Could you try radeon-quickfix-kmp in OBS home:tiwai:bnc955096 repo with 4.4.x kernel? It contains the backports from 4.5-rc regarding radeon driver. It doesn't contain backports for drm core, so something might be still missing, though. There are for openSUSE_Factory and Kernel-stable: the former is for the latest openSUSE TW kernel while the latter is for the latest OBS Kernel:stable.