linux-kernel - Re: [PATCH v2] drm/nouveau/pmu: fix timeout on GP108

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Date:   Thu, 25 Feb 2021 02:37:40 -0300
From:   Diego Viola <diego.viola@...il.com>
To:     Ben Skeggs <skeggsb@...il.com>
Cc:     Alexandre Courbot <gnurou@...il.com>,
        Roy Spliet <nouveau@...iet.org>,
        Ben Skeggs <bskeggs@...hat.com>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] drm/nouveau/pmu: fix timeout on GP108

On Thu, Feb 25, 2021 at 2:22 AM Diego Viola <diego.viola@...il.com> wrote:
>
> Hi Ben,
>
> I can confirm that your last two patches[0][1] fix the timeout issues
> (those from a normal boot and from suspend/resume).
>
> [0] https://github.com/skeggsb/linux/commit/90224a17437b1f39dbecbb385567c1fce958f992
> [1] https://github.com/skeggsb/linux/commit/0ee6dc49601359042fd254bbd8ba6b4685b4d0d7
>
> Tested-by: Diego Viola <diego.viola@...il.com>
>
> on both patches.
>
> Thanks, I appreciate it a lot.
>
> Diego
>
> On Wed, Feb 24, 2021 at 6:50 AM Ben Skeggs <skeggsb@...il.com> wrote:
> >
> > On Wed, 17 Feb 2021 at 13:30, Alexandre Courbot <gnurou@...il.com> wrote:
> > >
> > > On Wed, Feb 17, 2021 at 1:20 AM Diego Viola <diego.viola@...il.com> wrote:
> > > >
> > > > This code times out on GP108, probably because the BIOS puts it into a
> > > > bad state.
> > > >
> > > > Since we reset the PMU on driver load anyway, we are at no risk from
> > > > missing a response from it since we are not waiting for one to begin
> > > > with.
> > >
> > > This looks safe to me, provided indeed that the PMU's reset is not
> > > called outside of initialization (which for GP108 is shouldn't be
> > > IIRC?).
> > ISTR that the PMU FW we use prior to GM200 might depend on that being there.
> >
> > I've posted a proposed alternate fix here[1], as we probably shouldn't
> > have been touching PMU there anyway on those GPUs.
> >
> > Ben.
> >
> > [1] https://github.com/skeggsb/linux/commit/90224a17437b1f39dbecbb385567c1fce958f992
> >
> > >
> > > >
> > > > Signed-off-by: Diego Viola <diego.viola@...il.com>
> > > > ---
> > > >  drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c | 6 +-----
> > > >  1 file changed, 1 insertion(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> > > > index a0fe607c9c07..5c802f2d00cb 100644
> > > > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> > > > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
> > > > @@ -102,12 +102,8 @@ nvkm_pmu_reset(struct nvkm_pmu *pmu)
> > > >         if (!pmu->func->enabled(pmu))
> > > >                 return 0;
> > > >
> > > > -       /* Inhibit interrupts, and wait for idle. */
> > > > +       /* Inhibit interrupts. */
> > > >         nvkm_wr32(device, 0x10a014, 0x0000ffff);
> > > > -       nvkm_msec(device, 2000,
> > > > -               if (!nvkm_rd32(device, 0x10a04c))
> > > > -                       break;
> > > > -       );
> > > >
> > > >         /* Reset. */
> > > >         if (pmu->func->reset)
> > > > --
> > > > 2.30.1
> > > >
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel@...ts.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel

Ugh, sorry for breaking the regular email flow/order. Damn you gmail!

Regards,
Diego

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