plasmashell 100% cpu on screen lock

[Martin Tang]

When the screen is locked, plasmashell 100% a CPU core because of a misbehaving IM icon in the system tray.

By default, "set my status to away when the screen saver is activated" is enabled in IM settings, and the IM icon is also shown on the plasma panel. When the screen is locked, the IM status is set to away and the icon changes (at this point I can't see what's happening behind the lock screen). ssh'ing in, I can see that kwin/plasmashell/xorg are pegging a single core, probably because the icon is rapidly updating or something.

Workaround:
1. Disabling "set my status to away when the screen saver is activated" prevents the issue from happening
2. Hiding the IM icon from the system tray also works.

Affected packages:
plasma-workspace 4:5.2.1-0ubuntu3
kde-telepathy 0.9.0ubuntu1

[Martin Tang (infinitesimal)]

Actually, this can also be (inconsistently) triggered by manually switching the IM status around (either from the contact list or from the tray icon). I only use Google Talk, and certain statuses always trigger high CPU usage, some statuses never trigger high CPU usage, and some are inconsistent.

Never high CPU usage:
Available

Always high CPU usage:
Busy

Sometimes:
Everything else

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[DimanNe (dimanne)]

I have recently encountered this problem again at my notebook.

System info:
plasmashell 5.5.5
OS: Kubuntu 16.04
Also, I have two (physical) monitors, and I noticed this problem began to arise after I detached/attached notebook from dock station or after hibernation

Backtraces, perf top:
I ran "top -H" and it said there are two threads on my system, which are eating CPU - plasmashell and Xorg, so here is "hottest" backtraces of these threads collected with
perf top -t 3136 -d 5 --call-graph dwarf (where 3136 is thread Id from top output)
Thread of plasmashell - http://pastebin.com/GPMkrWz8 (see text after RAW Paste Data)
Thread of Xorg - http://pastebin.com/ZH0x7F7i (see text after RAW Paste Data)

[Scarlett Gately Moore (scarlettmoore)]

This bug is very old, if it remains an issue please update the bug with info from a supported release.