[Intel-gfx] [PATCH] drm/i915: We don't need display's suspend/resume operations when !HAS_DISPLAY

[Chris Wilson]

Quoting Rodrigo Vivi (2019-07-18 22:14:45)
> On Thu, Jul 18, 2019 at 09:58:16PM +0100, Chris Wilson wrote:
> > Quoting Rodrigo Vivi (2019-07-18 21:49:12)
> > > +void intel_display_power_resume_early(struct drm_i915_private *i915)
> > > +{
> > > +       if (!HAS_DISPLAY(i915))
> > > +               return;
> > > +
> > > +       if (INTEL_GEN(i915) >= 11 || IS_GEN9_LP(i915)) {
> > > +               gen9_sanitize_dc_state(i915);
> > 
> > Are you sure that whatever state you are resuming from agrees with your
> > notion of !display? The sanitize routines are supposed to be about
> > cleaning up after third parties who don't play by the same rules.
> 
> I don't expect any function setting any kind of dc states when we don't
> have display. Besides the path that sets DC_STATE_EN is and neeeds to
> be sanitized is also covered by this patch and this shouldn't happen.
> 
> Or am I missing something else?

It's not about us, it's about whatever else runs in between. And
remember !HAS_DISPLAY() is also a user setting, not merely a reflection
of probed hw.
-Chris