There is not much special about KMS, just make sure it is enabled in the kernel configuration, and boot with radeon.modeset=1 if it's not enabled by default. See also https://wiki.ubuntu.com/X/RadeonKMS
There is not much special about KMS, just make sure it is enabled in the kernel configuration, and boot with radeon.modeset=1 if it's not enabled by default. See also https:/ /wiki.ubuntu. com/X/RadeonKMS