Hi Ben, this is not a forum, it's a bug reporting tool. You'll need to wait until your distribution ships linux kernel 4.0 (I assume that would be Lubuntu 15.04 or 15.10). Then it should "just work". If it doesn't, you can create a new ticket here, report the issue, and attach all relevant information to it (ask for help at #radeon channel on freenode irc in that case).