diff --git a/drivers/staging/goldfish/goldfish_audio.c b/drivers/staging/goldfish/goldfish_audio.c
index 23a206d59790..b360d07564b1 100644
--- a/drivers/staging/goldfish/goldfish_audio.c
+++ b/drivers/staging/goldfish/goldfish_audio.c
@@ -36,6 +36,7 @@ MODULE_VERSION("1.0");
 struct goldfish_audio {
 	char __iomem *reg_base;
 	int irq;
+	/* lock protects access to buffer_status and to device registers */
 	spinlock_t lock;
 	wait_queue_head_t wait;