AMD Vega 12 GPU Support Lands In Mesa 18.1-devel
The patch is quite small for adding the Vega 12 support to RadeonSI Gallium3D with the bulk of the enablement needed in the AMDGPU kernel driver. As tiny as the patch is, it's currently not marked for back-porting into Mesa 18.0 stable series.
It's likely not for backporting since the Vega 12 support does require an updated addrlib which was also merged today to Mesa Git. That addrlib update is a few hundred lines of code with that library used for texture addressing and alignment calculations.
Mesa 18.1 should be released by late May or June with this Vega 12 GPU support and much more. So far we haven't seen any Vega 12 patches for the Mesa RADV Vulkan driver (update: there are patches pending on the mailing list) or the separate AMDVLK driver. So far most bets are on this new GPU either being their new discrete Vega mobile GPU or some RX 500 series successor.
Update: There is now merged RADV support thanks to Valve's Samuel Pitoiset.