[Xcb] libX11 / xcb / glibc / xine-lib Problem

[Josh Triplett]

On Thu, Mar 10, 2011 at 11:22:04AM +0100, vdr at helmutauer.de wrote:
> I don't know if this is the right place , but i'll try my luck :)
> I have a gentoo based HTPC distribution, and i'm working on a stable
> solution to get HDTV running with vdr backend and a xine-lib 1.2 based
> frontend with vdpau.
> This scenario worked well with glibc 2.10, libX11 < 1.4 including xcb and
> xcb.
> After upgrading to glibc 2.11 i have to use the "LOCKDISPLAY" workaround,
> which implents a call to XLockDisplay()/XUnlockDisplay() around all vdpau
> video surface calls, to prevent a hangup of the xine frontend.
> If I use libX11 without xcb this LOCKDISPLAY workaround is not necessary.
> Now with libX11 > 1.4 its no longer possible not to use xcb.
> 
> The LOCKDISPLAY workaround has the disandvantage, that frames were
> dropped, so at the moment my distribution stucks at libX11 without xcb,
> but thats not a long term solution.
> Unfortunately I have no knowledge about these libs, and I can only guess
> which of the affected parts ( glibc, libX1, xcb or xine-lib ) is causing
> the problem, so any help of you will be highly appreciated to track down
> the problem.
> 
> Thanks for any hints

How quickly and reliably can you reproduce the hang?

Does downgrading to glibc 2.10 and keeping everything else the same make
the hang go away?

I'd suggest starting with a backtrace of all threads when the hang
occurs.  (In gdb, "thread apply all bt", and make sure you have debug
symbols available for the various libraries involved.)

- Josh Triplett