Now that I think more about this scenario, why the change in position on PS? AMD's whole angle with their offerings is on the open source side of the spectrum. They build it and give everyone full access and/or build the initial tools and release the source. The two possibilities I can think of is 1) Su took Raja to task about performance improving features that don't help sell cards now. This caused them to go the driver route. It's contrary to their typical way of doing things though. or 2) If something is actually broken in Vega there would be no way you could expose it to devs. They would have to build the work around in the driver.