I forgot to say that I use XFCE.

Are you also using Xfce in Debian?

And is that the same kernel version as in your Debian system?

Do some benchmarks and find out for yourself. FWIW I use Arch with their linux-zen kernel, which has a similar patch set as the Liquorix kernels, but I can't notice any difference compared to the vanilla kernel version.

Did you check it was actually applied?

cat /proc/cmdline

You can also try acpi_backlight=video & acpi_backlight=native but they will only make a difference if you don't have an acpi_video0 directory in /sys/class/backlight/.

Do the xbacklight or brightnessctl packages work? You can bind keys to run those commands but if xev doesn't recognise the actual backlight keys then you'll have to use others.

For other backlight-related tips check the ArchWiki: https://wiki.archlinux.org/title/Backlight

I find GNOME to be the most effective in respect of backlight control with recalcitrant hardware so be sure to try https://wiki.archlinux.org/title/Backli … with_GNOME — the gdbus command is supplied by the libglib2.0-bin package.

Linux devuan 5.10.0-11-amd64 #1 SMP Debian 5.10.92-1 (2022-01-18) x86_64 GNU/Linux

This is the one I currently use. Although I mostly use xanmod one. It doesn't work there either. Btw, do you think xanmod would really improve this device's performance? It has atom N450 CPU 1.66 ghz.

Btw I found this article in debian wiki: https://wiki.debian.org/InstallingDebia … ung%20N150

They say add that acpi_backlight=vendor line to the grub, which I did. I am not a newbie btw, I did it right

Not a big problem for me though. I could live with this.

EDIT: find the kernel version with

uname -a

Which desktop is this? Is it Xfce?

Are the brightness keys recognised if you run

xev

^ That command is provided by the x11-utils package.

No, they are not recognized by xev

Are the brightness keys recognised if you run

xev

^ That command is provided by the x11-utils package.

In debian, fn brightness buttons do work properly.