But before getting too excited, there isn't any new GPU support code as part of these 23 patches that touch several hundred lines of code. These patches are just prepping the driver infrastructure for being able to handle AMD's new GPUs but without actually adding in any new support at this time.
There are a fair amount of UVD/VCE changes along with other low-level alterations in prepping for new hardware support. Hopefully this is a sign it won't be too much longer before seeing Vega support patches published for the AMDGPU+RadeonSI open-source driver stack.
The earliest we'll see AMD Vega GPU support land would be for Linux 4.12, with the merge window for that likely being in late April or perhaps early May. Linux 4.12.0 stable would then be released in late June or early July. The big contingency though on the AMD Vega support is needing to land the AMDGPU DC/DAL display code, as AMD developers have previously indicated their new hardware will only be making use of the new display code paths. Latest rumors are that AMD Radeon RX Vega may be officially launching on 30 May.
The 23 prep patches for new ASICs can be found via this patch series.