AMD's Alex Deucher has released the xf86-video-ati 6.12.2 driver this morning, not to be confused with the official Catalyst 9.4 proprietary driver that will come later this month. The open-source ATI driver update has a fair number of changes for this point release. In particular, the 6.12.2 release has lots of bug fixes and Textured Video / X-Video
improvements. Additionally, there is mode-setting support for the ATI Radeon HD 4890
graphics card that was released late last month usng the ATI RV790 GPU.
The bug fixes vary throughout and include a Mac Mini connector fix, some DCE 3.2 fixes, an X-Video sync fix when in multi-head mode, R600/700-specific work, an AtomBIOS code clean-up, and a few driver improvements.
The release announcement with source download links and the change-log can be found on the X.Org mailing list