Brightness controls no longer work

[Xabifk]

xbacklight changes the the value in /sys/class/backlight/faustus/brightness but my screen is only affected by changes in /sys/class/backlight/amdgpu_bl0/brightness
If I remove faustus, xbacklight works as intended.

I use an Asus FX505DT

$ uname -a
Linux Maximegalon 5.6.6-arch1-1 #1 SMP PREEMPT Tue, 21 Apr 2020 10:35:16 +0000 x86_64 GNU/Linux
$ modinfo faustus
filename:       /lib/modules/5.6.6-arch1-1/extra/faustus.ko.xz
license:        GPL
description:    Backport of Asus Generic WMI Driver
author:         Corentin Chary <corentin.chary@gmail.com>, Yong Wang <yong.y.wang@intel.com>
srcversion:     BD28779796F3429299C4D1F
depends:        wmi,sparse-keymap,rfkill
retpoline:      Y
name:           faustus
vermagic:       5.6.6-arch1-1 SMP preempt mod_unload
parm:           let_it_burn:Disable DMI check, force load (bool)

I also made the changes that make compilation possible on my kernel version.

[hackbnw]

Could you try updating? I've merged linux mainline. The backlight should behave exactly the same as in default platform driver asus_wmi.

[Xabifk]

It doesn't seem to work. I don't know if it's a configuration problem on my part.\n xbacklight uses faustus, but the rest of the system does not

[hackbnw]

Ok, don't know what the issue is with xbacklight, fun thing being I don't have asus backlight device at all. It looks like you could try providing correct configuration in Xorg config: https://wiki.archlinux.org/index.php/Backlight#xbacklight

Also I have found that it always reverts to backlight type "vendor" if you don't have CONFIG_ACPI_VIDEO enabled, I don't known if you configured the kernel yourself or is it some standard OS kernel?

$ cat /boot/config-<version>| grep CONFIG_ACPI_VIDEO
CONFIG_ACPI_VIDEO=m

Either way this should also be exactly the same when you use default driver.

[Xabifk]

I don't have a config file there. I really don't know what happened, it just stopped working after a kernel update - I think

As I'm the only one affected by this you can close the issue if you want. I'll come back with a solution if I found one. For now I just manually write to /sys/class/backlight/amdgpu_bl0/brightness

[ferretwithaberet]

Same issue for me on my FX505DT.

Edit: Forgot to mention mine is called amdgpu_bl1, also I tried to do /etc/X11/xorg.conf.d/20-amdgpu.conf

section "Device"
     Identifier "AMD"
     Driver "amdgpu"
     Option "Backlight" "faustus"
EndSection

which did not work, but same as Xabifk, I can set the value in amdgpu_bl1/brightness to control it