diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index ea78d70de9f3..c3f83476f996 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1693,7 +1693,7 @@ fail:
 }
 EXPORT_SYMBOL(drm_atomic_helper_prepare_planes);
 
-bool plane_crtc_active(struct drm_plane_state *state)
+static bool plane_crtc_active(const struct drm_plane_state *state)
 {
 	return state->crtc && state->crtc->state->active;
 }