The prominent change warranting the xf86-video-intel 2.21.5 release addresses a crashing problem for Intel's forthcoming "Haswell" hardware. "Haswell reintroduces a command to load the scanline window from the command stream and so requires its own specialised wait-for-vsync routine - failure to do so was then causing hangs when trying to do tearfree video or use a compositor."
Other changes include preventing a buffer leak in certain cases, fixing offset transformation for fallback gradient paths, preventing GLAMOR acceleration from crashing when misconfigured, preventing UXA from crashing, some compilation fixes, rendering fixes, and other changes.
Chris Wilson of Intel's Open-Source Technology Center continues to lead the DDX driver with 33 changes for this fifth 2.21 point release while NVIDIA's Aaron Plattner committed one fix. Most of Wilson's work on the driver continues to be around optimizing the SNA acceleration architecture.
The release announcement for the xf86-video-intel 2.21.5 DDX driver can be read on the xorg-announce list.