Brightness shortcut keys change contrast/gamma, not brightness.

[manaskarekar]

I apologize if this is not the right place to bring this up. I am using Lubuntu 20.04 LTS.

The Shortcut application is bound to lxqt-config-brightness instead of some variation of lxqt-backlight_backend.

The first command changes the gamma/contrast, not the brightness. The second one changes the brightness (at least as I understand it in this context).

Possible Solution

Binding the correct command in the shortcuts application should be able to address this but there are two issues. With that:

1. lxqt-backlight_backend requires root permissions, but you can use pkexec lxqt-backlight_backend --inc[--dec].
2. Neither of these seems to work if bound from the shortcut app. I tried enclosing the command in quotes but it wasn't saved with quotes in globalkeyshortcuts.conf. I couldn't manually save that in the file either.

I also tried creating an alias for the command and assigning that to the shortcut, but that doesn't work either.

All the lxqt-backlight_backend based solutions work from the terminal, but can't get the shortcuts to work.

The Brightness Settings application does the right thing.

Steps to Reproduce (for bugs)

Fire up the "Global Actions Manager" (the shortcuts app) and use brightness up shortcut to see the contrast changing. This is not what happens if you increase the brightness using the brightness application.

Context

This is a very basic feature and a major regression coming from LXDE. This feature is used (by me) multiple times a day and there is no clear way to set up the shortcut.

System Information

• Distribution & Version: Lubuntu 20.04 LTS.
• Kernel: 5.4.0-26.
• Qt Version: 5.12.8
• liblxqt Version: 0.14.1
• lxqt-build-tools Version: Unsure
• Package version: Unsure

I'd be more than happy to help! Apologies if I'm missing something obvious somewhere.

[mmortal03]

@manaskarekar , was this fixed? I'm on Debian 12 using LXQt, and if I add the following keyboard shortcut command in "Global Actions Manager" to my relevant key:
pkexec lxqt-backlight_backend --inc

It works for me.

Edit: One minor point, before I could run that, I did have to install: liblxqt-backlight-helper, which may also require liblxqt1

[manaskarekar]

@mmortal03 Thanks for mentioning your solution. I'll try it if I ever move back to LXQt!

I quit pursuing this after a while and moved on to XFCE (for various reasons). I would love to come back and try LXQt again but it's hard to move away from a working setup.

[mmortal03]

Speaking of, the whole reason I even went looking for this was because, unlike Xfce, LXQt didn't have most of the keyboard Fn keys implemented for my laptop model. (A very old Samsung laptop, with only the volume Fn keys working by default.)

I tested most of the other desktop environments offered with Debian (Xfce, Cinnamon, GNOME, and Plasma) and the Fn keys all just work™ in those! My reply is a side effect of LXQt's minimalism, lol.

[manaskarekar]

Speaking of, the whole reason I even went looking for this was because, unlike Xfce, LXQt didn't have most of the keyboard Fn keys implemented for my laptop model. (A very old Samsung laptop, with only the volume Fn keys working by default.)

I tested most of the other desktop environments offered with Debian (Xfce, Cinnamon, GNOME, and Plasma) and the Fn keys all _just work_™ in those! My reply is a side effect of LXQt's minimalism, lol.

I hear you, I loved that minimalism on LXDE and used it for well over 10 years everywhere. With the move to LXQt, the polish was lost (as you would expect for such a large undertaking).

I'll try it out another time for sure.