FS#78536 - [powerdevil] Disable DDCUTIL until «Battery and Brightness» Plasma applet supports it

Attached to Project: Arch Linux
Opened by ratijas (ratijas) - Wednesday, 17 May 2023, 10:31 GMT
Last edited by Antonio Rojas (arojas) - Thursday, 18 May 2023, 18:21 GMT
Task Type Bug Report
Category Packages: Extra
Status Closed
Assigned To Antonio Rojas (arojas)
Felix Yan (felixonmars)
Architecture All
Severity Medium
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 3
Private No

Details

Description:

Apparently an experimental feature -DHAVE_DDCUTIL=ON has been turned on in powerdevil recently, with the reasoning that "Reenable ddcutil, all issues are supposed to be fixed now". Matter of fact, even if some underlying technical issues got fixed, external API is not ready to work with multiple brightness devices. This results in people with laptops and adjustable monitors loosing control over laptop's embedded screen brightness.

PowerDevil data source of "powermanagement" Plasma Data Engine only exposes a single pair or "Screen Brightness" int and "Screen Brightness Available" bool properties. Plasma «Battery and Brightness» applet only shown one Display Brightness slider.

Additional info:
* package version: 5.27.5-2
* config: -DHAVE_DDCUTIL=ON
* link to upstream bug reports: https://bugs.kde.org/buglist.cgi?quicksearch=powerdevil%20ddc&list_id=2367724

Steps to reproduce:
Upgrade Arch on a laptop, connect external monitor with DDC/CI supported, reboot.
This task depends upon

Closed by  Antonio Rojas (arojas)
Thursday, 18 May 2023, 18:21 GMT
Reason for closing:  Fixed
Additional comments about closing:  powerdevil 5.27.5-3
Comment by Lex Onderwater (ReLaxLex) - Wednesday, 17 May 2023, 11:57 GMT
I also ran into this issue. Next to that there appear to other issues with using ddcutil at the moment. Powerdevil service is failing directly after login:

<code>
08:10:42 systemd[3744]: Starting Powerdevil...
08:10:42 libddcutil[8175]: Initializing. ddcutil version 1.4.1
08:10:42 libddcutil[8175]: Library initialization complete.
08:10:48 systemd[3744]: plasma-powerdevil.service: start operation timed out. Terminating.
08:10:48 systemd[3744]: plasma-powerdevil.service: Failed with result 'timeout'.
08:10:48 systemd[3744]: Failed to start Powerdevil.
08:10:48 systemd[3744]: plasma-powerdevil.service: Scheduled restart job, restart counter is at 83.
08:10:48 systemd[3744]: Stopped Powerdevil.
08:10:48 systemd[3744]: Starting Powerdevil...
08:10:48 libddcutil[8186]: Initializing. ddcutil version 1.4.1
08:10:48 libddcutil[8186]: Library initialization complete.
08:10:49 kclockd[4360]: PowerDevil found on DBus
08:10:49 systemd[3744]: Started Powerdevil.
</code>

In the end it will start but only external monitor brightness can be adjusted. But even that is not working correctly when the screen dims, after resume the brightness is not restored. But can be adjusted to normal by running `ddcutil setvcp 10 100`.
Comment by Quang Ngô (ngoquang2708) - Wednesday, 17 May 2023, 14:44 GMT
I ran into this too, and I *accidentally* report it to upstream :D
https://bugs.kde.org/show_bug.cgi?id=469895
Comment by Antonio Rojas (arojas) - Thursday, 18 May 2023, 18:21 GMT
Note that this is no longer considered experimental and is enabled by default for Plasma 6, so you may want to push upstream for the issues to be fixed before release.

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