https://bugs.freedesktop.org/show_bug.cgi?id=71448
--- Comment #28 from Christian König deathsimple@vodafone.de --- Created attachment 93072 --> https://bugs.freedesktop.org/attachment.cgi?id=93072&action=edit Fix.
Sorry that it took me so long to find this. It's a rather simple issue that the IRQ support for UVD on SI wasn't activated.
With this patch in place I now get 52fps with 1080p H264 decoding.