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linux:notes:kernel_parameters [2024/09/10 16:20] – Sean Rhonelinux:notes:kernel_parameters [2026/07/28 08:46] (current) – [systemd-boot] 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 typewriter apostrophes '''like this' '', but GRUB handles it fine+  * https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt 
 +  * https://www.kernel.org/doc/Documentation/fb/modedb.rst
  
-====== General ======+===== systemd-boot =====
  
-===== Low-Latency =====+  * :!: 2024: ''systemd-boot'' didn't handle typewriter apostrophes ''like 'var' here'', 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]] didn't delete old ''initrd'' automatically, didn't handle typewriter apostrophes, didn't support ''dracut.conf'' settings, and didn't seem faster than GRUB
  
-****+====== Resources ======
  
-  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
  
 ===== CPU Idle ===== ===== CPU Idle =====
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   * 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
- 
-  idle=halt 
  
 ===== OSI ===== ===== OSI =====
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   * 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
- 
-  acpi_osi='Linux' 
- 
-  acpi_osi='Windows 2017' 
  
 ==== Spinesnap ==== ==== Spinesnap ====
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   acpi_osi='!' acpi_osi='Windows 2017'   acpi_osi='!' acpi_osi='Windows 2017'
  
-===== Reboot =====+====== Spinesnap ======
  
-  * Does hard reboots +===== Main =====
-  * :!: ''reboot=efi'' causes a Dell Latitude 5591 to not reboot+
  
-  reboot='pci'+  * [[linux;distros;opensuse_tumbleweed_gnome|openSUSE Tumbleweed (GNOME)]] 
 +  * 2025/07/20
  
-  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>
  
-===== Modern Standby =====+===== General =====
  
-  * https://fwupd.github.io/libfwupdplugin/hsi.html#org.fwupd.hsi.SuspendToIdle+<code>acpi_osi='Linux' reboot='pci' nohz='off' preempt='none' cpuidle.off='1'</code>
  
-  mem_sleep_default='s2idle'+===== PCI =====
  
-===== IOMMU =====+<code>enable_mtrr_cleanup iomem='relaxed' pcie_ports='native' pci='nocrs,pcie_bus_perf,realloc,pcie_scan_all,big_root_window'</code>
  
-  * :!: ''iommu=off'' should not be used ([[http://www.xillybus.com/tutorials/iommu-swiotlb-linux|source]])+===== i915 =====
  
-  iommu='pt'+<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>
  
-===== PCI =====+===== Mitigations =====
  
-****+  * 2025/08/08: openSUSE can't have either ''mitigations'' option set on the text line through YaST ((''mitigations'' gets removed by GUI CPU mitigations option, and text-includes the ''i915.'' option; i915 needs set in [[linux:notes:modprobe.d_tweaks#i915|modprobe.d]]))
  
-  pci='pcie_bus_perf,realloc,pcie_scan_all,big_root_window'+<code>mitigations='off' i915.mitigations='off'</code>
  
-===== Interrupt Remapping =====+===== NVMe =====
  
-****+<code>nvme.noacpi='1' nvme.poll_queues='4' nvme.use_threaded_interrupts='1'</code>
  
-  intremap='off'+===== Power-saving =====
  
-===== Custom Resolution =====+<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>
  
-  * https://docs.kernel.org/fb/modedb.html+===== Display =====
  
-  * Necessary for Wayland, and also works on Xorg as an alternative to ''xorg.conf'' +<code>video='HDMI-A-1:1920x1080MR@75'</code>
-  * :?: ''HDMI-A-1'' is the same for a AMD 6600 XT and Intel UHD 630; it's possible this works for all GPUs or there's some standard?+
  
-==== Acer S721HL ====+===== IOMMU =====
  
-  * Increase refresh rate for 1080p from default 60Hz to 75Hz+  * 2026/07/28: ''swiotlb=noforce'' caused USB2/EHCI controller failure on Boulderback
  
-  video='HDMI-A-1:1920x1080MR@75'+<code>swiotlb='noforce' iommu='force' intel_iommu='on'</code>
  
-==== TCL 55S405 ====+====== Other ======
  
-  * Solves instability on some AMD GPUs at 4K@60Hz on HDMI +<code>rootflags='data=writeback'</code>
-  * 2024/04/29: From old notes and untested with ''M''+
  
-  video='HDMI-A-1:3840x2160MR@60'+<code>threadirqs</code>
  
-====== AMD ======+<code>idle=halt</code>
  
-===== Memory Encryption =====+<code>mem_sleep_default='s2idle'</code>
  
-  * https://fwupd.github.io/libfwupdplugin/hsi.html#org.fwupd.hsi.EncryptedRam +<code>intremap='off'</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+
  
-  mem_encrypt='on'+<code>mem_encrypt='on'</code>
  
 ====== AMDGPU ====== ====== AMDGPU ======
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   * Allows use of Overdrive options for overclocking and increasing the Power Limit   * Allows use of Overdrive options for overclocking and increasing the Power Limit
   * See [[https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/amd/include/amd_shared.h#L203|amd_shared.h]] for more ''PP_FEATURE_MASK'' values   * See [[https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/amd/include/amd_shared.h#L203|amd_shared.h]] for more ''PP_FEATURE_MASK'' values
-  * :!: ''0xffffffff'' can be used to enable everything, but may cause issues with unstable features+  * :?: ''0xffffffff'' can be used to enable everything, but may cause issues with unstable features
  
   sudo grubby --args='amdgpu.ppfeaturemask=0xfff7ffff' --update-kernel='ALL'   sudo grubby --args='amdgpu.ppfeaturemask=0xfff7ffff' --update-kernel='ALL'
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 ==== Verify ==== ==== Verify ====
- 
-**** 
  
   cat '/sys/module/amdgpu/parameters/ppfeaturemask'   cat '/sys/module/amdgpu/parameters/ppfeaturemask'
- 
-====== Intel ====== 
- 
-===== i915 ===== 
- 
-**** 
- 
-  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 ===== 
- 
-  * Requires CPU SVM to be enabled in BIOS 
- 
-  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' 
  
 ====== NVIDIA ====== ====== NVIDIA ======
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 ==== Blacklist nouveau ==== ==== Blacklist nouveau ====
- 
-**** 
  
   modprobe.blacklist='nouveau'   modprobe.blacklist='nouveau'
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 ==== Enable nvidia-modeset ==== ==== Enable nvidia-modeset ====
- 
-**** 
  
   nvidia-drm.modeset='1'   nvidia-drm.modeset='1'
  
 ===== PAT ===== ===== PAT =====
- 
-  * TODO: Find information about this 
  
   nvidia.NVreg_UsePageAttributeTable='1'   nvidia.NVreg_UsePageAttributeTable='1'
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   * Allows loading of GSP firmware   * Allows loading of GSP firmware
   * This doesn't appear necessary for the open kernel module   * This doesn't appear necessary for the open kernel module
-  * :!: 2022/07/20 515.57: this caused AoE2:DE to crash GNOME on-startup+  * :!: 2022/07/20 515.57: Caused AoE2:DE to crash GNOME on-startup
  
   nvidia.NVreg_EnableGpuFirmware='1'   nvidia.NVreg_EnableGpuFirmware='1'
  
 ==== Verify ==== ==== Verify ====
- 
-**** 
  
   nvidia-smi -q | grep 'GSP'   nvidia-smi -q | grep 'GSP'
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   * 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
  
   usbcore.quirks='1b1c:1b75:bgmn'   usbcore.quirks='1b1c:1b75:bgmn'
- 
-====== Coreboot ====== 
- 
-===== Flashing ===== 
- 
-  * This is needed to relax permissions for Coreboot firmware to be flashed internally 
-  * :!: This should be removed after flashing 
- 
-  iomem='relaxed' 
  
/usr/local/www/wiki/data/attic/linux/notes/kernel_parameters.1725999600.txt.gz · Last modified: by Sean Rhone