PlasmaShell and Compositing Problems

[vtpoet]

https://bugs.kde.org/show_bug.cgi?id=361211

https://bugs.launchpad.net/ubuntu/+s...a/+bug/1510959

http://askubuntu.com/questions/58492...issing-letters

https://bugs.launchpad.net/ubuntu/+s...4/+bug/1311488

I experienced none of these problems on any of my systems until upgrading to 16.04. I would recommend steering clear of Kubuntu 16.04 for the foreseeable future (if your current installation is working) or until KDE devs, at the very least, acknowledge the problem and show some effort toward solving it.

Not sure what's causing this: a regression in the kernel or kde itself... but as far as the end user is concerned, it doesn't matter.

[Teunis]

To take my 4 computer example, on Intel and nVidia I have not seen these problems.

[jlittle]

... I experienced none of these problems on any of my systems until upgrading to 16.04...

Those problems say "corrupt font cache" to me, but surely others have had the same thought. Such can be caused by using sudo with GUI programs, you might check that out.

Regards, John Little

[vtpoet]

Those problems say "corrupt font cache" to me, but surely others have had the same thought. Such can be caused by using sudo with GUI programs, you might check that out.

Regards, John Little

Okay, that's easy to test. I'll try rebuilding the font cache. See what happens.

[vtpoet]

And I found another report of this bug:

http://askubuntu.com/questions/60644...-kubuntu-14-10

[Teunis]

I guess I've been lucky...

With 'Compositing' in the title of this posting I have to ask is this problem only present when Desktop Effects is switched on?

Shift+Alt+F12 will toggle it.

[vtpoet]

I guess I've been lucky...

With 'Compositing' in the title of this posting I have to ask is this problem only present when Desktop Effects is switched on?

Shift+Alt+F12 will toggle it.

Yeah, I've tried that to no avail. I've also tried restarting plasmashell. The only "workaround" is to restart the system. And *that* makes me wonder about the real source of this problem. It only occurs after I've suspended the system (on one system). On the System76 laptop, I often don't get that far. The window decorations will disappear and no amount of twiddling will get me back a usable system until I've rebooted.

Again, I have to stress, both these systems worked beautifully through three iterations of Kubuntu -- that is, until 16.04.

[vtpoet]

The good news is that the "missing letters" issue appears to have gone away---updates? I don't know...

The bad news is that I think I've narrowed down the bug causing all my suspend/compositing/plasmashell problems (which might have been related to the missing letters(?):

https://forum.kde.org/viewtopic.php?...spend+problems

https://bugs.kde.org/show_bug.cgi?id=356394

https://bugs.kde.org/show_bug.cgi?id=357551

So, we can confirm that I'm not insane and also that this might to be fixed with QT 5.6. When is the Kubuntu Backport PPA going to be available to Xenial? Or NEON? I'm ready for this bug/mess to go away.

[vtpoet]

Good news. I switched from Kernel 4.4x to 4.2x and all my problems magically vanished. Every last one of them. Based on this link:

https://wiki.ubuntu.com/Kernel/MainlineBuilds

Whatever this kernel regression is, it played some nasty games on my system.