drm/amd/display: add detect caps for edp

1. The caps detect sequence for edp is different from dp.
   Added separate function for edp.
2. Removed max_link_setting and replaced it with verified
   to avoid confusion.
3. Reverted sink count guard for edp powerdown as unnecessary
   with the changes above.

Signed-off-by: Roman Li <Roman.Li@amd.com>
Signed-off-by: Tony Cheng <tony.cheng@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -585,7 +585,7 @@ bool dc_link_detect(struct dc_link *link, bool boot)
 		}
 
 		case SIGNAL_TYPE_EDP: {
-			detect_dp_sink_caps(link);
+			detect_edp_sink_caps(link);
 			sink_caps.transaction_type =
 				DDC_TRANSACTION_TYPE_I2C_OVER_AUX;
 			sink_caps.signal = SIGNAL_TYPE_EDP;

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

@@ -1147,7 +1147,6 @@ bool dp_hbr_verify_link_cap(
 		LINK_SPREAD_DISABLED;
 	}
 
-	link->max_link_setting = link->verified_link_cap;
 
 	return success;
 }
@@ -1466,7 +1465,7 @@ void decide_link_settings(struct dc_stream *stream,
      * 2. could support the b/w requested by the timing
      */
 	while (current_link_setting.link_rate <=
-			link->max_link_setting.link_rate) {
+			link->verified_link_cap.link_rate) {
 		link_bw = bandwidth_in_kbps_from_link_settings(
 				&current_link_setting);
 		if (req_bw <= link_bw) {
@@ -1475,7 +1474,7 @@ void decide_link_settings(struct dc_stream *stream,
 		}
 
 		if (current_link_setting.lane_count <
-				link->max_link_setting.lane_count) {
+				link->verified_link_cap.lane_count) {
 			current_link_setting.lane_count =
 					increase_lane_count(
 							current_link_setting.lane_count);
@@ -2294,6 +2293,12 @@ void detect_dp_sink_caps(struct dc_link *link)
 	/* TODO save sink caps in link->sink */
 }
 
+void detect_edp_sink_caps(struct dc_link *link)
+{
+	retrieve_link_cap(link);
+	link->verified_link_cap = link->reported_link_cap;
+}
+
 void dc_link_dp_enable_hpd(const struct dc_link *link)
 {
 	struct link_encoder *encoder = link->link_enc;

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

@@ -114,9 +114,7 @@ void dp_disable_link_phy(struct dc_link *link, enum signal_type signal)
 
 	if (signal == SIGNAL_TYPE_EDP) {
 		link->link_enc->funcs->backlight_control(link->link_enc, false);
-		if (link->dpcd_sink_count)
-			link->link_enc->funcs->power_control(link->link_enc,
-									false);
+		link->link_enc->funcs->power_control(link->link_enc, false);
 	}
 
 	link->link_enc->funcs->disable_output(link->link_enc, signal);

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

@@ -744,7 +744,6 @@ struct dc_link {
 	 */
 	struct dc_link_settings reported_link_cap;
 	struct dc_link_settings verified_link_cap;
-	struct dc_link_settings max_link_setting;
 	struct dc_link_settings cur_link_settings;
 	struct dc_lane_settings cur_lane_setting;
 	struct dc_link_settings preferred_link_setting;

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

@@ -63,6 +63,8 @@ bool is_mst_supported(struct dc_link *link);
 
 void detect_dp_sink_caps(struct dc_link *link);
 
+void detect_edp_sink_caps(struct dc_link *link);
+
 bool is_dp_active_dongle(const struct dc_link *link);
 
 void dp_enable_mst_on_sink(struct dc_link *link, bool enable);