drm/amd/display: Reboot while unplug hdcp enabled dp from mst hub

[Why]
event_property_update does not check NULL pointer

[How]
check aconnector->base.state equals NULL
Reviewed-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: hersen wu <hersenxs.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -302,7 +302,7 @@ static void event_property_update(struct work_struct *work)
 	mutex_lock(&hdcp_work->mutex);
 
 
-	if (aconnector->base.state->commit) {
+	if (aconnector->base.state && aconnector->base.state->commit) {
 		ret = wait_for_completion_interruptible_timeout(&aconnector->base.state->commit->hw_done, 10 * HZ);
 
 		if (ret == 0) {
@@ -311,17 +311,25 @@ static void event_property_update(struct work_struct *work)
 		}
 	}
 
+	if (aconnector->base.state) {
 		if (hdcp_work->encryption_status != MOD_HDCP_ENCRYPTION_STATUS_HDCP_OFF) {
-		if (aconnector->base.state->hdcp_content_type == DRM_MODE_HDCP_CONTENT_TYPE0 &&
-		    hdcp_work->encryption_status <= MOD_HDCP_ENCRYPTION_STATUS_HDCP2_TYPE0_ON)
-			drm_hdcp_update_content_protection(&aconnector->base, DRM_MODE_CONTENT_PROTECTION_ENABLED);
-		else if (aconnector->base.state->hdcp_content_type == DRM_MODE_HDCP_CONTENT_TYPE1 &&
-			 hdcp_work->encryption_status == MOD_HDCP_ENCRYPTION_STATUS_HDCP2_TYPE1_ON)
-			drm_hdcp_update_content_protection(&aconnector->base, DRM_MODE_CONTENT_PROTECTION_ENABLED);
+			if (aconnector->base.state->hdcp_content_type ==
+				DRM_MODE_HDCP_CONTENT_TYPE0 &&
+			hdcp_work->encryption_status <=
+				MOD_HDCP_ENCRYPTION_STATUS_HDCP2_TYPE0_ON)
+				drm_hdcp_update_content_protection(&aconnector->base,
+					DRM_MODE_CONTENT_PROTECTION_ENABLED);
+			else if (aconnector->base.state->hdcp_content_type ==
+					DRM_MODE_HDCP_CONTENT_TYPE1 &&
+				hdcp_work->encryption_status ==
+					MOD_HDCP_ENCRYPTION_STATUS_HDCP2_TYPE1_ON)
+				drm_hdcp_update_content_protection(&aconnector->base,
+					DRM_MODE_CONTENT_PROTECTION_ENABLED);
 		} else {
-		drm_hdcp_update_content_protection(&aconnector->base, DRM_MODE_CONTENT_PROTECTION_DESIRED);
+			drm_hdcp_update_content_protection(&aconnector->base,
+				DRM_MODE_CONTENT_PROTECTION_DESIRED);
+		}
 	}
-
 
 	mutex_unlock(&hdcp_work->mutex);
 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
@@ -495,7 +503,9 @@ static void update_config(void *handle, struct cp_psp_stream_config *config)
 			(!!aconnector->base.state) ? aconnector->base.state->content_protection : -1,
 			(!!aconnector->base.state) ? aconnector->base.state->hdcp_content_type : -1);
 
-	hdcp_update_display(hdcp_work, link_index, aconnector, conn_state->hdcp_content_type, false);
+	if (conn_state)
+		hdcp_update_display(hdcp_work, link_index, aconnector,
+			conn_state->hdcp_content_type, false);
 }