diff --git a/mixer.c b/mixer.c
index 7b8540a..fd0ad8d 100644
--- a/mixer.c
+++ b/mixer.c
@@ -619,6 +619,9 @@
         }
 
     case SNDRV_CTL_ELEM_TYPE_IEC958:
+        ret = grp->ops->ioctl(grp->data, SNDRV_CTL_IOCTL_ELEM_READ, &ev);
+        if (ret < 0)
+            return ret;
         size = sizeof(ev.value.iec958);
         source = &ev.value.iec958;
         break;