Subject: Bug#1197: Multihead fullscreen not working with TCE client in displaymanager mode

From: Ulrich Sibiller <[email-masked]>
Date: Tue, 25 Jul 2017 22:11:28 +0200

On Tue, Jul 25, 2017 at 6:55 PM, Stefan Baur <[email-masked]> wrote:
> Hi folks,
>
> Just an idea - some XRANDR-related stuff that is specific to
> X2Go-TCE-Live is happening in this file:
>
> <https://code.x2go.org/gitweb?p=live-build-x2go.git;a=blob;f=config/includes.chroot/lib/live/config/2800-x2go-thinclientconfig;h=49b9f0f8e0f85d4471be6c4e1cbcad83115b3009;hb=65d1f40a812f4ae95dddd97c85b995b10ba9e678>
>
> Which, in turn, was inspired by this file from X2Go-TCE-Classic (NFS):
>
> <http://code.x2go.org/gitweb?p=x2gothinclient.git;a=blob_plain;f=displaymanager/sbin/x2gothinclientd;h=6897d42d17bd6778e7de5e62ec3f51727d4e8800;hb=HEAD>
>
> As this is specific to the TCEs, maybe this is the root cause of the
> difference you're seeing?

Hmmm, I doubt that. Usings NX the client side is not really doing
anything X wise. It's the nxagent that calls XineramaQueryScreens().
It asks the client side X server (the real X server) for its Xinerama
configuration. We have learned from the previous outputs that Walis
had sent that the real X server does not have Xinerama configured.
Therefore the agent does not see any Xinerama configuration. (The only
possible exception to this would be nxproxy running with LD_PRELOAD of
libfakexinerama.so which is not happening here.)

Now, in the Laptop scenario you can see via xrandr that nxagent has
gotten the Xinerama information somehow. Otherwise it would not have
been possible to setup two NX outputs/monitors/heads.

The two logfiles are almost the same except the last line where the in
the Laptop scenario you can see this line

Info: Screen [0] resized to geometry [3840x1080] fullscreen [1].

This line is printed if nxagent has received and processed a sizing
event. In the TCE scenario no sizing event was sent to nxagent which -
if really true - is probably the TCE window manager's fault.

Walid, can you please try pressing CTRL-ALT-F twice in the TCE
scenario? What is xrandr showing afterwards?

Uli