[PATCH 3/6] drm/radeon: Disable ULV even if unsupported

[Alex Deucher]

On Mon, Aug 4, 2025 at 12:09 PM Timur Kristóf <timur.kristof at gmail.com> wrote:
>
> On Mon, 2025-08-04 at 11:24 -0400, Alex Deucher wrote:
> > On Mon, Aug 4, 2025 at 10:18 AM Timur Kristóf
> > <timur.kristof at gmail.com> wrote:
> > >
> > > Backport of the same commit to amdgpu.
> > > This commit fixes some instability on Tahiti.
> >
> > Have you tested this with radeon?
> >
> > Alex
>
> Considering that ULV is currently always marked as unsupported by both
> radeon and amdgpu, and that the same patch fixes a real issue on
> amdgpu, I assume it would improve stability on radeon too.
>
> I leave it up to your judgement whether it's a good idea to apply this
> to radeon or not.
>
> That said, I haven't got a specific issue which this fixes on radeon.
> I only tested that Tahiti can boot with radeon with this patch
> included, but didn't do detailed testing other than that. Do you have
> something specific in mind that I should try?

That's fine.  I was thinking this contributed to the other issue you
were debugging, but you clarified that in the other patch.
Acked-by: Alex Deucher <alexander.deucher at amd.com>

Alex

>
> Timur
>
> >
> > >
> > > Fixes: a9e61410921b ("drm/radeon/kms: add dpm support for SI (v7)")
> > > Signed-off-by: Timur Kristóf <timur.kristof at gmail.com>
> > > ---
> > >  drivers/gpu/drm/radeon/si_dpm.c | 7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/radeon/si_dpm.c
> > > b/drivers/gpu/drm/radeon/si_dpm.c
> > > index 9deb91970d4d..47fba85436a7 100644
> > > --- a/drivers/gpu/drm/radeon/si_dpm.c
> > > +++ b/drivers/gpu/drm/radeon/si_dpm.c
> > > @@ -5073,10 +5073,13 @@ static int si_disable_ulv(struct
> > > radeon_device *rdev)
> > >  {
> > >         struct si_power_info *si_pi = si_get_pi(rdev);
> > >         struct si_ulv_param *ulv = &si_pi->ulv;
> > > +       PPSMC_Result r;
> > >
> > > +       r = si_send_msg_to_smc(rdev, PPSMC_MSG_DisableULV);
> > > +
> > > +       /* Only care about SMC reply when ULV is supported. */
> > >         if (ulv->supported)
> > > -               return (si_send_msg_to_smc(rdev,
> > > PPSMC_MSG_DisableULV) == PPSMC_Result_OK) ?
> > > -                       0 : -EINVAL;
> > > +               return (r == PPSMC_Result_OK) ? 0 : -EINVAL;
> > >
> > >         return 0;
> > >  }
> > > --
> > > 2.50.1
> > >