diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c
index 54f8b17476a1..573b06cf7cf5 100644
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -102,8 +102,10 @@ struct loopback_pcm {
 	/* flags */
 	unsigned int period_update_pending :1;
 	/* timer stuff */
-	unsigned int irq_pos;		/* fractional IRQ position */
-	unsigned int period_size_frac;
+	unsigned int irq_pos;		/* fractional IRQ position in jiffies
+					 * ticks
+					 */
+	unsigned int period_size_frac;	/* period size in jiffies ticks */
 	unsigned int last_drift;
 	unsigned long last_jiffies;
 	struct timer_list timer;