X Synchronization Fences have been talked about for well over a year and it comes down to allowing the synchronization of X rendering with direct rendering X clients, such as to allow synchronizing OpenGL-based compositing manager screen updates with X rendering. The patches for this were published by NVIDIA back in June and then went through two revisions since, with the last one coming about one month ago.
James writes to the xorg-devel list, "As I mentioned early on, I really want to get the fence sync work in server 1.10...If these remaining pieces get reviewed, I can send out pull requests for everything immediately. I've had this code out for review in some form for about 3 months now, so it'd be pretty disappointing if it had to sit around waiting for another release cycle."
Seeing as NVIDIA's X synchronization code has effectively been ready for months and under public review, where as the per-CRTC pixmap code is not even quite finished yet nor has gone through formal code review, hopefully this code will still make it in. This morning, Keith also pulled in Nokia's X-Video RePut work.