drm/amd/display: Skip on writeback when it's not applicable

commit ecedd99a9369fb5cde601ae9abd58bca2739f1ae upstream.

[WHY]
dynamic memory safety error detector (KASAN) catches and generates error
messages "BUG: KASAN: slab-out-of-bounds" as writeback connector does not
support certain features which are not initialized.

[HOW]
Skip them when connector type is DRM_MODE_CONNECTOR_WRITEBACK.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3199
Reviewed-by: Harry Wentland <[email protected]>
Reviewed-by: Rodrigo Siqueira <[email protected]>
Acked-by: Roman Li <[email protected]>
Signed-off-by: Alex Hung <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Signed-off-by: Xiangyu Chen <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Alex Hung

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -2990,6 +2990,10 @@ static int dm_resume(void *handle)
 	/* Do mst topology probing after resuming cached state*/
 	drm_connector_list_iter_begin(ddev, &iter);
 	drm_for_each_connector_iter(connector, &iter) {
+
+		if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
+			continue;
+
 		aconnector = to_amdgpu_dm_connector(connector);
 		if (aconnector->dc_link->type != dc_connection_mst_branch ||
 		    aconnector->mst_port)
@@ -5722,6 +5726,9 @@ get_highest_refresh_rate_mode(struct amdgpu_dm_connector *aconnector,
 		&aconnector->base.probed_modes :
 		&aconnector->base.modes;
 
+	if (aconnector->base.connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
+		return NULL;
+
 	if (aconnector->freesync_vid_base.clock != 0)
 		return &aconnector->freesync_vid_base;
 
@@ -8242,6 +8249,9 @@ static void amdgpu_dm_commit_audio(struct drm_device *dev,
 			continue;
 
 	notify:
+		if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
+			continue;
+
 		aconnector = to_amdgpu_dm_connector(connector);
 
 		mutex_lock(&adev->dm.audio_lock);