this is confirmed by upstream : 02:19 < aaronp> tepsipakki: I reproduced the problem and filed bug 302927. 02:32 < aaronp> tepsipakki: It looks like what's happening is that XPending is calling XLockDisplay and then encounters an IO error, which calls exit, and libGL calls XESetCloseDisplay as part of its cleanup path.
** Changed in: linux-restricted-modules-2.6.20 (Ubuntu) Importance: Undecided => Low Status: Unconfirmed => Confirmed -- Closing glxgears window causes xcb_xlib_lock assertion and sound interruption https://launchpad.net/bugs/91077 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs