After DRI2 offloading was pulled into the X.Org Server along with other DDX API changes and other work being led by David Airlie of Red Hat, the driver changes are now landing. X.Org Server 1.13 will be released later this month with the server-side support, so the important X.Org graphics drivers are now being updated in mainline so they will be able to take advantage of the new xorg-server capabilities.
To the xf86-video-nouveau driver, Airlie over the night committed to master support for DRI2 offload and provider object support.
To xf86-video-ati, Airlie made similar changes with DRI2 offload and support for shared pixmaps.
For the xf86-video-intel driver there were also similar changes.