drm/amd/display: To prevent detecting new sink from spurious HPD

Signed-off-by: Martin Tsai <martin.tsai@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

@@ -649,27 +649,34 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 		sink_init_data.link = link;
 		sink_init_data.sink_signal = sink_caps.signal;
 
-		if (link->local_sink)	{
-			sink = link->local_sink;
-		} else {
-			sink_init_data.link = link;
-			sink_init_data.sink_signal = sink_caps.signal;
-
 		sink = dc_sink_create(&sink_init_data);
 		if (!sink) {
 			DC_ERROR("Failed to create sink!\n");
 			return false;
 		}
+
+		if (link->local_sink) {
+			edid_status = dm_helpers_read_local_edid(
+				link->ctx,
+				link,
+				sink);
+
+			if (edid_status == EDID_OK) {
+				// Edid is not the same, to update the local sink with new sink.
 				sink->dongle_max_pix_clk = sink_caps.max_hdmi_pixel_clock;
 				sink->converter_disable_audio = converter_disable_audio;
-
 				link->local_sink = sink;
 			}
+		} else {
+			sink->dongle_max_pix_clk = sink_caps.max_hdmi_pixel_clock;
+			sink->converter_disable_audio = converter_disable_audio;
+			link->local_sink = sink;
 
 			edid_status = dm_helpers_read_local_edid(
 				link->ctx,
 				link,
 				sink);
+		}
 
 		switch (edid_status) {
 		case EDID_BAD_CHECKSUM:
@@ -762,7 +769,7 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 						link->ctx,
 						link,
 						sink);
-			if (edid_status != EDID_OK) {
+			if (edid_status != EDID_OK && edid_status != EDID_THE_SAME) {
 				link_disconnect_sink(link);
 				link->type = dc_connection_none;
 				sink_caps.signal = SIGNAL_TYPE_NONE;

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

@@ -151,6 +151,7 @@ enum dc_edid_status {
 	EDID_BAD_INPUT,
 	EDID_NO_RESPONSE,
 	EDID_BAD_CHECKSUM,
+	EDID_THE_SAME,
 };
 
 /* audio capability from EDID*/