Bug 435968

Summary:	Kernel 5.11.14-200.fc33.x86_64 Causes KDE Digital Clock Display to Miss (Lag) 1 Second Every 2 to 3 Seconds
Product:	[Plasma] plasmashell	Reporter:	Shadders <richard.shadbolt>
Component:	Digital Clock widget	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	minor	CC:	kdelibs-bugs-null, nate, nicolas.fella
Priority:	NOR
Version First Reported In:	5.20.0
Target Milestone:	1.0
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Shadders 2021-04-20 18:31:53 UTC

SUMMARY
The digital clock in the system tray has a lag every 2 to 3 seconds, which causes 1 second display to be skipped. That is the display is 16:28:50, then 16:28:51, then a lag, then 16:28:53, so the time 16:28:52 has been missed, or not displayed.

Plasmashell --version is : 5.20.5

Using Fedora 33 and this occurs with kernel 5.11.14, but does NOT occur with kernel 5.11.13 and 5.11.12. 

STEPS TO REPRODUCE
1. Boot system with kernel 5.11.14 and once booted, examine the digital clock
2. Digital clock exhibits a lag and misses displaying the correct second count every 2 to 3 seconds
3. Reboot with kernel 5.11.12, or 5.11.13, and issue not encountered. 

OBSERVED RESULT
Lag issue experienced where times skip one of the seconds, caused by a lag/stall. 

EXPECTED RESULT
Digital clock should be updated every second

SOFTWARE/OS VERSIONS
Windows: N/A
macOS: N/A
Linux/KDE Plasma: Fedora 33, 5.20.5
(available in About System)
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.79.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Raised redhat bug report :
https://bugzilla.redhat.com/show_bug.cgi?id=1950975

This has occurred in previous Fedora version and kernel :
https://bugzilla.redhat.com/show_bug.cgi?id=1838790

Comment 1 Nate Graham 2021-04-21 18:53:31 UTC

If the problem only started happening with that kernel version, it sounds like it's a kernel bug. :) You'll want to report this to the kernel folks.

Comment 2 Shadders 2021-04-21 20:11:12 UTC

(In reply to Nate Graham from comment #1)
> If the problem only started happening with that kernel version, it sounds
> like it's a kernel bug. :) You'll want to report this to the kernel folks.

Hi Nate,
Thanks - i reported to redhat using their system - but, after discussion on a fedora forum, i retried the kernel and it did not occur. I am beginning to think it was packagekitd that runs at boot time that is causing the problem - i saw no high processor usage at the time it occurred (18 April 2021). I tried to implement the packagekitd manually, but since it had already run this morning, then nothing to do and it was processed in a second. 
Will wait until tomorrow and then report back if it occurs.
Thanks and regards,
Shadders.

Comment 3 Shadders 2021-04-23 09:55:03 UTC

To confirm, packagekitd is not running at boot time and the issue has not repeated.