libX11: Changes to 'master'

[Jamey Sharp]

 src/xcb_io.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

New commits:
commit fd85aca7a616c595fc17b2520f84316a11e8906f
Author: Jamey Sharp <jamey at minilop.net>
Date:   Mon Mar 14 14:45:35 2011 -0700

    Ignore user locks after sleeping in _XReply and _XReadEvents.
    
    This bug appears as a hang in applications that wait for replies from
    multiple threads, where one such thread has taken a user lock using
    XLockDisplay.
    
    Prior to this fix, the code could deadlock in this way: If thread 1 goes
    to sleep waiting for a reply, and then thread 2 takes a user lock and
    waits for a reply, then thread 2 will wait for thread 1 to process its
    reply (because responses must be processed in order), but thread 1 will
    wait for thread 2 to drop its user lock.
    
    Fixed by making thread 1 not wait for thread 2 to drop its user lock.
    This makes the semantics of user locks hard to define, but they were
    already hard to define. The new behavior appears to be consistent with
    the way Xlib worked historically, anyway.
    
    Fixes: http://lists.freedesktop.org/archives/xcb/2011-March/006802.html
    
    There was a similar potential for deadlock in _XReadEvents, fixed the
    same way, with the same caveats about user-lock semantics.
    
    Signed-off-by: Jamey Sharp <jamey at minilop.net>