Linux: libxcb assertion failure causes program crash

[pholz]

My program uses multiple GL contexts (in their own threads) and a Quick context. It crashes predictably with a SIGABRT and the following message:

../../src/xcb_conn.c:186: write_vec: Assertion `!c->out.queue_len' failed.

"This":https://bugreports.qt-project.org/browse/QTBUG-31935 bug seems to be the same. Neither of the proposed solutions (calling XinitThreads(), or patching libxcb as directed, or both) solves the problem - the patched version just causes a segfault down the line instead of failing the assertion.

The bug is closed (because it's not a Qt bug) and the only relevant bug in xcb is similarly closed (they don't think it's xcb's fault either).

The problem only appears to occur on my laptop (using integrated graphics / mesa gl), all on Ubuntu 13.10.

Any help would be appreciated!

[sierdzio]

You can find a bit more experienced low level hackers on the Qt Interest mailing list. Maybe somebody would have an answer for you there.