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| linux:notes:kernel_parameters [2024/08/13 18:47] – created Sean Rhone | linux:notes:kernel_parameters [2025/09/13 18:08] (current) – Sean Rhone |
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| * Various kernel options | * Various kernel options |
| * https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html | * https://docs.kernel.org/admin-guide/kernel-parameters.html |
| * :!: systemd-boot does not like apostrophes '''like this' '', but GRUB handles it fine | * https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt |
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| ====== General ====== | ===== systemd-boot ===== |
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| ===== Low-Latency ===== | * :!: 2024: ''systemd-boot'' doesn't handle typewriter apostrophes '''like this' '', but GRUB handles it fine ((above kernel params page mentions double-quote usage)) |
| | * :!: 2024/05/18: ''systemd-boot'' on [[linux;distros;opensuse_tumbleweed_gnome|oS TW]] doesn't delete old ''initrd''s automatically, doesn't handle typewriter apostrophes, doesn't support ''dracut.conf'' settings, and doesn't seem faster than GRUB |
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| **** | ====== Resources ====== |
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| preempt='full' threadirqs nohz='off' | ===== General ===== |
| | |
| | * https://fwupd.github.io/libfwupdplugin/hsi.html#org.fwupd.hsi.SuspendToIdle |
| | * :!: ''iommu=off'' should not be used ([[http://www.xillybus.com/tutorials/iommu-swiotlb-linux|source]]) |
| | * https://docs.kernel.org/fb/modedb.html |
| | * https://fwupd.github.io/libfwupdplugin/hsi.html#org.fwupd.hsi.EncryptedRam |
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| ===== CPU Idle ===== | ===== CPU Idle ===== |
| * https://docs.kernel.org/admin-guide/pm/cpuidle.html | * https://docs.kernel.org/admin-guide/pm/cpuidle.html |
| * https://community.intel.com/t5/Software-Tuning-Performance/Benchmark-performance-increases-with-deeper-C-states-linux/td-p/1051623 | * https://community.intel.com/t5/Software-Tuning-Performance/Benchmark-performance-increases-with-deeper-C-states-linux/td-p/1051623 |
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| idle=halt | |
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| ===== OSI ===== | ===== OSI ===== |
| * https://forum.manjaro.org/t/how-to-choose-the-proper-acpi-kernel-argument/1405 | * https://forum.manjaro.org/t/how-to-choose-the-proper-acpi-kernel-argument/1405 |
| * https://learn.microsoft.com/en-us/windows-hardware/drivers/acpi/winacpi-osi | * https://learn.microsoft.com/en-us/windows-hardware/drivers/acpi/winacpi-osi |
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| acpi_osi='Linux' | |
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| acpi_osi='Windows 2017' | |
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| ==== Spinesnap ==== | ==== Spinesnap ==== |
| acpi_osi='!' acpi_osi='Windows 2017' | acpi_osi='!' acpi_osi='Windows 2017' |
| |
| ===== Reboot ===== | ====== Spinesnap ====== |
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| * Does hard reboots | ===== Main ===== |
| * :!: ''reboot=efi'' causes a Dell Latitude 5591 to not reboot | |
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| reboot='pci' | * [[linux;distros;opensuse_tumbleweed_gnome|openSUSE Tumbleweed (GNOME)]] |
| | * 2025/07/20 |
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| reboot='efi' | <code>acpi_osi='Linux' reboot='pci' idle='halt' nohz='off' preempt='full' iommu='pt' pci='nocrs,pcie_bus_perf,realloc,pcie_scan_all,big_root_window' pcie_aspm='off' pcie_port_pm='off' ahci.mobile_lpm_policy='1' iwlmvm.power_scheme='1' nvme_core.default_ps_max_latency_us='0' nvme.noacpi='1' nowatchdog modprobe.blacklist='iTCO_wdt' tsc='nowatchdog' snd_hda_intel.power_save='0' usbcore.autosuspend='-1' i915.mitigations='off' i915.enable_fbc='0' i915.enable_psr='0' i915.enable_dc='0' i915.enable_guc='3' i915.guc_log_level='0' i915.nuclear_pageflip='1' rootflags='data=writeback'</code> |
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| ===== Modern Standby ===== | ===== General ===== |
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| * https://fwupd.github.io/libfwupdplugin/hsi.html#org.fwupd.hsi.SuspendToIdle | **** |
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| mem_sleep_default='s2idle' | <code>acpi_osi='Linux' reboot='pci' nohz='off' preempt='none' cpuidle.off='1'</code> |
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| ===== IOMMU ===== | ===== PCI ===== |
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| * :!: ''iommu=off'' should not be used ([[http://www.xillybus.com/tutorials/iommu-swiotlb-linux|source]]) | **** |
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| iommu='pt' | <code>enable_mtrr_cleanup iomem='relaxed' pcie_ports='native' pci='nocrs,pcie_bus_perf,realloc,pcie_scan_all,big_root_window'</code> |
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| ===== PCI ===== | ===== i915 ===== |
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| **** | **** |
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| pci='pcie_bus_perf,realloc,pcie_scan_all,big_root_window' | <code>i915.enable_fbc='0' i915.enable_psr='0' i915.panel_use_ssc='0' i915.enable_guc='3' i915.guc_log_level='0' i915.nuclear_pageflip='1' i915.enable_hangcheck='0'</code> |
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| ===== Interrupt Remapping ===== | ===== Mitigations ===== |
| | |
| | * :!: 2025/08/08: openSUSE cannot have either ''mitigations'' option set on the text line through YaST ((''mitigations'' gets removed by something else likely related to the CPU mitigations option, and includes the ''i915.'' option)) |
| | |
| | <code>mitigations='off' i915.mitigations='off'</code> |
| | |
| | ===== NVMe ===== |
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| **** | **** |
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| intremap='off' | <code>nvme.noacpi='1' nvme.poll_queues='4' nvme.use_threaded_interrupts='1'</code> |
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| ===== Custom Resolution ===== | ===== Power-saving ===== |
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| * https://docs.kernel.org/fb/modedb.html | **** |
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| * Necessary for Wayland, and also works on Xorg as an alternative to ''xorg.conf'' | <code>nowatchdog modprobe.blacklist='iTCO_wdt' tsc='nowatchdog' ahci.mobile_lpm_policy='1' iwlmvm.power_scheme='1' nvme_core.default_ps_max_latency_us='0' pcie_aspm='off' pcie_port_pm='off' snd_hda_intel.power_save='0' usbcore.autosuspend='-1'</code> |
| * :?: ''HDMI-A-1'' is the same for an AMD 6600 XT and Intel UHD 630; it's possible this works for all GPUs or there's some standard? | |
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| ==== Acer S721HL ==== | ===== Display ===== |
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| * Increase refresh rate for 1080p from default 60Hz to 75Hz | **** |
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| video='HDMI-A-1:1920x1080MR@75' | <code>video='HDMI-A-1:1920x1080MR@75'</code> |
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| ==== TCL 55S405 ==== | ===== IOMMU ===== |
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| * Solves instability on some AMD GPUs at 4K@60Hz on HDMI | **** |
| * 2024/04/29: From old notes and untested | |
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| video='HDMI-A-1:3840x2160MR@60' | <code>swiotlb='noforce' iommu='force' intel_iommu='on'</code> |
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| ====== AMD ====== | ====== Other ====== |
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| ===== Memory Encryption ===== | <code>rootflags='data=writeback'</code> |
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| * https://fwupd.github.io/libfwupdplugin/hsi.html#org.fwupd.hsi.EncryptedRam | <code>threadirqs</code> |
| * :!: Requires CPU SVM to be enabled in BIOS ((AMDGPU will likely panic on-boot if ''mem_encrypt'' is enabled without SVM)) | |
| * Disable TSME in BIOS if using this | <code>idle=halt</code> |
| | |
| | <code>mem_sleep_default='s2idle'</code> |
| | |
| | <code>intremap='off'</code> |
| | |
| | <code>mem_encrypt='on'</code> |
| | |
| | ===== TPM Integrity ===== |
| |
| mem_encrypt='on' | * https://www.phoronix.com/news/Linux-TPM-Disable-PCR-Integrity |
| | * TODO: Option name (probably ''off'') |
| | |
| | <code>tpm.disable_pcr_integrity=</code> |
| |
| ====== AMDGPU ====== | ====== AMDGPU ====== |
| cat '/sys/module/amdgpu/parameters/ppfeaturemask' | cat '/sys/module/amdgpu/parameters/ppfeaturemask' |
| |
| ====== Intel ====== | ===== Disable PSR ===== |
| |
| ===== i915 ===== | * :?: ''0x15'' was seen somewhere for something |
| | * 2025/03/04: Untested |
| **** | |
| | |
| i915.enable_dc=0 i915.enable_fbc=0 i915.enable_psr=0 i915.enable_psr2_sel_fetch=0 i915.enable_hangcheck=0 i915.panel_use_ssc=0 i915.guc_log_level=0 i915.nuclear_pageflip=1 i915.request_timeout_ms=200000 i915.enable_guc=3 | |
| | |
| ===== IOMMU ===== | |
| | |
| * TODO: HSI? | |
| | |
| intel_iommu='on' | |
| | |
| ===== Firmware ===== | |
| | |
| * This enables GuC and HuC firmware loading ((do this even if unsure because seemingly not even Intel is aware of how certain hardware pre-12th-gen/AL loads the firmware; worst-case it just won't load)) | |
| |
| i915.enable_guc='3' | amdgpu.dcdebugmask=0x10 |
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| ====== NVIDIA ====== | ====== NVIDIA ====== |
| * https://github.com/ckb-next/ckb-next/wiki/Troubleshooting#usbhid-quirks | * https://github.com/ckb-next/ckb-next/wiki/Troubleshooting#usbhid-quirks |
| * :!: Seemingly only needed with the mouse plugged directly to the motherboard, and not through USB-C docks | * :!: Seemingly only needed with the mouse plugged directly to the motherboard, and not through USB-C docks |
| | * :?: 2024/09/30: Without that quirk, mouse failed immediately after setting ''preempt=none'' from a USB-C dock |
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| usbcore.quirks='1b1c:1b75:bgmn' | usbcore.quirks='1b1c:1b75:bgmn' |
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| ====== Coreboot ====== | |
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| ===== Flashing ===== | |
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| * This is needed to relax permissions for Coreboot firmware to be flashed internally | |
| * :!: This should be removed after flashing | |
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| iomem='relaxed' | |
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