diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index ec006ed..ee6bc2d 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -56,6 +56,8 @@
 	size_t fifo_size;		/* fifo size in bytes */
 };
 
+struct snd_pcm_substream;
+
 struct snd_pcm_ops {
 	int (*open)(struct snd_pcm_substream *substream);
 	int (*close)(struct snd_pcm_substream *substream);