Commit 3fd20292 authored by Martin Tsai's avatar Martin Tsai Committed by Alex Deucher
Browse files

drm/amd/display: Check lane status again after link training done 



[Why]
Some monitors could suffer symbol unlock but cannot send HPD IRQ to
notic source device to handle link loss. This makes monitor stuck in
abnormal status and causes black screen.

[How]
According to the suggestion from scalar vendor, to check lane status
again after link training done. That can improve the comaptibility
from current production monitors.

Signed-off-by: default avatarMartin Tsai <martin.tsai@amd.com>
Reviewed-by: default avatarAric Cyr <Aric.Cyr@amd.com>
Acked-by: default avatarEryk Brol <eryk.brol@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent bc0cd807

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

+50 −0
Original line number Diff line number Diff line
@@ -1133,6 +1133,45 @@ static inline enum link_training_result perform_link_training_int( 
	return status;

}



static enum link_training_result check_link_loss_status(

	struct dc_link *link,

	const struct link_training_settings *link_training_setting)

{

	enum link_training_result status = LINK_TRAINING_SUCCESS;

	unsigned int lane01_status_address = DP_LANE0_1_STATUS;

	union lane_status lane_status;

	uint8_t dpcd_buf[4] = {0};

	uint32_t lane;



	core_link_read_dpcd(

		link,

		lane01_status_address,

		(uint8_t *)(dpcd_buf),

		sizeof(dpcd_buf));



	/*parse lane status*/

	for (lane = 0; lane < link->cur_link_settings.lane_count; lane++) {

		/*

		 * check lanes status

		 */

		lane_status.raw = get_nibble_at_index(&dpcd_buf[0], lane);



		if (!lane_status.bits.CHANNEL_EQ_DONE_0 ||

			!lane_status.bits.CR_DONE_0 ||

			!lane_status.bits.SYMBOL_LOCKED_0) {

			/* if one of the channel equalization, clock

			 * recovery or symbol lock is dropped

			 * consider it as (link has been

			 * dropped) dp sink status has changed

			 */

			status = LINK_TRAINING_LINK_LOSS;

			break;

		}

	}



	return status;

}



static void initialize_training_settings(

	 struct dc_link *link,

	const struct dc_link_settings *link_setting,
@@ -1372,6 +1411,9 @@ static void print_status_message( 
	case LINK_TRAINING_LQA_FAIL:

		lt_result = "LQA failed";

		break;

	case LINK_TRAINING_LINK_LOSS:

		lt_result = "Link loss";

		break;

	default:

		break;

	}
@@ -1531,6 +1573,14 @@ enum link_training_result dc_link_dp_perform_link_training( 
				status);

	}



	/* delay 5ms after Main Link output idle pattern and then check

	 * DPCD 0202h.

	 */

	if (link->connector_signal != SIGNAL_TYPE_EDP && status == LINK_TRAINING_SUCCESS) {

		msleep(5);

		status = check_link_loss_status(link, &lt_settings);

	}



	/* 6. print status message*/

	print_status_message(link, &lt_settings, status);

drivers/gpu/drm/amd/display/include/link_service_types.h

+2 −0
Original line number Diff line number Diff line
@@ -66,6 +66,8 @@ enum link_training_result { 
	/* other failure during EQ step */

	LINK_TRAINING_EQ_FAIL_EQ,

	LINK_TRAINING_LQA_FAIL,

	/* one of the CR,EQ or symbol lock is dropped */

	LINK_TRAINING_LINK_LOSS,

};



struct link_training_settings {