I'm going to guess it would require kernel support, but certainly graphics card driver support. AMD and Intel not so difficult, just patch and recompile; NVIDIA's binary blob ha ha fat chance. Stick it in a repo somewhere outside of the zone of copyright control, add it to your package manager, boom, done.

I bet it's not even much code. A struct or two that map the contents of the 2.1 handshake, and an extension to a switch statement that says what to do if it comes down the wire.