http://support.amd.com/en-us/kb-articles/Pages/AMDGPU-PRO-Beta-Driver-for-Vulkan-Release-Notes.aspx
For those still living in the world of FGLRX. AMD doesn't do FGLRX anymore.
(its only for legacy stuff now, so STOP complaining about it).
Open-source drivers (radeonsi and amdgpu) support ONLY OpenGL4.2 at this moment in the latest commits (oibaf is the best one on PPA Launchpad).