Bug 438698

Summary:	Display brightness controls have no effect
Product:	[Unmaintained] Powerdevil	Reporter:	Yevgeny Kosarzhevsky <phaoost>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	isma.af, kde, kde, nate
Priority:	NOR
Version First Reported In:	5.20.5
Target Milestone:	---
Platform:	Other
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=438687
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Yevgeny Kosarzhevsky 2021-06-15 22:21:00 UTC

I cannot change display brightness using brightness keys or battery and brightness controls. They have no effect. OSD shows percentage but brightness remains the same.

I am able to change brightness from terminal using command:

sudo echo 30 > /sys/class/backlight/amdgpu_bl0/brightness

Comment 1 Nate Graham 2021-06-16 17:36:41 UTC

What CPU and chipset are you using? Something AMD, clearly, but which one in particular?

Comment 2 Yevgeny Kosarzhevsky 2021-06-16 17:51:56 UTC

This is AMD Ryzen 7 PRO 4750U with Radeon Graphics, AMD Renoir chipset. Lenovo P14s Gen 1

Comment 3 Nate Graham 2021-06-16 17:54:44 UTC

We have another report of someone with the same hardware in Bug 438687 experiencing the inhibition functionality not working properly. I wonder if these are problems specific to that chipset.

Needs someone more experienced in this than I am to investigate.

Comment 4 Yevgeny Kosarzhevsky 2021-06-17 15:01:41 UTC

I don't think this is related, as inhibition works correctly for me, I tried off/on inhibition and it worked as expected both times.

The problem is that I cannot find where can I configure path to /sys/class/backlight/amdgpu_bl0/brightness in powerdevil instead of the default one.

Comment 5 Yevgeny Kosarzhevsky 2021-06-27 08:54:28 UTC

After reading some internet I've fixed the issue by blacklisting thinkpad_acpi module. Screen backlight control keys worked for me after reboot then.

Comment 6 Ismael Asensio 2022-01-04 16:41:53 UTC

User reported the issue being fixed