diff --git a/libweston/backend-drm/drm-internal.h b/libweston/backend-drm/drm-internal.h
index 18bc46bf1..fb913a73b 100644
--- a/libweston/backend-drm/drm-internal.h
+++ b/libweston/backend-drm/drm-internal.h
@@ -337,6 +337,7 @@ struct drm_pending_state {
 };
 
 enum drm_output_propose_state_mode {
+	DRM_OUTPUT_PROPOSE_STATE_INVALID = 0, /**< Invalid state */
 	DRM_OUTPUT_PROPOSE_STATE_MIXED, /**< mix renderer & planes */
 	DRM_OUTPUT_PROPOSE_STATE_RENDERER_AND_CURSOR, /**< only assign to renderer & cursor plane */
 	DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY, /**< only assign to renderer */
diff --git a/libweston/backend-drm/state-propose.c b/libweston/backend-drm/state-propose.c
index 6047301bb..258351b7d 100644
--- a/libweston/backend-drm/state-propose.c
+++ b/libweston/backend-drm/state-propose.c
@@ -46,6 +46,7 @@
 #include "shared/weston-assert.h"
 
 static const char *const drm_output_propose_state_mode_as_string[] = {
+	[DRM_OUTPUT_PROPOSE_STATE_INVALID] = "invalid(uninitialized) state",
 	[DRM_OUTPUT_PROPOSE_STATE_MIXED] = "mixed state",
 	[DRM_OUTPUT_PROPOSE_STATE_RENDERER_AND_CURSOR] = "renderer-and-cursor state",
 	[DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY] = "renderer-only state",