Revert "drm/i915/dp: use VBT provided eDP params if available"

This reverts commit 869184a6.

This is required for the Sony Vaio Jesse was working on at the time, but
breaks most other eDP machines - machines that were working in earlier
kernels.
Reported-and-tested-by: Dave Airlie <airlied@redhat.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=31188Tested-by: Zhao Jian <jian.j.zhao@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_dp.c

@@ -584,17 +584,6 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
 		mode->clock = dev_priv->panel_fixed_mode->clock;
 	}
 
-	/* Just use VBT values for eDP */
-	if (is_edp(intel_dp)) {
-		intel_dp->lane_count = dev_priv->edp.lanes;
-		intel_dp->link_bw = dev_priv->edp.rate;
-		adjusted_mode->clock = intel_dp_link_clock(intel_dp->link_bw);
-		DRM_DEBUG_KMS("eDP link bw %02x lane count %d clock %d\n",
-			      intel_dp->link_bw, intel_dp->lane_count,
-			      adjusted_mode->clock);
-		return true;
-	}
-
 	for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
 		for (clock = 0; clock <= max_clock; clock++) {
 			int link_avail = intel_dp_max_data_rate(intel_dp_link_clock(bws[clock]), lane_count);
@@ -613,6 +602,19 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
 		}
 	}
 
+	if (is_edp(intel_dp)) {
+		/* okay we failed just pick the highest */
+		intel_dp->lane_count = max_lane_count;
+		intel_dp->link_bw = bws[max_clock];
+		adjusted_mode->clock = intel_dp_link_clock(intel_dp->link_bw);
+		DRM_DEBUG_KMS("Force picking display port link bw %02x lane "
+			      "count %d clock %d\n",
+			      intel_dp->link_bw, intel_dp->lane_count,
+			      adjusted_mode->clock);
+
+		return true;
+	}
+
 	return false;
 }
 
@@ -1087,21 +1089,11 @@ intel_get_adjust_train(struct intel_dp *intel_dp)
 }
 
 static uint32_t
-intel_dp_signal_levels(struct intel_dp *intel_dp)
+intel_dp_signal_levels(uint8_t train_set, int lane_count)
 {
-	struct drm_device *dev = intel_dp->base.base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	uint32_t signal_levels = 0;
-	u8 train_set = intel_dp->train_set[0];
-	u32 vswing = train_set & DP_TRAIN_VOLTAGE_SWING_MASK;
-	u32 preemphasis = train_set & DP_TRAIN_PRE_EMPHASIS_MASK;
+	uint32_t	signal_levels = 0;
 
-	if (is_edp(intel_dp)) {
-		vswing = dev_priv->edp.vswing;
-		preemphasis = dev_priv->edp.preemphasis;
-	}
-
-	switch (vswing) {
+	switch (train_set & DP_TRAIN_VOLTAGE_SWING_MASK) {
 	case DP_TRAIN_VOLTAGE_SWING_400:
 	default:
 		signal_levels |= DP_VOLTAGE_0_4;
@@ -1116,7 +1108,7 @@ intel_dp_signal_levels(struct intel_dp *intel_dp)
 		signal_levels |= DP_VOLTAGE_1_2;
 		break;
 	}
-	switch (preemphasis) {
+	switch (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) {
 	case DP_TRAIN_PRE_EMPHASIS_0:
 	default:
 		signal_levels |= DP_PRE_EMPHASIS_0;
@@ -1202,18 +1194,6 @@ intel_channel_eq_ok(struct intel_dp *intel_dp)
 	return true;
 }
 
-static bool
-intel_dp_aux_handshake_required(struct intel_dp *intel_dp)
-{
-	struct drm_device *dev = intel_dp->base.base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (is_edp(intel_dp) && dev_priv->no_aux_handshake)
-		return false;
-
-	return true;
-}
-
 static bool
 intel_dp_set_link_train(struct intel_dp *intel_dp,
 			uint32_t dp_reg_value,
@@ -1226,9 +1206,6 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
 	I915_WRITE(intel_dp->output_reg, dp_reg_value);
 	POSTING_READ(intel_dp->output_reg);
 
-	if (!intel_dp_aux_handshake_required(intel_dp))
-		return true;
-
 	intel_dp_aux_native_write_1(intel_dp,
 				    DP_TRAINING_PATTERN_SET,
 				    dp_train_pat);
@@ -1261,11 +1238,10 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 	POSTING_READ(intel_dp->output_reg);
 	intel_wait_for_vblank(dev, intel_crtc->pipe);
 
-	if (intel_dp_aux_handshake_required(intel_dp))
-		/* Write the link configuration data */
-		intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,
-					  intel_dp->link_configuration,
-					  DP_LINK_CONFIGURATION_SIZE);
+	/* Write the link configuration data */
+	intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,
+				  intel_dp->link_configuration,
+				  DP_LINK_CONFIGURATION_SIZE);
 
 	DP |= DP_PORT_EN;
 	if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
@@ -1283,7 +1259,7 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 			signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
 			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
 		} else {
-			signal_levels = intel_dp_signal_levels(intel_dp);
+			signal_levels = intel_dp_signal_levels(intel_dp->train_set[0], intel_dp->lane_count);
 			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
 		}
 
@@ -1297,37 +1273,33 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 			break;
 		/* Set training pattern 1 */
 
-		udelay(500);
-		if (intel_dp_aux_handshake_required(intel_dp)) {
+		udelay(100);
+		if (!intel_dp_get_link_status(intel_dp))
 			break;
-		} else {
-			if (!intel_dp_get_link_status(intel_dp))
-				break;
 
-			if (intel_clock_recovery_ok(intel_dp->link_status, intel_dp->lane_count)) {
-				clock_recovery = true;
-				break;
-			}
+		if (intel_clock_recovery_ok(intel_dp->link_status, intel_dp->lane_count)) {
+			clock_recovery = true;
+			break;
+		}
 
-			/* Check to see if we've tried the max voltage */
-			for (i = 0; i < intel_dp->lane_count; i++)
-				if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
-					break;
-			if (i == intel_dp->lane_count)
+		/* Check to see if we've tried the max voltage */
+		for (i = 0; i < intel_dp->lane_count; i++)
+			if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
 				break;
+		if (i == intel_dp->lane_count)
+			break;
 
-			/* Check to see if we've tried the same voltage 5 times */
-			if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
-				++tries;
-				if (tries == 5)
-					break;
-			} else
-				tries = 0;
-			voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
+		/* Check to see if we've tried the same voltage 5 times */
+		if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
+			++tries;
+			if (tries == 5)
+				break;
+		} else
+			tries = 0;
+		voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
 
-			/* Compute new intel_dp->train_set as requested by target */
-			intel_get_adjust_train(intel_dp);
-		}
+		/* Compute new intel_dp->train_set as requested by target */
+		intel_get_adjust_train(intel_dp);
 	}
 
 	intel_dp->DP = DP;
@@ -1354,7 +1326,7 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
 			signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
 			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
 		} else {
-			signal_levels = intel_dp_signal_levels(intel_dp);
+			signal_levels = intel_dp_signal_levels(intel_dp->train_set[0], intel_dp->lane_count);
 			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
 		}
 
@@ -1368,28 +1340,24 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
 					     DP_TRAINING_PATTERN_2))
 			break;
 
-		udelay(500);
-
-		if (!intel_dp_aux_handshake_required(intel_dp)) {
+		udelay(400);
+		if (!intel_dp_get_link_status(intel_dp))
 			break;
-		} else {
-			if (!intel_dp_get_link_status(intel_dp))
-				break;
 
-			if (intel_channel_eq_ok(intel_dp)) {
-				channel_eq = true;
-				break;
-			}
+		if (intel_channel_eq_ok(intel_dp)) {
+			channel_eq = true;
+			break;
+		}
 
-			/* Try 5 times */
-			if (tries > 5)
-				break;
+		/* Try 5 times */
+		if (tries > 5)
+			break;
 
-			/* Compute new intel_dp->train_set as requested by target */
-			intel_get_adjust_train(intel_dp);
-			++tries;
-		}
+		/* Compute new intel_dp->train_set as requested by target */
+		intel_get_adjust_train(intel_dp);
+		++tries;
 	}
+
 	if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
 		reg = DP | DP_LINK_TRAIN_OFF_CPT;
 	else