diff --git a/arch/arm/mach-shmobile/board-mackerel.c b/arch/arm/mach-shmobile/board-mackerel.c
index f0cc307df640..c4a6a9b16d1b 100644
--- a/arch/arm/mach-shmobile/board-mackerel.c
+++ b/arch/arm/mach-shmobile/board-mackerel.c
@@ -192,6 +192,16 @@
  *
  */
 
+/*
+ * FSI - AK4642
+ *
+ * it needs amixer settings for playing
+ *
+ * amixer set "Headphone" on
+ * amixer set "HPOUTL Mixer DACH" on
+ * amixer set "HPOUTR Mixer DACH" on
+ */
+
 /*
  * FIXME !!
  *