Stale image on X11 server after lost connection

[José Tomás Tocino García]

I'm sorry for the late reply. I've realized I made a mistake in the initial
post, the server is actually running motif windows manager.

The output of xlsclients is:

# xlsclients -al
Window 0x60005b:
  Machine:  localhost.localdomain
  Name:  mwm
  Icon Name:  mwm
  Command:  /usr/bin/mwm
  Instance/Class:  mwm/Mwm

The output of xwininfo is:

# xwininfo -root -tree

xwininfo: Window id: 0xde (the root window) (has no name)

  Root window id: 0xde (the root window) (has no name)
  Parent window id: 0x0 (none)
     13 children:
     0x600088 (has no name): ()  800x600+0+0  +0+0
        1 child:
        0x600089 (has no name): ()  800x600+0+0  +0+0
           1 child:
           0x800005 "CTM - tc3": (" CTM " " CTM ")  800x600+0+0  +0+0
     0x60008a (has no name): ()  62x79+0+0  +0+0
     0x800007 (has no name): ()  1x1+0+0  +0+0
     0x800003 (has no name): ()  3x3+0+0  +0+0
     0x60005e (has no name): ()  5x5+0+0  +0+0
        1 child:
        0x60005f (has no name): ()  117x153+0+0  +0+0
     0xa00001 (has no name): ()  10x10+-20+-20  +-20+-20
     0x60005b "mwm": ("mwm" "Mwm")  10x10+10000+0  +10000+0
     0x600055 (has no name): ()  5x5+0+0  +0+0
        1 child:
        0x600056 (has no name): ()  84x175+0+0  +0+0
     0x600054 (has no name): ()  1x1+0+0  +0+0
     0x600023 (has no name): ()  10x10+-100+-100  +-100+-100
     0x600015 (has no name): ()  10x10+10000+10000  +10000+10000
        1 child:
        0x600016 (has no name): ()  10x10+0+0  +10000+10000
     0x600007 (has no name): ()  1x1+0+0  +0+0
     0x600006 "mwm": ("mwm" "Mwm")  1x1+0+0  +0+0

Where " CTM " is an executable running in a separate computer on the same
network, showing its content on the local X server using "export
DISPLAY=...". When that machine dies, the screen does not go black, instead
the last image of the CTM executable stays on screen.

Then if I try to do a netstat, I can see that the TCP connections from the
machine (that is now powered off) are still ESTABLISHED.

I guess there should be a way of activating a KEEPALIVE mechanism on the
connection to the Xorg, but I'm not quite sure how to do that. The
application is using Qt by the way, if it matters.

Regards.

El mié, 24 feb 2021 a las 10:18, Ilya Anfimov (<ilan at tzirechnoy.com>)
escribió:

> On Wed, Feb 17, 2021 at 05:13:45PM +0100, Jos?? Tom??s Tocino Garc??a
> wrote:
> >    Hello.
> >    I have an xorg server running in a Linux box with no wm, and a
> separate
> >    machine running an application exporting to the X server in the first
> >    machine.
> >
> >    The problem arises when the connection is lost between the two
> machines or
> >    the application exporting the display fails. The X111 server keeps a
> stale
> >    image on screen that is obviously unresponsive. I'd rather it turn
> black
> >    the moment the connection is lost.
> >
> >    Is there a way of forcing the X server to stop showing that stale
> image
> >    when the connection is lost? Not sure if it has something to do with
> it
> >    not having a wm.
> >    Thanks!
> >    Regards.
>
>  This looks rather strange. Usually connection failures
> closes tcp socket, then windows, created by the
> app should be destroyed be the server.
>  What does xlsclients -al and xwininfo -root -tree show
> before and after failure?
>  Does the client still connected? Does it's window(s) still exists?
>
> >    --
> >    Jose Tomas Tocino
> >    http://josetomastocino.com
> >    http://cadizenmoto.com
>
> > _______________________________________________
> > xorg at lists.x.org: X.Org support
> > Archives: http://lists.freedesktop.org/archives/xorg
> > Info: https://lists.x.org/mailman/listinfo/xorg
> > Your subscription address: %(user_address)s
>
> _______________________________________________
> xorg at lists.x.org: X.Org support
> Archives: http://lists.freedesktop.org/archives/xorg
> Info: https://lists.x.org/mailman/listinfo/xorg
> Your subscription address: %(user_address)s
>


-- 
José Tomás Tocino
http://josetomastocino.com
http://cadizenmoto.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.x.org/archives/xorg/attachments/20210406/a047465b/attachment.htm>