drm/amd/display: Reset PHY in link re-training

[Why]
Link training failed randomly when plugging USB-C display in/out.

[How]
If link training failed, reset PHY in link re-training.
Signed-off-by: Paul Hsieh <paul.hsieh@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -1495,7 +1495,6 @@ static enum dc_status enable_link_dp(
 	bool skip_video_pattern;
 	struct dc_link *link = stream->link;
 	struct dc_link_settings link_settings = {0};
-	enum dp_panel_mode panel_mode;
 	bool fec_enable;
 	int i;
 	bool apply_seamless_boot_optimization = false;
@@ -1531,40 +1530,17 @@ static enum dc_status enable_link_dp(
 	if (state->clk_mgr && !apply_seamless_boot_optimization)
 		state->clk_mgr->funcs->update_clocks(state->clk_mgr, state, false);
 
-	dp_enable_link_phy(
-		link,
-		pipe_ctx->stream->signal,
-		pipe_ctx->clock_source->id,
-		&link_settings);
-
-	if (stream->sink_patches.dppowerup_delay > 0) {
-		int delay_dp_power_up_in_ms = stream->sink_patches.dppowerup_delay;
-
-		msleep(delay_dp_power_up_in_ms);
-	}
-
-	panel_mode = dp_get_panel_mode(link);
-	dp_set_panel_mode(link, panel_mode);
-
-	/* We need to do this before the link training to ensure the idle pattern in SST
-	 * mode will be sent right after the link training */
-	link->link_enc->funcs->connect_dig_be_to_fe(link->link_enc,
-						    pipe_ctx->stream_res.stream_enc->id, true);
 	skip_video_pattern = true;
 
 	if (link_settings.link_rate == LINK_RATE_LOW)
 			skip_video_pattern = false;
 
-	if (link->aux_access_disabled) {
-		dc_link_dp_perform_link_training_skip_aux(link, &link_settings);
-
-		link->cur_link_settings = link_settings;
-		status = DC_OK;
-	} else if (perform_link_training_with_retries(
-			link,
+	if (perform_link_training_with_retries(
 			&link_settings,
 			skip_video_pattern,
-			LINK_TRAINING_ATTEMPTS)) {
+			LINK_TRAINING_ATTEMPTS,
+			pipe_ctx,
+			pipe_ctx->stream->signal)) {
 		link->cur_link_settings = link_settings;
 		status = DC_OK;
 	}

drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c

@@ -1433,23 +1433,58 @@ enum link_training_result dc_link_dp_perform_link_training(
 }
 
 bool perform_link_training_with_retries(
-	struct dc_link *link,
 	const struct dc_link_settings *link_setting,
 	bool skip_video_pattern,
-	int attempts)
+	int attempts,
+	struct pipe_ctx *pipe_ctx,
+	enum signal_type signal)
 {
 	uint8_t j;
 	uint8_t delay_between_attempts = LINK_TRAINING_RETRY_DELAY;
+	struct dc_stream_state *stream = pipe_ctx->stream;
+	struct dc_link *link = stream->link;
+	enum dp_panel_mode panel_mode = dp_get_panel_mode(link);
 
 	for (j = 0; j < attempts; ++j) {
 
-		if (dc_link_dp_perform_link_training(
+		dp_enable_link_phy(
+			link,
+			signal,
+			pipe_ctx->clock_source->id,
+			link_setting);
+
+		if (stream->sink_patches.dppowerup_delay > 0) {
+			int delay_dp_power_up_in_ms = stream->sink_patches.dppowerup_delay;
+
+			msleep(delay_dp_power_up_in_ms);
+		}
+
+		dp_set_panel_mode(link, panel_mode);
+
+		/* We need to do this before the link training to ensure the idle pattern in SST
+		 * mode will be sent right after the link training
+		 */
+		link->link_enc->funcs->connect_dig_be_to_fe(link->link_enc,
+								pipe_ctx->stream_res.stream_enc->id, true);
+
+		if (link->aux_access_disabled) {
+			dc_link_dp_perform_link_training_skip_aux(link, link_setting);
+			return true;
+		} else if (dc_link_dp_perform_link_training(
 				link,
 				link_setting,
 				skip_video_pattern) == LINK_TRAINING_SUCCESS)
 			return true;
 
+		/* latest link training still fail, skip delay and keep PHY on
+		 */
+		if (j == (attempts - 1))
+			break;
+
+		dp_disable_link_phy(link, signal);
+
 		msleep(delay_between_attempts);
+
 		delay_between_attempts += LINK_TRAINING_RETRY_DELAY;
 	}
 
@@ -2770,17 +2805,26 @@ bool dc_link_handle_hpd_rx_irq(struct dc_link *link, union hpd_irq_data *out_hpd
 					sizeof(hpd_irq_dpcd_data),
 					"Status: ");
 
-		perform_link_training_with_retries(link,
-			&link->cur_link_settings,
-			true, LINK_TRAINING_ATTEMPTS);
-
 		for (i = 0; i < MAX_PIPES; i++) {
 			pipe_ctx = &link->dc->current_state->res_ctx.pipe_ctx[i];
-			if (pipe_ctx && pipe_ctx->stream && pipe_ctx->stream->link == link &&
-					pipe_ctx->stream->dpms_off == false &&
-					pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
-				dc_link_allocate_mst_payload(pipe_ctx);
-			}
+			if (pipe_ctx && pipe_ctx->stream && pipe_ctx->stream->link == link)
+				break;
+		}
+
+		if (pipe_ctx == NULL || pipe_ctx->stream == NULL)
+			return false;
+
+		dp_disable_link_phy(link, pipe_ctx->stream->signal);
+
+		perform_link_training_with_retries(&link->cur_link_settings,
+			true, LINK_TRAINING_ATTEMPTS,
+			pipe_ctx,
+			pipe_ctx->stream->signal);
+
+		if (pipe_ctx && pipe_ctx->stream && pipe_ctx->stream->link == link &&
+				pipe_ctx->stream->dpms_off == false &&
+				pipe_ctx->stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
+			dc_link_allocate_mst_payload(pipe_ctx);
 		}
 
 		status = false;

drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c

@@ -333,20 +333,12 @@ void dp_retrain_link_dp_test(struct dc_link *link,
 			memset(&link->cur_link_settings, 0,
 				sizeof(link->cur_link_settings));
 
-			link->link_enc->funcs->enable_dp_output(
-						link->link_enc,
-						link_setting,
-						pipes[i].clock_source->id);
-			link->cur_link_settings = *link_setting;
-
-			dp_receiver_power_ctrl(link, true);
-
 			perform_link_training_with_retries(
-					link,
 					link_setting,
 					skip_video_pattern,
-					LINK_TRAINING_ATTEMPTS);
-
+					LINK_TRAINING_ATTEMPTS,
+					&pipes[i],
+					SIGNAL_TYPE_DISPLAY_PORT);
 
 			link->dc->hwss.enable_stream(&pipes[i]);
 

drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h

@@ -57,10 +57,11 @@ void decide_link_settings(
 	struct dc_link_settings *link_setting);
 
 bool perform_link_training_with_retries(
-	struct dc_link *link,
 	const struct dc_link_settings *link_setting,
 	bool skip_video_pattern,
-	int attempts);
+	int attempts,
+	struct pipe_ctx *pipe_ctx,
+	enum signal_type signal);
 
 bool is_mst_supported(struct dc_link *link);