diff --git a/sound/firewire/bebob/bebob_maudio.c b/sound/firewire/bebob/bebob_maudio.c
index fc470c60e433..42e6f22156f0 100644
--- a/sound/firewire/bebob/bebob_maudio.c
+++ b/sound/firewire/bebob/bebob_maudio.c
@@ -434,8 +434,8 @@ static struct snd_kcontrol_new special_sync_ctl = {
 	.get	= special_sync_ctl_get,
 };
 
-/* Digital interface control for special firmware */
-static char *const special_dig_iface_labels[] = {
+/* Digital input interface control for special firmware */
+static char *const special_dig_in_iface_labels[] = {
 	"S/PDIF Optical", "S/PDIF Coaxial", "ADAT Optical"
 };
 static int special_dig_in_iface_ctl_info(struct snd_kcontrol *kctl,
@@ -443,13 +443,13 @@ static int special_dig_in_iface_ctl_info(struct snd_kcontrol *kctl,
 {
 	einf->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
 	einf->count = 1;
-	einf->value.enumerated.items = ARRAY_SIZE(special_dig_iface_labels);
+	einf->value.enumerated.items = ARRAY_SIZE(special_dig_in_iface_labels);
 
 	if (einf->value.enumerated.item >= einf->value.enumerated.items)
 		einf->value.enumerated.item = einf->value.enumerated.items - 1;
 
 	strcpy(einf->value.enumerated.name,
-	       special_dig_iface_labels[einf->value.enumerated.item]);
+	       special_dig_in_iface_labels[einf->value.enumerated.item]);
 
 	return 0;
 }
@@ -504,9 +504,14 @@ static int special_dig_in_iface_ctl_set(struct snd_kcontrol *kctl,
 					 dig_in_fmt,
 					 params->dig_out_fmt,
 					 params->clk_lock);
-	if ((err < 0) || (params->dig_in_fmt > 0)) /* ADAT */
+	if (err < 0)
 		goto end;
 
+	/* For ADAT, optical interface is only available. */
+	if (params->dig_in_fmt > 0)
+		goto end;
+
+	/* For S/PDIF, optical/coaxial interfaces are selectable. */
 	err = avc_audio_set_selector(bebob->unit, 0x00, 0x04, dig_in_iface);
 	if (err < 0)
 		dev_err(&bebob->unit->device,
@@ -525,18 +530,22 @@ static struct snd_kcontrol_new special_dig_in_iface_ctl = {
 	.put	= special_dig_in_iface_ctl_set
 };
 
+/* Digital output interface control for special firmware */
+static char *const special_dig_out_iface_labels[] = {
+	"S/PDIF Optical and Coaxial", "ADAT Optical"
+};
 static int special_dig_out_iface_ctl_info(struct snd_kcontrol *kctl,
 					  struct snd_ctl_elem_info *einf)
 {
 	einf->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
 	einf->count = 1;
-	einf->value.enumerated.items = ARRAY_SIZE(special_dig_iface_labels) - 1;
+	einf->value.enumerated.items = ARRAY_SIZE(special_dig_out_iface_labels);
 
 	if (einf->value.enumerated.item >= einf->value.enumerated.items)
 		einf->value.enumerated.item = einf->value.enumerated.items - 1;
 
 	strcpy(einf->value.enumerated.name,
-	       special_dig_iface_labels[einf->value.enumerated.item + 1]);
+	       special_dig_out_iface_labels[einf->value.enumerated.item]);
 
 	return 0;
 }