Differences

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--- linux:notes:kernel_parameters [2025/08/04 09:29] – Sean Rhone
+++ linux:notes:kernel_parameters [2026/07/28 08:46] (current) – [systemd-boot] Sean Rhone
@@ Line 2: / Line 2: @@
   * Various kernel options
-  * https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
+  * https://docs.kernel.org/admin-guide/kernel-parameters.html
+  * https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt
+  * https://www.kernel.org/doc/Documentation/fb/modedb.rst
 ===== systemd-boot =====
-  * :!: 2024: ''systemd-boot'' doesn't handle typewriter apostrophes '''like this' '', but GRUB handles it fine ((above kernel params page mentions double-quote usage))
+  * :!: 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]] 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
+  * :!: 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 ======
@@ Line 46: / Line 48: @@
 ===== General =====
-****
 <code>acpi_osi='Linux' reboot='pci' nohz='off' preempt='none' cpuidle.off='1'</code>
 ===== PCI =====
-****
 <code>enable_mtrr_cleanup iomem='relaxed' pcie_ports='native' pci='nocrs,pcie_bus_perf,realloc,pcie_scan_all,big_root_window'</code>
 ===== i915 =====
-****
 <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>
@@ Line 65: / Line 61: @@
 ===== 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]]))
 <code>mitigations='off' i915.mitigations='off'</code>
 ===== NVMe =====
-****
 <code>nvme.noacpi='1' nvme.poll_queues='4' nvme.use_threaded_interrupts='1'</code>
 ===== Power-saving =====
-****
 <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>
 ===== Display =====
-****
 <code>video='HDMI-A-1:1920x1080MR@75'</code>
@@ Line 89: / Line 79: @@
 ===== IOMMU =====
-****
+  * 2026/07/28: ''swiotlb=noforce'' caused USB2/EHCI controller failure on Boulderback
 <code>swiotlb='noforce' iommu='force' intel_iommu='on'</code>
@@ Line 106: / Line 96: @@
 <code>mem_encrypt='on'</code>
-===== TPM Integrity =====
-  * https://www.phoronix.com/news/Linux-TPM-Disable-PCR-Integrity
-  * TODO: Option name (probably ''off'')
-<code>tpm.disable_pcr_integrity=</code>
 ====== AMDGPU ======
@@ Line 120: / Line 103: @@
   * 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
-  * :!: ''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'
@@ Line 127: / Line 110: @@
 ==== Verify ====
-****
   cat '/sys/module/amdgpu/parameters/ppfeaturemask'
-===== Disable PSR =====
-  * :?: ''0x15'' was seen somewhere for something
-  * 2025/03/04: Untested
-  amdgpu.dcdebugmask=0x10
 ====== NVIDIA ======
@@ Line 144: / Line 118: @@
 ==== Blacklist nouveau ====
-****
   modprobe.blacklist='nouveau'
@@ Line 156: / Line 128: @@
 ==== Enable nvidia-modeset ====
-****
   nvidia-drm.modeset='1'
 ===== PAT =====
-  * TODO: Find information about this
   nvidia.NVreg_UsePageAttributeTable='1'
@@ Line 172: / Line 140: @@
   * Allows loading of GSP firmware
   * 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'
 ==== Verify ====
-****
   nvidia-smi -q | grep 'GSP'
@@ Line 185: / Line 151: @@
   * 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'