Re: [PATCH 34/40] drm/i915: Add DP training pattern 3 for CHV

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Jul 29, 2014 at 09:34:34PM +0300, Ville Syrjälä wrote:
> On Tue, Jul 29, 2014 at 08:04:59PM +0200, Daniel Vetter wrote:
> > On Tue, Jul 29, 2014 at 10:01:57AM -0700, Jesse Barnes wrote:
> > > On Sat, 28 Jun 2014 02:04:25 +0300
> > > ville.syrjala@linux.intel.com wrote:
> > > 
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > 
> > > > CHV supports DP training pattern 3. Add the required stuff.
> > > > 
> > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/i915_reg.h |  2 ++
> > > >  drivers/gpu/drm/i915/intel_dp.c | 18 ++++++++++++++----
> > > >  2 files changed, 16 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > > index 85b59c4..8debe61 100644
> > > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > > @@ -3515,6 +3515,8 @@ enum punit_power_well {
> > > >  #define   DP_LINK_TRAIN_OFF		(3 << 28)
> > > >  #define   DP_LINK_TRAIN_MASK		(3 << 28)
> > > >  #define   DP_LINK_TRAIN_SHIFT		28
> > > > +#define   DP_LINK_TRAIN_PAT_3_CHV	(1 << 14)
> > > > +#define   DP_LINK_TRAIN_MASK_CHV	((3 << 28)|(1<<14))
> > > >  
> > > >  /* CPT Link training mode */
> > > >  #define   DP_LINK_TRAIN_PAT_1_CPT	(0 << 8)
> > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > > index 739dc43..a825ff1 100644
> > > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > > @@ -2900,7 +2900,10 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
> > > >  		}
> > > >  
> > > >  	} else {
> > > > -		*DP &= ~DP_LINK_TRAIN_MASK;
> > > > +		if (IS_CHERRYVIEW(dev))
> > > > +			*DP &= ~DP_LINK_TRAIN_MASK_CHV;
> > > > +		else
> > > > +			*DP &= ~DP_LINK_TRAIN_MASK;
> > > >  
> > > >  		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
> > > >  		case DP_TRAINING_PATTERN_DISABLE:
> > > > @@ -2913,8 +2916,12 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
> > > >  			*DP |= DP_LINK_TRAIN_PAT_2;
> > > >  			break;
> > > >  		case DP_TRAINING_PATTERN_3:
> > > > -			DRM_ERROR("DP training pattern 3 not supported\n");
> > > > -			*DP |= DP_LINK_TRAIN_PAT_2;
> > > > +			if (IS_CHERRYVIEW(dev)) {
> > > > +				*DP |= DP_LINK_TRAIN_PAT_3_CHV;
> > > > +			} else {
> > > > +				DRM_ERROR("DP training pattern 3 not supported\n");
> > > > +				*DP |= DP_LINK_TRAIN_PAT_2;
> > > > +			}
> > > >  			break;
> > > >  		}
> > > >  	}
> > > > @@ -3201,7 +3208,10 @@ intel_dp_link_down(struct intel_dp *intel_dp)
> > > >  		DP &= ~DP_LINK_TRAIN_MASK_CPT;
> > > >  		I915_WRITE(intel_dp->output_reg, DP | DP_LINK_TRAIN_PAT_IDLE_CPT);
> > > >  	} else {
> > > > -		DP &= ~DP_LINK_TRAIN_MASK;
> > > > +		if (IS_CHERRYVIEW(dev))
> > > > +			DP &= ~DP_LINK_TRAIN_MASK_CHV;
> > > > +		else
> > > > +			DP &= ~DP_LINK_TRAIN_MASK;
> > > >  		I915_WRITE(intel_dp->output_reg, DP | DP_LINK_TRAIN_PAT_IDLE);
> > > >  	}
> > > >  	POSTING_READ(intel_dp->output_reg);
> > > 
> > > I guess we could have a whole IS_CHV block, but that would probably add
> > > more code than it saved...
> > > 
> > > Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> > 
> > This won't do a hole lot without adding HBR2 support ...  Queued for
> > -next anyway, thanks for the patch.
> 
> What else is missing for HBR2?

Adjusting the check in intel_dp_max_link_bw. At least I haven't seen a
patch for that yet. Maybe missed it.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch