https://bugs.freedesktop.org/show_bug.cgi?id=89034
--- Comment #3 from Michel Dänzer michel@daenzer.net --- (In reply to smoki from comment #2)
Well i can but i need first to make a bottle of coffee because one llvm build takes 30 minutes on Kabini :D.
It shouldn't take that long after switching between the bisected commit and the one before it (or just re-applying/reverting it on top of whatever later commit you may have built last). If you're not using ccache yet, that might help a little as well.
I don't have gdm.log as i don't use it, plain startx is used.
Then something like
startx [...] 2>stderr.txt
should capture the stderr output in a file.