diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 9779ea1..b9ddd3d 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -409,6 +409,10 @@
 	/* framebuffer the connector is currently bound to */
 	struct drm_framebuffer *fb;
 
+	/* Temporary tracking of the old fb while a modeset is ongoing. Used
+	 * by drm_mode_set_config_internal to implement correct refcounting. */
+	struct drm_framebuffer *old_fb;
+
 	bool enabled;
 
 	/* Requested mode from modesetting. */