Bug#854594: dequeue_pending_request: Assertion `!xcb_xlib_unknown_req_in_deq' failed

[Yves-Alexis Perez <corsac@debian.org>]

Package: libx11-xcb1
Version: 2:1.6.4-3
Severity: normal

Hi,

gthumb crashes consistenly for me when trying to play a mp4 video (from
my Android smartphone). Console outputs points to libx11-xcb, with:

[xcb] Unknown request in queue while dequeuing
[xcb] Most likely this is a multi-threaded client and XInitThreads has
not been called
[xcb] Aborting, sorry about that.
gthumb: ../../src/xcb_io.c:165: dequeue_pending_request: Assertion
`!xcb_xlib_unknown_req_in_deq' failed.

The graphic adapter is i915 (Broadwell) and libva is installed, in case
it matters.

Maybe the bug actually lies in gthumb (or gtk), so please reassign if
needed. If you need more information, please ask.

Regards,
-- 
Yves-Alexis

-- System Information:
Debian Release: 9.0
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable'), (500, 'oldstable'), (450, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_FR.utf8, LC_CTYPE=fr_FR.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)