drm/amd/display: implement lttpr logic

1-If at least one repeater is present in the link and we are in non
transparent mode, perform clock recovery then channel equalization
with all repeaters one by one before training DPRX.

2-Mark the end of LT with a repeater by setting training pattern 0
at the end of channel equalization with each repeater.
Signed-off-by: abdoulaye berthe <abdoulaye.berthe@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -22,7 +22,7 @@
 	link->ctx->logger
 
 
-#define DP_REPEATER_CONFIGURATION_AND_STATUS_OFFSET   0x50
+#define DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE   0x50
 
 /* maximum pre emphasis level allowed for each voltage swing level*/
 static const enum dc_pre_emphasis voltage_swing_to_pre_emphasis[] = {
@@ -224,19 +224,31 @@ static enum dpcd_training_patterns
 	return dpcd_tr_pattern;
 }
 
+static inline bool is_repeater(struct dc_link *link, uint32_t offset)
+{
+	return (!link->is_lttpr_mode_transparent && offset != 0);
+}
+
 static void dpcd_set_lt_pattern_and_lane_settings(
 	struct dc_link *link,
 	const struct link_training_settings *lt_settings,
-	enum dc_dp_training_pattern pattern)
+	enum dc_dp_training_pattern pattern,
+	uint32_t offset)
 {
 	union dpcd_training_lane dpcd_lane[LANE_COUNT_DP_MAX] = { { {0} } };
-	const uint32_t dpcd_base_lt_offset =
-	DP_TRAINING_PATTERN_SET;
+
+	uint32_t dpcd_base_lt_offset;
+
 	uint8_t dpcd_lt_buffer[5] = {0};
 	union dpcd_training_pattern dpcd_pattern = { {0} };
 	uint32_t lane;
 	uint32_t size_in_bytes;
 	bool edp_workaround = false; /* TODO link_prop.INTERNAL */
+	dpcd_base_lt_offset = DP_TRAINING_PATTERN_SET;
+
+	if (is_repeater(link, offset))
+		dpcd_base_lt_offset = DP_TRAINING_PATTERN_SET_PHY_REPEATER1 +
+			((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
 
 	/*****************************************************************
 	* DpcdAddress_TrainingPatternSet
@@ -244,12 +256,12 @@ static void dpcd_set_lt_pattern_and_lane_settings(
 	dpcd_pattern.v1_4.TRAINING_PATTERN_SET =
 		dc_dp_training_pattern_to_dpcd_training_pattern(link, pattern);
 
-	dpcd_lt_buffer[DP_TRAINING_PATTERN_SET - dpcd_base_lt_offset]
+	dpcd_lt_buffer[DP_TRAINING_PATTERN_SET - DP_TRAINING_PATTERN_SET]
 		= dpcd_pattern.raw;
 
-	DC_LOG_HW_LINK_TRAINING("%s\n %x pattern = %x\n",
+	DC_LOG_HW_LINK_TRAINING("%s\n 0x%X pattern = %x\n",
 		__func__,
-		DP_TRAINING_PATTERN_SET,
+		dpcd_base_lt_offset,
 		dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
 
 	/*****************************************************************
@@ -271,19 +283,19 @@ static void dpcd_set_lt_pattern_and_lane_settings(
 		PRE_EMPHASIS_MAX_LEVEL ? 1 : 0);
 	}
 
-	/* concatinate everything into one buffer*/
+	/* concatenate everything into one buffer*/
 
 	size_in_bytes = lt_settings->link_settings.lane_count * sizeof(dpcd_lane[0]);
 
 	 // 0x00103 - 0x00102
 	memmove(
-		&dpcd_lt_buffer[DP_TRAINING_LANE0_SET - dpcd_base_lt_offset],
+		&dpcd_lt_buffer[DP_TRAINING_LANE0_SET - DP_TRAINING_PATTERN_SET],
 		dpcd_lane,
 		size_in_bytes);
 
-	DC_LOG_HW_LINK_TRAINING("%s:\n %x VS set = %x  PE set = %x max VS Reached = %x  max PE Reached = %x\n",
+	DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X VS set = %x  PE set = %x max VS Reached = %x  max PE Reached = %x\n",
 		__func__,
-		DP_TRAINING_LANE0_SET,
+		dpcd_base_lt_offset,
 		dpcd_lane[0].bits.VOLTAGE_SWING_SET,
 		dpcd_lane[0].bits.PRE_EMPHASIS_SET,
 		dpcd_lane[0].bits.MAX_SWING_REACHED,
@@ -498,8 +510,12 @@ static void get_lane_status_and_drive_settings(
 	const struct link_training_settings *link_training_setting,
 	union lane_status *ln_status,
 	union lane_align_status_updated *ln_status_updated,
-	struct link_training_settings *req_settings)
+	struct link_training_settings *req_settings,
+	uint32_t offset)
 {
+	unsigned int lane01_status_address = DP_LANE0_1_STATUS;
+	uint8_t lane_adjust_offset = 4;
+	unsigned int lane01_adjust_address;
 	uint8_t dpcd_buf[6] = {0};
 	union lane_adjust dpcd_lane_adjust[LANE_COUNT_DP_MAX] = { { {0} } };
 	struct link_training_settings request_settings = { {0} };
@@ -507,9 +523,16 @@ static void get_lane_status_and_drive_settings(
 
 	memset(req_settings, '\0', sizeof(struct link_training_settings));
 
+	if (is_repeater(link, offset)) {
+		lane01_status_address =
+				DP_LANE0_1_STATUS_PHY_REPEATER1 +
+				((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+		lane_adjust_offset = 3;
+	}
+
 	core_link_read_dpcd(
 		link,
-		DP_LANE0_1_STATUS,
+		lane01_status_address,
 		(uint8_t *)(dpcd_buf),
 		sizeof(dpcd_buf));
 
@@ -520,22 +543,28 @@ static void get_lane_status_and_drive_settings(
 		ln_status[lane].raw =
 			get_nibble_at_index(&dpcd_buf[0], lane);
 		dpcd_lane_adjust[lane].raw =
-			get_nibble_at_index(&dpcd_buf[4], lane);
+			get_nibble_at_index(&dpcd_buf[lane_adjust_offset], lane);
 	}
 
 	ln_status_updated->raw = dpcd_buf[2];
 
-	DC_LOG_HW_LINK_TRAINING("%s:\n%x Lane01Status = %x\n %x Lane23Status = %x\n ",
+	DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X Lane01Status = %x\n 0x%X Lane23Status = %x\n ",
 		__func__,
-		DP_LANE0_1_STATUS, dpcd_buf[0],
-		DP_LANE2_3_STATUS, dpcd_buf[1]);
+		lane01_status_address, dpcd_buf[0],
+		lane01_status_address + 1, dpcd_buf[1]);
+
+	lane01_adjust_address = DP_ADJUST_REQUEST_LANE0_1;
 
-	DC_LOG_HW_LINK_TRAINING("%s:\n %x Lane01AdjustRequest = %x\n %x Lane23AdjustRequest = %x\n",
+	if (is_repeater(link, offset))
+		lane01_adjust_address = DP_ADJUST_REQUEST_LANE0_1_PHY_REPEATER1 +
+				((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+
+	DC_LOG_HW_LINK_TRAINING("%s:\n 0x%X Lane01AdjustRequest = %x\n 0x%X Lane23AdjustRequest = %x\n",
 		__func__,
-		DP_ADJUST_REQUEST_LANE0_1,
-		dpcd_buf[4],
-		DP_ADJUST_REQUEST_LANE2_3,
-		dpcd_buf[5]);
+		lane01_adjust_address,
+		dpcd_buf[lane_adjust_offset],
+		lane01_adjust_address + 1,
+		dpcd_buf[lane_adjust_offset + 1]);
 
 	/*copy to req_settings*/
 	request_settings.link_settings.lane_count =
@@ -574,10 +603,18 @@ static void get_lane_status_and_drive_settings(
 
 static void dpcd_set_lane_settings(
 	struct dc_link *link,
-	const struct link_training_settings *link_training_setting)
+	const struct link_training_settings *link_training_setting,
+	uint32_t offset)
 {
 	union dpcd_training_lane dpcd_lane[LANE_COUNT_DP_MAX] = {{{0}}};
 	uint32_t lane;
+	unsigned int lane0_set_address;
+
+	lane0_set_address = DP_TRAINING_LANE0_SET;
+
+	if (is_repeater(link, offset))
+		lane0_set_address = DP_TRAINING_LANE0_SET_PHY_REPEATER1 +
+		((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
 
 	for (lane = 0; lane <
 		(uint32_t)(link_training_setting->
@@ -600,7 +637,7 @@ static void dpcd_set_lane_settings(
 	}
 
 	core_link_write_dpcd(link,
-		DP_TRAINING_LANE0_SET,
+		lane0_set_address,
 		(uint8_t *)(dpcd_lane),
 		link_training_setting->link_settings.lane_count);
 
@@ -623,9 +660,9 @@ static void dpcd_set_lane_settings(
 	}
 	*/
 
-	DC_LOG_HW_LINK_TRAINING("%s\n %x VS set = %x  PE set = %x max VS Reached = %x  max PE Reached = %x\n",
+	DC_LOG_HW_LINK_TRAINING("%s\n 0x%X VS set = %x  PE set = %x max VS Reached = %x  max PE Reached = %x\n",
 		__func__,
-		DP_TRAINING_LANE0_SET,
+		lane0_set_address,
 		dpcd_lane[0].bits.VOLTAGE_SWING_SET,
 		dpcd_lane[0].bits.PRE_EMPHASIS_SET,
 		dpcd_lane[0].bits.MAX_SWING_REACHED,
@@ -650,17 +687,6 @@ static bool is_max_vs_reached(
 
 }
 
-void dc_link_dp_set_drive_settings(
-	struct dc_link *link,
-	struct link_training_settings *lt_settings)
-{
-	/* program ASIC PHY settings*/
-	dp_set_hw_lane_settings(link, lt_settings);
-
-	/* Notify DP sink the PHY settings from source */
-	dpcd_set_lane_settings(link, lt_settings);
-}
-
 static bool perform_post_lt_adj_req_sequence(
 	struct dc_link *link,
 	struct link_training_settings *lt_settings)
@@ -693,7 +719,8 @@ static bool perform_post_lt_adj_req_sequence(
 			lt_settings,
 			dpcd_lane_status,
 			&dpcd_lane_status_updated,
-			&req_settings);
+			&req_settings,
+			DPRX);
 
 			if (dpcd_lane_status_updated.bits.
 					POST_LT_ADJ_REQ_IN_PROGRESS == 0)
@@ -750,6 +777,31 @@ static bool perform_post_lt_adj_req_sequence(
 
 }
 
+/* Only used for channel equalization */
+static uint32_t translate_training_aux_read_interval(uint32_t dpcd_aux_read_interval)
+{
+	unsigned int aux_rd_interval_us = 400;
+
+	switch (dpcd_aux_read_interval) {
+	case 0x01:
+		aux_rd_interval_us = 400;
+		break;
+	case 0x02:
+		aux_rd_interval_us = 4000;
+		break;
+	case 0x03:
+		aux_rd_interval_us = 8000;
+		break;
+	case 0x04:
+		aux_rd_interval_us = 16000;
+		break;
+	default:
+		break;
+	}
+
+	return aux_rd_interval_us;
+}
+
 static enum link_training_result get_cr_failure(enum dc_lane_count ln_count,
 					union lane_status *dpcd_lane_status)
 {
@@ -768,37 +820,55 @@ static enum link_training_result get_cr_failure(enum dc_lane_count ln_count,
 
 static enum link_training_result perform_channel_equalization_sequence(
 	struct dc_link *link,
-	struct link_training_settings *lt_settings)
+	struct link_training_settings *lt_settings,
+	uint32_t offset)
 {
 	struct link_training_settings req_settings;
 	enum dc_dp_training_pattern tr_pattern;
 	uint32_t retries_ch_eq;
+	uint32_t wait_time_microsec;
 	enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;
 	union lane_align_status_updated dpcd_lane_status_updated = { {0} };
 	union lane_status dpcd_lane_status[LANE_COUNT_DP_MAX] = { { {0} } };
 
+	/* Note: also check that TPS4 is a supported feature*/
+
 	tr_pattern = lt_settings->pattern_for_eq;
 
-	dp_set_hw_training_pattern(link, tr_pattern);
+	if (is_repeater(link, offset))
+		tr_pattern = DP_TRAINING_PATTERN_SEQUENCE_4;
+
+	dp_set_hw_training_pattern(link, tr_pattern, offset);
 
 	for (retries_ch_eq = 0; retries_ch_eq <= LINK_TRAINING_MAX_RETRY_COUNT;
 		retries_ch_eq++) {
 
-		dp_set_hw_lane_settings(link, lt_settings);
+		dp_set_hw_lane_settings(link, lt_settings, offset);
 
 		/* 2. update DPCD*/
 		if (!retries_ch_eq)
 			/* EPR #361076 - write as a 5-byte burst,
-			 * but only for the 1-st iteration*/
+			 * but only for the 1-st iteration
+			 */
+
 			dpcd_set_lt_pattern_and_lane_settings(
 				link,
 				lt_settings,
-				tr_pattern);
+				tr_pattern, offset);
 		else
-			dpcd_set_lane_settings(link, lt_settings);
+			dpcd_set_lane_settings(link, lt_settings, offset);
 
 		/* 3. wait for receiver to lock-on*/
-		wait_for_training_aux_rd_interval(link, lt_settings->eq_pattern_time);
+		wait_time_microsec = lt_settings->eq_pattern_time;
+
+		if (!link->is_lttpr_mode_transparent)
+			wait_time_microsec =
+					translate_training_aux_read_interval(
+						link->dpcd_caps.lttpr_caps.aux_rd_interval[offset]);
+
+		wait_for_training_aux_rd_interval(
+				link,
+				wait_time_microsec);
 
 		/* 4. Read lane status and requested
 		 * drive settings as set by the sink*/
@@ -808,7 +878,8 @@ static enum link_training_result perform_channel_equalization_sequence(
 			lt_settings,
 			dpcd_lane_status,
 			&dpcd_lane_status_updated,
-			&req_settings);
+			&req_settings,
+			offset);
 
 		/* 5. check CR done*/
 		if (!is_cr_done(lane_count, dpcd_lane_status))
@@ -827,13 +898,16 @@ static enum link_training_result perform_channel_equalization_sequence(
 	return LINK_TRAINING_EQ_FAIL_EQ;
 
 }
+#define TRAINING_AUX_RD_INTERVAL 100 //us
 
 static enum link_training_result perform_clock_recovery_sequence(
 	struct dc_link *link,
-	struct link_training_settings *lt_settings)
+	struct link_training_settings *lt_settings,
+	uint32_t offset)
 {
 	uint32_t retries_cr;
 	uint32_t retry_count;
+	uint32_t wait_time_microsec;
 	struct link_training_settings req_settings;
 	enum dc_lane_count lane_count = lt_settings->link_settings.lane_count;
 	enum dc_dp_training_pattern tr_pattern = DP_TRAINING_PATTERN_SEQUENCE_1;
@@ -843,7 +917,7 @@ static enum link_training_result perform_clock_recovery_sequence(
 	retries_cr = 0;
 	retry_count = 0;
 
-	dp_set_hw_training_pattern(link, tr_pattern);
+	dp_set_hw_training_pattern(link, tr_pattern, offset);
 
 	/* najeeb - The synaptics MST hub can put the LT in
 	* infinite loop by switching the VS
@@ -860,7 +934,8 @@ static enum link_training_result perform_clock_recovery_sequence(
 		/* 1. call HWSS to set lane settings*/
 		dp_set_hw_lane_settings(
 				link,
-				lt_settings);
+				lt_settings,
+				offset);
 
 		/* 2. update DPCD of the receiver*/
 		if (!retries_cr)
@@ -869,16 +944,23 @@ static enum link_training_result perform_clock_recovery_sequence(
 			dpcd_set_lt_pattern_and_lane_settings(
 					link,
 					lt_settings,
-					tr_pattern);
+					tr_pattern,
+					offset);
 		else
 			dpcd_set_lane_settings(
 					link,
-					lt_settings);
+					lt_settings,
+					offset);
 
 		/* 3. wait receiver to lock-on*/
+		wait_time_microsec = lt_settings->cr_pattern_time;
+
+		if (!link->is_lttpr_mode_transparent)
+			wait_time_microsec = TRAINING_AUX_RD_INTERVAL;
+
 		wait_for_training_aux_rd_interval(
 				link,
-				lt_settings->cr_pattern_time);
+				wait_time_microsec);
 
 		/* 4. Read lane status and requested drive
 		* settings as set by the sink
@@ -888,7 +970,8 @@ static enum link_training_result perform_clock_recovery_sequence(
 				lt_settings,
 				dpcd_lane_status,
 				&dpcd_lane_status_updated,
-				&req_settings);
+				&req_settings,
+				offset);
 
 		/* 5. check CR done*/
 		if (is_cr_done(lane_count, dpcd_lane_status))
@@ -1057,10 +1140,38 @@ static void initialize_training_settings(
 		lt_settings->enhanced_framing = 1;
 }
 
+static uint8_t convert_to_count(uint8_t lttpr_repeater_count)
+{
+	switch (lttpr_repeater_count) {
+	case 0x80: // 1 lttpr repeater
+		return 1;
+	case 0x40: // 2 lttpr repeaters
+		return 2;
+	case 0x20: // 3 lttpr repeaters
+		return 3;
+	case 0x10: // 4 lttpr repeaters
+		return 4;
+	case 0x08: // 5 lttpr repeaters
+		return 5;
+	case 0x04: // 6 lttpr repeaters
+		return 6;
+	case 0x02: // 7 lttpr repeaters
+		return 7;
+	case 0x01: // 8 lttpr repeaters
+		return 8;
+	default:
+		break;
+	}
+	return 0; // invalid value
+}
+
 static void configure_lttpr_mode(struct dc_link *link)
 {
 	/* aux timeout is already set to extended */
 	/* RESET/SET lttpr mode to enable non transparent mode */
+	uint8_t repeater_cnt;
+	uint32_t aux_interval_address;
+	uint8_t repeater_id;
 	enum lttpr_mode repeater_mode = phy_repeater_mode_transparent;
 
 	core_link_write_dpcd(link,
@@ -1074,9 +1185,43 @@ static void configure_lttpr_mode(struct dc_link *link)
 				DP_PHY_REPEATER_MODE,
 				(uint8_t *)&repeater_mode,
 				sizeof(repeater_mode));
+
+		repeater_cnt = convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+		for (repeater_id = repeater_cnt; repeater_id > 0; repeater_id--) {
+			aux_interval_address = DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1 +
+						((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (repeater_id - 1));
+			core_link_read_dpcd(
+				link,
+				aux_interval_address,
+				(uint8_t *)&link->dpcd_caps.lttpr_caps.aux_rd_interval[repeater_id - 1],
+				sizeof(link->dpcd_caps.lttpr_caps.aux_rd_interval[repeater_id - 1]));
+			link->dpcd_caps.lttpr_caps.aux_rd_interval[repeater_id - 1] &= 0x7F;
+		}
 	}
 }
 
+static void repeater_training_done(struct dc_link *link, uint32_t offset)
+{
+	union dpcd_training_pattern dpcd_pattern = { {0} };
+
+	const uint32_t dpcd_base_lt_offset =
+			DP_TRAINING_PATTERN_SET_PHY_REPEATER1 +
+				((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (offset - 1));
+	/* Set training not in progress*/
+	dpcd_pattern.v1_4.TRAINING_PATTERN_SET = DPCD_TRAINING_PATTERN_VIDEOIDLE;
+
+	core_link_write_dpcd(
+		link,
+		dpcd_base_lt_offset,
+		&dpcd_pattern.raw,
+		1);
+
+	DC_LOG_HW_LINK_TRAINING("%s\n 0x%X pattern = %x\n",
+		__func__,
+		dpcd_base_lt_offset,
+		dpcd_pattern.v1_4.TRAINING_PATTERN_SET);
+}
+
 static void print_status_message(
 	struct dc_link *link,
 	const struct link_training_settings *lt_settings,
@@ -1156,6 +1301,17 @@ static void print_status_message(
 				lt_spread);
 }
 
+void dc_link_dp_set_drive_settings(
+	struct dc_link *link,
+	struct link_training_settings *lt_settings)
+{
+	/* program ASIC PHY settings*/
+	dp_set_hw_lane_settings(link, lt_settings, DPRX);
+
+	/* Notify DP sink the PHY settings from source */
+	dpcd_set_lane_settings(link, lt_settings, DPRX);
+}
+
 bool dc_link_dp_perform_link_training_skip_aux(
 	struct dc_link *link,
 	const struct dc_link_settings *link_setting)
@@ -1172,10 +1328,10 @@ bool dc_link_dp_perform_link_training_skip_aux(
 	/* 1. Perform_clock_recovery_sequence. */
 
 	/* transmit training pattern for clock recovery */
-	dp_set_hw_training_pattern(link, pattern_for_cr);
+	dp_set_hw_training_pattern(link, pattern_for_cr, DPRX);
 
 	/* call HWSS to set lane settings*/
-	dp_set_hw_lane_settings(link, &lt_settings);
+	dp_set_hw_lane_settings(link, &lt_settings, DPRX);
 
 	/* wait receiver to lock-on*/
 	wait_for_training_aux_rd_interval(link, lt_settings.cr_pattern_time);
@@ -1183,10 +1339,10 @@ bool dc_link_dp_perform_link_training_skip_aux(
 	/* 2. Perform_channel_equalization_sequence. */
 
 	/* transmit training pattern for channel equalization. */
-	dp_set_hw_training_pattern(link, lt_settings.pattern_for_eq);
+	dp_set_hw_training_pattern(link, lt_settings.pattern_for_eq, DPRX);
 
 	/* call HWSS to set lane settings*/
-	dp_set_hw_lane_settings(link, &lt_settings);
+	dp_set_hw_lane_settings(link, &lt_settings, DPRX);
 
 	/* wait receiver to lock-on. */
 	wait_for_training_aux_rd_interval(link, lt_settings.eq_pattern_time);
@@ -1208,9 +1364,12 @@ enum link_training_result dc_link_dp_perform_link_training(
 {
 	enum link_training_result status = LINK_TRAINING_SUCCESS;
 	struct link_training_settings lt_settings;
+
 #ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
 	bool fec_enable;
 #endif
+	uint8_t repeater_cnt;
+	uint8_t repeater_id;
 
 	initialize_training_settings(
 			link,
@@ -1230,17 +1389,40 @@ enum link_training_result dc_link_dp_perform_link_training(
 	dp_set_fec_ready(link, fec_enable);
 #endif
 
+	if (!link->is_lttpr_mode_transparent) {
 		/* Configure lttpr mode */
-	if (!link->is_lttpr_mode_transparent)
 		configure_lttpr_mode(link);
 
 		/* 2. perform link training (set link training done
 		 *  to false is done as well)
 		 */
-	status = perform_clock_recovery_sequence(link, &lt_settings);
+		repeater_cnt = convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);
+
+		for (repeater_id = repeater_cnt; (repeater_id > 0 && status == LINK_TRAINING_SUCCESS);
+				repeater_id--) {
+			status = perform_clock_recovery_sequence(link, &lt_settings, repeater_id);
+
+			if (status != LINK_TRAINING_SUCCESS)
+				break;
+
+			status = perform_channel_equalization_sequence(link,
+					&lt_settings,
+					repeater_id);
+
+			if (status != LINK_TRAINING_SUCCESS)
+				break;
+
+			repeater_training_done(link, repeater_id);
+		}
+	}
+
+	if (status == LINK_TRAINING_SUCCESS) {
+		status = perform_clock_recovery_sequence(link, &lt_settings, DPRX);
 	if (status == LINK_TRAINING_SUCCESS) {
 		status = perform_channel_equalization_sequence(link,
-				&lt_settings);
+					&lt_settings,
+					DPRX);
+		}
 	}
 
 	if ((status == LINK_TRAINING_SUCCESS) || !skip_video_pattern) {
@@ -1393,10 +1575,11 @@ enum link_training_result dc_link_dp_sync_lt_attempt(
 	/* 2. perform link training (set link training done
 	 *  to false is done as well)
 	 */
-	lt_status = perform_clock_recovery_sequence(link, &lt_settings);
+	lt_status = perform_clock_recovery_sequence(link, &lt_settings, DPRX);
 	if (lt_status == LINK_TRAINING_SUCCESS) {
 		lt_status = perform_channel_equalization_sequence(link,
-						&lt_settings);
+						&lt_settings,
+						DPRX);
 	}
 
 	/* 3. Sync LT must skip TRAINING_PATTERN_SET:0 (video pattern)*/
@@ -3355,8 +3538,8 @@ bool dc_link_dp_set_test_pattern(
 	if (is_dp_phy_pattern(test_pattern)) {
 		/* Set DPCD Lane Settings before running test pattern */
 		if (p_link_settings != NULL) {
-			dp_set_hw_lane_settings(link, p_link_settings);
-			dpcd_set_lane_settings(link, p_link_settings);
+			dp_set_hw_lane_settings(link, p_link_settings, DPRX);
+			dpcd_set_lane_settings(link, p_link_settings, DPRX);
 		}
 
 		/* Blank stream if running test pattern */

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

@@ -19,6 +19,36 @@
 #include "resource.h"
 #endif
 
+static uint8_t convert_to_count(uint8_t lttpr_repeater_count)
+{
+	switch (lttpr_repeater_count) {
+	case 0x80: // 1 lttpr repeater
+		return 1;
+	case 0x40: // 2 lttpr repeaters
+		return 2;
+	case 0x20: // 3 lttpr repeaters
+		return 3;
+	case 0x10: // 4 lttpr repeaters
+		return 4;
+	case 0x08: // 5 lttpr repeaters
+		return 5;
+	case 0x04: // 6 lttpr repeaters
+		return 6;
+	case 0x02: // 7 lttpr repeaters
+		return 7;
+	case 0x01: // 8 lttpr repeaters
+		return 8;
+	default:
+		break;
+	}
+	return 0; // invalid value
+}
+
+static inline bool is_immediate_downstream(struct dc_link *link, uint32_t offset)
+{
+	return (convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt) == offset);
+}
+
 enum dc_status core_link_read_dpcd(
 	struct dc_link *link,
 	uint32_t address,
@@ -212,7 +242,8 @@ void dp_disable_link_phy_mst(struct dc_link *link, enum signal_type signal)
 
 bool dp_set_hw_training_pattern(
 	struct dc_link *link,
-	enum dc_dp_training_pattern pattern)
+	enum dc_dp_training_pattern pattern,
+	uint32_t offset)
 {
 	enum dp_test_pattern test_pattern = DP_TEST_PATTERN_UNSUPPORTED;
 
@@ -240,10 +271,14 @@ bool dp_set_hw_training_pattern(
 
 void dp_set_hw_lane_settings(
 	struct dc_link *link,
-	const struct link_training_settings *link_settings)
+	const struct link_training_settings *link_settings,
+	uint32_t offset)
 {
 	struct link_encoder *encoder = link->link_enc;
 
+	if (!link->is_lttpr_mode_transparent && !is_immediate_downstream(link, offset))
+		return;
+
 	/* call Encoder to set lane settings */
 	encoder->funcs->dp_set_lane_settings(encoder, link_settings);
 }

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

@@ -60,11 +60,13 @@ void dp_disable_link_phy_mst(struct dc_link *link, enum signal_type signal);
 
 bool dp_set_hw_training_pattern(
 	struct dc_link *link,
-	enum dc_dp_training_pattern pattern);
+	enum dc_dp_training_pattern pattern,
+	uint32_t offset);
 
 void dp_set_hw_lane_settings(
 	struct dc_link *link,
-	const struct link_training_settings *link_settings);
+	const struct link_training_settings *link_settings,
+	uint32_t offset);
 
 void dp_set_hw_test_pattern(
 	struct dc_link *link,