[clug] KDE desktop kinda freezing

Robert Edwards bob at cs.anu.edu.au
Sat Feb 8 21:26:09 UTC 2020

On 9/2/20 12:11 am, Tony Lewis via linux wrote:
> I've been running the current Kubuntu version for the last few months, 
> and I find that every so often it freezes.  I'm trying to find out what 
> causes it and what I can do to fix it.
> The symptoms are:
>   * the mouse cursor moves freely, but no actions do anything to windows
>   * the keyboard does nothing
>   * the desktop doesn't change, including panels with clocks in it
>   * audio keeps playing (e.g. spotify)
>   * I cannot successfully save my Windows VM from the command line (more
>     below)
> I can switch to text consoles, log in and do stuff.  Nothing unusual is 
> showing up in htop (i.e. no excessive disk or CPU usage, no excessive 
> memory, no meaningful swapping).
> Things I've tried:
>   * killing processes like the obvious contenders (for me) of Firefox,
>     Thunderbird and VirtualBox
>   * killing and restarting plasmashell
>   * looking for other desktopy processes and killing them
>   * starting an xterm from the command line into the desktop -
>     'DISPLAY=:0.0 xterm' - from the command line it looks like it
>     starts, but no change to the desktop
> The worst part of this is any loss of documents in my work Windows VM, 
> where I am not diligent in saving documents sometimes.  I try the 
> 'savestate' command, which works under normal circumstances, but under 
> this frozen desktop scenario, it doesn't complete; it freezes up 
> somewhere between 90 and 100% even if I leave it for hours.
> Eventually I have to pretty much just restart.
> What can I do to try and debug?
> Tony

Hi Tony,

Not sure about KDE/plasmashell, but most of your symptoms are not
inconsistent with the X focus remaining on a broken alert panel which
may be hidden under other windows. I think your "looking for other
desktopy processes and killing them" should have resolved this -
how confident are you that you have found all of them?

One thing to try might be to start another GUI in another Virtual
Terminal (doesn't even have to be KDE), and maybe run VirtualBox
in there for a while. If the issue is with the graphics driver/
hardware, then likely both desktops will freeze - if it is only
with KDE, then only the KDE one should have issues. This won't tell
you what the problem is, but will assist you in finding the fault.
Copy-pasting between desktops is problematic, but using the file
system should provide some work-arounds for that.

One of many links to help you do it:

I hope you are able to pin the culprit.

Bob Edwards.

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