Differences

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--- linux:notes:kernel_parameters [2025/08/08 16:52] – [Mitigations] 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 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))
+  * 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'