Bug 500843 - "Power Management settings could not be loaded" after recent update (6.3.1.1)
Summary: "Power Management settings could not be loaded" after recent update (6.3.1.1)
Status: RESOLVED UPSTREAM
Alias: None
Product: plasmashell
Classification: Plasma
Component: Power management & brightness (show other bugs)
Version: 6.3.1
Platform: Arch Linux Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-02-27 22:59 UTC by JJ
Modified: 2025-03-13 18:12 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed In: ddcutil 2.2.1
Sentry Crash Report:


Attachments
The error message displayed opening Power Management in settings. (43.55 KB, image/png)
2025-02-27 22:59 UTC, JJ
Details
powerdevil systemd status (88.33 KB, image/png)
2025-02-28 12:26 UTC, Victor
Details

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Description JJ 2025-02-27 22:59:25 UTC
Created attachment 178960 [details]
The error message displayed opening Power Management in settings.

SUMMARY
After a recent update (checking my package manager: 6.3.1.1, though I could have been updating it from 6.2.x) my Power Management settings are all messed up. The immediate effect is that:
1) my battery indicator applet disappears from the dock
2) my laptop increase/decrease screen brightness keys do not work
3) opening "Power Management" in settings displays a screen saying "Power Management settings could not be loaded" "The Power Management service appears not to be running."

This is the same behavior as found here: https://old.reddit.com/r/kde/comments/1iov47k/. However, I do not know what "Klassy" is or have it installed, and I am on Arch Linux, not Fedora.

STEPS TO REPRODUCE
Unreproducible. Even triggering the bug is not consistent. My indicator comes back on reboot, but disappears later, and I have not quite figured out what triggers it yet.

I'd be grateful for any advice in debugging and tracking this down... currently I have to run `acpi -i` in the terminal every so often to make sure my laptop does not crash.

OBSERVED RESULT
Discussed in Summary.

EXPECTED RESULT
The battery service to function normally.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.12.16-1-lts (Arch Linux)
KDE Plasma Version: 6.3.1
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2

ADDITIONAL INFORMATION
Comment 1 Nicolas Fella 2025-02-28 11:31:41 UTC
Please show the output of running "systemctl --user status plasma-powerdevil.service" while it's broken
Comment 2 Victor 2025-02-28 12:26:29 UTC
Created attachment 178975 [details]
powerdevil systemd status

I'm having the same problem with it, but in my case it's on the Desktop, whenever my screen comes back from sleep, Powerdevil stops working.
Comment 3 Nate Graham 2025-02-28 17:00:47 UTC
Let's let JJ respond before debugging further to make sure that both of you are hitting the same issue (Viktor's issue is an assert in DDC code).
Comment 4 Victor 2025-02-28 17:50:52 UTC
(In reply to Nate Graham from comment #3)
> Let's let JJ respond before debugging further to make sure that both of you
> are hitting the same issue (Viktor's issue is an assert in DDC code).

Yes, sorry, it's the first time I've sent a report and I found it a bit confusing, do you think I should do a separate report?
Comment 5 Nate Graham 2025-02-28 20:21:57 UTC
If JJ has the same assert in DDC that you have, then there's no need since your issue is the same. If not, then yeah, make a new bug report for your issue.
Comment 6 Victor 2025-02-28 20:26:56 UTC
I did some tests and it seems that this is related to a modified EDID so that I can force the use of pixel format RGB.

I undid the changes and so far I haven't had the error again.
Comment 7 Victor 2025-02-28 20:49:56 UTC
(In reply to Victor from comment #6)
> I did some tests and it seems that this is related to a modified EDID so
> that I can force the use of pixel format RGB.
> 
> I undid the changes and so far I haven't had the error again.

Nah, just happened again :( i'll wait for JJ and then open a new bug report if needed 

Thanks
Comment 8 JJ 2025-02-28 22:59:34 UTC
I rebooted shortly after reporting, and have not run into it again since - I'll update here when it next occurs.
Comment 9 19484 2025-03-02 01:35:40 UTC
Restoring default fonts can avoid crashes I suspect and font settings related
Comment 10 JJ 2025-03-13 03:20:33 UTC
I have (finally) re-triggered this bug. It has something to do with external monitors. The output of `systemctl --user status plasma-powerdevil.service` is below:

```bash
○ plasma-powerdevil.service - Powerdevil
     Loaded: loaded (/usr/lib/systemd/user/plasma-powerdevil.service; static)
     Active: inactive (dead) since Wed 2025-03-12 20:16:08 PDT; 2min 52s ago
   Duration: 3d 1h 29min 3.794s
 Invocation: e01035822b3544d19a9d159ddab777d0
    Process: 1203 ExecStart=/usr/lib/org_kde_powerdevil (code=killed, signal=TERM)
   Main PID: 1203 (code=killed, signal=TERM)
   Mem peak: 13.3M (swap: 7.1M)
        CPU: 1min 1.696s

Mar 12 20:16:08 arch org_kde_powerdevil[1203]: [346881] Emitting DDCA_Display_Status_Event[264544.462:  DDCA_EVENT_DISPLAY_CONNECTED, card1-HDMI-A-1, dref: DDCA_Display_Ref[11], io_path:/dev/i2c-1, ddc working: true]
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: [346881] libddcutil callback thread 0x7ab908014220 started
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: [346881] Started 1 event callback thread(s)
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: [346882] (ddc_open_display) Delay before rechecking attribute status: Slept for 1000 millisec
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: [346882] Assertion failed: "bus_info" in file ddc_packet_io.c at line 266
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: QtDBus: cannot relay signals from parent QObject(0x653488af7ab0 "") unless they are emitted in the object's thread QThread(0x653488a4f080 "Qt mainThread"). Current thread is QThread(0x653488bc3118 "").
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: [346882] Watch thread terminated.
Mar 12 20:16:08 arch org_kde_powerdevil[1203]: QMutex: destroying locked mutex
Mar 12 20:16:08 arch systemd[951]: plasma-powerdevil.service: Consumed 1min 1.696s CPU time, 13.3M memory peak, 7.1M memory swap peak.
```
Comment 11 Victor 2025-03-13 11:45:21 UTC
Yea it looks like we share the same error "assertion failed"
Comment 12 Nate Graham 2025-03-13 18:12:09 UTC
this should be fixed in ddcutil 2.2.1; please try again once that reaches your distro!