diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index 40cc3476..8e9f7112 100644
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -591,6 +591,8 @@ has_user_backlight_override(xf86OutputPtr output)
 		return NULL;
 
 	DBG(("%s(%s) requested %s\n", __FUNCTION__, output->name, str));
+	if (*str == '\0')
+		return str;
 
 	if (backlight_exists(str) == BL_NONE) {
 		xf86DrvMsg(output->scrn->scrnIndex, X_ERROR,