[PATCH 2/3] drm/i915: hide errors when probing for a reverse display port

[Benjamin Tissoires]

We check the polarity of the attached dp, so it is normal to fail.
Do not send errors to the users.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
 drivers/gpu/drm/i915/intel_dp.c | 74 ++++++++++++++++++++++++++++++++---------
 1 file changed, 58 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f2352d8..b740987 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3568,7 +3568,7 @@ static void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
 /* Enable corresponding port and start training pattern 1 */
 static bool
 _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
-			   uint32_t *DP)
+			   uint32_t *DP, bool probing)
 {
 	struct drm_encoder *encoder = &dp_to_dig_port(intel_dp)->base.base;
 	struct drm_device *dev = encoder->dev;
@@ -3576,6 +3576,7 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 	uint8_t voltage;
 	int voltage_tries, loop_tries;
 	uint8_t link_config[2];
+	char *error_str;
 
 	if (HAS_DDI(dev))
 		intel_ddi_prepare_link_retrain(encoder);
@@ -3600,7 +3601,11 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 	if (!intel_dp_reset_link_train(intel_dp, DP,
 				       DP_TRAINING_PATTERN_1 |
 				       DP_LINK_SCRAMBLING_DISABLE)) {
-		DRM_ERROR("failed to enable link training\n");
+		error_str = "failed to enable link training\n";
+		if (!probing)
+			DRM_ERROR(error_str);
+		else
+			DRM_DEBUG(error_str);
 		return false;
 	}
 
@@ -3612,7 +3617,11 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 
 		drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
 		if (!intel_dp_get_link_status(intel_dp, link_status)) {
-			DRM_ERROR("failed to get link status\n");
+			error_str = "failed to get link status\n";
+			if (!probing)
+				DRM_ERROR(error_str);
+			else
+				DRM_DEBUG(error_str);
 			break;
 		}
 
@@ -3632,7 +3641,11 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 			if (!intel_dp_reset_link_train(intel_dp, DP,
 						       DP_TRAINING_PATTERN_1 |
 						       DP_LINK_SCRAMBLING_DISABLE)) {
-				DRM_ERROR("failed to enable link training\n");
+				error_str = "failed to enable link training\n";
+				if (!probing)
+					DRM_ERROR(error_str);
+				else
+					DRM_DEBUG(error_str);
 				return false;
 			}
 			continue;
@@ -3645,7 +3658,11 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 		if (i == lane_count) {
 			++loop_tries;
 			if (loop_tries == 5) {
-				DRM_ERROR("too many full retries, give up\n");
+				error_str = "too many full retries, give up\n";
+				if (!probing)
+					DRM_ERROR(error_str);
+				else
+					DRM_DEBUG(error_str);
 				break;
 			}
 			intel_dp_reset_link_train(intel_dp, DP,
@@ -3659,7 +3676,11 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 		if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
 			++voltage_tries;
 			if (voltage_tries == 5) {
-				DRM_ERROR("too many voltage retries, give up\n");
+				error_str = "too many voltage retries, give up\n";
+				if (!probing)
+					DRM_ERROR(error_str);
+				else
+					DRM_DEBUG(error_str);
 				break;
 			}
 		} else
@@ -3668,7 +3689,11 @@ _intel_dp_start_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 
 		/* Update training set as requested by target */
 		if (!intel_dp_update_link_train(intel_dp, DP, link_status)) {
-			DRM_ERROR("failed to update link training\n");
+			error_str = "failed to update link training\n";
+			if (!probing)
+				DRM_ERROR(error_str);
+			else
+				DRM_DEBUG(error_str);
 			break;
 		}
 	}
@@ -3682,17 +3707,18 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 {
 	uint32_t DP = intel_dp->DP;
 
-	if (_intel_dp_start_link_train(intel_dp, intel_dp->lane_count, &DP))
+	if (_intel_dp_start_link_train(intel_dp, intel_dp->lane_count, &DP, false))
 		intel_dp->DP = DP;
 }
 
 static bool
 _intel_dp_complete_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
-			      uint32_t *DP)
+			      uint32_t *DP, bool probing)
 {
 	bool channel_eq = false;
 	int tries, cr_tries;
 	uint32_t training_pattern = DP_TRAINING_PATTERN_2;
+	char *error_str;
 
 	/* Training Pattern 3 for HBR2 ot 1.2 devices that support it*/
 	if (intel_dp->link_bw == DP_LINK_BW_5_4 || intel_dp->use_tps3)
@@ -3702,7 +3728,11 @@ _intel_dp_complete_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 	if (!intel_dp_set_link_train(intel_dp, DP,
 				     training_pattern |
 				     DP_LINK_SCRAMBLING_DISABLE)) {
-		DRM_ERROR("failed to start channel equalization\n");
+		error_str = "failed to start channel equalization\n";
+		if (!probing)
+			DRM_ERROR(error_str);
+		else
+			DRM_DEBUG(error_str);
 		return false;
 	}
 
@@ -3713,20 +3743,28 @@ _intel_dp_complete_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 		uint8_t link_status[DP_LINK_STATUS_SIZE];
 
 		if (cr_tries > 5) {
-			DRM_ERROR("failed to train DP, aborting\n");
+			error_str = "failed to train DP, aborting\n";
+			if (!probing)
+				DRM_ERROR(error_str);
+			else
+				DRM_DEBUG(error_str);
 			break;
 		}
 
 		drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
 		if (!intel_dp_get_link_status(intel_dp, link_status)) {
-			DRM_ERROR("failed to get link status\n");
+			error_str = "failed to get link status\n";
+			if (!probing)
+				DRM_ERROR(error_str);
+			else
+				DRM_DEBUG(error_str);
 			break;
 		}
 
 		/* Make sure clock is still ok */
 		if (!drm_dp_clock_recovery_ok(link_status, lane_count)) {
 			intel_dp->train_set_valid = false;
-			_intel_dp_start_link_train(intel_dp, lane_count, DP);
+			_intel_dp_start_link_train(intel_dp, lane_count, DP, probing);
 			intel_dp_set_link_train(intel_dp, DP,
 						training_pattern |
 						DP_LINK_SCRAMBLING_DISABLE);
@@ -3742,7 +3780,7 @@ _intel_dp_complete_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 		/* Try 5 times, then try clock recovery if that fails */
 		if (tries > 5) {
 			intel_dp->train_set_valid = false;
-			_intel_dp_start_link_train(intel_dp);
+			_intel_dp_start_link_train(intel_dp, lane_count, DP, probing);
 			intel_dp_set_link_train(intel_dp, DP,
 						training_pattern |
 						DP_LINK_SCRAMBLING_DISABLE);
@@ -3753,7 +3791,11 @@ _intel_dp_complete_link_train(struct intel_dp *intel_dp, uint8_t lane_count,
 
 		/* Update training set as requested by target */
 		if (!intel_dp_update_link_train(intel_dp, DP, link_status)) {
-			DRM_ERROR("failed to update link training\n");
+			error_str = "failed to update link training\n";
+			if (!probing)
+				DRM_ERROR(error_str);
+			else
+				DRM_DEBUG(error_str);
 			break;
 		}
 		++tries;
@@ -3774,7 +3816,7 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
 {
 	uint32_t DP = intel_dp->DP;
 
-	if (_intel_dp_complete_link_train(intel_dp, intel_dp->lane_count, &DP))
+	if (_intel_dp_complete_link_train(intel_dp, intel_dp->lane_count, &DP, false))
 		intel_dp->DP = DP;
 }
 
-- 
2.4.3

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