diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 1deef623c0810e36af237893e264d8813046848a..21613fe0c1a2a9576251486d30ea04eeac1fad17 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2055,7 +2055,7 @@ int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
 	}
 
 	host_iface = &usb_ifnum_to_if(chip->dev, ctrlif)->altsetting[0];
-	mixer->protocol = host_iface->desc.bInterfaceProtocol;
+	mixer->protocol = get_iface_desc(host_iface)->bInterfaceProtocol;
 
 	if ((err = snd_usb_mixer_controls(mixer)) < 0 ||
 	    (err = snd_usb_mixer_status_create(mixer)) < 0)