Black screen on Kubuntu 22 LXD container

[Michael Eager]

On 8/12/22 19:41, 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.
>>
>> Something similar happens running tightvnc-server:  I can open a remote
>> window using vncviewer but it is all gray and unresponsive.
>>
>> In both x2go and vnc windows, I can bring up a terminal window using
>> alt-F2 to display krunner and then running konsole. When I look at
>> environment symbols, I see the following:
>>
>> XDG_SESSION_TYPE=tty XDG_CURRENT_DESKTOP=KDE
>>
>> SDDM appears to be running, as does plasma_session.
>>
>> Anyone have any suggestions?
> 
> So my environment is /way/ different than yours (on the physical machine
> not a container and I start plasma from a CLI login, no graphical login
> manager) and I don't have any direct fix-it help to offer, but here's
> hoping this is at least of some help...
> 
> Since you can bring up krunner and run konsole (and presumably whatever
> other apps) from there...
> 
> The problem is that while most of the plasma environment is evidently
> running, plasmashell (which provides the desktop, panels, etc) is crashing
> or unresponsive, leaving nothing to paint a background or provide the
> usual shell.
> 
> Use your favorite task manager utility to check if it's running, either
> idle or busy-looping.  I like/use htop in a konsole window, but regular
> top should work, or an appropriate ps invocation (if you're like me you'd
> have to man ps to get an appropriate commandline, top/htop are nicer in
> that regard), or pgrep plasmashell, or... if you're lucky a ctrl-esc will
> launch plasma's own system activity task-lister or you can launch your
> favorite graphical alternative from konsole/krunner.
> 
> If it's running, kill it (htop and plasma's system activity lister can do
> it from within the app, or use kill/killall/pkill/whatever).
> 
> Then try starting plasmashell manually.  If you're lucky the restart will
> get it all going and you'll be fine from there.  If not, try restarting
> from konsole and see if it outputs any useful debugging as it crashes.
> OTOH, kde apps are /infamous/ for spitting out so much actually harmless
> effectively developer-interest-only "noise" that it can be impossible for
> an ordinary user like you or I to tell if there's anything actually of use
> in all that noise or not, especially if you don't have the output from a
> normal run to compare it against, so YMMV, but it's worth a shot.
> 
> Meanwhile, just saying kubuntu 22.04 doesn't really tell non-(k)ubuntu-
> users what plasma and frameworks versions you're running.  Since you can
> run konsole, do so, then from its menu select help, about konsole.  There,
> you can get the version information (on live-git-master plasma/frameworks
> updated a few days ago I see version 22.11.70, that's the konsole/plasma
> version) to report, and then on the components tab, the frameworks and qt
> versions (5.97.0 and 5.15.5 respectively, here), along with the windowing
> system (probably x11 for you, it's wayland here).  If you can find it
> other info like the vnc/x2go versions, LXD version info whatever form it
> takes (I wouldn't know), etc, might be useful as well.  Posting that
> should increase the chances of someone else being able to see they are
> running something comparable and thus being able to help even if not on
> (k)ubuntu, tho of course there's no guarantee.

Thanks.  I'll follow up.