drm/amd/display: disconnect on HPD low even if edid is the same

[Description]
There are many occasions we need to retrieve sink capability and
notify connectivity change to os even if edid is not changed
on a HPD toggle.
(HDMI2.0 display needs re-enable link on every hpd,
display changes other capability outside from edid
 need to be queried again and possibly reset the mode, etc.)

In these cases we cannot keep the same sink without letting DM know.
Signed-off-by: Wenjing Liu <Wenjing.Liu@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

@@ -566,6 +566,8 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 			link->local_sink)
 		return true;
 
+	link_disconnect_sink(link);
+
 	if (new_connection_type != dc_connection_none) {
 		link->type = new_connection_type;
 
@@ -656,28 +658,15 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 			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:
@@ -758,29 +747,16 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason)
 		if (link->type == dc_connection_mst_branch) {
 			LINK_INFO("link=%d, mst branch is now Disconnected\n",
 				link->link_index);
+
 			dm_helpers_dp_mst_stop_top_mgr(link->ctx, link);
 
 			link->mst_stream_alloc_table.stream_count = 0;
 			memset(link->mst_stream_alloc_table.stream_allocations, 0, sizeof(link->mst_stream_alloc_table.stream_allocations));
 		}
 
-		if (link->local_sink) {
-			sink = link->local_sink;
-			edid_status = dm_helpers_read_local_edid(
-						link->ctx,
-						link,
-						sink);
-			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;
 	}
-		} else {
-			link_disconnect_sink(link);
-			link->type = dc_connection_none;
-			sink_caps.signal = SIGNAL_TYPE_NONE;
-		}
-	}
 
 	LINK_INFO("link=%d, dc_sink_in=%p is now %s\n",
 		link->link_index, sink,