Root password request when changing screen brightness

[yasarciv]

Hello. Root password is requested while changing the screen brightness. Is this a problem with my system or is this the expected behavior? If this is the expected behavior, why is it necessary? Will the normal user not be able to change the screen brightness without root permission?
Lxqt version: 0.16
Qt version: 5.15.1
Kernel: 5.9.10

[tsujan]

No, it doesn't require root password.

Closing because it isn't reproducible but you could add comments; also, it'll be reopened if someone can reproduce it.

[yasarciv]

When I try to change the screen brightness, it opened this window
https://i.imgur.com/E7w6LXe.jpg

[yasarciv]

Terminal output is:
yasar [ ~ ]$ lxqt-backlight_backend --dec 5
Couldn't open /sys/class/backlight/acpi_video0/brightness: Permission denied
yasar [ ~ ]$

[tsujan]

I don't know about lxqt-backlight_backend but lxqt-config-brightness is the tool for changing brightness under LXQt, whether with its GUI or with command-line -- see lxqt-config-brightness --help.

[yasarciv]

There is the same situation. The terminal output when I press the Cancel button:

yasar [ ~ ]$ lxqt-config-brightness -s 60
Error executing command as another user: Not authorized

This incident has been reported.
yasar [ ~ ]$

[tsujan]

It works here, with two laptops, and I'm sure it works for others too.

I'm afraid you need to find the hidden factor that makes your system have a different behavior.

[yasarciv]

Yes, I guess so. Thanks.

[tsujan]

Please tell us if you find it!

[yasarciv]

Hello again. I am tried to test this issue on Void Linux. But there is the same situation.

[yasarciv]

The common property here is that both Void and our distribution are not systemd.
Is systemd required for Lxqt?

[yasarciv]

Also, when the Lxqt-0.14 version was installed on Void Linux, it did not ask for the password, at the moment, the system update started asking the password with the Lxqt-0.16 version.

[tsujan]

Is systemd required for Lxqt?

That may be the reason. @luis-pereira, does the lack of systemd necessitate a password prompt for changing backlight?

at the moment, the system update started asking the password

Your system update is not related to LXQt.

[yasarciv]

Complete system update, include Lxqt.

[tsujan]

I meant that if your system update asks for password, it is not related to LXQt.

[tsujan]

Never mind, I think the misunderstanding was caused by your English.

Anyhow, we should wait for @luis-pereira to know about the password prompt without systemd.

[yasarciv]

I am sorry for my bad English. What I mean is the password request for the screen brightness adjust.

[yasarciv]

The problem on Void Linux is caused by the login manager. When I logged in with lightdm or sddm it didn't ask password while changing brightness. But when I logged in with lxdm installed by default, it asked password while changing brightness.

I will search for the source of the problem and try to solve the solution in our own distribution. Thank you for your interest.