[Intel-gfx] [PATCH] drm/i915/icl: don't set CNL_DDI_CLOCk_REG_ACCESS_ON anymore

[Paulo Zanoni]

Em Qui, 2018-07-26 às 14:02 -0700, Souza, Jose escreveu:
> On Wed, 2018-07-25 at 17:12 -0700, Paulo Zanoni wrote:
> > The new recommendation from the spec is to simply not set this bit
> > anymore. Not setting the bit would prevent some hangs that our
> > driver
> > manages to avoid since commit c8af5274c3cb ("drm/i915: enable the
> > pipe/transcoder/planes later on HSW+"), and the theoretical
> > downside
> > of not setting the bit doesn't seem realistic according to the HW
> > team. Let's follow their recommendation.
> > 
> > BSpec: 20233
> > References: commit c8af5274c3cb ("drm/i915: enable the
> >  pipe/transcoder/planes later on HSW+")
> > Cc: José Roberto de Souza <jose.souza at intel.com>
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> Also another steps were removed from initialization too, the previous
> step 4 and parts of step 3 but if we really need to remove it we can
> do
> it another patch.

What I see is that what our code lists as Step 3 was moved on the spec
to be part of step 2. I can't find anything we should remove.

What I see that we may be missing is the text about initializing the
PCH clocks (step 1.b). We should probably do something about it.

> 
> Reviewed-by: José Roberto de Souza <jose.souza at intel.com>

Thanks!

> 
> > ---
> >  drivers/gpu/drm/i915/intel_runtime_pm.c | 4 ----
> >  1 file changed, 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
> > b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > index 6b5aa3b074ec..cf89141b2281 100644
> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > @@ -3372,10 +3372,6 @@ static void icl_display_core_init(struct
> > drm_i915_private *dev_priv,
> >  
> >  	/* 7. Setup MBUS. */
> >  	icl_mbus_init(dev_priv);
> > -
> > -	/* 8. CHICKEN_DCPR_1 */
> > -	I915_WRITE(GEN8_CHICKEN_DCPR_1,
> > I915_READ(GEN8_CHICKEN_DCPR_1)
> > > 
> > 
> > -					CNL_DDI_CLOCK_REG_ACCESS_O
> > N);
> >  }
> >  
> >  static void icl_display_core_uninit(struct drm_i915_private
> > *dev_priv)