Lines Matching +full:camera +full:- +full:command +full:- +full:set
16 force -- enable ACPI if default was off
17 on -- enable ACPI but allow fallback to DT [arm64,riscv64]
18 off -- disable ACPI if default was on
19 noirq -- do not use ACPI for IRQ routing
20 strict -- Be less tolerant of platforms that are not
22 rsdt -- prefer RSDT over (default) XSDT
23 copy_dsdt -- copy DSDT to memory
24 nospcr -- disable console in ACPI SPCR table as
41 If set to vendor, prefer vendor-specific driver
44 If set to video, use the ACPI video.ko driver.
45 If set to native, use the device's native backlight mode.
46 If set to none, disable the ACPI backlight interface.
73 Documentation/firmware-guide/acpi/debug.rst for more information about
131 Format: <byte> or <bitmap-list>
134 Disable auto-serialization of AML methods
137 auto-serialization feature.
155 Ignore the ACPI-based watchdog interface (WDAT) and let
176 acpi_osi=! # disable all built-in OS vendor
178 acpi_osi=!! # enable all built-in OS vendor
184 vendor string(s). Note that such command can only
188 specifying it multiple times through kernel command line
189 is meaningless. This command is useful when one do not
198 'acpi_osi=' command lines, the _OSI method will not
199 exist in the ACPI namespace. NOTE that such command can
201 multiple times through kernel command line is also
209 string(s). Note that such command can affect the
212 through kernel command line is meaningful. But it may
214 there are quirks related to this string. This command
240 For broken nForce2 BIOS resulting in XT-PIC timer.
249 as soon as the kernel's real-mode entry point is called.
266 sci_force_enable causes the kernel to set SCI_EN directly
287 See Documentation/sound/alsa-configuration.rst
294 align_va_addr= [X86-64]
299 CPU-intensive style benchmark, and it can vary highly in
302 32: only for 32-bit processes
303 64: only for 64-bit processes
304 on: enable for both 32- and 64-bit processes
305 off: disable for both 32- and 64-bit processes
315 Allow execve() of 32-bit applications and setting of the
317 subset of the CPUs support 32-bit EL0. When this
318 parameter is present, the set of CPUs supporting 32-bit
320 and hot-unplug operations may be restricted.
322 See Documentation/arch/arm64/asymmetric-32bit.rst for more
325 amd_iommu= [HW,X86-64]
328 fullflush - Deprecated, equivalent to iommu.strict=1
329 off - do not initialize any AMD IOMMU found in
331 force_isolation - Force device isolation for all
336 force_enable - Force enable the IOMMU on platforms known
339 pgtbl_v1 - Use v1 page table for DMA-API (Default).
340 pgtbl_v2 - Use v2 page table for DMA-API.
341 irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
342 nohugepages - Limit page-sizes used for v1 page-tables
344 v2_pgsizes_only - Limit page-sizes used for v1 page-tables
348 amd_iommu_dump= [HW,X86-64]
354 amd_iommu_intr= [HW,X86-64]
357 legacy - Use legacy interrupt remapping mode.
358 vapic - Use virtual APIC mode, which allows IOMMU
360 This mode requires kvm-amd.avic=1.
389 Disable amd-pstate preferred core.
402 Power management functions (SPARCstation-4/5 + deriv.)
404 Disable APC CPU standby support. SPARCstation-Fox does
405 not play well with APC CPU idle - disable it if you have
412 when initialising the APIC and IO-APIC components.
413 For X86-32, this can also be used to specify an APIC
436 0 -- disable.
437 1 -- enable.
438 Default value is set via kernel config option.
440 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
450 Set instructions support
476 atkbd.set= [HW] Select keyboard code set
488 audit= [KNL] Enable the audit sub-system
490 0 | off - kernel audit is disabled and can not be
492 unset - kernel audit is initialized but disabled and
494 1 | on - kernel audit is initialized and partially
500 audit_backlog_limit= [KNL] Set the audit queue size limit.
507 0 - Disable the BAU.
508 1 - Enable the BAU.
509 unset - Disable the BAU.
547 embedded devices based on command line input.
548 See Documentation/block/cmdline-partition.rst
559 Extended command line options can be added to an initrd
562 See Documentation/admin-guide/bootconfig.rst
567 bttv.pll= See Documentation/admin-guide/media/bttv.rst
576 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
595 inclusive. See arch/mips/include/asm/pgtable-bits.h
605 - foo isn't auto-mounted if you mount all cgroups in
607 - foo isn't visible as an individually mountable
609 - if foo is an optional feature then the feature is
615 Specifying "pressure" disables per-cgroup pressure
633 nosocket -- Disable socket memory accounting.
634 nokmem -- Disable kernel memory accounting.
635 nobpf -- Disable BPF memory accounting.
637 checkreqprot= [SELINUX] Set initial checkreqprot flag value.
640 0 -- check protection applied by kernel (includes
642 1 -- check protection requested by application.
643 Default value is set via a kernel config option.
654 numbers X. Note the Linux-specific bits are not necessarily
655 stable over kernel options, but the vendor-specific
675 force such clocks to be always-on nor does it reserve
679 information, see Documentation/driver-api/clk.rst.
681 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
698 [X86-32] pit,hpet,tsc;
705 [X86-64] hpet,tsc
711 architected timer so that code using WFE-based polling
725 clocksource-wdtest.holdoff= [KNL]
726 Set the time in seconds that the clocksource
731 cma=nn[MG]@[start[MG][-end[MG]]]
742 Sets the size of kernel per-numa memory area for
744 per-numa CMA altogether. And If this option is not
746 With per-numa CMA enabled, DMA users on node nid will
771 allocations, by default set to 256K.
773 com20020= [HW,NET] ARCnet - COM20020 chipset
777 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
781 ARCnet - COM90xx chipset (memory-mapped buffers)
789 When set to true, drop data on the 3215 console when
810 See Documentation/admin-guide/serial-console.rst for more
825 $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/*
826 /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0
839 Start an early, polled-mode console on the 8250/16550
842 MMIO inter-register address stride is either 8-bit
843 (mmio), 16-bit (mmio16), or 32-bit (mmio32).
847 the h/w is not re-initialized.
856 kernel command line.
874 syscall, or to executing "dmesg -S --raw" or to reading
898 disable the cpuidle sub-system
904 disable the cpufreq sub-system
912 [X86,EARLY] Delay for N microsec between assert and de-assert
924 Run kdump after running panic-notifiers and dumping
937 [KNL, X86-64, ARM64, RISCV, LoongArch] Select a region
940 See Documentation/admin-guide/kdump/kdump.rst for further details.
945 start-[end] where start and end are both
947 Documentation/admin-guide/kdump/kdump.rst for an example.
950 [KNL, X86-64, ARM64, RISCV, LoongArch] range could be
958 [KNL, X86-64, ARM64, RISCV, LoongArch] range under 4G.
964 for 32-bit devices won't run out. Kernel would try to allocate
967 --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB)
968 --> arm64: 128MiB
969 --> riscv: 128MiB
970 --> loongarch: 128MiB
978 [KNL] Disable crypto self-tests
986 csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
1001 See also Documentation/input/devices/joystick-parport.rst
1014 [KNL] verbose locking self-tests
1017 self-tests.
1019 (no extra messages), setting it to -1 (all bits set)
1020 will print _a_lot_ more information - normally only
1026 [KNL,EARLY] When CONFIG_DEBUG_PAGEALLOC is set, this
1045 [KNL,EARLY] When CONFIG_DEBUG_PAGEALLOC is set, this parameter
1055 Format: { on, no-mount, off }
1057 no-mount:
1062 get a -EPERM as result when trying to register files
1066 Default value is set in build-time with a kernel configuration.
1078 Documentation/admin-guide/mm/hugetlbpage.rst.
1082 [KNL] Debugging option to set a timeout in seconds for
1092 delayacct [KNL] Enable per-task delay accounting
1110 capability is set.
1131 Set number of hash buckets for dentry cache.
1182 entries for DMA-API debugging code. One entry is
1183 required per DMA-API allocation. Use this if the
1184 DMA-API debugging code disables itself because the
1188 With this option the DMA-API debugging driver
1205 This parameter overrides the compile time default set
1212 Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst
1226 An EDID data set will only be used for a particular
1229 data set by separating the files with a comma. An EDID
1230 data set with no connector name will be used for
1237 Control how the dt_cpu_ftrs device-tree binding is
1247 what data is available or for reverse-engineering.
1252 Documentation/admin-guide/dynamic-debug-howto.rst
1263 determined by stdout-path property in device tree's
1268 Start an early, polled-mode console on a Cadence
1279 Start an early, polled-mode console on the 8250/16550
1281 MMIO inter-register address stride is either 8-bit
1282 (mmio) or 32-bit (mmio32 or mmio32be).
1287 the uart clock frequency; if unspecified, it is set
1292 Start an early, polled-mode console on a pl011 serial
1296 the driver will use only 32-bit accessors to read/write
1305 Start an early, polled-mode console on a meson serial
1311 Start an early, polled-mode console on an msm serial
1317 Start an early, polled-mode console on an msm serial
1323 Start an early, polled-mode console on a serial port
1329 Start an early, polled-mode console on a serial port
1335 Use RISC-V SBI (Supervisor Binary Interface) for early
1353 Start an early, polled-mode console on a lantiq serial
1367 Start an early, polled-mode, output-only console on the
1372 Start an early, polled-mode console on the
1378 Start an early, polled-mode console on a Qualcomm
1386 coherent non-x86 systems that use system memory for
1472 no_disable_early_pci_dma: Leave the busmaster bit set
1485 Documentation/admin-guide/acpi/ssdt-overlays.rst for details.
1502 elanfreq= [X86-32]
1510 See Documentation/admin-guide/kdump/kdump.rst for details.
1521 The kernel tries to set a reasonable default.
1523 enforcing= [SELINUX] Set initial enforcing status.
1526 0 -- permissive (log only, no denials).
1527 1 -- enforcing (deny and log).
1563 See also Documentation/fault-injection/.
1567 See Documentation/admin-guide/sysctl/net.rst for
1571 See Documentation/admin-guide/blockdev/floppy.rst.
1573 forcepae [X86-32]
1580 fred= [X86-64]
1587 [FTRACE] will set and start the specified tracer
1600 instance that was created by the trace_instance= command
1631 ftrace_filter=[function-list]
1633 tracer at boot up. function-list is a comma-separated
1638 ftrace_notrace=[function-list]
1640 function-list. This list can be changed at run time
1644 ftrace_graph_filter=[function-list]
1647 function-list is a comma-separated list of functions
1651 ftrace_graph_notrace=[function-list]
1653 function-list. This list is a comma-separated list of
1673 off -- Don't create device links from firmware info.
1674 permissive -- Create device links from firmware info
1677 on -- Create device links from firmware info and use it
1679 rpm -- Like "on", but also use to order runtime PM.
1692 strict -- Default. Continue waiting on consumers to
1694 timeout -- Give up waiting on consumers and call
1704 See also Documentation/input/devices/joystick-parport.rst
1708 gart_fix_e820= [X86-64,EARLY] disable the fix e820 for K8 GART
1732 gcov_persist= [GCOV] When non-zero (default), profiling data for
1742 gpio-mockup.gpio_mockup_ranges
1745 gpio-mockup.gpio_mockup_named_lines
1777 against bounds-checking flaws in the kernel's
1783 [KNL] Should the hard-lockup detector generate
1789 for 64-bit NUMA, off otherwise.
1797 corresponding firmware-first mode error processing
1806 (that will set all pages holding image data
1807 during restoration read-only).
1831 hostname= [KNL,EARLY] Set the hostname (aka UTS nodename).
1835 Using this parameter to set the hostname makes it
1836 possible to ensure the hostname is correctly set before
1839 has been explicitly set, resulting in the calling
1844 hpet= [X86-32,HPET] option to control HPET usage
1853 registers. Default set by CONFIG_HPET_MMAP_DEFAULT.
1858 If this is the first HugeTLB parameter on the command
1861 number of pages to allocate per-node can be specified.
1862 See also Documentation/admin-guide/mm/hugetlbpage.rst.
1873 Documentation/admin-guide/mm/hugetlbpage.rst.
1884 boot-time allocation of gigantic hugepages is skipped.
1912 by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time
1918 hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
1938 Set device-properties for ACPI-enumerated I2C-attached
1939 touchscreen, to e.g. fix coordinates of upside-down
1947 Omit "=<val>" entirely Set a boolean device-property
1948 Unsigned number Set a u32 device-property
1949 Anything else Set a string device-property
1952 i2c_touchscreen_props=GDIX1001:touchscreen-inverted-x:
1953 touchscreen-inverted-y
1955 i2c_touchscreen_props=MSSL1680:touchscreen-size-x=1920:
1956 touchscreen-size-y=1080:touchscreen-inverted-y:
1957 firmware-name=gsl1680-vendor-model.fw:silead,home-button
1962 (disabled by default, and as a pre-condition
1964 i8042.direct [HW] Put keyboard port into non-translated mode
1970 i8042.noloop [HW] Disable the AUX Loopback command while probing
1978 suspend-to-ram transitions, only during s2r
1994 set the brightness of the panel backlight. Normally a
1997 to maximum brightness. If this parameter is set to 0
1999 is set to 1, a brightness value of 0 sets the backlight
2002 -1 -- never invert brightness
2003 0 -- machine default
2004 1 -- force brightness inversion
2006 ia32_emulation= [X86-64]
2008 When true, allows loading 32-bit programs and executing 32-bit
2024 idle=nomwait: Disable mwait for CPU C-states
2029 support for the idxd driver. By default it is set to
2035 for the device. By default it is set to false (0).
2044 of an ELF file header flag individually set by each
2052 legacy only accept legacy-NaN binaries, if supported
2054 2008 only accept 2008-NaN binaries, if supported
2065 'relaxed' straps the emulator for both legacy-NaN and
2066 2008-NaN, whereas 'strict' enables legacy-NaN only on
2075 Ignore loglevel setting - this will print /all/
2087 Set number of hash buckets for inode cache.
2116 mode bit set by either the effective uid (euid=0) or
2142 Formats: { "ima" | "ima-ng" | "ima-ngv2" | "ima-sig" |
2143 "ima-sigv2" }
2144 Default: "ima-ng"
2152 Set the minimal file size for using asynchronous hash.
2161 Set hashing buffer size. Default: 4k.
2177 stuff: Deploy RSB-fill mitigation when retpoline is
2182 Documentation/admin-guide/hw-vuln/indirect-target-selection.rst
2193 initcall_blacklist= [KNL] Do not execute a comma-separated list of
2194 initcall functions. Useful for debugging built-in
2221 Default set by CONFIG_INIT_ON_ALLOC_DEFAULT_ON.
2225 Default set by CONFIG_INIT_ON_FREE_DEFAULT_ON.
2239 0 -- basic integrity auditing messages. (Default)
2240 1 -- additional integrity auditing messages.
2268 could harm performance of some high-throughput
2277 1 to 9 specify maximum depth of C-state.
2286 algorithms for p-state selection. There are two
2287 P-state selection algorithms provided by
2290 on whether or not the hardware managed P-states
2297 used along with the hardware-managed P-states (HWP)
2301 in favor of acpi-cpufreq. Forcing the intel_pstate driver
2302 instead of acpi-cpufreq may disable platform features, such
2304 P-States information being indicated to OSPM and therefore
2307 or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
2320 Allow per-logical-CPU P-State performance control limits using
2323 intremap= [X86-64,Intel-IOMMU,EARLY]
2328 BIOS x2APIC opt-out request will be ignored
2354 0 - Try to allocate a 32-bit DMA address first, before
2356 1 - Allocate directly from the full usable range,
2358 greater than 32-bit addressing.
2362 0 - Lazy mode.
2368 1 - Strict mode.
2371 unset - Use value of CONFIG_IOMMU_DEFAULT_DMA_{LAZY,STRICT}.
2373 legacy driver-specific options takes precedence.
2378 0 - Use IOMMU translation for DMA.
2379 1 - Bypass the IOMMU for DMA.
2380 unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
2382 io7= [HW] IO7 for Marvel-based Alpha systems
2397 See Documentation/admin-guide/nfs/nfsroot.rst.
2414 irqaffinity= [SMP] Set the default irq affinity mask
2433 Enables support for pseudo-NMIs in the kernel. This
2451 isolcpus= [KNL,SMP,ISOL] Isolate a given set of CPUs from disturbance.
2452 [Deprecated - use cpusets instead]
2453 Format: [flag-list,]<cpu-list>
2479 move in and out of an isolated set anytime.
2484 "number of CPUs in system - 1".
2510 The format of <cpu-list> is described above.
2514 ivrs_ioapic [HW,X86-64]
2515 Provide an override to the IOAPIC-ID<->DEVICE-ID
2519 For example, to map IOAPIC-ID decimal 10 to
2525 * To map IOAPIC-ID decimal 10 to PCI device 00:14.0
2528 * To map IOAPIC-ID decimal 10 to PCI segment 0x1 and
2532 ivrs_hpet [HW,X86-64]
2533 Provide an override to the HPET-ID<->DEVICE-ID
2537 For example, to map HPET-ID decimal 10 to
2543 * To map HPET-ID decimal 0 to PCI device 00:14.0
2546 * To map HPET-ID decimal 10 to PCI segment 0x1 and
2550 ivrs_acpihid [HW,X86-64]
2551 Provide an override to the ACPI-HID:UID<->DEVICE-ID
2555 For example, to map UART-HID:UID AMD0020:0 to
2561 * To map UART-HID:UID AMD0020:0 to PCI segment is 0,
2564 * To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
2588 the kernel for non-movable allocations. The requested
2598 subsystem. Note that allocations like PTEs-from-HighMem
2606 for non-movable allocations and remaining memory is used
2617 gdb or control-c on the dbgp connection. When
2618 not using this parameter you use sysrq-g to break into
2623 or a supported polling keyboard driver (non-usb).
2650 Configure the RouterBoard 532 series on-chip
2653 kmemleak= [KNL,EARLY] Boot-time kmemleak enable/disable
2659 kprobe_event=[probe-list]
2661 The probe-list is a semicolon delimited list of probe
2665 arg1 and arg2, add to the command line;
2679 CONFIG_KUNIT to be set to be fully enabled. The
2691 execution by eliminating the write-protection faults
2718 virtualization on-demand when creating and destroying
2726 is that doing so may interfere with using out-of-tree
2753 back to huge pages. If the value is a non-zero N, KVM will
2758 kvm-amd.nested= [KVM,AMD] Control nested virtualization feature in
2761 kvm-amd.npt= [KVM,AMD] Control KVM's use of Nested Page Tables,
2762 a.k.a. Two-Dimensional Page Tables. Default is 1
2766 kvm-arm.hyp_lm_size_mb=
2769 memory than this into pKVM stage-1 at run-time may be fatal.
2771 kvm-arm.mode=
2777 nvhe: Standard nVHE-based mode, without support for
2780 protected: nVHE-based mode with support for guests whose
2785 nested: VHE-based mode with support for nested
2794 kvm-arm.protected_modules=
2799 kvm-arm.mode=protected.
2801 kvm-arm.protected_prefault=
2805 kvm-arm.vgic_v3_group0_trap=
2806 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0
2809 kvm-arm.vgic_v3_group1_trap=
2810 [KVM,ARM,EARLY] Trap guest accesses to GICv3 group-1
2813 kvm-arm.vgic_v3_common_trap=
2817 kvm-arm.vgic_v4_enable=
2821 kvm-arm.wfe_trap_policy=
2822 [KVM,ARM] Control when to set WFE instruction trap for
2826 trap: set WFE instruction trap
2830 kvm-arm.wfi_trap_policy=
2831 [KVM,ARM] Control when to set WFI instruction trap for
2835 trap: set WFI instruction trap
2847 kvm-intel.ept= [KVM,Intel] Control KVM's use of Extended Page Tables,
2848 a.k.a. Two-Dimensional Page Tables. Default is 1
2852 kvm-intel.emulate_invalid_guest_state=
2854 state. Ignored if kvm-intel.enable_unrestricted_guest=1,
2860 kvm-intel.flexpriority=
2865 kvm-intel.nested=
2869 kvm-intel.unrestricted_guest=
2875 kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault
2876 CVE-2018-3620.
2887 kvm-intel.vpid= [KVM,Intel] Control KVM's use of Virtual Processor
2907 on - enable the interface for the mitigation
2931 'nosmt=force' command line option.
2972 For details see: Documentation/admin-guide/hw-vuln/l1tf.rst
2978 lapic [X86-32,APIC,EARLY] Enable the local APIC even if BIOS
2982 value for LAPIC timer one-shot implementation. Default
3002 when set.
3005 libata.force= [LIBATA] Force configurations. The format is a comma-
3017 first fan-out link behind PMP device. It does not
3031 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
3038 * rstonce: only attempt one reset during hot-unplug
3053 * trim_zero: Indicate that TRIM command zeroes data.
3055 * max_trim_128m: Set 128M maximum trim size limit.
3065 READ LOG DMA EXT command to access logs.
3073 * max_sec_128: Set transfer size limit to 128 sectors.
3075 * max_sec_1024: Set or clear transfer size limit to
3078 * max_sec_lba48: Set or clear transfer size limit to
3081 * external: Mark port as external (hotplug-capable).
3114 Enable the kernel lockdown feature. If set to
3116 modify the running kernel are disabled. If set to
3122 Set the time limit in jiffies for a lock
3135 Specify the number of self-propagating call_rcu()
3136 chains to set up. These are used to ensure that
3143 occasional long-duration lock hold time. Defaults
3154 Set the number of locking read-acquisition kthreads.
3155 Defaults to being automatically set based on the
3159 Set the number of locking write-acquisition kthreads.
3162 Set time (s) after boot for CPU-hotplug testing.
3165 Set time (s) between CPU-hotplug operations, or
3166 zero to disable CPU-hotplug testing.
3169 Do periodic testing of real-time lock priority
3174 non-real-time spinlocks, due to their disabling
3175 of preemption. Note that non-realtime mutexes
3188 Set task-shuffle interval (jiffies). Shuffling
3189 tasks allows some CPUs to go into dyntick-idle
3193 Set time (s) after boot system shutdown. This
3194 is useful for hands-off automated testing.
3213 Run the write-side locktorture kthreads at
3214 sched_set_fifo() real-time priority.
3232 7 (KERN_DEBUG) debug-level messages
3244 logo.nologo [FB] Disables display of the built-in Linux logo.
3262 an IEEE 1284-compliant printer is attached; if
3268 time-consuming boot-time autodetection (up to 250 ms per
3288 Example: machtype=lemote-yeeloong-2f-7inch
3300 (loop.max_loop) unconditionally pre-created at init time. The default
3303 devices can be requested on-demand with the
3304 /dev/loop-control interface.
3306 mce [X86-32] Machine Check Exception
3308 mce=option [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
3311 See Documentation/admin-guide/md.rst.
3318 Control mitigation for the Micro-architectural Data
3333 full - Enable MDS mitigation on vulnerable CPUs
3334 full,nosmt - Enable MDS mitigation and disable
3336 off - Unconditionally disable MDS mitigation
3338 On TAA-affected machines, mds=off can be prevented by
3347 For details see: Documentation/admin-guide/hw-vuln/mds.rst
3349 mem=nn[KMG] [HEXAGON,EARLY] Set the memory size.
3362 [ARC,MICROBLAZE] - the limit applies only to low memory,
3365 [ARM64] - only limits memory covered by the linear
3378 [ARM,MIPS,EARLY] - override the memory layout
3383 multiple mem= parameters on the command line.
3385 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
3392 per-device physically contiguous DMA buffers.
3395 [KNL] Set the initial state for the memory hotplug
3397 set according to the
3400 See Documentation/admin-guide/mm/memory-hotplug.rst.
3425 Example: Exclude memory from 0x18690000-0x1869ffff
3439 memmap=<size>%<offset>-<oldtype>+<newtype>
3441 from <oldtype> to <newtype>. If "-<oldtype>" is left
3456 repeatable BIOS-originated corruption always
3495 pattern from a given set of patterns. Memtest
3500 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control
3506 Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst
3510 s2idle - Suspend-To-Idle
3511 shallow - Power-On Suspend or equivalent (if supported)
3512 deep - Suspend-To-RAM or equivalent (if supported)
3513 See Documentation/admin-guide/pm/sleep-states.rst.
3515 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
3531 0 - The attached screen is the 3.5" TFT
3532 1 - The attached screen is the 7" TFT
3533 2 - The VGA Shield is attached (1024x768)
3537 b - Enable backlight. The TFT backlight pin will be
3541 c - Enable the s3c camera interface.
3542 t - Reserved for enabling touchscreen support. The
3546 https://repo.or.cz/w/linux-2.6/mini2440.git
3550 CPU vulnerabilities. This is a set of curated,
3551 arch-independent options, each of which is an
3552 aggregation of existing arch-specific options.
3582 ssbd=force-off [ARM64]
3596 have other ways of avoiding SMT-based attacks.
3610 [KNL,EARLY] When CONFIG_DEBUG_MEMORY_INIT is set, this
3631 full - Enable mitigation on vulnerable CPUs
3633 full,nosmt - Enable mitigation and disable SMT on
3636 off - Unconditionally disable mitigation
3649 Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
3659 [KNL] When set to true, modules will use async probing
3668 [KNL] When CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS is set,
3671 if MODULE_DEBUG_AUTOLOAD_DUPS_TRACE is set, WARN_ON()s
3674 [KNL] When CONFIG_MODULE_SIG is set, this means that
3676 Note that if CONFIG_MODULE_SIG_FORCE is set, that
3679 module_blacklist= [KNL] Do not load a comma-separated list of
3704 movable_node [KNL,EARLY] Boot-time switch to make hotplugable memory
3711 Format: <name>,<region-number>,<size>,<offset>
3714 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
3742 Set to 2 or more if your graphical card needs more.
3753 something different and driver-specific.
3777 [NFSv4] set the total number of threads that the
3782 [NFS] set the TCP port on which the NFSv4 callback
3793 [NFS] enable 64-bit inode numbers.
3794 If zero, the NFS client will fake up a 32-bit inode
3796 of returning the full 64-bit number.
3797 The default is to return 64-bit inode numbers.
3800 [NFS] set the maximum lifetime for idmapper cache
3819 [NFSv4] When set to the default of '1', this option
3829 To turn off this behaviour, set the value to '0'.
3832 [NFS4] Specify an additional fixed unique ident-
3844 attempting to recover these locks, then set this
3862 whatever value is the default set by the layout
3863 driver. A non-zero value sets the minimum interval
3867 [NFSv4.2] When set to 1, the server will support
3868 server-to-server copies for which this server is
3872 [NFSv4] When set to the default of '1', the NFSv4
3880 server-to-server copy, knfsd temporarily mounts
3887 See Documentation/admin-guide/nfs/nfsroot.rst.
3889 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
3890 See Documentation/admin-guide/nfs/nfsroot.rst.
3893 See Documentation/admin-guide/nfs/nfsroot.rst.
3897 NMI stack-backtrace request.
3906 0 - turn hardlockup detector in nmi_watchdog off
3907 1 - turn hardlockup detector in nmi_watchdog on
3908 rNNN - configure the watchdog with raw perf event 0xNNN
3912 watchdog, if CONFIG_BOOTPARAM_HARDLOCKUP_PANIC is set)
3921 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
3925 no4lvl [RISCV,EARLY] Disable 4-level and 5-level paging modes.
3926 Forces kernel to use 3-level paging instead.
3928 no5lvl [X86-64,RISCV,EARLY] Disable 5-level paging mode. Forces
3929 kernel to use 4-level paging instead.
3962 no_entry_flush [PPC,EARLY] Don't flush the L1-D cache when entering the kernel.
3964 noexec32 [X86-64]
3965 This affects only 32-bit executables.
3966 noexec32=on: enable non-executable mappings (default)
3968 noexec32=off: disable non-executable mappings
3979 nofxsr [BUGS=X86-32] Disables x86 floating point extended
3981 legacy floating-point registers on task switch.
3992 compared. However, if this command-line option is
4019 In kernels built with CONFIG_NO_HZ_FULL=y, set
4033 nointremap [X86-64,Intel-IOMMU,EARLY] Do not enable interrupt
4035 [Deprecated - use intremap=off]
4041 noirqdebug [X86-32] Disables the code which attempts to detect and
4047 When CONFIG_RANDOMIZE_BASE is set, this disables
4051 no-kvmapf [X86,KVM,EARLY] Disable paravirtualized asynchronous page
4054 no-kvmclock [X86,KVM,EARLY] Disable paravirtualized KVM clock driver
4056 nolapic [X86-32,APIC,EARLY] Do not enable or use the local APIC.
4058 nolapic_timer [X86-32,APIC,EARLY] Do not use the local APIC timer.
4060 nomce [X86-32] Disable Machine Check Exception
4062 nomfgpt [X86-32] Disable Multi-Function General Purpose
4068 not load if they could possibly displace the pre-
4071 perform display-mode changes or accelerated rendering.
4084 nopcid [X86-64,EARLY] Disable the PCID cpu feature.
4089 nopti [X86-64,EARLY]
4105 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
4111 no-scroll [VGA] Disables scrollback.
4112 This is required for the Braillex ib80-piezo Braille
4115 nosgx [X86-64,SGX,EARLY] Disables Intel SGX kernel support.
4135 nosoftlockup [KNL] Disable the soft-lockup detector.
4141 nospectre_bhb [ARM64,EARLY] Disable all mitigations for Spectre-BHB (branch
4154 no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
4164 [PPC,EARLY] Don't flush the L1-D cache after accessing user data.
4175 is set.
4177 no-vmw-sched-clock
4182 soft-lockup and NMI watchdog (hard-lockup).
4186 nox2apic [X86-64,APIC,EARLY] Do not enable x2APIC mode.
4189 LEGACY_XAPIC_DISABLED bit set in the
4194 enabling legacy floating-point and sse state.
4216 n. So during boot up some boot time memory for per-cpu
4217 variables need be pre-allocated for later physical cpu
4223 Disable NUMA, Only set up a single NUMA node
4247 This can be set from sysctl after boot.
4248 See Documentation/admin-guide/sysctl/vm.rst for details.
4251 See Documentation/core-api/debugging-via-ohci1394.rst for more
4256 command is not properly ACKed, override the length
4258 waiting for the ACK, so if this is set too high
4266 onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration
4270 boundary - index of last SLC block on Flex-OneNAND.
4272 lock - Configure if Flex-OneNAND boundary should be locked.
4291 page_owner= [KNL,EARLY] Boot-time page_owner enabling option.
4297 page_poison= [KNL,EARLY] Boot-time parameter changing the state of
4318 Hexadecimal bitmask representing the set of TAINT flags
4320 called with any of the flags in this set.
4324 bitmask set on panic_on_taint.
4325 See Documentation/admin-guide/tainted-kernels.rst for
4365 are specified on the command line, starting
4378 Set to non-zero to probe primary and secondary ISA
4384 Set to non-zero if a chip is present that snoops speed
4389 Set to 1, 2, or 3 for HT 6560A on the primary channel,
4395 Set to 1, 2, or 3 for HT 6560B on the primary channel,
4401 IORDY enable mask. Set individual bits to allow IORDY
4413 Set to 1, 2, or 3 for Opti 82c611A on the primary
4419 Set to 1, 2, or 3 for Opti 82c465MV on the primary
4425 PIO mode mask for autospeed devices. Set individual
4432 Set to non-zero to probe tertiary and further ISA
4448 Set to non-zero to probe QDI controllers. By default
4449 set to 1 if CONFIG_PATA_QDI_MODULE, 0 otherwise.
4453 Set to non-zero to probe Winbond controllers. Use
4456 By default set to 1 if CONFIG_PATA_WINBOND_VLB_MODULE,
4461 Supported PIO mode mask. Set individual bits to allow
4476 or a set of devices (<pci_dev>). These are
4500 bios [X86-32] force use of PCI BIOS, don't access
4502 has a non-standard PCI host bridge.
4503 nobios [X86-32] disallow use of PCI BIOS, only direct
4509 data in IO port 0xCFC, both 32-bit).
4511 Mechanism 2 (IO port 0xCF8 is an 8-bit port for
4512 the function, IO port 0xCFA, also 8-bit, sets
4514 through ports 0xC000-0xCFFF).
4521 root domains (aka PCI segments, in ACPI-speak).
4529 disable the use of MSI interrupts system-wide.
4534 primary IO-APIC for bridges that cannot disable
4541 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
4558 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
4565 F0000h-100000h range.
4570 assign-busses [X86] Always assign all PCI bus
4591 <linux-pci@vger.kernel.org>.
4595 a bug to <linux-pci@vger.kernel.org>.
4607 bfsort Sort PCI devices into breadth-first order.
4610 nobfsort Don't sort PCI devices into breadth-first order.
4612 tuning and use the BIOS-configured MPS defaults.
4613 pcie_bus_safe Set every device's MPS to the largest value
4615 pcie_bus_perf Set device MPS to the largest allowable MPS
4616 based on its parent bus. Also set MRRS (Max
4620 pcie_bus_peer2peer Set every device's MPS to 128B, which
4622 configuration allows peer-to-peer DMA between
4625 that hot-added devices will work.
4640 A PCI-PCI bridge can be specified if resource
4646 for 4096-byte alignment.
4648 end-to-end CRC checking). Only effective if
4679 noats [PCIE, Intel-IOMMU, AMD-IOMMU]
4710 bit-0 : ACS Source Validation
4711 bit-1 : ACS Translation Blocking
4712 bit-2 : ACS P2P Request Redirect
4713 bit-3 : ACS P2P Completion Redirect
4714 bit-4 : ACS Upstream Forwarding
4715 bit-5 : ACS P2P Egress Control
4716 bit-6 : ACS Direct Translated P2P
4726 Validation unchanged from whatever power-up
4727 or firmware set it to.
4748 dpc-native Use native PCIe service for DPC only. May
4770 Keep all power-domains already enabled by bootloader on,
4788 pirq= [SMP,APIC] Manual mp-table setup
4789 See Documentation/arch/x86/i386/IO-APIC.rst.
4793 See also Documentation/admin-guide/parport.rst.
4803 cleared). If a number is given, then MMCR1 is set to
4812 CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
4821 { on | off | curr | res | no-curr | no-res }
4845 Set the number of possible CPUs, overriding the
4866 none - Limited to cond_resched() calls
4867 voluntary - Limited to cond_resched() and might_sleep() calls
4868 full - Any section that isn't explicitly preempt disabled
4873 print-fatal-signals=
4879 coredump - etc.
4882 you might want to try "ulimit -i unlimited".
4894 or lockdep-detected issues (only if lock debug is on).
4902 Allows storing messages from non-panic CPUs into
4904 flushed to consoles by the panic-CPU on
4905 a best-effort basis.
4911 on - unlimited logging to /dev/kmsg from userspace
4912 off - logging to /dev/kmsg disabled
4913 ratelimit - ratelimit the logging
4922 overridden without restrictions. This option may be set to
4924 - 'always': traditional behavior always allows mem overrides.
4925 - 'ptrace': only allow mem overrides for active ptracers.
4926 - 'never': never allow mem overrides.
4930 Limit processor to maximum C-state
4934 Ignore the _CST method to determine C-states,
4941 Param: "schedule" - profile schedule points.
4942 Param: "kvm" - profile VM exits.
4943 Param: <number> - step/bucket size as a power of 2 for
4961 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
4967 [HW,MOUSE] Set desired mouse resolution, in dpi.
4974 pti= [X86-64] Control Page Table Isolation of user and
4979 on - unconditionally enable
4980 off - unconditionally disable
4981 auto - kernel detects whether your CPU model is
4987 [KNL] Number of legacy pty's. Overwrites compiled-in
4999 See Documentation/admin-guide/md.rst.
5002 See Documentation/admin-guide/blockdev/ramdisk.rst.
5021 cross-syscall address exposures. This is only
5027 ras=option[,option,...] [KNL] RAS-specific options
5033 rcu_nocbs[=cpu-list]
5038 enable the no-callback CPU mode, which prevents
5043 "p" for RCU-preempt, "s" for RCU-sched, and "g"
5047 and real-time workloads. It can also improve
5051 list of CPUs is set to no-callback mode from boot.
5054 arguments are omitted, no CPU will be set to
5055 no-callback mode from boot but the mode may be
5066 This improves the real-time response for the
5073 Set maximum number of finished RCU callbacks to
5077 Do only a one-line RCU CPU stall warning when
5078 there is an ongoing too-long CSD-lock wait.
5084 If triggered before the RCU grace-period machinery
5093 Set the number of jiffies to delay each step of
5094 RCU grace-period cleanup.
5097 Set the number of jiffies to delay each step of
5098 RCU grace-period initialization.
5101 Set the number of jiffies to delay each step of
5102 RCU grace-period pre-initialization, that is,
5103 the propagation of recent CPU-hotplug changes up
5107 Set delay from grace-period initialization to
5113 Set delay between subsequent attempts to force
5118 Set required age in jiffies for a
5120 soliciting quiescent-state help from
5127 rcutree.jiffies_to_sched_qs. Any attempt to set
5132 Set the SCHED_FIFO priority of the RCU per-CPU
5135 and for the RCU grace-period kthreads (rcu_bh,
5137 set, valid values are 1-99 and the default is 1
5138 (the least-favored priority). Otherwise, when
5139 RCU_BOOST is not set, valid values are 0-99 and
5140 the default is zero (non-realtime operation).
5141 When RCU_NOCB_CPU is set, also adjust the
5145 On callback-offloaded (rcu_nocbs) CPUs,
5148 use of the ->nocb_bypass list. However, in the
5149 common non-flooded case, RCU queues directly to
5150 the main ->cblist in order to avoid the extra
5151 overhead of the ->nocb_bypass list and its lock.
5153 a single jiffy, RCU pre-queues the callbacks into
5154 the ->nocb_bypass queue. The definition of "too
5158 On callback-offloaded (rcu_nocbs) CPUs, avoid
5166 Set threshold of queued RCU callbacks beyond which
5170 Set threshold of queued RCU callbacks below which
5171 batch limiting is re-enabled.
5174 Set threshold of queued RCU callbacks beyond which
5175 RCU's force-quiescent-state scan will aggressively
5178 Set to less than zero to make this be set based
5183 Set the page-cache refill delay (in milliseconds)
5184 in response to low-memory conditions. The range
5188 Set the shift-right count to use to compute
5189 the callback-invocation batch limit bl from
5196 Please note that this callback-invocation batch
5197 limit applies only to non-offloaded callback
5206 cache-to-cache transfer latencies.
5212 and for NUMA systems with large remote-access
5225 Set the number of NOCB callback kthreads in
5228 the wakeup overhead on the global grace-period
5230 each group's NOCB grace-period kthread.
5233 Cause the grace-period kthread to get an extra
5235 it should at force-quiescent-state time.
5248 this specifies an rcu_read_unlock()-time delay
5252 of RCU-protected pointers after the relevant
5261 If set to zero, move all RCU_SOFTIRQ processing to
5262 per-CPU rcuc kthreads. Defaults to a non-zero
5291 grace-period primitives such as call_rcu().
5302 grace-period primitives.
5305 Set test-start holdoff period. The purpose of
5320 Set to measure performance of kfree_rcu() flooding.
5323 Test the double-argument variant of kfree_rcu().
5325 rcuscale.kfree_rcu_test_single, both the single-
5326 and double-argument variants are tested.
5329 Test the single-argument variant of kfree_rcu().
5331 rcuscale.kfree_rcu_test_double, both the single-
5332 and double-argument variants are tested.
5345 Set the minimum test run time in seconds. This
5346 does not affect the data-collection interval,
5351 Set number of RCU readers. The value -1 selects
5353 "n" less than -1 selects N-n+1, where N is again
5354 the number of CPUs. For example, -2 selects N
5355 (the number of CPUs), -3 selects N+1, and so on.
5356 A value of "n" less than or equal to -N selects
5360 Set number of RCU writers. The values operate
5369 complete. This is useful for hands-off automated
5376 Write-side holdoff between grace periods,
5381 Additional write-side holdoff between grace
5386 Set duration of force_quiescent_state bursts
5390 Set holdoff time within force_quiescent_state bursts
5394 Set wait time between force_quiescent_state bursts
5399 for RCU grace-period forward-progress testing
5406 Specify the fraction of a CPU-stall-warning
5407 period to do tight-loop forward-progress testing.
5411 forward-progress tests.
5415 need_resched() during tight-loop forward-progress
5419 Use conditional/asynchronous update-side
5423 Use expedited update-side primitives, if available.
5426 Use normal (non-expedited) asynchronous
5427 update-side primitives, if available.
5430 Use normal (non-expedited) synchronous
5431 update-side primitives, if available. If all
5435 they are all non-zero.
5443 Leak an RCU-protected pointer out of the reader.
5450 Set callbacks/threads for rcu_barrier() testing.
5453 Set number of concurrent RCU writers. These just
5458 Set number of RCU callback-offload togglers.
5462 Set the delay in milliseconds between successive
5463 callback-offload toggling attempts.
5466 Set number of RCU readers. The value -1 selects
5467 N-1, where N is the number of CPUs. A value
5468 "n" less than -1 selects N-n-2, where N is again
5469 the number of CPUs. For example, -2 selects N
5470 (the number of CPUs), -3 selects N+1, and so on.
5473 Enable debug-object double-call_rcu() testing.
5476 Set time (s) after boot for CPU-hotplug testing.
5479 Set time (jiffies) between CPU-hotplug operations,
5480 or zero to disable CPU-hotplug testing.
5483 Set the number of read-then-exit kthreads used
5485 task-exit processing.
5488 The number of times in a given read-then-exit
5489 episode that a set of read-then-exit kthreads
5494 read-then-exit testing episodes.
5497 Set task-shuffle interval (s). Shuffling tasks
5498 allows some CPUs to go into dyntick-idle mode
5502 Set time (s) after boot system shutdown. This
5503 is useful for hands-off automated testing.
5510 Sleep while stalling if set. This will result
5512 any other stall-related activity. Note that
5518 in scheduling-while-atomic splats.
5527 Disable interrupts while stalling if set, but only
5528 on the first stall in the set.
5537 grace-period kthread to test RCU CPU stall
5563 Test RCU's dyntick-idle handling. See also the
5607 Set timeout for RCU CPU stall warning messages.
5612 Set timeout for expedited RCU CPU stall warning
5633 Use expedited grace-period primitives, for
5637 real-time latency, and degrade energy efficiency.
5641 Use only normal grace-period primitives,
5644 real-time latency, CPU utilization, and
5646 increased grace-period latency. This parameter
5653 only normal grace-period primitives. No effect
5659 post-boot attempt at an expedited RCU grace
5660 period to instead use normal non-expedited
5661 grace-period processing.
5664 Set the maximum number of callbacks present
5669 set to the default value of -1.
5672 Set the minimum number of callback-queuing-time
5673 lock-contention events per jiffy required to
5674 cause the RCU Tasks flavors to switch to per-CPU
5676 when rcupdate.rcu_task_enqueue_lim is set to
5677 the default value of -1.
5680 Set the number of callback queues to use for the
5682 of -1 allows this to be automatically (and
5687 Set time in jiffies during which RCU tasks will
5690 number avoids disturbing real-time workloads,
5695 cancel laziness on that CPU. Use -1 to disable
5701 Set initial timeout in jiffies for RCU task stall
5705 only printed prior to the stall-warning message
5723 Set timeout in jiffies for RCU task stall
5730 Set timeout in milliseconds RCU Tasks asynchronous
5737 Set timeout in milliseconds RCU Tasks
5753 force - Override the decision by the kernel to hide the
5773 (prefix with 'panic_' to set mode for panic
5781 Set test-start holdoff period. The purpose of
5793 Set the number of loops over the synchronization
5796 but the default has already reduced the per-pass
5801 Set number of readers. The default value of -1
5806 Set number of runs, each of which is dumped onto
5810 Set the read-side critical-section duration,
5814 Specify the read-protection implementation to test.
5839 [KNL, SMP] Set scheduler's default relax_domain_level.
5840 See Documentation/admin-guide/cgroup-v1/cpusets.rst.
5852 used for systems that do not wipe the RAM, and this command
5870 reservetop= [X86-32,EARLY]
5887 See Documentation/power/swsusp-and-swap-files.rst
5903 AMD-based UNRET and IBPB mitigations alone do not stop
5905 sibling threads. For that reason, STIBP is used on pro-
5909 off - no mitigation
5910 auto - automatically select a migitation
5911 auto,nosmt - automatically select a mitigation,
5915 ibpb - On AMD, mitigate short speculation
5920 ibpb,nosmt - Like "ibpb" above but will disable SMT
5924 unret - Force enable untrained return thunks,
5925 only effective on AMD f15h-f17h based
5927 unret,nosmt - Like unret, but will disable SMT when STIBP
5959 ro [KNL] Mount root device read-only on boot
5962 on Mark read-only kernel memory as read-only (default).
5963 off Leave read-only kernel memory writable for debugging.
5964 full Mark read-only kernel memory and aliases as read-only
5971 debug-uart get routed to the D+ and D- pins of the usb
5977 block/early-lookup.c for details.
5985 rootflags= [KNL] Set root filesystem mount option string
5987 rootfstype= [KNL] Set root filesystem type
6002 rw [KNL] Mount root device read-write on boot
6007 Set s390 IOTLB flushing mode
6031 solution to mutex-based priority inversion.
6043 [KNL, SMP] Set a decay shift for scheduler thermal
6061 to 10 seconds for built-in smp_call_function()
6068 that requesting even small non-zero numbers of
6075 The default of -1 specifies a number of kthreads
6080 test before initiating CPU-hotplug operations.
6084 CPU-hotplug operations. Specifying zero (which
6085 is the default) disables CPU-hotplug operations.
6091 Non-zero values are useful for automated tests.
6100 to the set of CPUs under test.
6114 "wait" parameter. A value of -1 selects the
6115 default if all other weights are -1. However,
6117 value of -1 will instead select a weight of zero.
6122 non-zero "wait" parameter. See weight_single.
6135 non-zero "wait" parameter. See weight_single
6147 non-zero "wait" parameter. See weight_single
6152 contention on all systems with CONFIG_MAXSMP set.
6154 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
6155 1 -- enable.
6166 0 -- disable.
6167 1 -- enable.
6170 serialnumber [BUGS=X86-32]
6172 sev=option[,option...] [X86-64] See Documentation/arch/x86/x86_64/boot-options.rst
6180 to set it to "all" by meaning -- no limit here.
6251 using the csdlock_debug- kernel parameter.
6256 system. By default, let CSD-lock acquisition
6258 for this value provides a 5-minute timeout.
6260 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
6261 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
6262 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
6263 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
6264 smsc-ircc2.ircc_irq= [HW] IRQ line
6265 smsc-ircc2.ircc_dma= [HW] DMA channel
6266 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
6271 smt= [KNL,MIPS,S390,EARLY] Set the maximum number of threads
6276 Default: -1 (no limit)
6279 [KNL] Should the soft-lockup detector generate panics.
6282 A value of 1 instructs the soft-lockup detector
6283 to panic the machine when a soft-lockup occurs. It is
6286 respective build-time switch to that functionality.
6289 [KNL] Should the soft-lockup detector generate
6294 See Documentation/admin-guide/laptops/sonypi.rst
6301 on - (default) Enable the HW or SW mitigation as
6304 vmexit - On systems which don't have the HW mitigation
6307 protected from VM-originated BHI attacks, but
6309 off - Disable the mitigation.
6316 on - unconditionally enable, implies
6318 off - unconditionally disable, implies
6320 auto - kernel detects whether your CPU model is
6339 retpoline - replace indirect branches
6340 retpoline,generic - Retpolines
6341 retpoline,lfence - LFENCE; indirect branch
6342 retpoline,amd - alias for retpoline,lfence
6343 eibrs - Enhanced/Auto IBRS
6344 eibrs,retpoline - Enhanced/Auto IBRS + Retpolines
6345 eibrs,lfence - Enhanced/Auto IBRS + LFENCE
6346 ibrs - use IBRS to protect kernel
6356 on - Unconditionally enable mitigations. Is
6359 off - Unconditionally disable mitigations. Is
6362 prctl - Indirect branch speculation is enabled,
6368 - Like "prctl" above, but only STIBP is
6374 - Same as "prctl" above, but all seccomp
6379 - Like "seccomp" above, but only STIBP is
6384 auto - Kernel selects the mitigation depending on
6395 off - Disable mitigation
6396 microcode - Enable microcode mitigation only
6397 safe-ret - Enable sw-only safe RET mitigation (default)
6398 ibpb - Enable mitigation by issuing IBPB on
6400 ibpb-vmexit - Issue IBPB only on VMEXIT
6401 (cloud-specific mitigation)
6426 on - Unconditionally disable Speculative Store Bypass
6427 off - Unconditionally enable Speculative Store Bypass
6428 auto - Kernel detects whether the CPU model contains an
6434 prctl - Control Speculative Store Bypass per thread
6438 seccomp - Same as "prctl" above, but all seccomp threads
6446 on,auto - On Power8 and Power9 insert a store-forwarding
6450 off - No action.
6464 off - not enabled
6466 warn - the kernel will emit rate-limited warnings
6474 fatal - the kernel will send SIGBUS to applications
6479 ratelimit:N -
6480 Set system wide rate limit to N bus locks
6499 Certain CPUs are vulnerable to an MDS-like
6519 This kernel-boot parameter defaults to 128,
6520 but takes effect only when the low-order four
6537 instead of the compile-time CONFIG_NR_CPUS.
6541 grace-period sequence counter wrap for the
6542 srcu_data structure's ->srcu_gp_seq_needed field.
6543 The greater the number of bits set in this kernel
6553 expediting. Set to zero to disable automatic
6557 Specifies the number of no-delay instances
6564 Specifies the per-grace-period phase, number of
6565 non-sleeping polls of readers. Beyond this limit,
6571 Specifies number of microseconds of non-sleeping
6572 delay between each non-sleeping poll of readers.
6575 Specifies the number of update-side contention
6580 set for contention-based conversions to occur.
6590 force-on: Unconditionally enable mitigation for
6592 force-off: Unconditionally disable mitigation for
6607 Setting this to true through kernel command line will
6609 consumed by the stack hash table. By default this is set
6615 stacktrace_filter=[function-list]
6617 will trace at boot up. function-list is a comma-separated
6625 Set the STI (builtin display/keyboard on the HP-PARISC
6627 as the initial boot-console.
6664 using these two parameters to set the minimum and
6687 to global on non-NUMA machines)
6703 is set. Default value is 5.
6712 <int> -- Number of I/O TLB slabs
6713 <int> -- Second integer after comma. Number of swiotlb
6716 force -- force using of bounce buffers even if they
6718 noforce -- Never use bounce buffers (for debugging)
6723 Set a sysctl parameter, right before loading the init
6728 later by a loaded module cannot be set this way.
6733 Ignore sysrq setting - this boot parameter will
6738 Set the number of tcp_metrics_hash slots.
6741 cache size. See Documentation/networking/ip-sysctl.rst
6748 Specify "mem" (for Suspend-to-RAM) or "standby" (for
6753 wakeup-capable RTC alarm.
6756 Set number of hash buckets for TCP connection
6759 -1: disable all active trip points in all thermal zones
6763 -1: disable all critical trip points in all thermal zones
6770 -1: disable all passive trip points
6776 <deci-seconds>: poll all this frequency
6780 Format: <size>[KMG],<size>[KMG]:<state>;<size>[KMG]-<size>[KMG]:<state>
6785 See Documentation/admin-guide/mm/transhuge.rst for more
6801 Prevent the CPU-hotplug component of torturing
6805 Dump the ftrace buffer at torture-test shutdown,
6809 with rotating-rust storage.
6814 disables verbose-printk() sleeping.
6817 Duration of each verbose-printk() sleep in jiffies.
6823 TPM2_PCR_Extend command. Consider this in a situation
6839 for the FIFO interface. By default it is set to false
6842 https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
6867 When tp_printk (above) is set, it can cause a lot of noise
6872 This command line option will stop the printing of events
6876 [FTRACE] will set tracing buffer size on each cpu.
6878 trace_clock= [FTRACE] Set the clock used for tracing events
6880 local - Use the per CPU time stamp counter
6884 global - Event time stamps are synchronize across
6887 counter - Simple counting of events (1, 2, ..)
6891 uptime - Use jiffies as the time stamp.
6892 perf - Use the same clock that perf uses.
6893 mono - Use ktime_get_mono_fast_ns() for time stamps.
6894 mono_raw - Use ktime_get_raw_fast_ns() for time
6896 boot - Use ktime_get_boot_fast_ns() for time stamps.
6900 trace_event=[event-list]
6901 [FTRACE] Set and start specified trace events in order
6902 to facilitate early boot debugging. The event-list is a
6903 comma-separated list of trace events to enable. See
6906 trace_instance=[instance-info]
6931 traceoff - Have the tracing instance tracing disabled after it is created.
6932 traceprintk - Have trace_printk() write into this trace instance
6971 trace_options=[option-list]
6973 The option-list is a comma delimited list of options
6980 stack trace of each event), add to the command line:
6987 trace_trigger=[trigger-list]
6989 Set a trigger on top of a specific event, with an optional
7016 This option can also be set at run time via the sysctl
7024 See Documentation/admin-guide/mm/transhuge.rst
7032 - "tpm"
7033 - "tee"
7034 - "caam"
7035 - "dcp"
7045 - "kernel"
7046 - the same value as trusted.source: "tpm" or "tee"
7047 - "default"
7070 off - disable the mitigation
7071 on - enable the mitigation (default)
7072 user - mitigate only user/kernel transitions
7073 vm - mitigate only guest/host transitions
7081 high-resolution timer mode on older hardware, and in
7117 on - Enable TSX on the system. Although there are
7120 several previous speculation-related CVEs, and
7124 off - Disable TSX on the system. (Note that this
7132 auto - Disable TSX if X86_BUG_TAA is present,
7137 See Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7143 Similar to Micro-architectural Data Sampling (MDS)
7158 full - Enable TAA mitigation on vulnerable CPUs
7161 full,nosmt - Enable TAA mitigation and disable SMT on
7164 vulnerable to cross-thread TAA attacks.
7165 off - Unconditionally disable TAA mitigation
7167 On MDS-affected machines, tsx_async_abort=off can be
7179 Documentation/admin-guide/hw-vuln/tsx_async_abort.rst
7185 See also Documentation/input/devices/joystick-parport.rst
7187 udbg-immortal [PPC] When debugging early kernel crashes that
7193 Set number of hash buckets for UDP/UDP-Lite connections
7195 uhci-hcd.ignore_oc=
7197 Some badly-designed motherboards generate lots of
7199 anything. Set this parameter to avoid log spamming.
7206 unwind_debug [X86-64,EARLY]
7214 (default -1 = authorized (same as 1),
7220 for newly-detected USB devices (default 2). This
7222 autosuspended. Devices for which the delay is set
7226 [USB] Set to log all usbfs traffic (default 0 = off).
7233 [USB] Set to cycle leds on hubs (default 0 = off).
7248 [USB] Specifies timeout for the initial 64-byte
7255 [USB] A list of quirk entries to augment the built-in
7258 VendorID:ProductID:Flags. The IDs are 4-digit hex
7259 numbers and Flags is a set of letters. Each letter
7260 will change the built-in quirk; setting it if it is
7261 clear and clearing it if it is set. The letters have
7265 a 255-byte read);
7269 Set-Interface requests);
7288 (bInterval-1).
7326 usb-storage.delay_use=
7333 usb-storage.quirks=
7335 override the built-in unusual_devs list. List
7338 and Product ID values (4-digit hex numbers) and
7339 Flags is a set of characters, each corresponding
7340 to a common usb-storage quirk flag as follows:
7348 READ_DISC_INFO command, not on uas);
7350 READ_CAPACITY_16 command);
7352 command, uas only);
7361 command, uas only);
7369 initial READ(10) command, not on uas);
7382 medium is write-protected).
7391 1 - undefined instruction events
7392 2 - system calls
7393 4 - invalid data aborts
7394 8 - SIGSEGV faults
7395 16 - SIGBUS faults
7411 vdso32= [X86] Control the 32-bit vDSO
7412 vdso32=1: enable 32-bit VDSO
7413 vdso32=0 or vdso32=2: disable 32-bit VDSO
7416 details. If CONFIG_COMPAT_VDSO is set, the default is
7423 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
7430 If set to 1, on receiving an ACPI notify event
7433 the allocated input device. If set to 0, video driver
7454 vga= [BOOT,X86-32] Select a particular video mode
7456 Documentation/admin-guide/svga.rst.
7471 - Disable all of the above options
7486 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
7487 Format: <command>
7489 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
7490 Format: <command>
7492 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
7493 Format: <command>
7497 hypervisor to a guest via speculative side-channels.
7499 off - disable the mitigation
7500 ibpb - use Indirect Branch Prediction Barrier
7502 force - force vulnerability detection even on
7505 vsyscall= [X86-64,EARLY]
7508 code). Most statically-linked binaries and older
7532 see VGA-softcursor.txt. Default: 2 = underline.
7537 This is a 16-member array composed of values
7538 ranging from 0-255.
7543 This is a 16-member array composed of values
7544 ranging from 0-255.
7549 This is a 16-member array composed of values
7550 ranging from 0-255.
7555 Set system-wide default UTF-8 mode for all tty's.
7556 Default is 1, i.e. UTF-8 mode is enabled for all
7561 Format=<-1|0|1>
7562 Set system-wide default for whether a cursor
7563 is shown on new VTs. Default is -1,
7568 vt.italic= [VT] Default color for italic text; 0-15.
7571 vt.underline= [VT] Default color for underlined text; 0-15.
7575 see Documentation/watchdog/watchdog-parameters.rst
7576 or other driver-specific files in the
7581 Set the hard lockup detector stall duration
7583 threshold is set to twice the value. A value of 0
7590 Format: <cpu-list>
7611 Per-cpu work items which run for longer than this
7614 them from noticeably delaying other per-cpu work
7617 If CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel
7623 If CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel
7632 Per-cpu workqueues are generally preferred because
7634 locality; unfortunately, per-cpu workqueues tend to
7637 Enabling this makes the per-cpu workqueues which
7651 Documentation/core-api/workqueue.rst.
7664 forces round-robin CPU selection to flush out
7672 on - Enable writecombine, use WUC for ioremap_wc()
7673 off - Disable writecombine, use SUC for ioremap_wc()
7675 x2apic_phys [X86-64,APIC,EARLY] Use x2apic physical mode instead of
7679 xen_512gb_limit [KNL,X86-64,XEN]
7689 ide-disks -- unplug primary master IDE devices
7690 aux-ide-disks -- unplug non-primary-master IDE devices
7691 nics -- unplug network devices
7692 all -- unplug all emulated devices (NICs and IDE disks)
7693 unnecessary -- unplugging emulated devices is
7696 never -- do not unplug even if version check succeeds
7710 Select whether to always use non-faulting (safe) MSR
7730 xen_timer_slop= [X86-64,XEN,EARLY]
7731 Set the timer slop (in nanoseconds) for the virtual Xen
7755 preferred over the 2-level event handling, as it is
7772 xive.store-eoi=off [PPC]
7778 xhci-hcd.quirks [USB,KNL]