Nouveau - Oct 2019 - [PATCH v3] pci: prevent putting nvidia GPUs into lower device states on certain intel bridges

Hi Karol,

Sorry for commenting late, I just came back from vacation.

On Wed, Oct 16, 2019 at 04:44:49PM +0200, Karol Herbst
wrote:
> Fixes state transitions of Nvidia Pascal GPUs from D3cold into higher
device
> states.
> 
> v2: convert to pci_dev quirk
>     put a proper technical explanation of the issue as a in-code comment
> v3: disable it only for certain combinations of intel and nvidia hardware
> 
> Signed-off-by: Karol Herbst <kherbst at redhat.com>
> Cc: Bjorn Helgaas <bhelgaas at google.com>
> Cc: Lyude Paul <lyude at redhat.com>
> Cc: Rafael J. Wysocki <rjw at rjwysocki.net>
> Cc: Mika Westerberg <mika.westerberg at intel.com>
> Cc: linux-pci at vger.kernel.org
> Cc: linux-pm at vger.kernel.org
> Cc: dri-devel at lists.freedesktop.org
> Cc: nouveau at lists.freedesktop.org
> ---
>  drivers/pci/pci.c    | 11 ++++++++++
>  drivers/pci/quirks.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
I may be missing something but why you can't do this in the nouveau
driver itself?

On Mon, Oct 21, 2019 at 02:00:46PM +0200, Karol Herbst
wrote:
> On Mon, Oct 21, 2019 at 1:40 PM Mika Westerberg
> <mika.westerberg at intel.com> wrote:
> >
> > Hi Karol,
> >
> > Sorry for commenting late, I just came back from vacation.
> >
> > On Wed, Oct 16, 2019 at 04:44:49PM +0200, Karol Herbst wrote:
> > > Fixes state transitions of Nvidia Pascal GPUs from D3cold into
higher device
> > > states.
> > >
> > > v2: convert to pci_dev quirk
> > >     put a proper technical explanation of the issue as a in-code
comment
> > > v3: disable it only for certain combinations of intel and nvidia
hardware
> > >
> > > Signed-off-by: Karol Herbst <kherbst at redhat.com>
> > > Cc: Bjorn Helgaas <bhelgaas at google.com>
> > > Cc: Lyude Paul <lyude at redhat.com>
> > > Cc: Rafael J. Wysocki <rjw at rjwysocki.net>
> > > Cc: Mika Westerberg <mika.westerberg at intel.com>
> > > Cc: linux-pci at vger.kernel.org
> > > Cc: linux-pm at vger.kernel.org
> > > Cc: dri-devel at lists.freedesktop.org
> > > Cc: nouveau at lists.freedesktop.org
> > > ---
> > >  drivers/pci/pci.c    | 11 ++++++++++
> > >  drivers/pci/quirks.c | 52
++++++++++++++++++++++++++++++++++++++++++++
> >
> > I may be missing something but why you can't do this in the
nouveau
> > driver itself?
> 
> What do you mean precisely? Move the quirk into nouveau, but keep the
> changes to pci core?
No, just block runtime PM from the device in nouveau driver.