[Intel-gfx] [PATCH v2] drm/i915: Fix init_clock_gating for resume

[Ville Syrjälä]

On Thu, Nov 16, 2017 at 04:14:50PM +0000, Chris Wilson wrote:
> Quoting Ville Syrjala (2017-11-16 16:02:15)
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Moving the init_clock_gating() call from intel_modeset_init_hw() to
> > intel_modeset_gem_init() had an unintended effect of not applying
> > some workarounds on resume. This, for example, cause some kind of
> > corruption to appear at the top of my IVB Thinkpad X1 Carbon LVDS
> > screen after hibernation. Fix the problem by explicitly calling
> > init_clock_gating() from the resume path.
> > 
> > I really hope this doesn't break something else again. At least
> > the problems reported at https://bugs.freedesktop.org/show_bug.cgi?id=103549
> > didn't make a comeback, even after a hibernate cycle.
> > 
> > v2: Reorder the init_clock_gating vs. modeset_init_hw to match
> >     the display reset path (Rodrigo)
> > 
> > Cc: stable at vger.kernel.org
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Fixes: 6ac43272768c ("drm/i915: Move init_clock_gating() back to where it was")
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index 3423d873123a..fb584b821fb3 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -1709,6 +1709,7 @@ static int i915_drm_resume(struct drm_device *dev)
> >         i915_gem_resume(dev_priv);
> >  
> >         intel_modeset_init_hw(dev);
> > +       intel_init_clock_gating(dev_priv);
> 
> The repetition of GT stuff here shouldn't be a problem, since they
> should match the values in the reloaded context. (If not, we have bigger
> problems!) And the bits that aren't in the context do need to be
> restored.
> 
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

Pushed to dinq. Thanks for the reviews.

-- 
Ville Syrjälä
Intel OTC