/etc/X11/XF86Config-4 should have the line "Mode 0666" in the DRI section
in order to allow the normal user to use 3D accelaration "out of the box".
Don't know if this is a bug or intentional, that's why it's low/low....
That would allow anybody on the system to read/write to these devices, which
isn't a good thing securitywise.
It isn't a security issue anymore, and is fixed in Rawhide.