[PATCH v4] pci: prevent putting nvidia GPUs into lower device states on certain intel bridges

[Karol Herbst]

anybody any other ideas? It seems that both patches don't really fix
the issue and I have no idea left on my side to try out. The only
thing left I could do to further investigate would be to reverse
engineer the Nvidia driver as they support runpm on Turing+ GPUs now,
but I've heard users having similar issues to the one Lyude told us
about... and I couldn't verify that the patches help there either in a
reliable way.

On Wed, Nov 27, 2019 at 8:55 PM Lyude Paul <lyude at redhat.com> wrote:
>
> On Wed, 2019-11-27 at 12:51 +0100, Karol Herbst wrote:
> > On Wed, Nov 27, 2019 at 12:49 PM Mika Westerberg
> > <mika.westerberg at intel.com> wrote:
> > > On Tue, Nov 26, 2019 at 06:10:36PM -0500, Lyude Paul wrote:
> > > > Hey-this is almost certainly not the right place in this thread to
> > > > respond,
> > > > but this thread has gotten so deep evolution can't push the subject
> > > > further to
> > > > the right, heh. So I'll just respond here.
> > >
> > > :)
> > >
> > > > I've been following this and helping out Karol with testing here and
> > > > there.
> > > > They had me test Bjorn's PCI branch on the X1 Extreme 2nd generation,
> > > > which
> > > > has a turing GPU and 8086:1901 PCI bridge.
> > > >
> > > > I was about to say "the patch fixed things, hooray!" but it seems that
> > > > after
> > > > trying runtime suspend/resume a couple times things fall apart again:
> > >
> > > You mean $subject patch, no?
> > >
> >
> > no, I told Lyude to test the pci/pm branch as the runpm errors we saw
> > on that machine looked different. Some BAR error the GPU reported
> > after it got resumed, so I was wondering if the delays were helping
> > with that. But after some cycles it still caused the same issue, that
> > the GPU disappeared. Later testing also showed that my patch also
> > didn't seem to help with this error sadly :/
> >
> > > > [  686.883247] nouveau 0000:01:00.0: DRM: suspending object tree...
> > > > [  752.866484] ACPI Error: Aborting method \_SB.PCI0.PEG0.PEGP.NVPO due
> > > > to previous error (AE_AML_LOOP_TIMEOUT) (20190816/psparse-529)
> > > > [  752.866508] ACPI Error: Aborting method \_SB.PCI0.PGON due to
> > > > previous error (AE_AML_LOOP_TIMEOUT) (20190816/psparse-529)
> > > > [  752.866521] ACPI Error: Aborting method \_SB.PCI0.PEG0.PG00._ON due
> > > > to previous error (AE_AML_LOOP_TIMEOUT) (20190816/psparse-529)
> > >
> > > This is probably the culprit. The same AML code fails to properly turn
> > > on the device.
> > >
> > > Is acpidump from this system available somewhere?
>
> Attached it to this email
>
> > >
> --
> Cheers,
>         Lyude Paul