Both AMD's and Intel's OSS drivers are 'clean room' separate codebases to their internal closed drivers. It may be that they are specifically avoiding some feat

Both AMD's and Intel's OSS drivers are 'clean room' separate codebases to their internal closed drivers. It may be that they are specifically avoiding some features/rewriting possibly infringing code in these cases. As far as I know, we have yet to have an open driver to get the same performance as their closed windows ones in all cases. There may be reasons behind that.