The big feature up to now was Intel SNA acceleration support by default while early on it also had Ubuntu XMir support until Intel decided to revert the support. With today's xf86-video-intel 2.99.912 development release, there's even more features to add for the 3.0 release.
What Intel's Chris Wilson says are the final round of features are variable cursor support, support for DRI3 and Present, improved DRI2 support, handling for X.Org Server 1.16, Userptr support, and precursor work for DisplayPort Multi-Stream Transport. Here's some more on these features:
- The variable cursor support is for handling cursors of different sizes, now up to a size of 256x256 pixel max as allowed by the Intel hardware. This is mainly for getting rid of the 64x64 cursor limitation that's becoming more of a problem now with HiDPI displays.
- Finally last week the mainline support was added for DRI3 support and the Present extension. DRI3 involves using FDs with DMA-BUF to pass objects around rather than global GEM handles. The DRI3 Present extension is about swapping screen contents in a more synchronized manner. X.Org Server 1.15 since late 2013 has supported DRI3+Present.
- Support for X.Org Server 1.16, which is expected to see its official release in July.
- Userptr support when paired with the Linux 3.16 kernel or newer. As explained earlier, the userptr support allows user-space to wrap up any malloc'ed memory allocations into GEM buffer objects.
- DisplayPort Multi-Stream Transport (MST) is currently under development. The support isn't yet complete but from the DDX side, some of the necessary xf86-video-intel driver changes are being made for handling it in the future.
More information on the changes for this latest Intel 3.0 X.Org driver pre-release can be found via this Git commit.