IMHO, I think that AMD should today already (in parallel to RadeonHD) outsource the project of making a open source Gallium3D device-driver for ATI GPUs to a dedicated team working full-time on it while the Gallium architecture is still in early development, ...same as how Intel have hired Tungsten Graphics to do the heavy lifting for them.
That way AMD could get some early saying on how Gallium should be designed from the ground, before it is too late and the wheel have to be reinvented from scratch again.
In order words, hire professionals to get the job done quicker.
I'll quote myself from other thread.
How about the just released 3D documentation for R300-R500? Is it enought to implement near fglrx (or even better) 3D support in open source radeon driver for R300?
I'm looking espesially for vertex and pixel shaders and other "magic things" in 3D code which fglrx has and radeon doesn't have, yet.
Yes, we believe we have provided enough support for all the GL2.x functionality. Having said that, implementing a driver to actually *do* all that is a non-trivial amount of work.
First priority is going to be getting the current level of functionality working reliably on all the new ASICs, but we did want to get enough info out so that Gallium and GL2.x work could also be tackled. One of the participants on the review team was our SW OGL architect, who was advising in part on which features we needed in order to support a fully functional OpenGL driver.