diff --git a/sound/soc/sh/rcar/src.c b/sound/soc/sh/rcar/src.c
index 585ffba0244b..628af8f3920d 100644
--- a/sound/soc/sh/rcar/src.c
+++ b/sound/soc/sh/rcar/src.c
@@ -5,6 +5,15 @@
 // Copyright (C) 2013 Renesas Solutions Corp.
 // Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
 
+/*
+ * You can use Synchronous Sampling Rate Convert (if no DVC)
+ *
+ *	amixer set "SRC Out Rate" on
+ *	aplay xxx.wav &
+ *	amixer set "SRC Out Rate" 96000 // convert rate to 96000Hz
+ *	amixer set "SRC Out Rate" 22050 // convert rate to 22050Hz
+ */
+
 /*
  * you can enable below define if you don't need
  * SSI interrupt status debug message when debugging