Back in May was when Intel provided initial MSAA support within their Mesa DRI driver for 2x and 4x MSAA support on Sandy Bridge and Ivy Bridge hardware. In July they then tackled CMS MSAA support for Ivy Bridge, which is Compressed Multi-sample Surface Multi-Scene Anti-Aliasing.
The latest work by Paul Berry allows for 8x MSAA support on Ivy Bridge. The Sandy Bridge limit continues to be 4x MSAA.
A set of eight patches is required to up the anti-aliasing limit, which for now can be found on the mesa-dev mailing list.