diff options
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 68 |
1 files changed, 44 insertions, 24 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a465d5242774..fb388c6c8c60 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -703,6 +703,17 @@ condev= [HW,S390] console device conmode= + con3215_drop= [S390] 3215 console drop mode. + Format: y|n|Y|N|1|0 + When set to true, drop data on the 3215 console when + the console buffer is full. In this case the + operator using a 3270 terminal emulator (for example + x3270) does not have to enter the clear key for the + console output to advance and the kernel to continue. + This leads to a much faster boot time when a 3270 + terminal emulator is active. If no 3270 terminal + emulator is used, this parameter has no effect. + console= [KNL] Output console device and options. tty<n> Use the virtual console device <n>. @@ -831,7 +842,7 @@ memory region [offset, offset + size] for that kernel image. If '@offset' is omitted, then a suitable offset is selected automatically. - [KNL, X86-64] Select a region under 4G first, and + [KNL, X86-64, ARM64] Select a region under 4G first, and fall back to reserve region above 4G when '@offset' hasn't been specified. See Documentation/admin-guide/kdump/kdump.rst for further details. @@ -851,26 +862,23 @@ available. It will be ignored if crashkernel=X is specified. crashkernel=size[KMG],low - [KNL, X86-64] range under 4G. When crashkernel=X,high + [KNL, X86-64, ARM64] range under 4G. When crashkernel=X,high is passed, kernel could allocate physical memory region above 4G, that cause second kernel crash on system that require some amount of low memory, e.g. swiotlb requires at least 64M+32K low memory, also enough extra low memory is needed to make sure DMA buffers for 32-bit devices won't run out. Kernel would try to allocate - at least 256M below 4G automatically. + default size of memory below 4G automatically. The default + size is platform dependent. + --> x86: max(swiotlb_size_or_default() + 8MiB, 256MiB) + --> arm64: 128MiB This one lets the user specify own low range under 4G for second kernel instead. 0: to disable low allocation. It will be ignored when crashkernel=X,high is not used or memory reserved is below 4G. - [KNL, ARM64] range in low memory. - This one lets the user specify a low range in the - DMA zone for the crash dump kernel. - It will be ignored when crashkernel=X,high is not used - or memory reserved is located in the DMA zones. - cryptomgr.notests [KNL] Disable crypto self-tests @@ -3777,12 +3785,15 @@ shutdown the other cpus. Instead use the REBOOT_VECTOR irq. - nomodeset Disable kernel modesetting. DRM drivers will not perform - display-mode changes or accelerated rendering. Only the - system framebuffer will be available for use if this was - set-up by the firmware or boot loader. + nomodeset Disable kernel modesetting. Most systems' firmware + sets up a display mode and provides framebuffer memory + for output. With nomodeset, DRM and fbdev drivers will + not load if they could possibly displace the pre- + initialized output. Only the system framebuffer will + be available for use. The respective drivers will not + perform display-mode changes or accelerated rendering. - Useful as fallback, or for testing and debugging. + Useful as error fallback, or for testing and debugging. nomodule Disable module load @@ -4566,17 +4577,15 @@ ramdisk_start= [RAM] RAM disk image start address - random.trust_cpu={on,off} - [KNL] Enable or disable trusting the use of the - CPU's random number generator (if available) to - fully seed the kernel's CRNG. Default is controlled - by CONFIG_RANDOM_TRUST_CPU. + random.trust_cpu=off + [KNL] Disable trusting the use of the CPU's + random number generator (if available) to + initialize the kernel's RNG. - random.trust_bootloader={on,off} - [KNL] Enable or disable trusting the use of a - seed passed by the bootloader (if available) to - fully seed the kernel's CRNG. Default is controlled - by CONFIG_RANDOM_TRUST_BOOTLOADER. + random.trust_bootloader=off + [KNL] Disable trusting the use of the a seed + passed by the bootloader (if available) to + initialize the kernel's RNG. randomize_kstack_offset= [KNL] Enable or disable kernel stack offset @@ -6959,3 +6968,14 @@ memory, and other data can't be written using xmon commands. off xmon is disabled. + + amd_pstate= [X86] + disable + Do not enable amd_pstate as the default + scaling driver for the supported processors + passive + Use amd_pstate as a scaling driver, driver requests a + desired performance on this abstract scale and the power + management firmware translates the requests into actual + hardware states (core frequency, data fabric and memory + clocks etc.) |