It's not really a standard though, each GPU has a totally different set of ioctls and device files to the point that you can't write against a generic kernel interface either way. AFAIK, the only DRI/DRM interface with two used clients is amdgpu (of which one of the clients is proprietary).

And part of the discussion on the mailing list is how to integrate this with DRI/DRM and dma-buf so it can be used by more Linux clients with less work (although still non zero like you'd have on a DRI scheme as well).