Arnd Bergmann of Linaro/IBM said at Linux Collaboration Summit that he expects to see an open GPU driver released in 2011. He doesn't strike me as a wild prognosticator, so he must know that one of the major vendors is considering a release their driver code. Once one vendor has done so, if they aren't sued to bits by others, perhaps we'll see real progress with GPUs.
I wonder how releasing the drivers would affect the GPU designers' business. On the one hand, they can monopolize the support and tools business around their closed products. On the other hand, the closed driver model may limit adoption of their products and will prevent community contribution of patches and other valuable ideas.
I read somewhere that Nvidia was actively collaborating with the developers of the Nouveau open-source drivers for their products. And not too long ago, Broadcom joined the Linux Foundation. TI is all in on open-source, so they may be pressuring Imagination Technologies about their drivers. So I think there's a glimmer of hope on the GPU front if no good news just yet.