GENERIC_TIME The generic timeofday code is enabled.
NFS Appropriate NFS support is enabled.
OSS OSS sound support is enabled.
+ PV_OPS A paravirtualized kernel
PARIDE The ParIDE subsystem is enabled.
PARISC The PA-RISC architecture is enabled.
PCI PCI bus support is enabled.
Documentation/scsi/.
SELINUX SELinux support is enabled.
SERIAL Serial support is enabled.
+ SH SuperH architecture is enabled.
SMP The kernel is an SMP kernel.
SPARC Sparc architecture is enabled.
SWSUSP Software suspend is enabled.
See header of drivers/scsi/53c7xx.c.
See also Documentation/scsi/ncr53c7xx.txt.
- acpi= [HW,ACPI] Advanced Configuration and Power Interface
+ acpi= [HW,ACPI,X86-64,i386]
+ Advanced Configuration and Power Interface
Format: { force | off | ht | strict | noirq }
force -- enable ACPI if default was off
off -- disable ACPI if default was on
See also Documentation/pm.txt, pci=noacpi
+ acpi_apic_instance= [ACPI, IOAPIC]
+ Format: <int>
+ 2: use 2nd APIC table, if available
+ 1,0: use 1st APIC table
+ default: 0
+
acpi_sleep= [HW,ACPI] Sleep options
Format: { s3_bios, s3_mode }
See Documentation/power/video.txt
acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
Format: To spoof as Windows 98: ="Microsoft Windows"
- acpi_osi= [HW,ACPI] empty param disables _OSI
+ acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
+ acpi_osi="string1" # add string1 -- only one string
+ acpi_osi="!string2" # remove built-in string2
+ acpi_osi= # disable all strings
acpi_serialize [HW,ACPI] force serialization of AML methods
that require a timer override, but don't have
HPET
- acpi_dbg_layer= [HW,ACPI]
+ acpi.debug_layer= [HW,ACPI]
Format: <int>
Each bit of the <int> indicates an ACPI debug layer,
1: enable, 0: disable. It is useful for boot time
debugging. After system has booted up, it can be set
- via /proc/acpi/debug_layer.
-
- acpi_dbg_level= [HW,ACPI]
+ via /sys/module/acpi/parameters/debug_layer.
+ CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
+ Available bits (add the numbers together) to enable debug output
+ for specific parts of the ACPI subsystem:
+ 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
+ 0x10 namespace 0x20 parser 0x40 dispatcher
+ 0x80 executer 0x100 resources 0x200 acpica debugger
+ 0x400 os services 0x800 acpica disassembler.
+ The number can be in decimal or prefixed with 0x in hex.
+ Warning: Many of these options can produce a lot of
+ output and make your system unusable. Be very careful.
+
+ acpi.debug_level= [HW,ACPI]
Format: <int>
Each bit of the <int> indicates an ACPI debug level,
1: enable, 0: disable. It is useful for boot time
debugging. After system has booted up, it can be set
- via /proc/acpi/debug_level.
+ via /sys/module/acpi/parameters/debug_level.
+ CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
+ Available bits (add the numbers together) to enable different
+ debug output levels of the ACPI subsystem:
+ 0x01 error 0x02 warn 0x04 init 0x08 debug object
+ 0x10 info 0x20 init names 0x40 parse 0x80 load
+ 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
+ 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
+ 0x10000 resources 0x20000 user requests 0x40000 package.
+ The number can be in decimal or prefixed with 0x in hex.
+ Warning: Many of these options can produce a lot of
+ output and make your system unusable. Be very careful.
- acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
- acpi_generic_hotkey [HW,ACPI]
- Allow consolidated generic hotkey driver to
- override platform specific driver.
- See also Documentation/acpi-hotkey.txt.
+ acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
acpi_pm_good [IA-32,X86-64]
Override the pmtimer bug detection: force the kernel
clocksource is not available, it defaults to PIT.
Format: { pit | tsc | cyclone | pmtmr }
+ clocksource= [GENERIC_TIME] Override the default clocksource
+ Format: <string>
+ Override the default clocksource and use the clocksource
+ with the name specified.
+ Some clocksource names to choose from, depending on
+ the platform:
+ [all] jiffies (this is the base, fallback clocksource)
+ [ACPI] acpi_pm
+ [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
+ pxa_timer,timer3,32k_counter,timer0_1
+ [AVR32] avr32
+ [IA-32] pit,hpet,tsc,vmi-timer;
+ scx200_hrt on Geode; cyclone on IBM x440
+ [MIPS] MIPS
+ [PARISC] cr16
+ [S390] tod
+ [SH] SuperH
+ [SPARC64] tick
+ [X86-64] hpet,tsc
+
code_bytes [IA32] How many bytes of object code to print in an
oops report.
Range: 0 - 8192
Format: <area>[,<node>]
See also Documentation/networking/decnet.txt.
+ default_blu= [VT]
+ Format: <blue0>,<blue1>,<blue2>,...,<blue15>
+ Change the default blue palette of the console.
+ This is a 16-member array composed of values
+ ranging from 0-255.
+
+ default_grn= [VT]
+ Format: <green0>,<green1>,<green2>,...,<green15>
+ Change the default green palette of the console.
+ This is a 16-member array composed of values
+ ranging from 0-255.
+
+ default_red= [VT]
+ Format: <red0>,<red1>,<red2>,...,<red15>
+ Change the default red palette of the console.
+ This is a 16-member array composed of values
+ ranging from 0-255.
+
+ default_utf8= [VT]
+ Format=<0|1>
+ Set system-wide default UTF-8 mode for all tty's.
+ Default is 0 and by setting to 1, it enables UTF-8
+ mode for all newly opened or allocated terminals.
+
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.
dtc3181e= [HW,SCSI]
- earlyprintk= [IA-32,X86-64]
+ earlyprintk= [IA-32,X86-64,SH]
earlyprintk=vga
earlyprintk=serial[,ttySn[,baudrate]]
idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
See Documentation/ide.txt.
- idle= [HW]
- Format: idle=poll or idle=halt
+ idle= [X86]
+ Format: idle=poll or idle=mwait
+ Poll forces a polling idle loop that can slightly improves the performance
+ of waking up a idle CPU, but will use a lot of power and make the system
+ run hot. Not recommended.
+ idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
+ to not use it because it doesn't save as much power as a normal idle
+ loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
+ as idle=poll.
ignore_loglevel [KNL]
Ignore loglevel setting - this will print /all/
inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
Format: <irq>
- combined_mode= [HW] control which driver uses IDE ports in combined
- mode: legacy IDE driver, libata, or both
- (in the libata case, libata.atapi_enabled=1 may be
- useful as well). Note that using the ide or libata
- options may affect your device naming (e.g. by
- changing hdc to sdb).
- Format: combined (default), ide, or libata
-
inttest= [IA64]
io7= [HW] IO7 for Marvel based alpha systems
lapic [IA-32,APIC] Enable the local APIC even if BIOS
disabled it.
+ lapic_timer_c2_ok [IA-32,x86-64,APIC] trust the local apic timer in
+ C2 power state.
+
lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
Format: addr:<io>,irq:<irq>
+ legacy_serial.force [HW,IA-32,X86-64]
+ Probe for COM ports at legacy addresses even
+ if PNPBIOS or ACPI should describe them. This
+ is for working around firmware defects.
+
llsc*= [IA64] See function print_params() in
arch/ia64/sn/kernel/llsc4.c.
Format: <1-256>
maxcpus= [SMP] Maximum number of processors that an SMP kernel
- should make use of
+ should make use of.
+ Using "nosmp" or "maxcpus=0" will disable SMP
+ entirely (the MPS table probe still happens, though).
+ A command-line option of "maxcpus=<NUM>", where <NUM>
+ is an integer greater than 0, limits the maximum number
+ of CPUs activated in SMP mode to <NUM>.
+ Using "maxcpus=1" on an SMP kernel is the trivial
+ case of an SMP kernel with only one CPU.
max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
equal to this physical address is ignored.
mga= [HW,DRM]
- migration_cost=
- [KNL,SMP] debug: override scheduler migration costs
- Format: <level-1-usecs>,<level-2-usecs>,...
- This debugging option can be used to override the
- default scheduler migration cost matrix. The numbers
- are indexed by 'CPU domain distance'.
- E.g. migration_cost=1000,2000,3000 on an SMT NUMA
- box will set up an intra-core migration cost of
- 1 msec, an inter-core migration cost of 2 msecs,
- and an inter-node migration cost of 3 msecs.
-
- WARNING: using the wrong values here can break
- scheduler performance, so it's only for scheduler
- development purposes, not production environments.
-
- migration_debug=
- [KNL,SMP] migration cost auto-detect verbosity
- Format=<0|1|2>
- If a system's migration matrix reported at bootup
- seems erroneous then this option can be used to
- increase verbosity of the detection process.
- We default to 0 (no extra messages), 1 will print
- some more information, and 2 will be really
- verbose (probably only useful if you also have a
- serial console attached to the system).
-
- migration_factor=
- [KNL,SMP] multiply/divide migration costs by a factor
- Format=<percent>
- This debug option can be used to proportionally
- increase or decrease the auto-detected migration
- costs for all entries of the migration matrix.
- E.g. migration_factor=150 will increase migration
- costs by 50%. (and thus the scheduler will be less
- eager migrating cache-hot tasks)
- migration_factor=80 will decrease migration costs
- by 20%. (thus the scheduler will be more eager to
- migrate tasks)
-
- WARNING: using the wrong values here can break
- scheduler performance, so it's only for scheduler
- development purposes, not production environments.
-
mousedev.tap_time=
[MOUSE] Maximum time between finger touching and
leaving touchpad surface for touch to be considered
when set.
Format: <int>
- noaliencache [MM, NUMA] Disables the allcoation of alien caches in
- the slab allocator. Saves per-node memory, but will
- impact performance on real NUMA hardware.
+ noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
+ caches in the slab allocator. Saves per-node memory,
+ but will impact performance.
noalign [KNL,ARM]
nolapic [IA-32,APIC] Do not enable or use the local APIC.
+ nolapic_timer [IA-32,APIC] Do not use the local APIC timer.
+
noltlbs [PPC] Do not use large page/tlb entries for kernel
lowmem mapping on PPC40x.
nomce [IA-32] Machine Check Exception
+ noreplace-paravirt [IA-32,PV_OPS] Don't patch paravirt_ops
+
+ noreplace-smp [IA-32,SMP] Don't replace SMP instructions
+ with UP alternatives
+
noresidual [PPC] Don't use residual data on PReP machines.
noresume [SWSUSP] Disables resume and restores original swap
This sorting is done to get a device
order compatible with older (<= 2.4) kernels.
nobfsort Don't sort PCI devices into breadth-first order.
+ cbiosize=nn[KMG] The fixed amount of bus space which is
+ reserved for the CardBus bridge's IO window.
+ The default value is 256 bytes.
+ cbmemsize=nn[KMG] The fixed amount of bus space which is
+ reserved for the CardBus bridge's memory
+ window. The default value is 64 megabytes.
pcmv= [HW,PCMCIA] BadgePAD 4
slram= [HW,MTD]
+ slub_debug [MM, SLUB]
+ Enabling slub_debug allows one to determine the culprit
+ if slab objects become corrupted. Enabling slub_debug
+ creates guard zones around objects and poisons objects
+ when not in use. Also tracks the last alloc / free.
+ For more information see Documentation/vm/slub.txt.
+
+ slub_max_order= [MM, SLUB]
+ Determines the maximum allowed order for slabs. Setting
+ this too high may cause fragmentation.
+ For more information see Documentation/vm/slub.txt.
+
+ slub_min_objects= [MM, SLUB]
+ The minimum objects per slab. SLUB will increase the
+ slab order up to slub_max_order to generate a
+ sufficiently big slab to satisfy the number of objects.
+ The higher the number of objects the smaller the overhead
+ of tracking slabs.
+ For more information see Documentation/vm/slub.txt.
+
+ slub_min_order= [MM, SLUB]
+ Determines the mininum page order for slabs. Must be
+ lower than slub_max_order
+ For more information see Documentation/vm/slub.txt.
+
+ slub_nomerge [MM, SLUB]
+ Disable merging of slabs of similar size. May be
+ necessary if there is some reason to distinguish
+ allocs to different slabs.
+ For more information see Documentation/vm/slub.txt.
+
smart2= [HW]
Format: <io1>[,<io2>[,...,<io8>]]
+ smp-alt-once [IA-32,SMP] On a hotplug CPU system, only
+ attempt to substitute SMP alternatives once at boot.
+
+ smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
+ smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
+ smsc-ircc2.ircc_sir= [HW] SIR base I/O port
+ smsc-ircc2.ircc_fir= [HW] FIR base I/O port
+ smsc-ircc2.ircc_irq= [HW] IRQ line
+ smsc-ircc2.ircc_dma= [HW] DMA channel
+ smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
+ 0: Toshiba Satellite 1800 (GP data pin select)
+ 1: Fast pin select (default)
+ 2: ATC IRMode
+
snd-ad1816a= [HW,ALSA]
snd-ad1848= [HW,ALSA]
stifb= [HW]
Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
+ sunrpc.pool_mode=
+ [NFS]
+ Control how the NFS server code allocates CPUs to
+ service thread pools. Depending on how many NICs
+ you have and where their interrupts are bound, this
+ option will affect which CPUs will do NFS serving.
+ Note: this parameter cannot be changed while the
+ NFS server is running.
+
+ auto the server chooses an appropriate mode
+ automatically using heuristics
+ global a single global pool contains all CPUs
+ percpu one pool for each CPU
+ pernode one pool for each NUMA node (equivalent
+ to global on non-NUMA machines)
+
swiotlb= [IA-64] Number of I/O TLB slabs
switches= [HW,M68k]
time Show timing data prefixed to each printk message line
- clocksource= [GENERIC_TIME] Override the default clocksource
- Override the default clocksource and use the clocksource
- with the name specified.
-
tipar.timeout= [HW,PPT]
Set communications timeout in tenths of a second
(default 15).
Note that genuine overcurrent events won't be
reported either.
+ usbcore.autosuspend=
+ [USB] The autosuspend time delay (in seconds) used
+ for newly-detected USB devices (default 2). This
+ is the time required before an idle device will be
+ autosuspended. Devices for which the delay is set
+ to a negative value won't be autosuspended at all.
+
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
- vdso= [IA-32]
+ vdso= [IA-32,SH]
+ vdso=2: enable compat VDSO (default with COMPAT_VDSO)
vdso=1: enable VDSO (default)
vdso=0: disable VDSO mapping