drm permissions error with i965 on amd64 6.2 with libGL applications

"libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: i965"

I can solve it by changing the permissions on /dev/drm0 to rw for users but:

(1) I am not sure if that introduces a realistic security risk.
(2) The permissions are reverted on reboot making a minor annoyance to
reset them.

Advice?