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

From: Walid MOGHRABI <[email-masked]>
Date: Wed, 26 Jul 2017 10:35:22 +0200 (CEST)

Hi guys,

Just to give a bit more informations on my TCE setup : it is not based on the live-build scripts because it is not well suited for Ubuntu 16.04 and to be honest, I never managed to get a working live build that way so I gave up.
My TCE image is more or less a tweaked ubuntu 16.04 debbotstrapped image with x2gothinclient-displaymanager installed (+ a few more things but really, this is a pretty basic ubuntu server image + x2gothinclient installed)

By the way, Stefan put the finger on one point : in /usr/sbin/x2gothinclientd, I commented the whole randr stuff block (from line 114 to line 175) to make a try then restarted the x2gothinclient-displaymanager but while it didn't fix my multimonitor support within the X2Go session, it fixed a bad ordering of the monitors.
Before that, my monitors were inverted (right was left and left was right), commenting this block lead to right ordering of the monitors this time.

Concerning your test Uli, doing "Ctrl+Alt+F" within the X2Go session on the TCE did nothing.
I don't know if it was meant to do anything but I did it many times following the action by a xrandr output in the console, nothing changed, same values all the time (one big screen, not 2)

Regards,
Walid Moghrabi

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----- Mail original ----- 

De: "Ulrich Sibiller" <[email-masked]> 
À: "Stefan Baur" <[email-masked]> 
Cc: [email-masked], "Walid MOGHRABI" <[email-masked]> 
Envoyé: Mardi 25 Juillet 2017 22:11:28 
Objet: Re: Bug#1197: Multihead fullscreen not working with TCE client in displaymanager mode 

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
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