Bug 438698 - Display brightness controls have no effect
Summary: Display brightness controls have no effect
Status: RESOLVED WORKSFORME
Alias: None
Product: Powerdevil
Classification: Unmaintained
Component: general (other bugs)
Version First Reported In: 5.20.5
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-06-15 22:21 UTC by Yevgeny Kosarzhevsky
Modified: 2022-01-04 16:41 UTC (History)
4 users (show)

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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