This 2D acceleration for the half-year-old Radeon HD 7000 series graphics cards isn't using traditional 2D EXA acceleration within the X.Org DDX, but the 2D is being piped over the RadeonSI Gallium3D driver using Intel's GLAMOR.
Michel Dänzer announced this work to the xorg-driver-ati mailing list this morning. "The main purpose of these changes is to allow using this driver on SI hardware and playing with the (still quite limited) Gallium radeonsi driver in an X environment. Longer term, glamor might be interesting for older Radeons as well. Right now, its main drawbacks are missing XVideo support (shouldn't be hard to add to glamor), and occasionally quite annoying diagonal tearing."
GLAMOR is the means of 2D-over-OpenGL acceleration that Intel China developers introduced last year. GLAMOR is still an experimental option within the Intel driver, but last time it's been benchmarked, Intel SNA and UXA worked much better than GLAMOR. Aside from Intel's use, this is the first time seeing GLAMOR deployed elsewhere.
It's interesting to see AMD going with GLAMOR rather than working on the Xorg state tracker built into Gallium3D that's already been working for previous generations of Radeon GPUs.
The "RadeonSI" Gallium3D driver that supports this latest-generation Radeon HD 7000 series hardware is still being raised and so far is rather useless for end-users, even though the HD 7000 hardware has been in the market-place for months and has been well supported by the Catalyst driver.
It will be interesting to see how the Radeon HD 7000 series performs 2D-wise now with GLAMOR. There's some discussion about this 2D acceleration choice on the ATI driver mailing list.