On Saturday, Kenneth Graunke of Intel published a set of patches for the i965 Mesa driver that he thinks might be able to resolve the Sandy Bridge GPU hang issues. For at least some Sandy Bridge owners in certain configurations, with DOTA 2 and other games the Sandy Bridge GPU will hang every few minutes. Kenneth's patches don't appear to eliminate the driver issues but rather allow DOTA 2 to run for about three hours before hanging. There's also some Ivy Bridge hangs with the Mesa driver too.
The current patches for trying to address hang issues with the Intel Mesa driver can be found on the Mesa mailing list. "These patches add some missing flushing, which appears to help. I'm still getting GPU hangs, but they're much less frequent, and now have an IPEHR of MI_SEMAPHORE_MBOX. I suspect those may be due to bugs in my performance monitoring code, rather than upstream problems...I'm not sure if these should go to stable or not. Probably, but adding more flushes could introduce hangs just as easily as it could fix them (at least on Sandybridge), so I'm always nervous about that. Patch 6 actually applies to Ivybridge, and may help with some issues there as well."