Dear Maintainer, When booting with 3 monitors, internal laptopscreen, 2 external monitors, GDM refuses to bring up the login screen, instead it shows 3 black screens with a cursor. The cursor can happily move between all 3 screens. Booting with only 2 screens, laptop + external monitor, works fine. After logging in, I can happily plug in the third monitor and have a tripple-head desktop. Last time I checked on Ubuntu, a few months ago, this all worked normally, so it has worked at 'some' point in the past. This on a mid 2013 macbook pro retina, 00:02.0 VGA compatible controller: Intel Corporation Device 0a2e (rev 09) [ 2.598451] fbcon: inteldrmfb (fb0) is primary device [ 3.996610] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device model name: Intel(R) Core(TM) i5-4258U CPU @ 2.40GHz