diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
index 2c7b9c9..7423f99 100644
--- a/sound/usb/mixer.h
+++ b/sound/usb/mixer.h
@@ -53,6 +53,7 @@
 	int cached;
 	int cache_val[MAX_CHANNELS];
 	u8 initialized;
+	void *private_data;
 };
 
 int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,