PCI/ASPM: Clarify that pcie_aspm=off means leave ASPM untouched

Previously we claimed "pcie_aspm=off" meant that ASPM would be disabled, which is wrong. Correct this to say that with "pcie_aspm=off", Linux doesn't touch any ASPM configuration at all. ASPM may have been enabled by firmware, and that will be left unchanged. See "aspm_support_enabled". Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Bjorn Helgaas <[email protected]> Reviewed-by: David E. Box <[email protected]>
torvalds · May 3, 2024 · 2e0239d · 2e0239d
1 parent 4cece76
commit 2e0239d
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
@@ -4590,9 +4590,10 @@
  norid [S390] ignore the RID field and force use of
  one PCI domain per PCI function
 
- pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
+ pcie_aspm= [PCIE] Forcibly enable or ignore PCIe Active State Power
  Management.
- off Disable ASPM.
+ off Don't touch ASPM configuration at all. Leave any
+ configuration done by firmware unchanged.
  force Enable ASPM even on devices that claim not to support it.
  WARNING: Forcing ASPM on may cause system lockups.