[Intel-gfx] [PATCH 1/2] drm/i915/dp: Explicitly disable symbol scrambling while training

[Adam Jackson]

The DP spec says training patterns 1 and 2 are to be sent non-scrambled,
and the GPU docs claim that happens (or at least, there's no explicit
scrambling control).  But the sink may be confused if we don't
explicitly tell it what we're doing, so play it safe.

Signed-off-by: Adam Jackson <ajax at redhat.com>
---
 drivers/gpu/drm/i915/intel_dp.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e2aced6..7af1f24 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1369,7 +1369,8 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 			reg = DP | DP_LINK_TRAIN_PAT_1;
 
 		if (!intel_dp_set_link_train(intel_dp, reg,
-					     DP_TRAINING_PATTERN_1))
+					     DP_TRAINING_PATTERN_1 |
+					     DP_LINK_SCRAMBLING_DISABLE))
 			break;
 		/* Set training pattern 1 */
 
@@ -1444,7 +1445,8 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
 
 		/* channel eq pattern */
 		if (!intel_dp_set_link_train(intel_dp, reg,
-					     DP_TRAINING_PATTERN_2))
+					     DP_TRAINING_PATTERN_2 |
+					     DP_LINK_SCRAMBLING_DISABLE))
 			break;
 
 		udelay(400);
-- 
1.7.6