diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index a99f720..7a8c79d 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -1177,7 +1177,8 @@
 	struct snd_mixer_oss *mixer = entry->private_data;
 	char line[128], str[32], idxstr[16];
 	const char *cptr;
-	int ch, idx;
+	unsigned int idx;
+	int ch;
 	struct snd_mixer_oss_assign_table *tbl;
 	struct slot *slot;