drm/i915: Fix DP enhanced framing for CPT

Currently we're always enabling enhanced framing on CPT even if the sink
doesn't support it. Fix this up by actaully looking at what the sink
tells us.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 227e77e..d86e1f9 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1582,7 +1582,16 @@
 
 		intel_dp->DP |= crtc->pipe << 29;
 	} else if (HAS_PCH_CPT(dev) && port != PORT_A) {
+		u32 trans_dp;
+
 		intel_dp->DP |= DP_LINK_TRAIN_OFF_CPT;
+
+		trans_dp = I915_READ(TRANS_DP_CTL(crtc->pipe));
+		if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
+			trans_dp |= TRANS_DP_ENH_FRAMING;
+		else
+			trans_dp &= ~TRANS_DP_ENH_FRAMING;
+		I915_WRITE(TRANS_DP_CTL(crtc->pipe), trans_dp);
 	} else {
 		if (!HAS_PCH_SPLIT(dev) && !IS_VALLEYVIEW(dev))
 			intel_dp->DP |= intel_dp->color_range;