Comment 34 for bug 419501

Simple test case for many xcb-based libX11 bugs:

ico -threads 10

You will likely get a deadlock, "_XAllocID: Assertion `ret != inval_id' failed." or the error mentioned here.

Locally we have problems with any X program that uses multi-threading since the switch to libxcb X11. Sometimes one or two bugs will be fixed but then others will turn up. We have resorted to maintaining our own compile of pre-xcb libX11 in order to make our in-house programs reliable.

At this point I think libxcb libX11 is a failed experiment. If the threading bugs haven't been fixed after a couple years now, will they ever be? Should we simply revert to the old libX11? Last time this was suggested the answer was that compiz depended on xcb, but is some desktop eye-candy really more important than real applications working that people use to get real work done?

Someone found the root cause of another of these bugs recently, so maybe there is hope:
http://lists.freedesktop.org/archives/xcb/2009-October/005102.html