The xf86-video-intel 2.21.13 driver was released on Sunday by Intel's Chris Wilson. This latest Intel X.Org driver update has some performance regression fixes plus fixes the Intel X.Org driver to build on non-Linux systems.
Some of the fixes done by Chris in the latest driver update include avoiding potential memory corruption, an Ironlake performance regression from flushing after every operation, a conflict when probing the initial KMS configuration for zaphod heads, and stop being overly restrictive about rejecting stale DRI2 buffers.
Chris Wilson is responsible for all 54 changes found in the xf86-video-intel 2.21.13 graphics driver update, which is just coming a short time since the previous Intel X.Org driver point release.
More details on all of the xf86-video-intel 2.21.13 changes can be found via the xorg-announce list