/usr/share/xsessions/xgl.desktop:
[Desktop Entry] Encoding=UTF-8 Name=Xgl Comment=Start an Xgl Session Exec=/usr/local/bin/startxgl Icon= Type=Application
/usr/local/bin/startxgl:
#!/bin/sh Xgl -fullscreen :1 -ac -br -accel glx:pbuffer -accel xv:pbuffer -xorgAc & sleep 4 export DISPLAY=:1 exec gnome-session
Note the xorgAc option, which removes access restrictions and allows
proper power management. Oops... looks like that doesn't work at the
moment. Better luck next time.