Comment 18 for bug 1209397

xserver-xorg-glamoregl is not in main, so xserver-xorg-video-radeon is not being built with glamor support in the ubuntu archive.

if you apt-get install xserver-xorg-glamoregl, apt-get source xserver-xorg-video-radeon, then build and install the deb locally, there will be 3d support. When xserver-xorg-glamoregl moves from universe to main the xserver-xorg-video-radeon package will include glamor

tested this on a radeon hd7850