Ubuntu does not enable it by default, as it mixes poorly with some drivers: <a href="https:&#x2F;&#x2F;wiki.ubuntu.com&#x2F;X&#x2F;Rootless" rel="nofollow">https:&#x2F;&#x2F;wiki.ubuntu.com&#x2F;X&#x2F;Rootless</a><p>AMD only added KMS to their proprietary driver last year, and Nvidia this year (and IIRC only in a beta driver so far); and systemd makes the permission handling a lot easier. So Ubuntu will transition to it eventually, but didn&#x27;t have all puzzle pieces until too recently for even 16.04 LTS.