I updated to libevdev-0.6-1.fc20.i686 after booting the screen stays black where usually GDM should show up. It's not black as in "turned off" it's more a black as the LCD shows still backlight. After downgrading to libevdev-0.5-1.fc20.i686 everything worked as expected. Sorry I am not able to provide any logs or something.
*** This bug has been marked as a duplicate of bug 1046426 ***