Arch Linux

ollosh

Member

Registered: 2022-09-20

Posts: 51

[SOLVED] Sudo needs to be used to change brightness all of a sudden

All of a sudden I have to use sudo to edit /sys/class/backlight/amdpgu_bl0/brightness even though I do have a udev rule to enable video group to edit it.
As I had an issue with https://bbs.archlinux.org/viewtopic.php … 8#p2079038 I've removed acpi_backlight=video line from my grub config.
For a while everything was working fine, but all of a sudden I have to use sudo to do that. What could be an issue?

kernel: 6.1.12-arch1-1
udev rule:

ACTION=="add", \
SUBSYSTEM=="backlight", \
RUN+="/bin/chgrp video /sys/class/backlight/%k/brightness", \
RUN+="/bin/chmod g+w /sys/class/backlight/%k/brightness"

Last edited by ollosh (2023-02-28 18:38:22)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,653

Re: [SOLVED] Sudo needs to be used to change brightness all of a sudden

As a sanity check, what are the output of groups 
and of ls -l /sys/class/backlight/amdpgu_bl0/brightness

Last edited by ewaller (2023-02-26 19:02:30)

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ollosh

Member

Registered: 2022-09-20

Posts: 51

Re: [SOLVED] Sudo needs to be used to change brightness all of a sudden

Actually I had a typo in the post, it's supposed to be /sys/class/backlight/amdgpu_bl0/brightness

Anyways here are the logs
groups:

network power rtkit docker video storage wheel ollosh

ls -l:

-rw-r--r-- 1 root root 4096 Feb 26 20:31 /sys/class/backlight/amdgpu_bl0/brightness

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,653

Re: [SOLVED] Sudo needs to be used to change brightness all of a sudden

That shows the udev rule did not change the group or the group permissions for that pseudo file.
Any clues in the Journal as to what may have happened when it tried?

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Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
The shortest way to ruin a country is to give power to demagogues.— Dionysius of Halicarnassus
---
How to Ask Questions the Smart Way

ollosh

Member

Registered: 2022-09-20

Posts: 51

Re: [SOLVED] Sudo needs to be used to change brightness all of a sudden

Ok I feel kind of stupid now. I'm using stow for my configurations and I used it also for udev rules and guess what for this or that reason symlinks weren't there anymore Just stowing again fixed my issue