drm/amd/display: Not fallback if link BW is smaller than req BW

[Why]
When the link BW is smaller than the request BW,
the DP LT just kept running and fallback to lower link config.
DP LT just aborted if is_hpd_pending bit is high.
But is_hpd_pending bit indicates a new HPD event received.
It doesn't mean the HPD is low.

[How]
Abort the DP LT if the link BW is smaller than the request BW.
Remove checking is_hpd_pending bit in DP LT.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Cruise <cruise.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c

@@ -1704,10 +1704,13 @@ bool perform_link_training_with_retries(
 			is_link_bw_min = ((cur_link_settings.link_rate <= LINK_RATE_LOW) &&
 				(cur_link_settings.lane_count <= LANE_COUNT_ONE));
 
-			if (is_link_bw_low)
+			if (is_link_bw_low) {
 				DC_LOG_WARNING(
 					"%s: Link(%d) bandwidth too low after fallback req_bw(%d) > link_bw(%d)\n",
 					__func__, link->link_index, req_bw, link_bw);
+
+				return false;
+			}
 		}
 
 		msleep(delay_between_attempts);

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training_dpia.c

@@ -430,10 +430,6 @@ static enum link_training_result dpia_training_cr_non_transparent(
 		retry_count++;
 	}
 
-	/* Abort link training if clock recovery failed due to HPD unplug. */
-	if (link->is_hpd_pending)
-		result = LINK_TRAINING_ABORT;
-
 	DC_LOG_HW_LINK_TRAINING(
 		"%s\n DPIA(%d) clock recovery\n -hop(%d)\n - result(%d)\n - retries(%d)\n - status(%d)\n",
 		__func__,
@@ -537,10 +533,6 @@ static enum link_training_result dpia_training_cr_transparent(
 		retry_count++;
 	}
 
-	/* Abort link training if clock recovery failed due to HPD unplug. */
-	if (link->is_hpd_pending)
-		result = LINK_TRAINING_ABORT;
-
 	DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) clock recovery\n -hop(%d)\n - result(%d)\n - retries(%d)\n",
 		__func__,
 		link->link_id.enum_id - ENUM_ID_1,
@@ -731,10 +723,6 @@ static enum link_training_result dpia_training_eq_non_transparent(
 				lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
 	}
 
-	/* Abort link training if equalization failed due to HPD unplug. */
-	if (link->is_hpd_pending)
-		result = LINK_TRAINING_ABORT;
-
 	DC_LOG_HW_LINK_TRAINING(
 		"%s\n DPIA(%d) equalization\n - hop(%d)\n - result(%d)\n - retries(%d)\n - status(%d)\n",
 		__func__,
@@ -822,10 +810,6 @@ static enum link_training_result dpia_training_eq_transparent(
 				lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
 	}
 
-	/* Abort link training if equalization failed due to HPD unplug. */
-	if (link->is_hpd_pending)
-		result = LINK_TRAINING_ABORT;
-
 	DC_LOG_HW_LINK_TRAINING("%s\n DPIA(%d) equalization\n - hop(%d)\n - result(%d)\n - retries(%d)\n",
 		__func__,
 		link->link_id.enum_id - ENUM_ID_1,