diff --git a/include/video/omapdss.h b/include/video/omapdss.h
index c7cfdad8124..31b77469c15 100644
--- a/include/video/omapdss.h
+++ b/include/video/omapdss.h
@@ -510,6 +510,7 @@ struct omap_dss_device {
 		} dispc;
 
 		struct {
+			/* regn is one greater than TRM's REGN value */
 			u16 regn;
 			u16 regm;
 			u16 regm_dispc;