ALSA ALSA sound support is enabled.
APIC APIC support is enabled.
APM Advanced Power Management support is enabled.
+ AVR32 AVR32 architecture is enabled.
AX25 Appropriate AX.25 support is enabled.
BLACKFIN Blackfin architecture is enabled.
DRM Direct Rendering Management support is enabled.
PPT Parallel port support is enabled.
PS2 Appropriate PS/2 support is enabled.
RAM RAM disk support is enabled.
+ ROOTPLUG The example Root Plug LSM is enabled.
S390 S390 architecture is enabled.
SCSI Appropriate SCSI support is enabled.
A lot of drivers has their options described inside of
Documentation/scsi/.
+ SECURITY Different security models are enabled.
SELINUX SELinux support is enabled.
SERIAL Serial support is enabled.
SH SuperH architecture is enabled.
strict -- Be less tolerant of platforms that are not
strictly ACPI specification compliant.
- See also Documentation/pm.txt, pci=noacpi
+ See also Documentation/power/pm.txt, pci=noacpi
acpi_apic_instance= [ACPI, IOAPIC]
Format: <int>
default: 0
acpi_sleep= [HW,ACPI] Sleep options
- Format: { s3_bios, s3_mode }
- See Documentation/power/video.txt
+ Format: { s3_bios, s3_mode, s3_beep }
+ See Documentation/power/video.txt for s3_bios and s3_mode.
+ s3_beep is for debugging; it makes the PC's speaker beep
+ as soon as the kernel's real-mode entry point is called.
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
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_pm_good [X86-32,X86-64]
Override the pmtimer bug detection: force the kernel
to assume that this machine's pmtimer latches its value
apm= [APM] Advanced Power Management
See header of arch/i386/kernel/apm.c.
- applicom= [HW]
- Format: <mem>,<irq>
-
arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
Format: <io>,<irq>,<nodeID>
Format: <io>,<irq>,<mode>
See header of drivers/net/hamradio/baycom_ser_hdx.c.
- blkmtd_device= [HW,MTD]
- blkmtd_erasesz=
- blkmtd_ro=
- blkmtd_bs=
- blkmtd_count=
-
boot_delay= Milliseconds to delay each printk during boot.
Values larger than 10 seconds (10000) are changed to
no delay (0).
possible to determine what the correct size should be.
This option provides an override for these situations.
- chandev= [HW,NET] Generic channel device initialisation
+ security= [SECURITY] Choose a security module to enable at boot.
+ If this boot parameter is not specified, only the first
+ security module asking for security registration will be
+ loaded. An invalid security module name will be treated
+ as if no module has been chosen.
+
+ capability.disable=
+ [SECURITY] Disable capabilities. This would normally
+ be used only if an alternative security model is to be
+ configured. Potentially dangerous and should only be
+ used if you are entirely sure of the consequences.
+
+ ccw_timeout_log [S390]
+ See Documentation/s390/CommonIO for details.
+
+ cgroup_disable= [KNL] Disable a particular controller
+ Format: {name of the controller(s) to disable}
+ {Currently supported controllers - "memory"}
checkreqprot [SELINUX] Set initial checkreqprot flag value.
Format: { "0" | "1" }
Value can be changed at runtime via
/selinux/checkreqprot.
+ cio_ignore= [S390]
+ See Documentation/s390/CommonIO for details.
+
+ cio_msg= [S390]
+ See Documentation/s390/CommonIO for details.
+
clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
[Deprecated]
Forces specified clocksource (if available) to be used
[SPARC64] tick
[X86-64] hpet,tsc
- code_bytes [IA32] How many bytes of object code to print in an
- oops report.
+ clearcpuid=BITNUM [X86]
+ Disable CPUID feature X for the kernel. See
+ include/asm-x86/cpufeature.h for the valid bit numbers.
+ Note the Linux specific bits are not necessarily
+ stable over kernel options, but the vendor specific
+ ones should be.
+ Also note that user programs calling CPUID directly
+ or using the feature without checking anything
+ will still see it. This just prevents it from
+ being used by the kernel or shown in /proc/cpuinfo.
+ Also note the kernel might malfunction if you disable
+ some critical bits.
+
+ code_bytes [IA32/X86_64] How many bytes of object code to print
+ in an oops report.
Range: 0 - 8192
Default: 64
over the 8254 in addition to over the IO-APIC. The
kernel tries to set a sensible default.
- hpet= [X86-32,HPET] option to disable HPET and use PIT.
- Format: disable
+ hpet= [X86-32,HPET] option to control HPET usage
+ Format: { enable (default) | disable | force }
+ disable: disable HPET and use PIT instead
+ force: allow force enabled of undocumented chips (ICH4,
+ VIA, nVidia)
com20020= [HW,NET] ARCnet - COM20020 chipset
Format:
UART at the specified I/O port or MMIO address.
The options are the same as for ttyS, above.
+ no_console_suspend
+ [HW] Never suspend the console
+ Disable suspending of consoles during suspend and
+ hibernate operations. Once disabled, debugging
+ messages can reach various consoles while the rest
+ of the system is being put to sleep (ie, while
+ debugging driver suspend/resume hooks). This may
+ not work reliably with all consoles, but is known
+ to work with serial and VGA consoles.
+
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
[KNL] Reserve a chunk of physical memory to
hold a kernel to switch to with kexec on panic.
+ crashkernel=range1:size1[,range2:size2,...][@offset]
+ [KNL] Same as above, but depends on the memory
+ in the running system. The syntax of range is
+ start-[end] where start and end are both
+ a memory unit (amount[KMG]). See also
+ Documentation/kdump/kdump.txt for a example.
+
cs4232= [HW,OSS]
Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
cs89x0_media= [HW,NET]
Format: { rj45 | aui | bnc }
- cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
-
dasd= [HW,NET]
See header of drivers/s390/block/dasd_devmap.c.
1 will print _a lot_ more information - normally
only useful to kernel developers.
- decnet= [HW,NET]
+ decnet.addr= [HW,NET]
Format: <area>[,<node>]
See also Documentation/networking/decnet.txt.
- default_blu= [VT]
+ vt.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]
+ vt.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]
+ vt.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]
+ vt.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.
+ Default is 1, i.e. UTF-8 mode is enabled for all
+ newly opened terminals.
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.
See drivers/char/README.epca and
Documentation/digiepca.txt.
- dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
- support available.
- Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
+ disable_mtrr_trim [X86, Intel and AMD only]
+ By default the kernel will trim any uncacheable
+ memory out of your available memory pool based on
+ MTRR settings. This parameter disables that behavior,
+ possibly causing your machine to run very slowly.
dmasound= [HW,OSS] Sound subsystem buffers
eata= [HW,SCSI]
- ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
- Format: <int>
- 0: polling mode
- non-0: interrupt mode (default)
-
- eda= [HW,PS2]
-
- edb= [HW,PS2]
-
edd= [EDD]
Format: {"of[f]" | "sk[ipmbr]"}
See comment in arch/i386/boot/edd.S
- eicon= [HW,ISDN]
- Format: <id>,<membase>,<irq>
-
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.
gamma= [HW,DRM]
+ gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
+ Format: off | on
+ default: on
+
gdth= [HW,SCSI]
See header of drivers/scsi/gdth.c.
Format: <cyl>,<head>,<sect>
hd?= [HW] (E)IDE subsystem
- hd?lun= See Documentation/ide.txt.
+ hd?lun= See Documentation/ide/ide.txt.
highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
size of <nn>. This works even on boxes that have no
See Documentation/isdn/README.HiSax.
hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
+ hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
i8042.direct [HW] Put keyboard port into non-translated mode
i8042.dumbkbd [HW] Pretend that controller can only read data from
(Don't attempt to blink the leds)
i8042.noaux [HW] Don't check for auxiliary (== mouse) port
i8042.nokbd [HW] Don't check/create keyboard port
+ i8042.noloop [HW] Disable the AUX Loopback command while probing
+ for the AUX port
i8042.nomux [HW] Don't check presence of an active multiplexing
controller
i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
ide= [HW] (E)IDE subsystem
- Format: ide=nodma or ide=doubler or ide=reverse
- See Documentation/ide.txt.
-
- ide?= [HW] (E)IDE subsystem
- Format: ide?=noprobe or chipset specific parameters.
- See Documentation/ide.txt.
+ Format: ide=nodma or ide=doubler
+ See Documentation/ide/ide.txt.
idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
- See Documentation/ide.txt.
+ See Documentation/ide/ide.txt.
idle= [X86]
Format: idle=poll or idle=mwait
loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
as idle=poll.
+ ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
+ Claim all unknown PCI IDE storage controllers.
+
ignore_loglevel [KNL]
Ignore loglevel setting - this will print /all/
kernel messages to the console. Useful for debugging.
inttest= [IA64]
+ iommu= [x86]
+ off
+ force
+ noforce
+ biomerge
+ panic
+ nopanic
+ merge
+ nomerge
+ forcesac
+ soft
+
+
+ intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
+ off
+ Disable intel iommu driver.
+ igfx_off [Default Off]
+ By default, gfx is mapped as normal device. If a gfx
+ device has a dedicated DMAR unit, the DMAR unit is
+ bypassed by not enabling DMAR with this option. In
+ this case, gfx device will use physical address for
+ DMA.
+ forcedac [x86_64]
+ With this option iommu will not optimize to look
+ for io virtual address below 32 bit forcing dual
+ address cycle on pci bus for cards supporting greater
+ than 32 bit addressing. The default is to look
+ for translation below 32 bit and if not available
+ then look in the higher range.
+ strict [Default Off]
+ With this option on every unmap_single operation will
+ result in a hardware IOTLB flush operation as opposed
+ to batching them for performance.
+
+ io_delay= [X86-32,X86-64] I/O delay method
+ 0x80
+ Standard port 0x80 based delay
+ 0xed
+ Alternate port 0xed based delay (needed on some systems)
+ udelay
+ Simple two microseconds delay
+ none
+ No delay
+
io7= [HW] IO7 for Marvel based alpha systems
See comment before marvel_specify_io7 in
arch/alpha/kernel/core_marvel.c.
ip= [IP_PNP]
- See Documentation/nfsroot.txt.
+ See Documentation/filesystems/nfsroot.txt.
ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
See comment before ip2_setup() in
kstack=N [X86-32,X86-64] Print N words from the kernel stack
in oops dumps.
+ kgdboc= [HW] kgdb over consoles.
+ Requires a tty driver that supports console polling.
+ (only serial suported for now)
+ Format: <serial_device>[,baud]
+
l2cr= [PPC]
+ l3cr= [PPC]
+
lapic [X86-32,APIC] Enable the local APIC even if BIOS
disabled it.
lapic_timer_c2_ok [X86-32,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>
+ libata.dma= [LIBATA] DMA control
+ libata.dma=0 Disable all PATA and SATA DMA
+ libata.dma=1 PATA and SATA Disk DMA only
+ libata.dma=2 ATAPI (CDROM) DMA only
+ libata.dma=4 Compact Flash DMA only
+ Combinations also work, so libata.dma=3 enables DMA
+ for disks and CDROMs, but not CFs.
libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
when set.
Format: <int>
+ libata.force= [LIBATA] Force configurations. The format is comma
+ separated list of "[ID:]VAL" where ID is
+ PORT[:DEVICE]. PORT and DEVICE are decimal numbers
+ matching port, link or device. Basically, it matches
+ the ATA ID string printed on console by libata. If
+ the whole ID part is omitted, the last PORT and DEVICE
+ values are used. If ID hasn't been specified yet, the
+ configuration applies to all ports, links and devices.
+
+ If only DEVICE is omitted, the parameter applies to
+ the port and all links and devices behind it. DEVICE
+ number of 0 either selects the first device or the
+ first fan-out link behind PMP device. It does not
+ select the host link. DEVICE number of 15 selects the
+ host link and device attached to it.
+
+ The VAL specifies the configuration to force. As long
+ as there's no ambiguity shortcut notation is allowed.
+ For example, both 1.5 and 1.5G would work for 1.5Gbps.
+ The following configurations can be forced.
+
+ * Cable type: 40c, 80c, short40c, unk, ign or sata.
+ Any ID with matching PORT is used.
+
+ * SATA link speed limit: 1.5Gbps or 3.0Gbps.
+
+ * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
+ udma[/][16,25,33,44,66,100,133] notation is also
+ allowed.
+
+ * [no]ncq: Turn on or off NCQ.
+
+ If there are multiple matching configurations changing
+ the same attribute, the last one is used.
+
load_ramdisk= [RAM] List of ramdisks to load from floppy
See Documentation/ramdisk.txt.
[SCSI] Maximum number of LUNs received.
Should be between 1 and 16384.
- mca-pentium [BUGS=X86-32]
-
mcatest= [IA-64]
mce [X86-32] Machine Check Exception
+ mce=option [X86-64] See Documentation/x86_64/boot-options.txt
+
md= [HW] RAID subsystems devices and level
See Documentation/md.txt.
memmap=nn[KMG]$ss[KMG]
[KNL,ACPI] Mark specific memory as reserved.
Region of memory to be used, from ss to ss+nn.
+ Example: Exclude memory from 0x18690000-0x1869ffff
+ memmap=64K$0x18690000
+ or
+ memmap=0x10000$0x18690000
+
+ memtest= [KNL,X86_64] Enable memtest
+ Format: <integer>
+ range: 0,4 : pattern number
+ default : 0 <disable>
meye.*= [HW] Set MotionEye Camera parameters
See Documentation/video4linux/meye.txt.
Multi-Function General Purpose Timers on AMD Geode
platforms.
+ mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
+ the BIOS has incorrectly applied a workaround. TinyBIOS
+ version 0.98 is known to be affected, 0.99 fixes the
+ problem by letting the user disable the workaround.
+
mga= [HW,DRM]
mousedev.tap_time=
file if at all.
nfsaddrs= [NFS]
- See Documentation/nfsroot.txt.
+ See Documentation/filesystems/nfsroot.txt.
nfsroot= [NFS] nfs root filesystem for disk-less boxes.
- See Documentation/nfsroot.txt.
+ See Documentation/filesystems/nfsroot.txt.
nfs.callback_tcpport=
[NFS] set the TCP port on which the NFSv4 callback
of returning the full 64-bit number.
The default is to return 64-bit inode numbers.
+ nmi_debug= [KNL,AVR32] Specify one or more actions to take
+ when a NMI is triggered.
+ Format: [state][,regs][,debounce][,die]
+
nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
noapic [SMP,APIC] Tells the kernel to not make use of any
IOAPICs that may be present in the system.
- noasync [HW,M68K] Disables async and sync negotiation for
- all devices.
-
nobats [PPC] Do not use BATs for mapping kernel lowmem
on "Classic" PPC cores.
nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
+ noefi [X86-32,X86-64] Disable EFI runtime services support.
+
noexec [IA-64]
noexec [X86-32,X86-64]
+ On X86-32 available only on PAE configured kernels.
noexec=on: enable non-executable mappings (default)
- noexec=off: disable nn-executable mappings
+ noexec=off: disable non-executable mappings
+
+ noexec32 [X86-64]
+ This affects only 32-bit executables.
+ noexec32=on: enable non-executable mappings (default)
+ read doesn't imply executable mappings
+ noexec32=off: disable non-executable mappings
+ read implies executable mappings
nofxsr [BUGS=X86-32] Disables x86 floating point extended
register save and restore. The kernel will only save
legacy floating-point registers on task switch.
+ noclflush [BUGS=X86] Don't use the CLFLUSH instruction
+
nohlt [BUGS=ARM]
no-hlt [BUGS=X86-32] Tells the kernel that the hlt
nowb [ARM]
+ nptcg= [IA64] Override max number of concurrent global TLB
+ purges which is reported from either PAL_VM_SUMMARY or
+ SAL PALO.
+
numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
one of ['zone', 'node', 'default'] can be specified
This can be set from sysctl after boot.
nomsi [MSI] If the PCI_MSI kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of MSI interrupts system-wide.
- nosort [X86-32] Don't sort PCI devices according to
- order given by the PCI BIOS. This sorting is
- done to get a device order compatible with
- older kernels.
biosirq [X86-32] Use PCI BIOS calls to get the interrupt
routing table. These calls are known to be buggy
on several machines and they hang the machine
Param: "schedule" - profile schedule points.
Param: <number> - step/bucket size as a power of 2 for
statistical time based profiling.
- Param: "sleep" - profile D-state sleeping (millisecs)
+ Param: "sleep" - profile D-state sleeping (millisecs).
+ Requires CONFIG_SCHEDSTATS
+ Param: "kvm" - profile VM exits.
processor.max_cstate= [HW,ACPI]
Limit processor to maximum C-state
raid= [HW,RAID]
See Documentation/md.txt.
- ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
- See Documentation/ramdisk.txt.
-
ramdisk_blocksize= [RAM]
See Documentation/ramdisk.txt.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
- New name for the ramdisk parameter.
See Documentation/ramdisk.txt.
- rcu.blimit= [KNL,BOOT] Set maximum number of finished
- RCU callbacks to process in one batch.
+ rcupdate.blimit= [KNL,BOOT]
+ Set maximum number of finished RCU callbacks to process
+ in one batch.
- rcu.qhimark= [KNL,BOOT] Set threshold of queued
+ rcupdate.qhimark= [KNL,BOOT]
+ Set threshold of queued
RCU callbacks over which batch limiting is disabled.
- rcu.qlowmark= [KNL,BOOT] Set threshold of queued
- RCU callbacks below which batch limiting is re-enabled.
+ rcupdate.qlowmark= [KNL,BOOT]
+ Set threshold of queued RCU callbacks below which
+ batch limiting is re-enabled.
rdinit= [KNL]
Format: <full_path>
Useful for devices that are detected asynchronously
(e.g. USB and MMC devices).
+ root_plug.vendor_id=
+ [ROOTPLUG] Override the default vendor ID
+
+ root_plug.product_id=
+ [ROOTPLUG] Override the default product ID
+
+ root_plug.debug=
+ [ROOTPLUG] Enable debugging output
+
rw [KNL] Mount root device read-write on boot
S [KNL] Run init in single mode
sa1100ir [NET]
See drivers/net/irda/sa1100_ir.c.
- sb= [HW,OSS]
- Format: <io>,<irq>,<dma>,<dma2>
-
sbni= [NET] Granch SBNI12 leased line adapter
sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
Format: <vendor>:<model>:<flags>
(flags are integer value)
- scsi_logging= [SCSI]
+ scsi_logging_level= [SCSI] a bit mask of logging levels
+ See drivers/scsi/scsi_logging.h for bits. Also
+ settable via sysctl at dev.scsi.logging_level
+ (/proc/sys/dev/scsi/logging_level).
+ There is also a nice 'scsi_logging_level' script in the
+ S390-tools package, available for download at
+ http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
discovered. async scans them in kernel threads,
serialnumber [BUGS=X86-32]
- sg_def_reserved_size= [SCSI]
-
shapers= [NET]
Maximal number of shapers.
st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
See Documentation/scsi/st.txt.
- st0x= [HW,SCSI]
- See header of drivers/scsi/seagate.c.
-
sti= [PARISC,HW]
Format: <num>
Set the STI (builtin display/keyboard on the HP-PARISC
<deci-seconds>: poll all this frequency
0: no polling (default)
- time Show timing data prefixed to each printk message line
- [deprecated, see 'printk.time']
-
tipar.timeout= [HW,PPT]
Set communications timeout in tenths of a second
(default 15).
tipar.delay= [HW,PPT]
Set inter-bit delay in microseconds (default 10).
- tmc8xx= [HW,SCSI]
- See header of drivers/scsi/seagate.c.
-
tmscsim= [HW,SCSI]
See comment before function dc390_setup() in
drivers/scsi/tmscsim.c.
vdso=1: enable VDSO (default)
vdso=0: disable VDSO mapping
+ vdso32= [X86-32,X86-64]
+ vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
+ vdso32=1: enable 32-bit VDSO (default)
+ vdso32=0: disable 32-bit VDSO mapping
+
vector= [IA-64,SMP]
vector=percpu: enable percpu vector domain
norandmaps Don't use address space randomization
Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
- unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
- This is useful to get more information why
- you got a "dwarf2 unwinder stuck"
-
______________________________________________________________________
TODO: