https://bugs.freedesktop.org/show_bug.cgi?id=79850
--- Comment #12 from Michel Dänzer michel@daenzer.net --- I noticed artifacts as you're describing in armagetronad. It's actually DRI2CanFlip() which failed, because the window pixmap is not the screen pixmap. This turned out to be because SDL 1.2 enables backing store when supported: https://bugzilla.libsdl.org/show_bug.cgi?id=2602
Even if awesomenauts doesn't use SDL 1.2, it might be worth disabling backing store via
Option "BackingStore" "off"
in xorg.conf or the -bs Xorg command line switch.