1 files changed, 7 insertions, 1 deletions
diff --git a/libvo/vo_null.c b/libvo/vo_null.c
index 30f4b06cc7..e0d68ea661 100644
--- a/libvo/vo_null.c
+++ b/libvo/vo_null.c
@@ -21,6 +21,7 @@
  *
  */
 
+#include <errno.h>
 #include "config.h"
 #include "video_out.h"
 #include "video_out_internal.h"
@@ -92,7 +93,12 @@ static void check_events(void)
 
 static uint32_t preinit(const char *arg)
 {
-  return 0;
+    if(arg) 
+    {
+	printf("vo_null: Unknown subdevice: %s\n",arg);
+	return ENOSYS;
+    }
+    return 0;
 }
 
 static uint32_t control(uint32_t request, void *data, ...)