Black screen on Kubuntu 22 LXD container

[René J.V. Bertin]

On Saturday August 13 2022 02:41:17 Duncan wrote:
>Michael Eager posted on Wed, 10 Aug 2022 06:40:46 -0700 as excerpted:
>
>> I'm running Kubuntu 22.04 in an LXD container.
>> 
>> When I connect using x2go, KDE starts up (I see the splash screen) but
>> then the screen goes black with a cursor. After a short time, the lock
>> screen is shown, with password field, so I think that x2go is working.
>> When I log in, the screen goes black.  There is a cursor, but neither
>> left nor right clicks have any effect.


I suppose this means your session and x2go run on 2 different machines

To me it sounds like KDE could be trying to use compositing on a (remote) display channel that doesn't support this. Normally it should turn off the feature if it detects that it isn't supported but maybe there's a miscommunication going on here. One possible way to determine this is to open a terminal emulator or even to ssh in, and replace the KWin window manager with a simple WM that supports the --replace argument (e.g. xfwm4, which can be started with --compositor=off to ensure it won't use this feature).
If that gives you more than just a black screen you can then use the GUI to disable the compositor in KWin, or experiment with different backends. The older KWin version I use, for instance, can use (emulate?) compositing with the legacy XRender backend, which happens to work better with my GPU and supports the few GUI effects I find useful. (NB: you can switch back to KWin with `kwin_x11 --replace &`)

Are there other ways you can connect to the container, VNC for instance?

R.