[Intel-gfx] [PATCH 4/7] drm/i915: Factor out a helper to disable the DPCD training pattern

[Imre Deak]

To prepare for a follow-up LTTPR change factor out a helper to disable
the training pattern in DPCD. We'll need to do this for each LTTPR
(without programming the port to output the idle pattern) when training
in LTTPR non-transparent mode.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 .../drm/i915/display/intel_dp_link_training.c | 28 +++++++++++--------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 0c3809891bd2..6994a32244dc 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -102,30 +102,34 @@ void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
 		intel_dp->train_set[lane] = v | p;
 }
 
+static bool intel_dp_disable_dpcd_training_pattern(struct intel_dp *intel_dp)
+{
+	u8 val = DP_TRAINING_PATTERN_DISABLE;
+
+	return drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET, &val, 1) == 1;
+}
+
 static bool
 intel_dp_set_link_train(struct intel_dp *intel_dp,
 			u8 dp_train_pat)
 {
 	u8 buf[sizeof(intel_dp->train_set) + 1];
-	int ret, len;
+	int len;
 
 	intel_dp_program_link_training_pattern(intel_dp, dp_train_pat);
 
-	buf[0] = dp_train_pat;
 	if ((dp_train_pat & ~DP_LINK_SCRAMBLING_DISABLE) ==
-	    DP_TRAINING_PATTERN_DISABLE) {
+	    DP_TRAINING_PATTERN_DISABLE)
 		/* don't write DP_TRAINING_LANEx_SET on disable */
-		len = 1;
-	} else {
-		/* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
-		memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
-		len = intel_dp->lane_count + 1;
-	}
+		return intel_dp_disable_dpcd_training_pattern(intel_dp);
 
-	ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
-				buf, len);
+	buf[0] = dp_train_pat;
+	/* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
+	memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
+	len = intel_dp->lane_count + 1;
 
-	return ret == len;
+	return drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
+				 buf, len) == len;
 }
 
 static bool
-- 
2.17.1