From: Zhan Liu <zhan.liu@amd.com>
Date: Thu, 16 Apr 2020 18:20:56 +0000 (-0400)
Subject: drm/amd/display: Remove aconnector condition check for dpcd read
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1c256f40bf8e9f4723c9e84c7e3a1105e1db0ad9;p=linux.git

drm/amd/display: Remove aconnector condition check for dpcd read

[Why]
Aconnector is not necessary to be NULL in order to read dpcd
successfully.

Actually if we rely on checking aconnector here, we won't be able
to turn off all displays before doing display detection. That will
cause some MST hubs not able to light up.

[How]
Remove aconnector check when turning off all displays at
hardware initialization stage.

Signed-off-by: Zhan Liu <zhan.liu@amd.com>
Reviewed-by: Joseph Gravenor <joseph.gravenor@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 9f41efddc9bc5..4a081e544123a 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -1333,30 +1333,28 @@ void dcn10_init_hw(struct dc *dc)
 				continue;
 
 			/*
-			 * core_link_read_dpcd() will invoke dm_helpers_dp_read_dpcd(),
-			 * which needs to read dpcd info with the help of aconnector.
-			 * If aconnector (dc->links[i]->prev) is NULL, then dpcd status
-			 * cannot be read.
+			 * If any of the displays are lit up turn them off.
+			 * The reason is that some MST hubs cannot be turned off
+			 * completely until we tell them to do so.
+			 * If not turned off, then displays connected to MST hub
+			 * won't light up.
 			 */
-			if (dc->links[i]->priv) {
-				/* if any of the displays are lit up turn them off */
-				status = core_link_read_dpcd(dc->links[i], DP_SET_POWER,
-								&dpcd_power_state, sizeof(dpcd_power_state));
-				if (status == DC_OK && dpcd_power_state == DP_POWER_STATE_D0) {
-					/* blank dp stream before power off receiver*/
-					if (dc->links[i]->link_enc->funcs->get_dig_frontend) {
-						unsigned int fe = dc->links[i]->link_enc->funcs->get_dig_frontend(dc->links[i]->link_enc);
-
-						for (j = 0; j < dc->res_pool->stream_enc_count; j++) {
-							if (fe == dc->res_pool->stream_enc[j]->id) {
-								dc->res_pool->stream_enc[j]->funcs->dp_blank(
-											dc->res_pool->stream_enc[j]);
-								break;
-							}
+			status = core_link_read_dpcd(dc->links[i], DP_SET_POWER,
+							&dpcd_power_state, sizeof(dpcd_power_state));
+			if (status == DC_OK && dpcd_power_state == DP_POWER_STATE_D0) {
+				/* blank dp stream before power off receiver*/
+				if (dc->links[i]->link_enc->funcs->get_dig_frontend) {
+					unsigned int fe = dc->links[i]->link_enc->funcs->get_dig_frontend(dc->links[i]->link_enc);
+
+					for (j = 0; j < dc->res_pool->stream_enc_count; j++) {
+						if (fe == dc->res_pool->stream_enc[j]->id) {
+							dc->res_pool->stream_enc[j]->funcs->dp_blank(
+										dc->res_pool->stream_enc[j]);
+							break;
 						}
 					}
-					dp_receiver_power_ctrl(dc->links[i], false);
 				}
+				dp_receiver_power_ctrl(dc->links[i], false);
 			}
 		}
 	}