Re: Is NVIDIA ever going to fix the xinerama + composite problems?
I suspect that the reason that this is low on XOrgs list is because the open source commumity is in the process of transitioning away from xinerama to xrandr 1.2 and eventually xinerama will go away. It is also my understanding that the composit specific issues with xinermama are fairly significant at the architectural level and will not be easy to solve. So it comes down to how you use the resources that are available. We can either get composit/xinerama and have full featured xrandr 1.2 delayed or we can get full featured xrandr 1.2 sooner. Because xinermama is now legacy XOrg is focusing on moving xrandr 1.2 forward.
Of course this sort of begs the real question. When will the nvidia driver have xrandr 1.2 support? Most of the open source drivers have at least some xrandr 1.2 support (even the nouvea and nv drivers) and this is rapidly maturing but we have yet to see anything in this area from nvidia even though they said that this was on their list of thing to do over a year ago.