On Thu, Oct 23, 2025 at 01:06:26PM -0500, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <[email protected]>
>
> f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree
> platforms") enabled Clock Power Management and L1 PM Substates, but those
> features depend on CLKREQ# and possibly other device-specific
> configuration. We don't know whether CLKREQ# is supported, so we shouldn't
> blindly enable Clock PM and L1 PM Substates.
>
> Enable only ASPM L0s and L1, and only when both ends of the link advertise
> support for them.
>
> Fixes: f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for
> devicetree platforms")
> Reported-by: Christian Zigotzky <[email protected]>
> Link:
> https://lore.kernel.org/r/[email protected]/
> Reported-by: FUKAUMI Naoki <[email protected]>
> Closes:
> https://lore.kernel.org/r/[email protected]/
> Reported-by: Herve Codina <[email protected]>
> Link: https://lore.kernel.org/r/[email protected]/
> Reported-by: Diederik de Haas <[email protected]>
> Link: https://lore.kernel.org/r/[email protected]/
> Signed-off-by: Bjorn Helgaas <[email protected]>
> Tested-by: FUKAUMI Naoki <[email protected]>
> ---
> I intend this for v6.18-rc3.
Note that this will regress ASPM on Qualcomm platforms further by
disabling L1SS for devices that do not use pwrctrl (e.g. NVMe). ASPM
with pwrctrl is already broken since 6.15. [1]
Reverting also a729c1664619 ("PCI: qcom: Remove custom ASPM enablement
code") should avoid the new regression until a proper fix for the 6.15
regression is in place.
Johan
[1] https://lore.kernel.org/lkml/[email protected]/
