drm/i915/dp: Explicitly disable symbol scrambling while training
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@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 1c3a36f..8aecb07 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1370,7 +1370,8 @@
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 */
@@ -1445,7 +1446,8 @@
/* 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);