drm/amd/display: Release remote dc_sink under mst scenario

[Why]
Observe that we have several problems while releasing remote dc_sink
under mst cases.

- When unplug mst branch device from the source, we now try to free all
  remote dc_sinks in dm_helpers_dp_mst_stop_top_mgr(). However, there are
  bugs while we're releasing dc_sinks here. First of all,
  link->remote_sinks[] array get shuffled within
  dc_link_remove_remote_sink(). As the result, increasing the array index
  within the releasing loop is wrong. Secondly, it tries to call
  dc_sink_release() to release the dc_sink of the same aconnector every
  time in the loop. Which can't release dc_sink of all aconnector in the
  mst topology.
- There is no code path for us to release remote dc_sink for disconnected
  sst monitor which unplug event is notified by CSN sideband message. Which
  means we'll use stale dc_sink data to represent later on connected
  monitor. Also, has chance to break the maximum remote dc_sink number
  constraint.

[How]
Distinguish unplug event of mst scenario into 2 cases.

* Unplug sst/legacy stream sink off the mst topology
- Release related remote dc_sink in detec_ctx().

* Unplug mst branch device off the mst topology
- Release related remote dc_sink in early_unregister()

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Aurabindo Jayamohanan Pillai <Aurabindo.Pillai@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 1 insertions, 17 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 7c799ddc1d27..137645d40b72 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -451,7 +451,6 @@ bool dm_helpers_dp_mst_stop_top_mgr(
 		struct dc_link *link)
 {
 	struct amdgpu_dm_connector *aconnector = link->priv;
-	uint8_t i;
 
 	if (!aconnector) {
 		DRM_ERROR("Failed to find connector for link!");
@@ -463,22 +462,7 @@ bool dm_helpers_dp_mst_stop_top_mgr(
 
 	if (aconnector->mst_mgr.mst_state == true) {
 		drm_dp_mst_topology_mgr_set_mst(&aconnector->mst_mgr, false);
-
-		for (i = 0; i < MAX_SINKS_PER_LINK; i++) {
-			if (link->remote_sinks[i] == NULL)
-				continue;
-
-			if (link->remote_sinks[i]->sink_signal ==
-			    SIGNAL_TYPE_DISPLAY_PORT_MST) {
-				dc_link_remove_remote_sink(link, link->remote_sinks[i]);
-
-				if (aconnector->dc_sink) {
-					dc_sink_release(aconnector->dc_sink);
-					aconnector->dc_sink = NULL;
-					aconnector->dc_link->cur_link_settings.lane_count = 0;
-				}
-			}
-		}
+		link->cur_link_settings.lane_count = 0;
 	}
 
 	return false;