AMD wasn't pushing code for better performance, they were pushing a janky abstraction layer for their devices to make porting their Windows driver easier, that

AMD wasn't pushing code for better performance, they were pushing a janky abstraction layer for their devices to make porting their Windows driver easier, that basically did what NVidia does and skipped a lot of the existing DRM infrastructure in the kernel. If you want to write a kernel driver that's effectively a Russian train toilet nobody will stop you, and you can feel free to maintain the engineering effort on it - but it's not going to be accepted into the mainline Kernel and you'll have to maintain it out of tree. If AMD wants a shim to make it easier to port their Windows drivers over that's perfectly acceptable, but they need to work with the existing DRM infrastructure and the people that maintain it to get a kosher driver that everyone can be happy with.