The New AMD GPU Open-Source Driver On Linux 4.2 Works, But Still A Lot Of Work Ahead

Alex's Mesa branch also isn't closely re-based against upstream Mesa and thus doesn't yet have all the latest GL4 goodies, etc. Until the AMDGPU support is in mainline Mesa, most Tonga / Carrizo users will be off-limits for this hardware accelerated open-source support.

There's also the new xf86-video-amdgpu DDX driver for X.Org that needs to work its way into Linux distribution repositories. Like the GCN support in xf86-video-ati, GLAMOR is depended upon for 2D acceleration over OpenGL.

Prior to building the forked Mesa code, I also built LLVM SVN from Git, which is now for tracking LLVM 3.8.0. Once building all of this user-space code and riding the Linux 4.2 kernel, the AMDGPU stack was working! The Radeon R9 285 was working with OpenGL 3.3 acceleration!

It will be nicer once all of the user-space code is mainline, which ideally will happen in time for Ubuntu 15.10 and Fedora 23. Even still, it was nice that AMDGPU plays nicely out-of-the-box with Linux 4.2 on xf86-video-modesetting, so at least there is proper KMS support.

Before getting too excited though, for Tonga in the Linux 4.2 kernel there isn't yet any power management support... Hopefully it will come for Linux 4.3. We also don't know yet the exact plans for open-source Fiji GPU support for handling the Radeon R9 Fury graphics cards, but hopefully that will come soon enough, but given the timing and that they don't seem to have started on it yet and would need to clear legal review, I doubt it won't come until at least Linux 4.4.