AMD GPU
AMD GPU is the kernel module that can be used to support post-HD7000 or Tahiti GPUs. To enable graphics on these systems you would do the following:
Install the drm-kmod package
$ sudo pkg install drm-kmod
Take note of the post-install package message as it contains important information - specifically add this to your /etc/rc.conf or /etc/rc.conf.d/amd file:
kld_list="/boot/modules/amdgpu.ko"
Ensure that your UID is a member of the "video" group.
Restart your system; you should see the amdgpu.ko get loaded and a flash on your console as we switch over to the new display driver.
Start Xorg via your usual method (i.e. startx, GDM, etc.)
Radeon KMS
Radeon KMS is a distinct driver intended for older AMD based GPUs that are available in pre-HD7000 or Tahiti GPUs. To enable graphics on systems with these GPUs you would do the following:
Install the drm-kmod package
$ sudo pkg install drm-kmod
Take note of the post-install package message as it contains important information - specifically add this to your /etc/rc.conf or /etc/rc.conf.d/radeon file:
kld_list="/boot/modules/radeonkms.ko"
Ensure that your UID is a member of the "video" group.
Restart your system; you should see the radeonkms.ko get loaded and a flash on your console as we switch over to the new display driver.
Start Xorg via your usual method (i.e. startx, GDM, etc.)