[PATCH v2 1/2] drm/amd: Disallow s0ix without BIOS support again

[Alex Deucher]

On Wed, May 31, 2023 at 9:26 AM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> On Tue, May 30, 2023 at 6:34 PM Mario Limonciello
> <mario.limonciello at amd.com> wrote:
> >
> > commit cf488dcd0ab7 ("drm/amd: Allow s0ix without BIOS support") showed
> > improvements to power consumption over suspend when s0ix wasn't enabled in
> > BIOS and the system didn't support S3.
> >
> > This patch however was misguided because the reason the system didn't
> > support S3 was because SMT was disabled in OEM BIOS setup.
> > This prevented the BIOS from allowing S3.
> >
> > Also allowing GPUs to use the s2idle path actually causes problems if
> > they're invoked on systems that may not support s2idle in the platform
> > firmware. `systemd` has a tendency to try to use `s2idle` if `deep` fails
> > for any reason, which could lead to unexpected flows.
> >
> > The original commit also fixed a problem during resume from suspend to idle
> > without hardware support, but this is no longer necessary with commit
> > ca4751866397 ("drm/amd: Don't allow s0ix on APUs older than Raven")
> >
> > Revert commit cf488dcd0ab7 ("drm/amd: Allow s0ix without BIOS support")
> > to make it match the expected behavior again.
> >
> > Cc: Rafael Ávila de Espíndola <rafael at espindo.la>
> > Link: https://github.com/torvalds/linux/blob/v6.1/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c#L1060
> > Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2599
> > Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
>
> Patch 1 is:
> Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
> Patch 2 seems a bit much, but I could be convinced if you think it
> will actually help more than a warn would.  Users already assume warn
> is a kernel crash.  I'm not sure the average user makes a distinction
> between warn and err.
>

You'll need to revert d2a197a45daacd ("drm/amd: Only run s3 or s0ix if
system is configured properly") as well, otherwise, we'll break
runtime pm.

Alex

> Alex
>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > index aeeec211861c..e1b01554e323 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > @@ -1092,16 +1092,20 @@ bool amdgpu_acpi_is_s0ix_active(struct amdgpu_device *adev)
> >          * S0ix even though the system is suspending to idle, so return false
> >          * in that case.
> >          */
> > -       if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
> > +       if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) {
> >                 dev_warn_once(adev->dev,
> >                               "Power consumption will be higher as BIOS has not been configured for suspend-to-idle.\n"
> >                               "To use suspend-to-idle change the sleep mode in BIOS setup.\n");
> > +               return false;
> > +       }
> >
> >  #if !IS_ENABLED(CONFIG_AMD_PMC)
> >         dev_warn_once(adev->dev,
> >                       "Power consumption will be higher as the kernel has not been compiled with CONFIG_AMD_PMC.\n");
> > -#endif /* CONFIG_AMD_PMC */
> > +       return false;
> > +#else
> >         return true;
> > +#endif /* CONFIG_AMD_PMC */
> >  }
> >
> >  #endif /* CONFIG_SUSPEND */
> > --
> > 2.34.1
> >