[X2Go-Dev] Different behavior of X2Go Client from Desktop and TCE

[Ulrich Sibiller]

On Thu, May 17, 2018 at 2:45 PM, Oleksandr Shneyder
<o.shneyder at phoca-gmbh.de> wrote:
> Am 17.05.2018 um 14:33 schrieb Ulrich Sibiller:
>> On Thu, May 17, 2018 at 2:13 PM, Oleksandr Shneyder
>> <o.shneyder at phoca-gmbh.de> wrote:
>>> Nope, it looks for me, that nxproxy window get information about screens
>>> from WM. If WM is not started, nxproxy get just the window geometry.
>>> With started WM we have correct display information on server side.
>>> Xinerama starts to work with WM even if X2Go Session already running. I
>>> made some experiments like:
>>>
>>> 1. Starting tce without WM.
>>> 2. Connect to TC with ssh.
>>> 3. Open X2Go Session. At this moment Xinerama in X2Go session not
>>> working. I have one big screen over two monitors.
>>
>> What exactly do you mean by "open x2go session"?
>
> I mean start X2Go session from TC
>
>>
>>> 4. Starting WM on the TC. At this moment Xinerama starts to work in the
>>> running X2Go session immediately.
>>>
>>> It worked in TCE for me in 100% of cases. Independent when I'm starting
>>> WM - before X2Go Client, after X2Go Client or even when X2Go Session
>>> already running. I'll implement this solution in classic TCE and will
>>> let my customers test it.
>
>
>
>> I'd prefer understanding what's going on first. nxagent is running
>
> You can easily reproduce this issue by running x2goclient without WM.
> It's not really important for me now, why it's not working without WM. I
> think NX using some WM-Based function to determine screen configuration
> on the client side. I don't have resources to investigate this issue
> right now and it's not critical for me.
>
>
>>  if (nxagentGrabServerInfo.grabstate == SERVER_GRABBED &&
>> nxagentGrabServerInfo.client != NULL)
> ....................
>> And XineramaQueryScreens ins finally called in
>> nxagentAdjustRandRXinerama. BUT: If nxagentAdjustRandRXinerama FAILS
>> to get that data it will NOT fall back to the version you see but to
>> reporting ONE screen (called NX1, IIRC). So all this fails somewhere
>> else.
>
> No, if I'm starting the session from TC without WM, I don't have screen
> with name NX1. xrandr output looks in this case like this:
>
> Screen 0: minimum 320 x 240, current 2560 x 1024, maximum 2560 x 1200
> default connected 2560x1024+0+0 0mm x 0mm
>    1360x768      60.00
>    320x240       60.00
>    1024x600      60.00
>    1280x800      60.00
>    1600x900      60.00
>    1600x1200     60.00
>
> Only if I starting session from TC with running WM, I have screens with
> names NX1, NX2, etc.
>

That's what I am saying. It is NOT the xinerama code going nuts, the
difference is happening somewhere else in nxagent. I will try to
determine the cause tonight.

Uli