Comment 3 for bug 269302

This is not a xserver-xorg-video-intel problem since it works after you log in. The problem is caused by the lack of dynamic display configuration support in the packaged GDM (2.20). A new version is being developed with support for dynamic configuration, but it is not clear which version will be included in GNOME 2.24:

http://mail.gnome.org/archives/desktop-devel-list/2008-September/msg00013.html