I am currently running Ubuntu 15.04 64-bit on a machine with a Radeon R9 270X GPU.
I've grabbed the latest 64-bit Linux build from this page (currently 2.75-a08f8a4) and I have installed the latest Catalyst drivers directly from AMD's website (currently 15.20.1046-150622a-186193C).
However, no matter what I do, I still don't see an OpenCL option anywhere in Blender's user preferences:
What am I missing or doing wrong?
Note: I tried setting the
CYCLES_OPENCL_SPLIT_KERNEL_TEST=1 environment variable but it made no difference.