$ grep radeon /var/log/Xorg.0.log
(II) LoadModule: "radeon"
(II) Loading /usr/lib/xorg/modules/drivers/radeon_drv.so
(II) Module radeon: vendor="X.Org Foundation"
(II) Loading sub module "radeon"
(II) LoadModule: "radeon"
(II) Reloading /usr/lib/xorg/modules/drivers/radeon_drv.so
(II) RADEON(0): [drm] created "radeon" driver at busid "pci:0000:02:00.0"