Intel's UXA Acceleration Now Supports DisplayPort MST
The Red Hat developer has been working on DisplayPort Multi-Stream Transport for many months and it's turning out well. The Multi-Stream Transport support is for daisy-chaining multiple DisplayPort connections, as needed by some 4K displays and other higher-end setups, and for David's main Linux use-case is the technology is used by some recent Lenovo ThinkPad docks.
Up to now the xf86-video-intel driver has supported DP MST along the modern SNA code-path -- the default 2D acceleration method of the xf86-video-intel 3.0 development code -- while only this weekend it's now supported by UXA, the slower 2D code-path used by default on older versions of the Intel DDX driver. Adding the MST support to UXA brought in just over 300 lines of new code per this Git commit and the code will be found in the next development release of xf86-video-intel 3.0, the seemingly never-ending driver release.