Appears to be an old issue reported upstream (https://bugzilla.gnome.org/show_bug.cgi?id=567522).
It would be nice, to not try endlessly launch non-existing X server, and probably to set daemon/NoConsole at runtime after first gdm-simple-slave failure. In current situation syslog is polluted with repeated error message about non-existing Xorg binary. -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]

