[Discuss-gnuradio] gr-fosphor driver issues

I'm using an AMD radeon HD 7900 in my computer. When i run a flowgraph that has an instance of fosphor it shuts down immediately and returns the following error:

Using Volk machine: avx_64_mmx

[+] Selected device: Tahiti

libGL error: unable to load driver: swrast_dri.so

libGL error: failed to load driver: swrast

python2: indirect_init.c:956: __glXNewIndirectAPI: Assertion `o > 0' failed.

I've installed the 14.12 drivers from AMD's site (on osmo's site it only names drivers up to 14.12, even though the current version is 15.12), there are 3 choices (proprietary, minimal and developer OGL/OCL), which one should I use?

I've followed the instructions on http://sdr.osmocom.org/trac/wiki/fosphor

I have two laptops successfully running fosphor, but they have nvidia and intel video cards, i've never worked with AMD before.

any help would be much appreciated

-b