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

From: Bjorn Helgaas
Date: Mon Apr 29 2024 - 15:18:41 EST


From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

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".

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index bb884c14b2f6..4bc281d6e8d3 100644
--- 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.

--
2.34.1