I can confirm the bug. My edgy system displays a black screen after boot. When I press ALT, I see the login screen of tty1. Then when I press ALT-F7 it will start X and kdm will run normally.
-- KDM fails to launch X on edgy https://launchpad.net/bugs/59242 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs