Currently these 140 patches for "Vega10" support in RadeonSI is limited to OpenGL 3.1 compliance since geometry shaders and tessellation are not yet working. However, Marek is working on that support now, so most likely they will come soon and Marek will be able to get OpenGL 4.5 running on Vega prior to the presumed May launch.
These Vega RadeonSI patches also include support in Gallium3D for the new GPU's UVD video decoding and VCE video encoding.
The patches can be found on Mesa-dev and 57 of the patches are for updating addrlib, a texture addressing and alignment calculator used by their Radeon Software / Catalyst driver.
It will be interesting to see when these RadeonSI Vega patches land. The Mesa 17.1 branching is set to happen in mid-April, which would only give them a few weeks to merge the massive patch-set in time for this three-month update to Mesa. But they could wait until the Vega support is mainlined in the AMDGPU DRM driver, but that won't happen until around late April when the Linux 4.12 merge window is to open. So it might not end up having mainline support in Mesa until the v17.2 release later this summer. Of course, that's also assuming the AMDGPU DC code is also accepted in mainline for Linux 4.12 as it's a prerequisite for the Vega10 DRM support.