[PATCH] PCI/ASPM: Enable only L0s and L1 for devicetree platforms

[Bjorn Helgaas]

On Thu, Oct 23, 2025 at 09:59:41PM +0200, Diederik de Haas wrote:
> Hi Bjorn,
> 
> Thanks for the patch :-)
> 
> On Thu Oct 23, 2025 at 8:25 PM CEST, Bjorn Helgaas wrote:
> > On Thu, Oct 23, 2025 at 01:06:26PM -0500, Bjorn Helgaas wrote:
> >> From: Bjorn Helgaas <bhelgaas at google.com>
> >> 
> >> 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 <chzigotzky at xenosoft.de>
> >> Link: https://lore.kernel.org/r/db5c95a1-cf3e-46f9-8045-a1b04908051a@xenosoft.de/
> >> Reported-by: FUKAUMI Naoki <naoki at radxa.com>
> >> Closes: https://lore.kernel.org/r/22594781424C5C98+22cb5d61-19b1-4353-9818-3bb2b311da0b@radxa.com/
> >> Reported-by: Herve Codina <herve.codina at bootlin.com>
> >> Link: https://lore.kernel.org/r/20251015101304.3ec03e6b@bootlin.com/
> >> Reported-by: Diederik de Haas <diederik at cknow-tech.com>
> >> Link: https://lore.kernel.org/r/DDJXHRIRGTW9.GYC2ULZ5WQAL@cknow-tech.com/
> >> Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
> >> Tested-by: FUKAUMI Naoki <naoki at radxa.com>
> >
> > Provisionally applied to pci/for-linus, hoping to make v6.18-rc3.
> >
> > Happy to add any testing reports or amend as needed.
> 
> My build with your patch (on top of 6.18-rc2) just finished, so I
> installed it and rebooted into it.
> Happy to report that everything seems to be working fine and I can't
> find any errors, warnings or other messages with 'nvme' in dmesg that
> indicate sth could be wrong. IOW: it does indeed fix the issue I
> reported earlier. So feel free to add my:
> 
> Tested-by: Diederik de Haas <diederik at cknow-tech.com>

That's tremendous, thank you for all your help and testing!  I know 
it's frustrating and time consuming when things break, and I really
appreciate your reports and help.

Bjorn