0x01 error 0x02 warn 0x04 init 0x08 debug object | |
214 | 0x10 info 0x20 init names 0x40 parse 0x80 load | |
215 | 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region | |
216 | 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects | |
217 | 0x10000 resources 0x20000 user requests 0x40000 package. | |
218 | The number can be in decimal or prefixed with 0x in hex. | |
219 | Warning: Many of these options can produce a lot of | |
220 | output and make your system unusable. Be very careful. | |
221 | ||
1da177e4 LT |
222 | |
223 | acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT | |
224 | ||
5d0cf410 | 225 | acpi_pm_good [IA-32,X86-64] |
226 | Override the pmtimer bug detection: force the kernel | |
227 | to assume that this machine's pmtimer latches its value | |
228 | and always returns good values. | |
229 | ||
66759a01 CE |
230 | enable_timer_pin_1 [i386,x86-64] |
231 | Enable PIN 1 of APIC timer | |
a9913044 RD |
232 | Can be useful to work around chipset bugs |
233 | (in particular on some ATI chipsets). | |
66759a01 CE |
234 | The kernel tries to set a reasonable default. |
235 | ||
236 | disable_timer_pin_1 [i386,x86-64] | |
237 | Disable PIN 1 of APIC timer | |
238 | Can be useful to work around chipset bugs. | |
239 | ||
1da177e4 LT |
240 | ad1848= [HW,OSS] |
241 | Format: <io>,<irq>,<dma>,<dma2>,<type> | |
242 | ||
1da177e4 LT |
243 | advansys= [HW,SCSI] |
244 | See header of drivers/scsi/advansys.c. | |
245 | ||
246 | advwdt= [HW,WDT] Advantech WDT | |
247 | Format: <iostart>,<iostop> | |
248 | ||
249 | aedsp16= [HW,OSS] Audio Excel DSP 16 | |
250 | Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq> | |
251 | See also header of sound/oss/aedsp16.c. | |
a9913044 | 252 | |
1da177e4 LT |
253 | aha152x= [HW,SCSI] |
254 | See Documentation/scsi/aha152x.txt. | |
255 | ||
256 | aha1542= [HW,SCSI] | |
257 | Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]] | |
258 | ||
259 | aic7xxx= [HW,SCSI] | |
260 | See Documentation/scsi/aic7xxx.txt. | |
261 | ||
262 | aic79xx= [HW,SCSI] | |
263 | See Documentation/scsi/aic79xx.txt. | |
264 | ||
1da177e4 LT |
265 | amijoy.map= [HW,JOY] Amiga joystick support |
266 | Map of devices attached to JOY0DAT and JOY1DAT | |
267 | Format: <a>,<b> | |
268 | See also Documentation/kernel/input/joystick.txt | |
269 | ||
270 | analog.map= [HW,JOY] Analog joystick and gamepad support | |
271 | Specifies type or capabilities of an analog joystick | |
272 | connected to one of 16 gameports | |
273 | Format: <type1>,<type2>,..<type16> | |
274 | ||
a9913044 RD |
275 | apc= [HW,SPARC] |
276 | Power management functions (SPARCstation-4/5 + deriv.) | |
1da177e4 LT |
277 | Format: noidle |
278 | Disable APC CPU standby support. SPARCstation-Fox does | |
279 | not play well with APC CPU idle - disable it if you have | |
280 | APC and your system crashes randomly. | |
281 | ||
a9913044 | 282 | apic= [APIC,i386] Change the output verbosity whilst booting |
1da177e4 LT |
283 | Format: { quiet (default) | verbose | debug } |
284 | Change the amount of debugging information output | |
285 | when initialising the APIC and IO-APIC components. | |
a9913044 | 286 | |
1da177e4 LT |
287 | apm= [APM] Advanced Power Management |
288 | See header of arch/i386/kernel/apm.c. | |
289 | ||
290 | applicom= [HW] | |
291 | Format: <mem>,<irq> | |
a9913044 | 292 | |
1da177e4 LT |
293 | arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards |
294 | Format: <io>,<irq>,<nodeID> | |
295 | ||
296 | ataflop= [HW,M68k] | |
297 | ||
298 | atarimouse= [HW,MOUSE] Atari Mouse | |
299 | ||
300 | atascsi= [HW,SCSI] Atari SCSI | |
301 | ||
302 | atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, | |
303 | EzKey and similar keyboards | |
304 | ||
305 | atkbd.reset= [HW] Reset keyboard during initialization | |
306 | ||
a9913044 RD |
307 | atkbd.set= [HW] Select keyboard code set |
308 | Format: <int> (2 = AT (default), 3 = PS/2) | |
1da177e4 LT |
309 | |
310 | atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar | |
311 | keyboards | |
312 | ||
313 | atkbd.softraw= [HW] Choose between synthetic and real raw mode | |
314 | Format: <bool> (0 = real, 1 = synthetic (default)) | |
a9913044 RD |
315 | |
316 | atkbd.softrepeat= [HW] | |
317 | Use software keyboard repeat | |
1da177e4 LT |
318 | |
319 | autotest [IA64] | |
320 | ||
1da177e4 LT |
321 | baycom_epp= [HW,AX25] |
322 | Format: <io>,<mode> | |
a9913044 | 323 | |
1da177e4 LT |
324 | baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem |
325 | Format: <io>,<mode> | |
326 | See header of drivers/net/hamradio/baycom_par.c. | |
327 | ||
a9913044 RD |
328 | baycom_ser_fdx= [HW,AX25] |
329 | BayCom Serial Port AX.25 Modem (Full Duplex Mode) | |
1da177e4 LT |
330 | Format: <io>,<irq>,<mode>[,<baud>] |
331 | See header of drivers/net/hamradio/baycom_ser_fdx.c. | |
332 | ||
a9913044 RD |
333 | baycom_ser_hdx= [HW,AX25] |
334 | BayCom Serial Port AX.25 Modem (Half Duplex Mode) | |
1da177e4 LT |
335 | Format: <io>,<irq>,<mode> |
336 | See header of drivers/net/hamradio/baycom_ser_hdx.c. | |
337 | ||
338 | blkmtd_device= [HW,MTD] | |
339 | blkmtd_erasesz= | |
340 | blkmtd_ro= | |
341 | blkmtd_bs= | |
342 | blkmtd_count= | |
343 | ||
344 | bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) | |
a9913044 RD |
345 | bttv.radio= Most important insmod options are available as |
346 | kernel args too. | |
1da177e4 LT |
347 | bttv.pll= See Documentation/video4linux/bttv/Insmod-options |
348 | bttv.tuner= and Documentation/video4linux/bttv/CARDLIST | |
349 | ||
350 | BusLogic= [HW,SCSI] | |
351 | See drivers/scsi/BusLogic.c, comment before function | |
352 | BusLogic_ParseDriverOptions(). | |
353 | ||
354 | c101= [NET] Moxa C101 synchronous serial card | |
355 | ||
356 | cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection. | |
357 | Sometimes CPU hardware bugs make them report the cache | |
358 | size incorrectly. The kernel will attempt work arounds | |
359 | to fix known problems, but for some CPUs it is not | |
360 | possible to determine what the correct size should be. | |
361 | This option provides an override for these situations. | |
362 | ||
1da177e4 LT |
363 | chandev= [HW,NET] Generic channel device initialisation |
364 | ||
365 | checkreqprot [SELINUX] Set initial checkreqprot flag value. | |
366 | Format: { "0" | "1" } | |
367 | See security/selinux/Kconfig help text. | |
a9913044 RD |
368 | 0 -- check protection applied by kernel (includes |
369 | any implied execute protection). | |
1da177e4 LT |
370 | 1 -- check protection requested by application. |
371 | Default value is set via a kernel config option. | |
a9913044 RD |
372 | Value can be changed at runtime via |
373 | /selinux/checkreqprot. | |
374 | ||
734efb46 | 375 | clock= [BUGS=IA-32, HW] gettimeofday clocksource override. |
376 | [Deprecated] | |
3f6dee9b | 377 | Forces specified clocksource (if available) to be used |
734efb46 | 378 | when calculating gettimeofday(). If specified |
3f6dee9b | 379 | clocksource is not available, it defaults to PIT. |
1da177e4 LT |
380 | Format: { pit | tsc | cyclone | pmtmr } |
381 | ||
3d6ac984 RD |
382 | clocksource= [GENERIC_TIME] Override the default clocksource |
383 | Format: <string> | |
384 | Override the default clocksource and use the clocksource | |
385 | with the name specified. | |
386 | Some clocksource names to choose from, depending on | |
387 | the platform: | |
388 | [all] jiffies (this is the base, fallback clocksource) | |
389 | [ACPI] acpi_pm | |
390 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, | |
391 | pxa_timer,timer3,32k_counter,timer0_1 | |
392 | [AVR32] avr32 | |
393 | [IA-32] pit,hpet,tsc,vmi-timer; | |
394 | scx200_hrt on Geode; cyclone on IBM x440 | |
395 | [MIPS] MIPS | |
396 | [PARISC] cr16 | |
397 | [S390] tod | |
398 | [SH] SuperH | |
399 | [SPARC64] tick | |
400 | [X86-64] hpet,tsc | |
401 | ||
86c41837 CE |
402 | code_bytes [IA32] How many bytes of object code to print in an |
403 | oops report. | |
404 | Range: 0 - 8192 | |
405 | Default: 64 | |
406 | ||
f9262c12 AK |
407 | disable_8254_timer |
408 | enable_8254_timer | |
409 | [IA32/X86_64] Disable/Enable interrupt 0 timer routing | |
410 | over the 8254 in addition to over the IO-APIC. The | |
411 | kernel tries to set a sensible default. | |
412 | ||
1da177e4 LT |
413 | hpet= [IA-32,HPET] option to disable HPET and use PIT. |
414 | Format: disable | |
415 | ||
1da177e4 | 416 | com20020= [HW,NET] ARCnet - COM20020 chipset |
a9913044 RD |
417 | Format: |
418 | <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] | |
1da177e4 LT |
419 | |
420 | com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) | |
421 | Format: <io>[,<irq>] | |
422 | ||
a9913044 RD |
423 | com90xx= [HW,NET] |
424 | ARCnet - COM90xx chipset (memory-mapped buffers) | |
1da177e4 LT |
425 | Format: <io>[,<irq>[,<memstart>]] |
426 | ||
427 | condev= [HW,S390] console device | |
428 | conmode= | |
a9913044 | 429 | |
1da177e4 LT |
430 | console= [KNL] Output console device and options. |
431 | ||
432 | tty<n> Use the virtual console device <n>. | |
433 | ||
434 | ttyS<n>[,options] | |
f1a1c2dc | 435 | ttyUSB0[,options] |
1da177e4 | 436 | Use the specified serial port. The options are of |
f1a1c2dc RD |
437 | the form "bbbbpnf", where "bbbb" is the baud rate, |
438 | "p" is parity ("n", "o", or "e"), "n" is number of | |
439 | bits, and "f" is flow control ("r" for RTS or | |
440 | omit it). Default is "9600n8". | |
441 | ||
442 | See Documentation/serial-console.txt for more | |
443 | information. See | |
444 | Documentation/networking/netconsole.txt for an | |
445 | alternative. | |
1da177e4 | 446 | |
18a8bd94 YL |
447 | uart[8250],io,<addr>[,options] |
448 | uart[8250],mmio,<addr>[,options] | |
1da177e4 LT |
449 | Start an early, polled-mode console on the 8250/16550 |
450 | UART at the specified I/O port or MMIO address, | |
451 | switching to the matching ttyS device later. The | |
452 | options are the same as for ttyS, above. | |
453 | ||
18a8bd94 YL |
454 | earlycon= [KNL] Output early console device and options. |
455 | uart[8250],io,<addr>[,options] | |
456 | uart[8250],mmio,<addr>[,options] | |
457 | Start an early, polled-mode console on the 8250/16550 | |
458 | UART at the specified I/O port or MMIO address. | |
459 | The options are the same as for ttyS, above. | |
460 | ||
1da177e4 | 461 | cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver |
a9913044 RD |
462 | Format: |
463 | <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] | |
1da177e4 LT |
464 | |
465 | cpia_pp= [HW,PPT] | |
466 | Format: { parport<nr> | auto | none } | |
467 | ||
dc009d92 EB |
468 | crashkernel=nn[KMG]@ss[KMG] |
469 | [KNL] Reserve a chunk of physical memory to | |
470 | hold a kernel to switch to with kexec on panic. | |
471 | ||
1da177e4 LT |
472 | cs4232= [HW,OSS] |
473 | Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq> | |
474 | ||
475 | cs89x0_dma= [HW,NET] | |
476 | Format: <dma> | |
477 | ||
478 | cs89x0_media= [HW,NET] | |
479 | Format: { rj45 | aui | bnc } | |
a9913044 | 480 | |
1da177e4 | 481 | cyclades= [HW,SERIAL] Cyclades multi-serial port adapter. |
a9913044 RD |
482 | |
483 | dasd= [HW,NET] | |
1da177e4 LT |
484 | See header of drivers/s390/block/dasd_devmap.c. |
485 | ||
486 | db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port | |
487 | (one device per port) | |
488 | Format: <port#>,<type> | |
489 | See also Documentation/input/joystick-parport.txt | |
490 | ||
491 | debug [KNL] Enable kernel debugging (events log level). | |
492 | ||
cae2ed9a IM |
493 | debug_locks_verbose= |
494 | [KNL] verbose self-tests | |
495 | Format=<0|1> | |
496 | Print debugging info while doing the locking API | |
497 | self-tests. | |
498 | We default to 0 (no extra messages), setting it to | |
499 | 1 will print _a lot_ more information - normally | |
500 | only useful to kernel developers. | |
501 | ||
1da177e4 LT |
502 | decnet= [HW,NET] |
503 | Format: <area>[,<node>] | |
504 | See also Documentation/networking/decnet.txt. | |
505 | ||
55ff9780 AD |
506 | default_blu= [VT] |
507 | Format: <blue0>,<blue1>,<blue2>,...,<blue15> | |
508 | Change the default blue palette of the console. | |
509 | This is a 16-member array composed of values | |
510 | ranging from 0-255. | |
511 | ||
512 | default_grn= [VT] | |
513 | Format: <green0>,<green1>,<green2>,...,<green15> | |
514 | Change the default green palette of the console. | |
515 | This is a 16-member array composed of values | |
516 | ranging from 0-255. | |
517 | ||
518 | default_red= [VT] | |
519 | Format: <red0>,<red1>,<red2>,...,<red15> | |
520 | Change the default red palette of the console. | |
521 | This is a 16-member array composed of values | |
522 | ranging from 0-255. | |
523 | ||
524 | default_utf8= [VT] | |
525 | Format=<0|1> | |
526 | Set system-wide default UTF-8 mode for all tty's. | |
527 | Default is 0 and by setting to 1, it enables UTF-8 | |
528 | mode for all newly opened or allocated terminals. | |
529 | ||
1da177e4 LT |
530 | dhash_entries= [KNL] |
531 | Set number of hash buckets for dentry cache. | |
a9913044 | 532 | |
1da177e4 LT |
533 | digi= [HW,SERIAL] |
534 | IO parameters + enable/disable command. | |
535 | ||
536 | digiepca= [HW,SERIAL] | |
537 | See drivers/char/README.epca and | |
538 | Documentation/digiepca.txt. | |
539 | ||
540 | dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA | |
541 | support available. | |
542 | Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]] | |
543 | ||
544 | dmasound= [HW,OSS] Sound subsystem buffers | |
545 | ||
546 | dscc4.setup= [NET] | |
547 | ||
548 | dtc3181e= [HW,SCSI] | |
549 | ||
e523d93c | 550 | earlyprintk= [IA-32,X86-64,SH] |
1da177e4 LT |
551 | earlyprintk=vga |
552 | earlyprintk=serial[,ttySn[,baudrate]] | |
553 | ||
a9913044 | 554 | Append ",keep" to not disable it when the real console |
1da177e4 LT |
555 | takes over. |
556 | ||
557 | Only vga or serial at a time, not both. | |
558 | ||
559 | Currently only ttyS0 and ttyS1 are supported. | |
560 | ||
561 | Interaction with the standard serial driver is not | |
562 | very good. | |
563 | ||
564 | The VGA output is eventually overwritten by the real | |
565 | console. | |
566 | ||
567 | eata= [HW,SCSI] | |
568 | ||
53f11d4f LB |
569 | ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode |
570 | Format: <int> | |
571 | 0: polling mode | |
572 | non-0: interrupt mode (default) | |
573 | ||
1da177e4 LT |
574 | eda= [HW,PS2] |
575 | ||
576 | edb= [HW,PS2] | |
577 | ||
578 | edd= [EDD] | |
579 | Format: {"of[f]" | "sk[ipmbr]"} | |
580 | See comment in arch/i386/boot/edd.S | |
581 | ||
a9913044 | 582 | eicon= [HW,ISDN] |
1da177e4 LT |
583 | Format: <id>,<membase>,<irq> |
584 | ||
585 | eisa_irq_edge= [PARISC,HW] | |
586 | See header of drivers/parisc/eisa.c. | |
587 | ||
588 | elanfreq= [IA-32] | |
589 | See comment before function elanfreq_setup() in | |
590 | arch/i386/kernel/cpu/cpufreq/elanfreq.c. | |
591 | ||
592 | elevator= [IOSCHED] | |
16ab3adf | 593 | Format: {"anticipatory" | "cfq" | "deadline" | "noop"} |
a9913044 RD |
594 | See Documentation/block/as-iosched.txt and |
595 | Documentation/block/deadline-iosched.txt for details. | |
596 | ||
aac04b32 | 597 | elfcorehdr= [IA-32, X86_64] |
a9913044 | 598 | Specifies physical address of start of kernel core |
aac04b32 VG |
599 | image elf header. Generally kexec loader will |
600 | pass this option to capture kernel. | |
601 | See Documentation/kdump/kdump.txt for details. | |
1da177e4 LT |
602 | |
603 | enforcing [SELINUX] Set initial enforcing status. | |
604 | Format: {"0" | "1"} | |
605 | See security/selinux/Kconfig help text. | |
606 | 0 -- permissive (log only, no denials). | |
607 | 1 -- enforcing (deny and log). | |
608 | Default value is 0. | |
609 | Value can be changed at runtime via /selinux/enforce. | |
610 | ||
1da177e4 LT |
611 | es1371= [HW,OSS] |
612 | Format: <spdif>,[<nomix>,[<amplifier>]] | |
613 | See also header of sound/oss/es1371.c. | |
a9913044 | 614 | |
1da177e4 LT |
615 | ether= [HW,NET] Ethernet cards parameters |
616 | This option is obsoleted by the "netdev=" option, which | |
617 | has equivalent usage. See its documentation for details. | |
618 | ||
619 | eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog. | |
620 | Format: <io>[,<irq>] | |
621 | ||
de1ba09b AM |
622 | failslab= |
623 | fail_page_alloc= | |
624 | fail_make_request=[KNL] | |
625 | General fault injection mechanism. | |
626 | Format: <interval>,<probability>,<space>,<times> | |
627 | See also /Documentation/fault-injection/. | |
628 | ||
1da177e4 LT |
629 | fd_mcs= [HW,SCSI] |
630 | See header of drivers/scsi/fd_mcs.c. | |
631 | ||
632 | fdomain= [HW,SCSI] | |
633 | See header of drivers/scsi/fdomain.c. | |
634 | ||
635 | floppy= [HW] | |
636 | See Documentation/floppy.txt. | |
637 | ||
1da177e4 LT |
638 | gamecon.map[2|3]= |
639 | [HW,JOY] Multisystem joystick and NES/SNES/PSX pad | |
640 | support via parallel port (up to 5 devices per port) | |
641 | Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> | |
642 | See also Documentation/input/joystick-parport.txt | |
643 | ||
644 | gamma= [HW,DRM] | |
645 | ||
646 | gdth= [HW,SCSI] | |
647 | See header of drivers/scsi/gdth.c. | |
648 | ||
649 | gpt [EFI] Forces disk with valid GPT signature but | |
650 | invalid Protective MBR to be treated as GPT. | |
651 | ||
1da177e4 LT |
652 | gvp11= [HW,SCSI] |
653 | ||
654 | hashdist= [KNL,NUMA] Large hashes allocated during boot | |
655 | are distributed across NUMA nodes. Defaults on | |
656 | for IA-64, off otherwise. | |
a9913044 | 657 | Format: 0 | 1 (for off | on) |
1da177e4 LT |
658 | |
659 | hcl= [IA-64] SGI's Hardware Graph compatibility layer | |
660 | ||
661 | hd= [EIDE] (E)IDE hard drive subsystem geometry | |
662 | Format: <cyl>,<head>,<sect> | |
663 | ||
664 | hd?= [HW] (E)IDE subsystem | |
665 | hd?lun= See Documentation/ide.txt. | |
666 | ||
667 | highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact | |
668 | size of <nn>. This works even on boxes that have no | |
669 | highmem otherwise. This also works to reduce highmem | |
670 | size on bigger boxes. | |
671 | ||
54cdfdb4 TG |
672 | highres= [KNL] Enable/disable high resolution timer mode. |
673 | Valid parameters: "on", "off" | |
674 | Default: "on" | |
675 | ||
1da177e4 LT |
676 | hisax= [HW,ISDN] |
677 | See Documentation/isdn/README.HiSax. | |
678 | ||
679 | hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages. | |
680 | ||
1da177e4 | 681 | i8042.direct [HW] Put keyboard port into non-translated mode |
84eb8d06 ML |
682 | i8042.dumbkbd [HW] Pretend that controller can only read data from |
683 | keyboard and cannot control its state | |
1da177e4 LT |
684 | (Don't attempt to blink the leds) |
685 | i8042.noaux [HW] Don't check for auxiliary (== mouse) port | |
945ef0d4 | 686 | i8042.nokbd [HW] Don't check/create keyboard port |
1da177e4 LT |
687 | i8042.nomux [HW] Don't check presence of an active multiplexing |
688 | controller | |
689 | i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX | |
690 | controllers | |
691 | i8042.panicblink= | |
692 | [HW] Frequency with which keyboard LEDs should blink | |
693 | when kernel panics (default is 0.5 sec) | |
694 | i8042.reset [HW] Reset the controller during init and cleanup | |
695 | i8042.unlock [HW] Unlock (ignore) the keylock | |
696 | ||
697 | i810= [HW,DRM] | |
698 | ||
e70c9d5e DT |
699 | i8k.ignore_dmi [HW] Continue probing hardware even if DMI data |
700 | indicates that the driver is running on unsupported | |
701 | hardware. | |
1da177e4 LT |
702 | i8k.force [HW] Activate i8k driver even if SMM BIOS signature |
703 | does not match list of supported models. | |
704 | i8k.power_status | |
705 | [HW] Report power status in /proc/i8k | |
706 | (disabled by default) | |
707 | i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN | |
708 | capability is set. | |
709 | ||
710 | ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter | |
711 | See Documentation/mca.txt. | |
712 | ||
713 | icn= [HW,ISDN] | |
714 | Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] | |
715 | ||
716 | ide= [HW] (E)IDE subsystem | |
717 | Format: ide=nodma or ide=doubler or ide=reverse | |
718 | See Documentation/ide.txt. | |
719 | ||
720 | ide?= [HW] (E)IDE subsystem | |
721 | Format: ide?=noprobe or chipset specific parameters. | |
722 | See Documentation/ide.txt. | |
a9913044 | 723 | |
1da177e4 LT |
724 | idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed |
725 | See Documentation/ide.txt. | |
726 | ||
f039b754 AK |
727 | idle= [X86] |
728 | Format: idle=poll or idle=mwait | |
729 | Poll forces a polling idle loop that can slightly improves the performance | |
730 | of waking up a idle CPU, but will use a lot of power and make the system | |
731 | run hot. Not recommended. | |
732 | idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose | |
733 | to not use it because it doesn't save as much power as a normal idle | |
734 | loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same | |
735 | as idle=poll. | |
a9913044 | 736 | |
79290822 IM |
737 | ignore_loglevel [KNL] |
738 | Ignore loglevel setting - this will print /all/ | |
739 | kernel messages to the console. Useful for debugging. | |
740 | ||
1da177e4 LT |
741 | ihash_entries= [KNL] |
742 | Set number of hash buckets for inode cache. | |
743 | ||
744 | in2000= [HW,SCSI] | |
745 | See header of drivers/scsi/in2000.c. | |
746 | ||
747 | init= [KNL] | |
748 | Format: <full_path> | |
749 | Run specified binary instead of /sbin/init as init | |
750 | process. | |
751 | ||
752 | initcall_debug [KNL] Trace initcalls as they are executed. Useful | |
753 | for working out where the kernel is dying during | |
754 | startup. | |
755 | ||
756 | initrd= [BOOT] Specify the location of the initial ramdisk | |
757 | ||
758 | inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver | |
759 | Format: <irq> | |
760 | ||
761 | inttest= [IA64] | |
762 | ||
763 | io7= [HW] IO7 for Marvel based alpha systems | |
764 | See comment before marvel_specify_io7 in | |
765 | arch/alpha/kernel/core_marvel.c. | |
766 | ||
767 | ip= [IP_PNP] | |
768 | See Documentation/nfsroot.txt. | |
769 | ||
770 | ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards | |
771 | See comment before ip2_setup() in drivers/char/ip2.c. | |
772 | ||
773 | ips= [HW,SCSI] Adaptec / IBM ServeRAID controller | |
774 | See header of drivers/scsi/ips.c. | |
775 | ||
72c4a13a SH |
776 | ports= [IP_VS_FTP] IPVS ftp helper module |
777 | Default is 21. | |
778 | Up to 8 (IP_VS_APP_MAX_PORTS) ports | |
779 | may be specified. | |
780 | Format: <port>,<port>.... | |
781 | ||
200803df AC |
782 | irqfixup [HW] |
783 | When an interrupt is not handled search all handlers | |
784 | for it. Intended to get systems with badly broken | |
785 | firmware running. | |
786 | ||
787 | irqpoll [HW] | |
788 | When an interrupt is not handled search all handlers | |
789 | for it. Also check all handlers each timer | |
790 | interrupt. Intended to get systems with badly broken | |
791 | firmware running. | |
792 | ||
1da177e4 | 793 | isapnp= [ISAPNP] |
a9913044 | 794 | Format: <RDP>,<reset>,<pci_scan>,<verbosity> |
1da177e4 LT |
795 | |
796 | isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. | |
22f2e280 DF |
797 | Format: |
798 | <cpu number>,...,<cpu number> | |
799 | or | |
800 | <cpu number>-<cpu number> (must be a positive range in ascending order) | |
801 | or a mixture | |
802 | <cpu number>,...,<cpu number>-<cpu number> | |
1da177e4 LT |
803 | This option can be used to specify one or more CPUs |
804 | to isolate from the general SMP balancing and scheduling | |
805 | algorithms. The only way to move a process onto or off | |
806 | an "isolated" CPU is via the CPU affinity syscalls. | |
807 | <cpu number> begins at 0 and the maximum value is | |
808 | "number of CPUs in system - 1". | |
809 | ||
810 | This option is the preferred way to isolate CPUs. The | |
a9913044 RD |
811 | alternative -- manually setting the CPU mask of all |
812 | tasks in the system -- can cause problems and | |
813 | suboptimal load balancer performance. | |
1da177e4 | 814 | |
a9913044 | 815 | iucv= [HW,NET] |
1da177e4 LT |
816 | |
817 | js= [HW,JOY] Analog joystick | |
818 | See Documentation/input/joystick.txt. | |
819 | ||
820 | keepinitrd [HW,ARM] | |
821 | ||
a9913044 | 822 | kstack=N [IA-32,X86-64] Print N words from the kernel stack |
1da177e4 LT |
823 | in oops dumps. |
824 | ||
825 | l2cr= [PPC] | |
826 | ||
a9913044 RD |
827 | lapic [IA-32,APIC] Enable the local APIC even if BIOS |
828 | disabled it. | |
1da177e4 | 829 | |
2e7c2838 | 830 | lapic_timer_c2_ok [IA-32,x86-64,APIC] trust the local apic timer in |
e585bef8 TG |
831 | C2 power state. |
832 | ||
1da177e4 LT |
833 | lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip |
834 | Format: addr:<io>,irq:<irq> | |
835 | ||
7e92b4fc BH |
836 | legacy_serial.force [HW,IA-32,X86-64] |
837 | Probe for COM ports at legacy addresses even | |
838 | if PNPBIOS or ACPI should describe them. This | |
839 | is for working around firmware defects. | |
840 | ||
a9913044 RD |
841 | llsc*= [IA64] See function print_params() in |
842 | arch/ia64/sn/kernel/llsc4.c. | |
1da177e4 LT |
843 | |
844 | load_ramdisk= [RAM] List of ramdisks to load from floppy | |
845 | See Documentation/ramdisk.txt. | |
846 | ||
a6b25b67 RD |
847 | lockd.nlm_grace_period=P [NFS] Assign grace period. |
848 | Format: <integer> | |
1da177e4 | 849 | |
a6b25b67 RD |
850 | lockd.nlm_tcpport=N [NFS] Assign TCP port. |
851 | Format: <integer> | |
852 | ||
853 | lockd.nlm_timeout=T [NFS] Assign timeout value. | |
854 | Format: <integer> | |
855 | ||
856 | lockd.nlm_udpport=M [NFS] Assign UDP port. | |
857 | Format: <integer> | |
1da177e4 LT |
858 | |
859 | logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver | |
860 | Format: <irq> | |
861 | ||
862 | loglevel= All Kernel Messages with a loglevel smaller than the | |
863 | console loglevel will be printed to the console. It can | |
864 | also be changed with klogd or other programs. The | |
865 | loglevels are defined as follows: | |
866 | ||
867 | 0 (KERN_EMERG) system is unusable | |
868 | 1 (KERN_ALERT) action must be taken immediately | |
869 | 2 (KERN_CRIT) critical conditions | |
870 | 3 (KERN_ERR) error conditions | |
871 | 4 (KERN_WARNING) warning conditions | |
872 | 5 (KERN_NOTICE) normal but significant condition | |
873 | 6 (KERN_INFO) informational | |
874 | 7 (KERN_DEBUG) debug-level messages | |
875 | ||
876 | log_buf_len=n Sets the size of the printk ring buffer, in bytes. | |
a9913044 RD |
877 | Format: { n | nk | nM } |
878 | n must be a power of two. The default size | |
879 | is set in the kernel config file. | |
1da177e4 LT |
880 | |
881 | lp=0 [LP] Specify parallel ports to use, e.g, | |
882 | lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses | |
883 | lp=reset first parallel port). 'lp=0' disables the | |
884 | lp=auto printer driver. 'lp=reset' (which can be | |
885 | specified in addition to the ports) causes | |
886 | attached printers to be reset. Using | |
887 | lp=port1,port2,... specifies the parallel ports | |
888 | to associate lp devices with, starting with | |
889 | lp0. A port specification may be 'none' to skip | |
890 | that lp device, or a parport name such as | |
891 | 'parport0'. Specifying 'lp=auto' instead of a | |
892 | port specification list means that device IDs | |
893 | from each port should be examined, to see if | |
894 | an IEEE 1284-compliant printer is attached; if | |
895 | so, the driver will manage that printer. | |
896 | See also header of drivers/char/lp.c. | |
897 | ||
898 | lpj=n [KNL] | |
899 | Sets loops_per_jiffy to given constant, thus avoiding | |
900 | time-consuming boot-time autodetection (up to 250 ms per | |
901 | CPU). 0 enables autodetection (default). To determine | |
902 | the correct value for your kernel, boot with normal | |
903 | autodetection and see what value is printed. Note that | |
904 | on SMP systems the preset will be applied to all CPUs, | |
905 | which is likely to cause problems if your CPUs need | |
906 | significantly divergent settings. An incorrect value | |
907 | will cause delays in the kernel to be wrong, leading to | |
908 | unpredictable I/O errors and other breakage. Although | |
909 | unlikely, in the extreme case this might damage your | |
910 | hardware. | |
911 | ||
912 | ltpc= [NET] | |
913 | Format: <io>,<irq>,<dma> | |
914 | ||
a9913044 RD |
915 | mac5380= [HW,SCSI] Format: |
916 | <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
1da177e4 | 917 | |
a9913044 RD |
918 | mac53c9x= [HW,SCSI] Format: |
919 | <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> | |
1da177e4 | 920 | |
a9913044 RD |
921 | machvec= [IA64] Force the use of a particular machine-vector |
922 | (machvec) in a generic kernel. | |
923 | Example: machvec=hpzx1_swiotlb | |
1da177e4 | 924 | |
a9913044 | 925 | max_loop= [LOOP] Maximum number of loopback devices that can |
1da177e4 LT |
926 | be mounted |
927 | Format: <1-256> | |
928 | ||
929 | maxcpus= [SMP] Maximum number of processors that an SMP kernel | |
78f92a82 RD |
930 | should make use of. |
931 | Using "nosmp" or "maxcpus=0" will disable SMP | |
932 | entirely (the MPS table probe still happens, though). | |
933 | A command-line option of "maxcpus=<NUM>", where <NUM> | |
934 | is an integer greater than 0, limits the maximum number | |
935 | of CPUs activated in SMP mode to <NUM>. | |
936 | Using "maxcpus=1" on an SMP kernel is the trivial | |
937 | case of an SMP kernel with only one CPU. | |
1da177e4 | 938 | |
2b2c3750 BP |
939 | max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or |
940 | equal to this physical address is ignored. | |
941 | ||
a9913044 | 942 | max_luns= [SCSI] Maximum number of LUNs to probe. |
1da177e4 LT |
943 | Should be between 1 and 2^32-1. |
944 | ||
945 | max_report_luns= | |
a9913044 | 946 | [SCSI] Maximum number of LUNs received. |
1da177e4 LT |
947 | Should be between 1 and 16384. |
948 | ||
949 | mca-pentium [BUGS=IA-32] | |
950 | ||
951 | mcatest= [IA-64] | |
952 | ||
1da177e4 LT |
953 | mce [IA-32] Machine Check Exception |
954 | ||
955 | md= [HW] RAID subsystems devices and level | |
956 | See Documentation/md.txt. | |
a9913044 | 957 | |
1da177e4 LT |
958 | mdacon= [MDA] |
959 | Format: <first>,<last> | |
960 | Specifies range of consoles to be captured by the MDA. | |
a9913044 | 961 | |
1da177e4 LT |
962 | mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory |
963 | Amount of memory to be used when the kernel is not able | |
964 | to see the whole system memory or for test. | |
965 | [IA-32] Use together with memmap= to avoid physical | |
966 | address space collisions. Without memmap= PCI devices | |
967 | could be placed at addresses belonging to unused RAM. | |
968 | ||
969 | mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel | |
970 | memory. | |
971 | ||
69cda7b1 | 972 | memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact |
1da177e4 LT |
973 | E820 memory map, as specified by the user. |
974 | Such memmap=exactmap lines can be constructed based on | |
975 | BIOS output or other requirements. See the memmap=nn@ss | |
976 | option description. | |
977 | ||
978 | memmap=nn[KMG]@ss[KMG] | |
979 | [KNL] Force usage of a specific region of memory | |
980 | Region of memory to be used, from ss to ss+nn. | |
981 | ||
982 | memmap=nn[KMG]#ss[KMG] | |
983 | [KNL,ACPI] Mark specific memory as ACPI data. | |
984 | Region of memory to be used, from ss to ss+nn. | |
985 | ||
986 | memmap=nn[KMG]$ss[KMG] | |
987 | [KNL,ACPI] Mark specific memory as reserved. | |
988 | Region of memory to be used, from ss to ss+nn. | |
989 | ||
990 | meye.*= [HW] Set MotionEye Camera parameters | |
991 | See Documentation/video4linux/meye.txt. | |
992 | ||
993 | mga= [HW,DRM] | |
994 | ||
995 | mousedev.tap_time= | |
996 | [MOUSE] Maximum time between finger touching and | |
997 | leaving touchpad surface for touch to be considered | |
998 | a tap and be reported as a left button click (for | |
999 | touchpads working in absolute mode only). | |
1000 | Format: <msecs> | |
1001 | mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices | |
1002 | reporting absolute coordinates, such as tablets | |
1003 | mousedev.yres= [MOUSE] Vertical screen resolution, used for devices | |
1004 | reporting absolute coordinates, such as tablets | |
1005 | ||
1006 | mpu401= [HW,OSS] | |
1007 | Format: <io>,<irq> | |
1008 | ||
1009 | MTD_Partition= [MTD] | |
1010 | Format: <name>,<region-number>,<size>,<offset> | |
1011 | ||
a9913044 RD |
1012 | MTD_Region= [MTD] Format: |
1013 | <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] | |
1da177e4 LT |
1014 | |
1015 | mtdparts= [MTD] | |
1016 | See drivers/mtd/cmdline.c. | |
1017 | ||
1018 | mtouchusb.raw_coordinates= | |
a9913044 RD |
1019 | [HW] Make the MicroTouch USB driver use raw coordinates |
1020 | ('y', default) or cooked coordinates ('n') | |
1da177e4 LT |
1021 | |
1022 | n2= [NET] SDL Inc. RISCom/N2 synchronous serial card | |
1023 | ||
1024 | NCR_D700= [HW,SCSI] | |
1025 | See header of drivers/scsi/NCR_D700.c. | |
1026 | ||
1027 | ncr5380= [HW,SCSI] | |
1028 | ||
1029 | ncr53c400= [HW,SCSI] | |
1030 | ||
1031 | ncr53c400a= [HW,SCSI] | |
1032 | ||
1033 | ncr53c406a= [HW,SCSI] | |
1034 | ||
1035 | ncr53c8xx= [HW,SCSI] | |
1036 | ||
1037 | netdev= [NET] Network devices parameters | |
1038 | Format: <irq>,<io>,<mem_start>,<mem_end>,<name> | |
1039 | Note that mem_start is often overloaded to mean | |
1040 | something different and driver-specific. | |
a9913044 RD |
1041 | This usage is only documented in each driver source |
1042 | file if at all. | |
1043 | ||
1da177e4 LT |
1044 | nfsaddrs= [NFS] |
1045 | See Documentation/nfsroot.txt. | |
1046 | ||
1047 | nfsroot= [NFS] nfs root filesystem for disk-less boxes. | |
1048 | See Documentation/nfsroot.txt. | |
1049 | ||
a72b4422 TM |
1050 | nfs.callback_tcpport= |
1051 | [NFS] set the TCP port on which the NFSv4 callback | |
1052 | channel should listen. | |
1053 | ||
58df095b TM |
1054 | nfs.idmap_cache_timeout= |
1055 | [NFS] set the maximum lifetime for idmapper cache | |
1056 | entries. | |
1057 | ||
1da177e4 LT |
1058 | nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels |
1059 | ||
1060 | no387 [BUGS=IA-32] Tells the kernel to use the 387 maths | |
1061 | emulation library even if a 387 maths coprocessor | |
1062 | is present. | |
1063 | ||
11ef697b KCA |
1064 | noacpi [LIBATA] Disables use of ACPI in libata suspend/resume |
1065 | when set. | |
1066 | Format: <int> | |
1067 | ||
c1aee215 CL |
1068 | noaliencache [MM, NUMA, SLAB] Disables the allocation of alien |
1069 | caches in the slab allocator. Saves per-node memory, | |
1070 | but will impact performance. | |
3395ee05 | 1071 | |
a9913044 RD |
1072 | noalign [KNL,ARM] |
1073 | ||
1da177e4 LT |
1074 | noapic [SMP,APIC] Tells the kernel to not make use of any |
1075 | IOAPICs that may be present in the system. | |
1076 | ||
1077 | noasync [HW,M68K] Disables async and sync negotiation for | |
1078 | all devices. | |
1079 | ||
1080 | nobats [PPC] Do not use BATs for mapping kernel lowmem | |
1081 | on "Classic" PPC cores. | |
1082 | ||
1083 | nocache [ARM] | |
a9913044 | 1084 | |
163ecdff SN |
1085 | nodelayacct [KNL] Disable per-task delay accounting |
1086 | ||
1da177e4 LT |
1087 | nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. |
1088 | ||
1089 | noexec [IA-64] | |
1090 | ||
a9913044 | 1091 | noexec [IA-32,X86-64] |
1da177e4 LT |
1092 | noexec=on: enable non-executable mappings (default) |
1093 | noexec=off: disable nn-executable mappings | |
1094 | ||
4f886511 CE |
1095 | nofxsr [BUGS=IA-32] Disables x86 floating point extended |
1096 | register save and restore. The kernel will only save | |
1097 | legacy floating-point registers on task switch. | |
1da177e4 LT |
1098 | |
1099 | nohlt [BUGS=ARM] | |
a9913044 | 1100 | |
1da177e4 LT |
1101 | no-hlt [BUGS=IA-32] Tells the kernel that the hlt |
1102 | instruction doesn't work correctly and not to | |
1103 | use it. | |
1104 | ||
1105 | nohalt [IA-64] Tells the kernel not to use the power saving | |
1106 | function PAL_HALT_LIGHT when idle. This increases | |
1107 | power-consumption. On the positive side, it reduces | |
1108 | interrupt wake-up latency, which may improve performance | |
1109 | in certain environments such as networked servers or | |
1110 | real-time systems. | |
1111 | ||
79bf2bb3 TG |
1112 | nohz= [KNL] Boottime enable/disable dynamic ticks |
1113 | Valid arguments: on, off | |
1114 | Default: on | |
1115 | ||
8542b200 ZA |
1116 | noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing |
1117 | ||
1da177e4 LT |
1118 | noirqdebug [IA-32] Disables the code which attempts to detect and |
1119 | disable unhandled interrupt sources. | |
1120 | ||
8542b200 ZA |
1121 | no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for |
1122 | broken timer IRQ sources. | |
1123 | ||
1da177e4 LT |
1124 | noisapnp [ISAPNP] Disables ISA PnP code. |
1125 | ||
1126 | noinitrd [RAM] Tells the kernel not to load any configured | |
1127 | initial RAM disk. | |
1128 | ||
1129 | nointroute [IA-64] | |
1130 | ||
1131 | nolapic [IA-32,APIC] Do not enable or use the local APIC. | |
1132 | ||
ad62ca2b TG |
1133 | nolapic_timer [IA-32,APIC] Do not use the local APIC timer. |
1134 | ||
1da177e4 LT |
1135 | noltlbs [PPC] Do not use large page/tlb entries for kernel |
1136 | lowmem mapping on PPC40x. | |
1137 | ||
312f1f01 H |
1138 | nomca [IA-64] Disable machine check abort handling |
1139 | ||
abe37e5a H |
1140 | nomce [IA-32] Machine Check Exception |
1141 | ||
959b4fdf JF |
1142 | noreplace-paravirt [IA-32,PV_OPS] Don't patch paravirt_ops |
1143 | ||
b7fb4af0 JF |
1144 | noreplace-smp [IA-32,SMP] Don't replace SMP instructions |
1145 | with UP alternatives | |
1146 | ||
1da177e4 LT |
1147 | noresidual [PPC] Don't use residual data on PReP machines. |
1148 | ||
a9913044 RD |
1149 | noresume [SWSUSP] Disables resume and restores original swap |
1150 | space. | |
1151 | ||
1da177e4 LT |
1152 | no-scroll [VGA] Disables scrollback. |
1153 | This is required for the Braillex ib80-piezo Braille | |
1154 | reader made by F.H. Papenmeier (Germany). | |
1155 | ||
1156 | nosbagart [IA-64] | |
1157 | ||
4f886511 CE |
1158 | nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support. |
1159 | ||
1da177e4 LT |
1160 | nosmp [SMP] Tells an SMP kernel to act as a UP kernel. |
1161 | ||
97842216 DJ |
1162 | nosoftlockup [KNL] Disable the soft-lockup detector. |
1163 | ||
1da177e4 LT |
1164 | nosync [HW,M68K] Disables sync negotiation for all devices. |
1165 | ||
1166 | notsc [BUGS=IA-32] Disable Time Stamp Counter | |
1167 | ||
1168 | nousb [USB] Disable the USB subsystem | |
1169 | ||
1170 | nowb [ARM] | |
a9913044 | 1171 | |
f0c0b2b8 KH |
1172 | numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. |
1173 | one of ['zone', 'node', 'default'] can be specified | |
1174 | This can be set from sysctl after boot. | |
1175 | See Documentation/sysctl/vm.txt for details. | |
1176 | ||
a61c2d78 DJ |
1177 | nr_uarts= [SERIAL] maximum number of UARTs to be registered. |
1178 | ||
1da177e4 LT |
1179 | opl3= [HW,OSS] |
1180 | Format: <io> | |
1181 | ||
1da177e4 LT |
1182 | oprofile.timer= [HW] |
1183 | Use timer interrupt instead of performance counters | |
1184 | ||
1da177e4 LT |
1185 | osst= [HW,SCSI] SCSI Tape Driver |
1186 | Format: <buffer_size>,<write_threshold> | |
1187 | See also Documentation/scsi/st.txt. | |
1188 | ||
1189 | panic= [KNL] Kernel behaviour on panic | |
1190 | Format: <timeout> | |
1191 | ||
1192 | parkbd.port= [HW] Parallel port number the keyboard adapter is | |
1193 | connected to, default is 0. | |
1194 | Format: <parport#> | |
1195 | parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, | |
1196 | 0 for XT, 1 for AT (default is AT). | |
a9913044 RD |
1197 | Format: <mode> |
1198 | ||
1199 | parport= [HW,PPT] Specify parallel ports. 0 disables. | |
1200 | Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } | |
1201 | Use 'auto' to force the driver to use any | |
1202 | IRQ/DMA settings detected (the default is to | |
1203 | ignore detected IRQ/DMA settings because of | |
1204 | possible conflicts). You can specify the base | |
1205 | address, IRQ, and DMA settings; IRQ and DMA | |
1206 | should be numbers, or 'auto' (for using detected | |
1207 | settings on that particular port), or 'nofifo' | |
1208 | (to avoid using a FIFO even if it is detected). | |
1209 | Parallel ports are assigned in the order they | |
1210 | are specified on the command line, starting | |
1211 | with parport0. | |
1212 | ||
1213 | parport_init_mode= [HW,PPT] | |
1214 | Configure VIA parallel port to operate in | |
1215 | a specific mode. This is necessary on Pegasos | |
1216 | computer where firmware has no options for setting | |
1217 | up parallel port mode and sets it to spp. | |
1218 | Currently this function knows 686a and 8231 chips. | |
1da177e4 LT |
1219 | Format: [spp|ps2|epp|ecp|ecpepp] |
1220 | ||
a9913044 RD |
1221 | pas2= [HW,OSS] Format: |
1222 | <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16> | |
1223 | ||
1da177e4 LT |
1224 | pas16= [HW,SCSI] |
1225 | See header of drivers/scsi/pas16.c. | |
1226 | ||
dd287796 AM |
1227 | pause_on_oops= |
1228 | Halt all CPUs after the first oops has been printed for | |
1229 | the specified number of seconds. This is to be used if | |
1230 | your oopses keep scrolling off the screen. | |
1231 | ||
1da177e4 LT |
1232 | pcbit= [HW,ISDN] |
1233 | ||
1234 | pcd. [PARIDE] | |
1235 | See header of drivers/block/paride/pcd.c. | |
1236 | See also Documentation/paride.txt. | |
1237 | ||
a9913044 RD |
1238 | pci=option[,option...] [PCI] various PCI subsystem options: |
1239 | off [IA-32] don't probe for the PCI bus | |
1240 | bios [IA-32] force use of PCI BIOS, don't access | |
1241 | the hardware directly. Use this if your machine | |
1242 | has a non-standard PCI host bridge. | |
1243 | nobios [IA-32] disallow use of PCI BIOS, only direct | |
1244 | hardware access methods are allowed. Use this | |
1245 | if you experience crashes upon bootup and you | |
1246 | suspect they are caused by the BIOS. | |
1247 | conf1 [IA-32] Force use of PCI Configuration | |
1248 | Mechanism 1. | |
1249 | conf2 [IA-32] Force use of PCI Configuration | |
1250 | Mechanism 2. | |
61be6d66 BH |
1251 | nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI |
1252 | Configuration | |
309e57df MW |
1253 | nomsi [MSI] If the PCI_MSI kernel config parameter is |
1254 | enabled, this kernel boot option can be used to | |
1255 | disable the use of MSI interrupts system-wide. | |
a9913044 RD |
1256 | nosort [IA-32] Don't sort PCI devices according to |
1257 | order given by the PCI BIOS. This sorting is | |
1258 | done to get a device order compatible with | |
1259 | older kernels. | |
1260 | biosirq [IA-32] Use PCI BIOS calls to get the interrupt | |
1261 | routing table. These calls are known to be buggy | |
1262 | on several machines and they hang the machine | |
1263 | when used, but on other computers it's the only | |
1264 | way to get the interrupt routing table. Try | |
1265 | this option if the kernel is unable to allocate | |
1266 | IRQs or discover secondary PCI buses on your | |
1267 | motherboard. | |
1268 | rom [IA-32] Assign address space to expansion ROMs. | |
1269 | Use with caution as certain devices share | |
1270 | address decoders between ROMs and other | |
1271 | resources. | |
1272 | irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be | |
1273 | assigned automatically to PCI devices. You can | |
1274 | make the kernel exclude IRQs of your ISA cards | |
1275 | this way. | |
120bb424 | 1276 | pirqaddr=0xAAAAA [IA-32] Specify the physical address |
a9913044 RD |
1277 | of the PIRQ table (normally generated |
1278 | by the BIOS) if it is outside the | |
1279 | F0000h-100000h range. | |
1280 | lastbus=N [IA-32] Scan all buses thru bus #N. Can be | |
1281 | useful if the kernel is unable to find your | |
1282 | secondary buses and you want to tell it | |
1283 | explicitly which ones they are. | |
1284 | assign-busses [IA-32] Always assign all PCI bus | |
1285 | numbers ourselves, overriding | |
1286 | whatever the firmware may have done. | |
1287 | usepirqmask [IA-32] Honor the possible IRQ mask stored | |
1288 | in the BIOS $PIR table. This is needed on | |
1289 | some systems with broken BIOSes, notably | |
1290 | some HP Pavilion N5400 and Omnibook XE3 | |
1291 | notebooks. This will have no effect if ACPI | |
1292 | IRQ routing is enabled. | |
1293 | noacpi [IA-32] Do not use ACPI for IRQ routing | |
1294 | or for PCI scanning. | |
1295 | routeirq Do IRQ routing for all PCI devices. | |
1296 | This is normally done in pci_enable_device(), | |
1297 | so this option is a temporary workaround | |
1298 | for broken drivers that don't call it. | |
1299 | firmware [ARM] Do not re-enumerate the bus but instead | |
1300 | just use the configuration from the | |
1301 | bootloader. This is currently used on | |
1302 | IXP2000 systems where the bus has to be | |
1303 | configured a certain way for adjunct CPUs. | |
0637a70a AK |
1304 | noearly [X86] Don't do any early type 1 scanning. |
1305 | This might help on some broken boards which | |
1306 | machine check when some devices' config space | |
1307 | is read. But various workarounds are disabled | |
1308 | and some IOMMU drivers will not work. | |
6b4b78fe MD |
1309 | bfsort Sort PCI devices into breadth-first order. |
1310 | This sorting is done to get a device | |
1311 | order compatible with older (<= 2.4) kernels. | |
1312 | nobfsort Don't sort PCI devices into breadth-first order. | |
4516a618 AN |
1313 | cbiosize=nn[KMG] The fixed amount of bus space which is |
1314 | reserved for the CardBus bridge's IO window. | |
1315 | The default value is 256 bytes. | |
1316 | cbmemsize=nn[KMG] The fixed amount of bus space which is | |
1317 | reserved for the CardBus bridge's memory | |
1318 | window. The default value is 64 megabytes. | |
6b4b78fe | 1319 | |
1da177e4 LT |
1320 | pcmv= [HW,PCMCIA] BadgePAD 4 |
1321 | ||
1322 | pd. [PARIDE] | |
1323 | See Documentation/paride.txt. | |
1324 | ||
1325 | pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at | |
1326 | boot time. | |
1327 | Format: { 0 | 1 } | |
1328 | See arch/parisc/kernel/pdc_chassis.c | |
1329 | ||
1330 | pf. [PARIDE] | |
1331 | See Documentation/paride.txt. | |
1332 | ||
1333 | pg. [PARIDE] | |
1334 | See Documentation/paride.txt. | |
1335 | ||
1336 | pirq= [SMP,APIC] Manual mp-table setup | |
1337 | See Documentation/i386/IO-APIC.txt. | |
1338 | ||
1339 | plip= [PPT,NET] Parallel port network link | |
1340 | Format: { parport<nr> | timid | 0 } | |
1341 | See also Documentation/parport.txt. | |
1342 | ||
1343 | pnpacpi= [ACPI] | |
1344 | { off } | |
1345 | ||
1346 | pnpbios= [ISAPNP] | |
1347 | { on | off | curr | res | no-curr | no-res } | |
1348 | ||
1349 | pnp_reserve_irq= | |
1350 | [ISAPNP] Exclude IRQs for the autoconfiguration | |
1351 | ||
1352 | pnp_reserve_dma= | |
1353 | [ISAPNP] Exclude DMAs for the autoconfiguration | |
1354 | ||
1355 | pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration | |
a9913044 | 1356 | Ranges are in pairs (I/O port base and size). |
1da177e4 LT |
1357 | |
1358 | pnp_reserve_mem= | |
a9913044 RD |
1359 | [ISAPNP] Exclude memory regions for the |
1360 | autoconfiguration. | |
1da177e4 LT |
1361 | Ranges are in pairs (memory base and size). |
1362 | ||
45807a1d IM |
1363 | print-fatal-signals= |
1364 | [KNL] debug: print fatal signals | |
1365 | print-fatal-signals=1: print segfault info to | |
1366 | the kernel console. | |
1367 | default: off. | |
1368 | ||
e84845c4 RD |
1369 | printk.time= Show timing data prefixed to each printk message line |
1370 | Format: <bool> (1/Y/y=enable, 0/N/n=disable) | |
1371 | ||
1da177e4 | 1372 | profile= [KNL] Enable kernel profiling via /proc/profile |
a9913044 RD |
1373 | Format: [schedule,]<number> |
1374 | Param: "schedule" - profile schedule points. | |
1375 | Param: <number> - step/bucket size as a power of 2 for | |
1376 | statistical time based profiling. | |
ece8a684 | 1377 | Param: "sleep" - profile D-state sleeping (millisecs) |
1da177e4 | 1378 | |
a9913044 | 1379 | processor.max_cstate= [HW,ACPI] |
1da177e4 LT |
1380 | Limit processor to maximum C-state |
1381 | max_cstate=9 overrides any DMI blacklist limit. | |
1382 | ||
41c0d868 LB |
1383 | processor.nocst [HW,ACPI] |
1384 | Ignore the _CST method to determine C-states, | |
1385 | instead using the legacy FADT method | |
1386 | ||
1da177e4 LT |
1387 | prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk |
1388 | before loading. | |
1389 | See Documentation/ramdisk.txt. | |
1390 | ||
a9913044 RD |
1391 | psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to |
1392 | probe for; one of (bare|imps|exps|lifebook|any). | |
1da177e4 LT |
1393 | psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports |
1394 | per second. | |
a9913044 RD |
1395 | psmouse.resetafter= [HW,MOUSE] |
1396 | Try to reset the device after so many bad packets | |
1da177e4 LT |
1397 | (0 = never). |
1398 | psmouse.resolution= | |
1399 | [HW,MOUSE] Set desired mouse resolution, in dpi. | |
1400 | psmouse.smartscroll= | |
a9913044 | 1401 | [HW,MOUSE] Controls Logitech smartscroll autorepeat. |
1da177e4 LT |
1402 | 0 = disabled, 1 = enabled (default). |
1403 | ||
1404 | pss= [HW,OSS] Personal Sound System (ECHO ESC614) | |
a9913044 RD |
1405 | Format: |
1406 | <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> | |
1da177e4 LT |
1407 | |
1408 | pt. [PARIDE] | |
1409 | See Documentation/paride.txt. | |
1410 | ||
7d2c502f | 1411 | quiet [KNL] Disable most log messages |
a9913044 | 1412 | |
1da177e4 LT |
1413 | r128= [HW,DRM] |
1414 | ||
1415 | raid= [HW,RAID] | |
1416 | See Documentation/md.txt. | |
1417 | ||
1418 | ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated] | |
1419 | See Documentation/ramdisk.txt. | |
1420 | ||
a9913044 | 1421 | ramdisk_blocksize= [RAM] |
1da177e4 | 1422 | See Documentation/ramdisk.txt. |
a9913044 | 1423 | |
1da177e4 LT |
1424 | ramdisk_size= [RAM] Sizes of RAM disks in kilobytes |
1425 | New name for the ramdisk parameter. | |
1426 | See Documentation/ramdisk.txt. | |
1427 | ||
21a1ea9e DS |
1428 | rcu.blimit= [KNL,BOOT] Set maximum number of finished |
1429 | RCU callbacks to process in one batch. | |
1430 | ||
1431 | rcu.qhimark= [KNL,BOOT] Set threshold of queued | |
1432 | RCU callbacks over which batch limiting is disabled. | |
1433 | ||
1434 | rcu.qlowmark= [KNL,BOOT] Set threshold of queued | |
1435 | RCU callbacks below which batch limiting is re-enabled. | |
1436 | ||
ffdfc409 OJ |
1437 | rdinit= [KNL] |
1438 | Format: <full_path> | |
1439 | Run specified binary instead of /init from the ramdisk, | |
1440 | used for early userspace startup. See initrd. | |
1441 | ||
1da177e4 LT |
1442 | reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode |
1443 | Format: <reboot_mode>[,<reboot_mode2>[,...]] | |
f3e299fe | 1444 | See arch/*/kernel/reboot.c or arch/*/kernel/process.c |
1da177e4 LT |
1445 | |
1446 | reserve= [KNL,BUGS] Force the kernel to ignore some iomem area | |
1447 | ||
461a9aff ZA |
1448 | reservetop= [IA-32] |
1449 | Format: nn[KMG] | |
1450 | Reserves a hole at the top of the kernel virtual | |
1451 | address space. | |
1452 | ||
7e96287d VG |
1453 | reset_devices [KNL] Force drivers to reset the underlying device |
1454 | during initialization. | |
1455 | ||
a9913044 RD |
1456 | resume= [SWSUSP] |
1457 | Specify the partition device for software suspend | |
1da177e4 | 1458 | |
ecbd0da1 RW |
1459 | resume_offset= [SWSUSP] |
1460 | Specify the offset from the beginning of the partition | |
1461 | given by "resume=" at which the swap header is located, | |
1462 | in <PAGE_SIZE> units (needed only for swap files). | |
1463 | See Documentation/power/swsusp-and-swap-files.txt | |
1464 | ||
0a7b35cb MN |
1465 | retain_initrd [RAM] Keep initrd memory after extraction |
1466 | ||
1da177e4 LT |
1467 | rhash_entries= [KNL,NET] |
1468 | Set number of hash buckets for route cache | |
1469 | ||
1470 | riscom8= [HW,SERIAL] | |
1471 | Format: <io_board1>[,<io_board2>[,...<io_boardN>]] | |
1472 | ||
1473 | ro [KNL] Mount root device read-only on boot | |
1474 | ||
1475 | root= [KNL] Root filesystem | |
1476 | ||
1477 | rootdelay= [KNL] Delay (in seconds) to pause before attempting to | |
1478 | mount the root filesystem | |
1479 | ||
1480 | rootflags= [KNL] Set root filesystem mount option string | |
1481 | ||
1482 | rootfstype= [KNL] Set root filesystem type | |
1483 | ||
cc1ed754 PO |
1484 | rootwait [KNL] Wait (indefinitely) for root device to show up. |
1485 | Useful for devices that are detected asynchronously | |
1486 | (e.g. USB and MMC devices). | |
1487 | ||
1da177e4 LT |
1488 | rw [KNL] Mount root device read-write on boot |
1489 | ||
1490 | S [KNL] Run init in single mode | |
1491 | ||
1492 | sa1100ir [NET] | |
1493 | See drivers/net/irda/sa1100_ir.c. | |
1494 | ||
1495 | sb= [HW,OSS] | |
1496 | Format: <io>,<irq>,<dma>,<dma2> | |
1497 | ||
1498 | sbni= [NET] Granch SBNI12 leased line adapter | |
a9913044 | 1499 | |
1da177e4 LT |
1500 | sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver |
1501 | Format: <io>[,<timeout>[,<isapnp>]] | |
1502 | ||
1503 | scsi_debug_*= [SCSI] | |
1504 | See drivers/scsi/scsi_debug.c. | |
1505 | ||
1506 | scsi_default_dev_flags= | |
1507 | [SCSI] SCSI default device flags | |
1508 | Format: <integer> | |
1509 | ||
1510 | scsi_dev_flags= [SCSI] Black/white list entry for vendor and model | |
1511 | Format: <vendor>:<model>:<flags> | |
1512 | (flags are integer value) | |
1513 | ||
1514 | scsi_logging= [SCSI] | |
1515 | ||
3e082a91 MW |
1516 | scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are |
1517 | discovered. async scans them in kernel threads, | |
1518 | allowing boot to proceed. none ignores them, expecting | |
1519 | user space to do the scan. | |
1520 | ||
1da177e4 LT |
1521 | selinux [SELINUX] Disable or enable SELinux at boot time. |
1522 | Format: { "0" | "1" } | |
1523 | See security/selinux/Kconfig help text. | |
1524 | 0 -- disable. | |
1525 | 1 -- enable. | |
1526 | Default value is set via kernel config option. | |
1527 | If enabled at boot time, /selinux/disable can be used | |
1528 | later to disable prior to initial policy load. | |
1529 | ||
4e5ab4cb JM |
1530 | selinux_compat_net = |
1531 | [SELINUX] Set initial selinux_compat_net flag value. | |
1532 | Format: { "0" | "1" } | |
1533 | 0 -- use new secmark-based packet controls | |
1534 | 1 -- use legacy packet controls | |
1535 | Default value is 0 (preferred). | |
1536 | Value can be changed at runtime via | |
1537 | /selinux/compat_net. | |
1538 | ||
1da177e4 LT |
1539 | serialnumber [BUGS=IA-32] |
1540 | ||
a9913044 RD |
1541 | sg_def_reserved_size= [SCSI] |
1542 | ||
1da177e4 LT |
1543 | shapers= [NET] |
1544 | Maximal number of shapers. | |
a9913044 | 1545 | |
1da177e4 LT |
1546 | sim710= [SCSI,HW] |
1547 | See header of drivers/scsi/sim710.c. | |
1548 | ||
1549 | simeth= [IA-64] | |
1550 | simscsi= | |
a9913044 | 1551 | |
1da177e4 LT |
1552 | slram= [HW,MTD] |
1553 | ||
f0630fff CL |
1554 | slub_debug[=options[,slabs]] [MM, SLUB] |
1555 | Enabling slub_debug allows one to determine the | |
1556 | culprit if slab objects become corrupted. Enabling | |
1557 | slub_debug can create guard zones around objects and | |
1558 | may poison objects when not in use. Also tracks the | |
1559 | last alloc / free. For more information see | |
1560 | Documentation/vm/slub.txt. | |
c1aee215 CL |
1561 | |
1562 | slub_max_order= [MM, SLUB] | |
f0630fff CL |
1563 | Determines the maximum allowed order for slabs. |
1564 | A high setting may cause OOMs due to memory | |
1565 | fragmentation. For more information see | |
1566 | Documentation/vm/slub.txt. | |
c1aee215 CL |
1567 | |
1568 | slub_min_objects= [MM, SLUB] | |
f0630fff CL |
1569 | The minimum number of objects per slab. SLUB will |
1570 | increase the slab order up to slub_max_order to | |
1571 | generate a sufficiently large slab able to contain | |
1572 | the number of objects indicated. The higher the number | |
1573 | of objects the smaller the overhead of tracking slabs | |
1574 | and the less frequently locks need to be acquired. | |
c1aee215 CL |
1575 | For more information see Documentation/vm/slub.txt. |
1576 | ||
1577 | slub_min_order= [MM, SLUB] | |
1578 | Determines the mininum page order for slabs. Must be | |
f0630fff | 1579 | lower than slub_max_order. |
c1aee215 CL |
1580 | For more information see Documentation/vm/slub.txt. |
1581 | ||
1582 | slub_nomerge [MM, SLUB] | |
f0630fff | 1583 | Disable merging of slabs with similar size. May be |
c1aee215 | 1584 | necessary if there is some reason to distinguish |
f0630fff CL |
1585 | allocs to different slabs. Debug options disable |
1586 | merging on their own. | |
c1aee215 CL |
1587 | For more information see Documentation/vm/slub.txt. |
1588 | ||
1da177e4 LT |
1589 | smart2= [HW] |
1590 | Format: <io1>[,<io2>[,...,<io8>]] | |
1591 | ||
b7fb4af0 JF |
1592 | smp-alt-once [IA-32,SMP] On a hotplug CPU system, only |
1593 | attempt to substitute SMP alternatives once at boot. | |
1594 | ||
d0d4f69b BH |
1595 | smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices |
1596 | smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port | |
1597 | smsc-ircc2.ircc_sir= [HW] SIR base I/O port | |
1598 | smsc-ircc2.ircc_fir= [HW] FIR base I/O port | |
1599 | smsc-ircc2.ircc_irq= [HW] IRQ line | |
1600 | smsc-ircc2.ircc_dma= [HW] DMA channel | |
1601 | smsc-ircc2.ircc_transceiver= [HW] Transceiver type: | |
1602 | 0: Toshiba Satellite 1800 (GP data pin select) | |
1603 | 1: Fast pin select (default) | |
1604 | 2: ATC IRMode | |
1605 | ||
1da177e4 LT |
1606 | snd-ad1816a= [HW,ALSA] |
1607 | ||
1608 | snd-ad1848= [HW,ALSA] | |
1609 | ||
1610 | snd-ali5451= [HW,ALSA] | |
1611 | ||
1612 | snd-als100= [HW,ALSA] | |
1613 | ||
1614 | snd-als4000= [HW,ALSA] | |
1615 | ||
1616 | snd-azt2320= [HW,ALSA] | |
1617 | ||
1618 | snd-cmi8330= [HW,ALSA] | |
1619 | ||
1620 | snd-cmipci= [HW,ALSA] | |
1621 | ||
1622 | snd-cs4231= [HW,ALSA] | |
1623 | ||
1624 | snd-cs4232= [HW,ALSA] | |
1625 | ||
1626 | snd-cs4236= [HW,ALSA] | |
1627 | ||
1628 | snd-cs4281= [HW,ALSA] | |
1629 | ||
1630 | snd-cs46xx= [HW,ALSA] | |
1631 | ||
1632 | snd-dt019x= [HW,ALSA] | |
1633 | ||
1634 | snd-dummy= [HW,ALSA] | |
1635 | ||
1636 | snd-emu10k1= [HW,ALSA] | |
1637 | ||
1638 | snd-ens1370= [HW,ALSA] | |
1639 | ||
1640 | snd-ens1371= [HW,ALSA] | |
1641 | ||
1642 | snd-es968= [HW,ALSA] | |
1643 | ||
1644 | snd-es1688= [HW,ALSA] | |
1645 | ||
1646 | snd-es18xx= [HW,ALSA] | |
1647 | ||
1648 | snd-es1938= [HW,ALSA] | |
1649 | ||
1650 | snd-es1968= [HW,ALSA] | |
1651 | ||
1652 | snd-fm801= [HW,ALSA] | |
1653 | ||
1654 | snd-gusclassic= [HW,ALSA] | |
1655 | ||
1656 | snd-gusextreme= [HW,ALSA] | |
1657 | ||
1658 | snd-gusmax= [HW,ALSA] | |
1659 | ||
1660 | snd-hdsp= [HW,ALSA] | |
1661 | ||
1662 | snd-ice1712= [HW,ALSA] | |
1663 | ||
1664 | snd-intel8x0= [HW,ALSA] | |
1665 | ||
1666 | snd-interwave= [HW,ALSA] | |
1667 | ||
1668 | snd-interwave-stb= | |
1669 | [HW,ALSA] | |
1670 | ||
1671 | snd-korg1212= [HW,ALSA] | |
1672 | ||
1673 | snd-maestro3= [HW,ALSA] | |
1674 | ||
1675 | snd-mpu401= [HW,ALSA] | |
1676 | ||
1677 | snd-mtpav= [HW,ALSA] | |
1678 | ||
1679 | snd-nm256= [HW,ALSA] | |
1680 | ||
1681 | snd-opl3sa2= [HW,ALSA] | |
1682 | ||
1683 | snd-opti92x-ad1848= | |
1684 | [HW,ALSA] | |
1685 | ||
1686 | snd-opti92x-cs4231= | |
1687 | [HW,ALSA] | |
1688 | ||
1689 | snd-opti93x= [HW,ALSA] | |
1690 | ||
1691 | snd-pmac= [HW,ALSA] | |
1692 | ||
1693 | snd-rme32= [HW,ALSA] | |
1694 | ||
1695 | snd-rme96= [HW,ALSA] | |
1696 | ||
1697 | snd-rme9652= [HW,ALSA] | |
1698 | ||
1699 | snd-sb8= [HW,ALSA] | |
1700 | ||
1701 | snd-sb16= [HW,ALSA] | |
1702 | ||
1703 | snd-sbawe= [HW,ALSA] | |
1704 | ||
1705 | snd-serial= [HW,ALSA] | |
1706 | ||
1707 | snd-sgalaxy= [HW,ALSA] | |
1708 | ||
1709 | snd-sonicvibes= [HW,ALSA] | |
1710 | ||
1711 | snd-sun-amd7930= | |
1712 | [HW,ALSA] | |
1713 | ||
1714 | snd-sun-cs4231= [HW,ALSA] | |
1715 | ||
1716 | snd-trident= [HW,ALSA] | |
1717 | ||
1718 | snd-usb-audio= [HW,ALSA,USB] | |
1719 | ||
1720 | snd-via82xx= [HW,ALSA] | |
1721 | ||
1722 | snd-virmidi= [HW,ALSA] | |
1723 | ||
1724 | snd-wavefront= [HW,ALSA] | |
1725 | ||
1726 | snd-ymfpci= [HW,ALSA] | |
a9913044 | 1727 | |
1da177e4 LT |
1728 | sonypi.*= [HW] Sony Programmable I/O Control Device driver |
1729 | See Documentation/sonypi.txt | |
1730 | ||
1731 | specialix= [HW,SERIAL] Specialix multi-serial port adapter | |
1732 | See Documentation/specialix.txt. | |
1733 | ||
1734 | spia_io_base= [HW,MTD] | |
1735 | spia_fio_base= | |
1736 | spia_pedr= | |
1737 | spia_peddr= | |
1738 | ||
1739 | sscape= [HW,OSS] | |
1740 | Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq> | |
a9913044 | 1741 | |
1da177e4 LT |
1742 | st= [HW,SCSI] SCSI tape parameters (buffers, etc.) |
1743 | See Documentation/scsi/st.txt. | |
1744 | ||
1745 | st0x= [HW,SCSI] | |
1746 | See header of drivers/scsi/seagate.c. | |
1747 | ||
1748 | sti= [PARISC,HW] | |
1749 | Format: <num> | |
1750 | Set the STI (builtin display/keyboard on the HP-PARISC | |
1751 | machines) console (graphic card) which should be used | |
1752 | as the initial boot-console. | |
1753 | See also comment in drivers/video/console/sticore.c. | |
1754 | ||
1755 | sti_font= [HW] | |
1756 | See comment in drivers/video/console/sticore.c. | |
1757 | ||
1758 | stifb= [HW] | |
1759 | Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] | |
1760 | ||
42a7fc4a GB |
1761 | sunrpc.pool_mode= |
1762 | [NFS] | |
1763 | Control how the NFS server code allocates CPUs to | |
1764 | service thread pools. Depending on how many NICs | |
1765 | you have and where their interrupts are bound, this | |
1766 | option will affect which CPUs will do NFS serving. | |
1767 | Note: this parameter cannot be changed while the | |
1768 | NFS server is running. | |
1769 | ||
1770 | auto the server chooses an appropriate mode | |
1771 | automatically using heuristics | |
1772 | global a single global pool contains all CPUs | |
1773 | percpu one pool for each CPU | |
1774 | pernode one pool for each NUMA node (equivalent | |
1775 | to global on non-NUMA machines) | |
1776 | ||
1da177e4 | 1777 | swiotlb= [IA-64] Number of I/O TLB slabs |
a9913044 | 1778 | |
1da177e4 LT |
1779 | switches= [HW,M68k] |
1780 | ||
1781 | sym53c416= [HW,SCSI] | |
1782 | See header of drivers/scsi/sym53c416.c. | |
1783 | ||
5d6f647f IM |
1784 | sysrq_always_enabled |
1785 | [KNL] | |
1786 | Ignore sysrq setting - this boot parameter will | |
1787 | neutralize any effect of /proc/sys/kernel/sysrq. | |
1788 | Useful for debugging. | |
1789 | ||
1da177e4 LT |
1790 | t128= [HW,SCSI] |
1791 | See header of drivers/scsi/t128.c. | |
1792 | ||
1793 | tdfx= [HW,DRM] | |
1794 | ||
1795 | thash_entries= [KNL,NET] | |
1796 | Set number of hash buckets for TCP connection | |
1797 | ||
1798 | time Show timing data prefixed to each printk message line | |
e84845c4 | 1799 | [deprecated, see 'printk.time'] |
1da177e4 LT |
1800 | |
1801 | tipar.timeout= [HW,PPT] | |
1802 | Set communications timeout in tenths of a second | |
1803 | (default 15). | |
1804 | ||
1805 | tipar.delay= [HW,PPT] | |
1806 | Set inter-bit delay in microseconds (default 10). | |
1807 | ||
1808 | tmc8xx= [HW,SCSI] | |
1809 | See header of drivers/scsi/seagate.c. | |
1810 | ||
1811 | tmscsim= [HW,SCSI] | |
1812 | See comment before function dc390_setup() in | |
1813 | drivers/scsi/tmscsim.c. | |
1814 | ||
1815 | tp720= [HW,PS2] | |
1816 | ||
1817 | trix= [HW,OSS] MediaTrix AudioTrix Pro | |
a9913044 RD |
1818 | Format: |
1819 | <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq> | |
1820 | ||
1da177e4 LT |
1821 | tsdev.xres= [TS] Horizontal screen resolution. |
1822 | tsdev.yres= [TS] Vertical screen resolution. | |
1823 | ||
a9913044 RD |
1824 | turbografx.map[2|3]= [HW,JOY] |
1825 | TurboGraFX parallel port interface | |
1826 | Format: | |
1827 | <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> | |
1da177e4 LT |
1828 | See also Documentation/input/joystick-parport.txt |
1829 | ||
1830 | u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter | |
1831 | See header of drivers/scsi/u14-34f.c. | |
1832 | ||
1833 | uart401= [HW,OSS] | |
1834 | Format: <io>,<irq> | |
1835 | ||
1836 | uart6850= [HW,OSS] | |
1837 | Format: <io>,<irq> | |
1838 | ||
5f8364b7 AS |
1839 | uhci-hcd.ignore_oc= |
1840 | [USB] Ignore overcurrent events (default N). | |
1841 | Some badly-designed motherboards generate lots of | |
1842 | bogus events, for ports that aren't wired to | |
1843 | anything. Set this parameter to avoid log spamming. | |
1844 | Note that genuine overcurrent events won't be | |
1845 | reported either. | |
1846 | ||
b5e795f8 AS |
1847 | usbcore.autosuspend= |
1848 | [USB] The autosuspend time delay (in seconds) used | |
1849 | for newly-detected USB devices (default 2). This | |
1850 | is the time required before an idle device will be | |
1851 | autosuspended. Devices for which the delay is set | |
eaafbc3a | 1852 | to a negative value won't be autosuspended at all. |
b5e795f8 | 1853 | |
1da177e4 LT |
1854 | usbhid.mousepoll= |
1855 | [USBHID] The interval which mice are to be polled at. | |
a9913044 | 1856 | |
e523d93c | 1857 | vdso= [IA-32,SH] |
1dbf527c | 1858 | vdso=2: enable compat VDSO (default with COMPAT_VDSO) |
e6e5494c IM |
1859 | vdso=1: enable VDSO (default) |
1860 | vdso=0: disable VDSO mapping | |
1861 | ||
1da177e4 LT |
1862 | video= [FB] Frame buffer configuration |
1863 | See Documentation/fb/modedb.txt. | |
1864 | ||
1865 | vga= [BOOT,IA-32] Select a particular video mode | |
a9913044 RD |
1866 | See Documentation/i386/boot.txt and |
1867 | Documentation/svga.txt. | |
1da177e4 LT |
1868 | Use vga=ask for menu. |
1869 | This is actually a boot loader parameter; the value is | |
1870 | passed to the kernel using a special protocol. | |
1871 | ||
a9913044 | 1872 | vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact |
1da177e4 LT |
1873 | size of <nn>. This can be used to increase the |
1874 | minimum size (128MB on x86). It can also be used to | |
1875 | decrease the size and leave more room for directly | |
1876 | mapped kernel RAM. | |
1877 | ||
585c3047 PO |
1878 | vmhalt= [KNL,S390] Perform z/VM CP command after system halt. |
1879 | Format: <command> | |
1da177e4 | 1880 | |
585c3047 PO |
1881 | vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. |
1882 | Format: <command> | |
1883 | ||
1884 | vmpoff= [KNL,S390] Perform z/VM CP command after power off. | |
1885 | Format: <command> | |
a9913044 | 1886 | |
1da177e4 LT |
1887 | waveartist= [HW,OSS] |
1888 | Format: <io>,<irq>,<dma>,<dma2> | |
a9913044 | 1889 | |
1da177e4 LT |
1890 | wd33c93= [HW,SCSI] |
1891 | See header of drivers/scsi/wd33c93.c. | |
1892 | ||
1893 | wd7000= [HW,SCSI] | |
1894 | See header of drivers/scsi/wd7000.c. | |
1895 | ||
1896 | wdt= [WDT] Watchdog | |
1897 | See Documentation/watchdog/watchdog.txt. | |
1898 | ||
1899 | xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. | |
1900 | xd_geo= See header of drivers/block/xd.c. | |
1901 | ||
1902 | xirc2ps_cs= [NET,PCMCIA] | |
a9913044 RD |
1903 | Format: |
1904 | <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] | |
1da177e4 | 1905 | |
a62eaf15 AK |
1906 | norandmaps Don't use address space randomization |
1907 | Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space | |
1908 | ||
6d0185ea JB |
1909 | unwind_debug=N N > 0 will enable dwarf2 unwinder debugging |
1910 | This is useful to get more information why | |
1911 | you got a "dwarf2 unwinder stuck" | |
1da177e4 | 1912 | |
a9913044 | 1913 | ______________________________________________________________________ |
1da177e4 LT |
1914 | |
1915 | TODO: | |
1916 | ||
1917 | Add documentation for ALSA options. | |
1918 | Add more DRM drivers. |