Plasma6 session in tigervnc: kglobalaccel 100% CPU

[Havin_it]

Hi,

Context: I'm running a plasma-6 X11 session on my laptop under tigervnc Xvnc. I normally start this by logging in on a console VT and running "vncserver :1" but the behaviour is the same if I use the initscript. Non-systemd profile.

When first connecting from another machine (typically using tigervnc client on Windows), everything is initially OK, but:

1. As soon as any key is pressed, kglobalacceld starts eating 100% CPU. At this point there are no other issues.

2. If kglobalacceld is killed, the session is stable but obviously minus the shortcuts kglobalaccel provides (shortcuts within apps, such as tab-switching in Yakuake, still work, but the global shortcut to open/close Yakuake does not).

3. If kglobalacceld is then re-launched, CPU stays calm, but now keyboard input is completely deactivated: no keystroke has any effect at all. In addition there are some weird UI quirks that suggest it "sees" multiple modifier-keys as being stuck down: for example, scroll-wheel on any window or the panel changes its opacity. It basically renders the session unnavigable.

There are no such issues in a proper, SDDM-launched plasma-x11 session, or in a Fluxbox session in the Xvnc context.

This is not an entirely novel issue: kglobalaccel5 had exactly the same CPU-thrash behaviour under Xvnc, but the difference was that after killing and relaunching it, it behaved perfectly. In plasma6, there seems no way to get it to recover.

I'd welcome advice on how to dig into this issue. Since I've just upgraded from KDE5 I feel a fresh profile might be an idea, but now that ~/.kde is not all in one neat bundle that seems harder to do. I'm also not sure whether this is likely to be classifiable as a KDE bug, a KDE-not-using-systemd bug or even a tigervnc bug (pretty sure a bugreport has to be made as a next step from here).