I just migrated to kde 4.8 on kubuntu 11.10. I get random freezes of the whole desktop, everytime for 20+ seconds. Windows interaction continues to work.

Is there any way to diagnose the problem, a workaround? Or should i downgrade to 4.7 until a few point releases are out.

Are you using updater applets of some kind?

You mean like muon updater or something? (not sure how its called in the new kubuntu version). I most probably do, since its a default application. Do you think it is related? I wonder if i can remove it or not.
Its not a "Applet" or widget actually, its "just" an entry in the systemtray.

Applications that run within plasma that use blocking dbus calls are most likely the culprit: I had the same issue with Apper until I stopped its "checker" process.

There is a bug entry for this problem: https://bugs.kde.org/show_bug.cgi?id=287002

If you use Plasma NM you can try compiling the nm09 branch, which includes some code to prevent freezing the desktop.

If you use Apper you can also disable its new updates module like described in comment #81 from the bug entry above.

Thank you. i have to check if i use apper or not (im at work right now), but at least it would be a workaround. That a single app can block the desktop like that is a huge problem, specially because its nearly impossible to find out which one it is. I will report back if i could solve the problem.

Apper was indeed installed. I'm testing now with it removed. Since the freezes where at random intervals, i can't yet be sure that it is fixed. Thanks for your quick help!

FYI, you can just prevent "apper-sentinel" from running and that should be enough to prevent the freezes.

I found out that gmail-plasmoid freezes my panel/plasma. I fixed it by changing fetch mechanism to "kde" in gmail-plasmoid settings.

I hope this helps someone

If you installed this applet from kde-apps, then I would recommend filing a report with them.
Applets operating in Plasma Desktop are able to rely on KDE Network access methods always being available, and so therefore always use them.