Re: [Bug 216877] New: Regression in PCI powermanagement breaks resume after suspend

[Thomas Witt]

On 04/01/2023 16:02, Bjorn Helgaas wrote:
> On Wed, Jan 04, 2023 at 09:44:25AM +0100, Thomas Witt wrote:
> > On 04/01/2023 01:30, Bjorn Helgaas wrote:
> > > On Mon, Jan 02, 2023 at 11:15:16AM -0600, Bjorn Helgaas wrote:
> > > > On Mon, Jan 02, 2023 at 02:02:51PM +0000, bugzilla-daemon@xxxxxxxxxx wrote:
> > > > > https://bugzilla.kernel.org/show_bug.cgi?id=216877
> > > > >
> > > > >               Bug ID: 216877
> > > > >              Summary: Regression in PCI powermanagement breaks resume after
> > > > >                       suspend
> > > > >       Kernel Version: 6.0.0-rc1
>
> BTW, if the bisect is correct, I think the regression actually is in
> v6.1-rc1, where 5e85eba6f50d ("PCI/ASPM: Refactor L1 PM Substates
> Control Register programming") appeared.
>
> > > > > Created attachment 303512
> > > > >     --> https://bugzilla.kernel.org/attachment.cgi?id=303512&action=edit
> > > > > output of git bisect log
> > > > >
> > > > > After commit 5e85eba6f50dc288c22083a7e213152bcc4b8208 "PCI/ASPM:
> > > > > Refactor L1 PM Substates Control Register programming" my Laptop
> > > > > does not resume PCI devices back from suspend.
> > >
> > > Thomas, could you try the debug patch below on top of v6.2-rc1?
> >
> > Thank you for that patch Bjorn, but as far as I can see it does not change
> > anything.
>
> Thanks for testing it.  Maybe Vidya will have more ideas.  The patch
> below (based on v6.2-rc1) would revert 5e85eba6f50d and 4ff116d0d5fd.
> If 5e85eba6f50d is the culprit, it should fix the regression.  It
> would also potentially break L1 substates after resume, so we'd like
> to avoid reverting it if possible.
>
> But the "Unable to change power state from D3hot to D0, device
> inaccessible" symptom suggests that the device is still in D3, which
> would be more like a wakeup issue than an ASPM issue.
>
> Your bisect log said 3e347969a577 ("PCI/PM: Reduce D3hot delay with
> usleep_range()") was "good", but it would be worth double-checking,
> e.g., see if reverting it from v6.2-rc1 makes any difference.
>
> Bjorn
>
> commit 61de2691d549 ("Revert "PCI/ASPM: Refactor L1 PM Substates Control Register programming"")
> parent 1b929c02afd3
> Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Date:   Wed Jan 4 08:38:53 2023 -0600
>
>      Revert "PCI/ASPM: Refactor L1 PM Substates Control Register programming"

With this patch on top of 6.2-rc1 suspend/resume works and my PCI 
devices come back online.