Marek Olšák published a set of seven patches to the Mesa mailing list today and one of the patches adds fast color clear support to RadeonSI. The code for fast color clear was ported in part from the R600 Gallium3D driver (where the feature has been present for a while) and works for both multi-sample and single-sample color buffers.
Fast color clears benefit the multi-sample anti-aliasing (MSAA) performance and thus we're excited to see the feature land for this driver that supports the AMD Radeon HD 7000 series GPUs and newer. This patch-set will likely be merged to Git soon with plenty of time ahead of Mesa 10.2.
If you missed it, be sure to checkout our recent R600/RadeonSI Gallium3D tests on Ubuntu 14.04 compared to the Catalyst driver where for some workloads this open-source code is running at ~80%+ the speed of AMD's binary blob.