Published last week and still baking were the "RadeonSI" tiling changes as they affect the Linux kernel with the Radeon DRM, the libdrm library, and the RadeonSI Mesa Gallium3D driver. Jerome Glisse has now put out the small xf86-video-ati patch for flipping on 2D color tiling within the Radeon X.Org driver.
The patch can be found on the xorg-driver-ati list. With a patched Radeon DDX, the ColorTiling2D option inside the xorg.conf needs to be set for actually turning on the feature.
It will likely be some time before the tiling feature is enabled by default for RadeonSI since the support needs to first be merged into the mainline Linux kernel (likely the Linux 3.10 kernel), the DDX is already dependent upon the new version of libdrm for building, and it also needs to appear within a released version of Mesa. The Mesa release will likely be Mesa 10.0, which isn't due out for about another half-year.
While I haven't yet run any RadeonSI tiling performance benchmarks, I do have R600g color tiling benchmarks that show off the performance gains for older generations of ATI/AMD Radeon graphics hardware.