X.Org Server 1.15 was released in late December and offered server-side support for DRI3 and Present, but only now is the Intel DDX driver (xf86-video-intel) offering integrated support for these latest open-source display technologies... Intel's DDX push today is also the first major X.Org driver integrating the support.
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.
In a series of Git commits today, Chris Wilson of Intel's Open-Source Technology Center added SNA support for DRI3, SNA support for Present, and also UXA support for these new X.Org features. The SNA DRI2 code also now supports real asynchronous page-flipping on supported versions of the kernel and xorg-server.
Perhaps now we will finally see the Intel X.Org 3.0 driver release...