Comment 0 for bug 1680378

Xmir freezes in mir_buffer_stream_get_graphics_region() from xmir_input_set_cursor()

Seems to happen a lot when testing Firefox and Chrome when entering/leaving the address bar...

(gdb) bt
#0 pthread_cond_wait@@GLIBC_2.3.2 ()
    at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1 0x00007fe9624f4c5c in std::condition_variable::wait(std::unique_lock<std::mutex>&) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#2 0x00007fe96556c6b2 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libmirclient.so.9
#3 0x00007fe9655709ed in ?? ()
   from /usr/lib/x86_64-linux-gnu/libmirclient.so.9
#4 0x00007fe965570517 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libmirclient.so.9
#5 0x00007fe965574f28 in mir_buffer_stream_get_graphics_region ()
   from /usr/lib/x86_64-linux-gnu/libmirclient.so.9
#6 0x0000563e52d4290e in xmir_input_set_cursor (cursor=0x563e5432fce0,
    xmir_input=<optimised out>, xmir_input=<optimised out>)
    at xmir-cursor.c:108
#7 0x0000563e52d91eab in miPointerUpdateSprite (pDev=0x563e540e3a90)
    at mipointer.c:468
#8 0x0000563e52d920fa in miPointerDisplayCursor (pDev=0x563e540e3a90,
    pScreen=0x563e537385b0, pCursor=0x563e5432fce0) at mipointer.c:206
#9 0x0000563e52d7ebf1 in CursorDisplayCursor (pDev=0x563e540e3a90,
    pScreen=0x563e537385b0, pCursor=0x563e5432fce0) at cursor.c:150
#10 0x0000563e52e074e0 in AnimCurDisplayCursor (pDev=0x563e540e3a90,
    pScreen=0x563e537385b0, pCursor=0x563e5432fce0) at animcur.c:220
#11 0x0000563e52e78cc8 in ChangeToCursor (pDev=0x563e540e3a90,
    cursor=0x563e5432fce0) at events.c:937
#12 0x0000563e52e7cbba in CheckMotion (ev=ev@entry=0x0, pDev=0x563e540e3a90)
    at events.c:3090
#13 0x0000563e52d432b1 in pointer_ensure_focus (
    xmir_window=xmir_window@entry=0x563e543956d0, dev=0x563e541119c0,
    sx=<optimised out>, sy=<optimised out>, xmir_input=<optimised out>)
    at xmir-input.c:228
#14 0x0000563e52d43345 in pointer_handle_motion (
    xmir_input=xmir_input@entry=0x563e54111860,
    xmir_window=xmir_window@entry=0x563e543956d0, pev=pev@entry=0x7fe950003ba0)
    at xmir-input.c:243
#15 0x0000563e52d438a0 in xmir_window_handle_input_event (
    xmir_input=xmir_input@entry=0x563e54111860,
    xmir_window=xmir_window@entry=0x563e543956d0, ev=<optimised out>)
    at xmir-input.c:491
#16 0x0000563e52d43b78 in xmir_handle_surface_event_in_main_thread (
    xmir_screen=<optimised out>, xmir_window=0x563e543956d0,
    arg=0x7fe950003ba0) at xmir-input.c:544
#17 0x0000563e52d453a9 in xmir_process_from_eventloop_except (w=0x0)
    at xmir-thread-proxy.c:102
#18 0x0000563e52eaa131 in ospoll_wait (ospoll=0x563e5372d790,
    timeout=<optimised out>) at ospoll.c:412
#19 0x0000563e52ea3a7c in WaitForSomething (are_ready=<optimised out>)
    at WaitFor.c:226
#20 0x0000563e52e6fc0a in Dispatch () at dispatch.c:422
#21 0x0000563e52e73e58 in dix_main (argc=6, argv=0x7ffec1136a68,
    envp=<optimised out>) at main.c:287
#22 0x00007fe9637d03f1 in __libc_start_main (main=0x563e52d3df70 <main>,
    argc=6, argv=0x7ffec1136a68, init=<optimised out>, fini=<optimised out>,
    rtld_fini=<optimised out>, stack_end=0x7ffec1136a58)
    at ../csu/libc-start.c:291
#23 0x0000563e52d3dfaa in _start ()