While the Linux 2.6.31-rc5 kernel should be released at any point now and the development is quickly winding down on this kernel, David Airlie is trying to push in a significant ATI KMS driver update into this kernel. David has asked Linus to pull in his latest set of patches, which contain a number of bug-fixes and code cleanups (along with a few additions like color tiling support) to both the ATI KMS code as well as the TTM memory manager. The ATI kernel mode-setting driver is just appearing within the staging area of the Linux 2.6.31 kernel, but still Linus may reject this latest pull request. There are 36 code commits that David is trying to get pulled into the 2.6.31 kernel, but Linus often has had problems with David's pull requests so late in the development cycles along with other differences in not seeing eye-to-eye.
The mailing list message surrounding this updated kernel mode-setting driver can be found on dri-devel.