Just four days ago was the xf86-video-intel 2.20.18 release that fixed some performance regressions, but a regression slipped into the 18th point release that mandated this quick .19 release. The issue causing this quick release was breaking USB DisplayLink slave outputs. The previous release had a bug causing the driver to flush the entire scan-out over the USB for every drawing operation, which made the performance of these USB-driven DisplayLink slaves completely unusable. This Sunday driver update should now fix that.
Also taken care of with the xf86-video-intel 2.20.19 release by Chris Wilson is implementing support for the GNOME Build API so the Intel driver is easier for integrators and distributors, a fix to correctly offset in-place trapezoids for sub-windows, explicitly prevent ring-switching for synchronized rendering to scan-outs, and the DisplayLink fix of clipping the dirty region to slave pixmaps.
In total there were 16 changes by Chris Wilson to the Intel DDX over the past four days while Adam Jackson and Colin Walters were each responsible for one commit.
The xf86-video-intel 2.20.19 driver release announcement can be found on the Xorg mailing list.