diff --git a/drivers/isdn/capi/capiutil.c b/drivers/isdn/capi/capiutil.c
index 36835ef3f340613df957ce98a26d5c16eabec20c..36c1b37cea0ac4ba7f4578ae9ae28454dcd75c2e 100644
--- a/drivers/isdn/capi/capiutil.c
+++ b/drivers/isdn/capi/capiutil.c
@@ -489,12 +489,17 @@ static char *mnames[] =
  * @cmd:	command number
  * @subcmd:	subcommand number
  *
- * Return value: static string, NULL if command/subcommand unknown
+ * Return value: static string
  */
 
 char *capi_cmd2str(u8 cmd, u8 subcmd)
 {
-	return mnames[command_2_index(cmd, subcmd)];
+	char *result;
+
+	result = mnames[command_2_index(cmd, subcmd)];
+	if (result == NULL)
+		result = "INVALID_COMMAND";
+	return result;
 }