Bug 442864 - System Settings freezes completely if 'Night Color' KCM is selected.
Summary: System Settings freezes completely if 'Night Color' KCM is selected.
Status: RESOLVED WORKSFORME
Alias: None
Product: systemsettings
Classification: Applications
Component: kcm_kscreen (other bugs)
Version First Reported In: 5.22.90
Platform: openSUSE Linux
: NOR major
Target Milestone: ---
Assignee: kscreen-bugs-null@kde.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-09-23 22:23 UTC by Lemuel Simon
Modified: 2021-11-19 00:23 UTC (History)
3 users (show)

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Description Lemuel Simon 2021-09-23 22:23:43 UTC 
SUMMARY
If System Settings is launched and the user navigates from 'Display and Monitor' -> 'Night Color', System Settings hangs for an extremely long time (2-5 minutes), before Night Color's settings screen is displayed. The user is forced to wait-it-out or kill it (as it looks frozen). It can be triggered every time the user switches between another KCM and Night Color.  

STEPS TO REPRODUCE
1. Open System Settings 
2. Go to 'Display and Monitor' -> 'Night Color'
3. Observe the freeze.

OBSERVED RESULT
System Settings freezes completely when selecting 'Night Color'.

EXPECTED RESULT
Night Color settings appear shortly after selecting it in System Settings.


SOFTWARE/OS VERSIONS
Operating System: openSUSE Leap 15.3
KDE Plasma Version: 5.22.90
KDE Frameworks Version: 5.86.0
Qt Version: 5.15.2
Kernel Version: 5.3.18-57-default (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-3320M CPU @ 2.60GHz
Memory: 7.6 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4000

ADDITIONAL INFORMATION
I'll also note that if Night Color is active, clicking on 'Display and Monitor' in System Settings would freeze the program and disable 'Night Color'. I wonder if it's vaguely related to this bug: https://bugs.kde.org/show_bug.cgi?id=428854  
 .I'll open another bug report for that. 

Running System Settings in the terminal doesn't give much information to work with (just deprecation warnings).
Comment 1 Nate Graham 2021-09-24 19:34:39 UTC 
Cannot reproduce.
Comment 2 Lemuel Simon 2021-09-24 19:38:17 UTC 
(In reply to Nate Graham from comment #1)
> Cannot reproduce.

You think I could get more information with strace? What does Night Color KCM do, when you click on it? Does it wait on the location data?
Comment 3 Lemuel Simon 2021-09-26 02:15:25 UTC 
Ok, I found something interesting. If I set the 'Activation Time' in the Night Color KCM to 'Sunset to Sunrise at Manual Location', it doesn't freeze at all.

However, clicking 'Detect Location' freezes System Settings as described in the initial bug report.

'Sunset to Sunrise at Current Location' also freezes System Settings, so I suspect that the act of 'finding my location' triggers this bug, every time.

I live in Trinidad and Tobago, so I don't know if Mozilla's Location API hates this area, given no one else has this issue...
Comment 4 Lemuel Simon 2021-11-19 00:23:00 UTC 
Since then, I have done a wipe and re-installation of '/' and preserved the '/home partition'. The bug is no longer reproducible in KDE 5.23.3, I'm certain that it was corruption on the root partition. I'll close the bug until I encounter it again. Thanks for your time.