https://bugzilla.kernel.org/show_bug.cgi?id=55941
--- Comment #6 from Alex Deucher alexdeucher@gmail.com 2013-04-07 16:30:00 --- (In reply to comment #4)
I have been very puzzled when reading your last message Alex, since I got (on debian) the exact same problem with a Mux system intel Ironlake/radeon Hd5650.
On mux-less systems you can't switch the displays since there are no displays connected to the dGPU.