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

[Timur Kristóf]

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?

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
> >