Dell XPS 9570 Backlight Broken

The brightness on gnome is controllable, but it does not affect the display brightness on the screen which seems to be stuck on maximum brightness.
The brightness is set to minimum after the laptop has awoken from sleep and cannot be changed.
This is a new installation, I also had some GPU driver issues which seem to be resolved however I’ve just seen the nvidia post, so that might be the cause of the issue?

Here’s some system information.

Linux manjaro 5.9.16-1-MANJARO #1 SMP PREEMPT Mon Dec 21 22:00:46 UTC 2020 x86_64 GNU/Linux
ls  /sys/class/backlight                                         
intel_backlight
sudo mhwd                                                        
[sudo] password for user: 
> 0000:01:00.0 (0302:10de:1c8c) Display controller nVidia Corporation:
--------------------------------------------------------------------------------
                  NAME               VERSION          FREEDRIVER           TYPE
--------------------------------------------------------------------------------
video-hybrid-intel-nvidia-prime            2020.11.30               false            PCI
video-hybrid-intel-nvidia-390xx-bumblebee            2020.11.30               false            PCI
          video-nvidia            2020.11.30               false            PCI
    video-nvidia-390xx            2020.11.30               false            PCI
           video-linux            2018.05.04                true            PCI


> 0000:00:02.0 (0300:8086:3e9b) Display controller Intel Corporation:
--------------------------------------------------------------------------------
                  NAME               VERSION          FREEDRIVER           TYPE
--------------------------------------------------------------------------------
video-hybrid-intel-nvidia-prime            2020.11.30               false            PCI
video-hybrid-intel-nvidia-390xx-bumblebee            2020.11.30               false            PCI
           video-linux            2018.05.04                true            PCI
     video-modesetting            2020.01.13                true            PCI
            video-vesa            2017.03.12                true            PCI
cat /etc/default/grub
...
Only changed parameters are shown
GRUB_CMDLINE_LINUX_DEFAULT="aspi_override=1 acpi_backlight=intel_backlight"

I’ve also tried these parameters acpi_backlight=vendor acpi_backlight=native acpi_backlight=video acpi_backlight=intel_backlight then ran the command sudo update-grub

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Output of journalctl --all | grep backlight

Feb 12 20:10:03 manjaro /usr/lib/gdm-x-session[1497]: (**) intel(0): Option "Backlight" "intel_backlight"
Feb 12 20:10:03 manjaro /usr/lib/gdm-x-session[1497]: (**) intel(0): Found backlight control interface intel_backlight (type 'raw') for output eDP1
Feb 12 20:10:08 manjaro /usr/lib/gdm-x-session[979]: (EE) intel(0): Failed to set backlight intel_backlight for output eDP1, disabling

You have too start with the BIOS. Disable any Legacy booting, disable Fastboot and if you see a setting for CSM turn it off. Then report.

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Checked the BIOS and Legacy booting and Fastboot is disabled, cannot find an option for CMS.

Found an option in the BIOS to change the display brightness which is a temporary fix but still cannot use the options on gnome.

Next, boot off of your usb installer and see if it works on the live ISO.

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Tested on live ISO, same issue happens

Next, I would remove the entries from the kernel in grub and upgrade to kernel 5.10 series using Manjaro Settings Manager.

Out of curiosity, does your media keys work?

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The kernel upgrade fixed the backlight! However, it seems to have broken the night light.

And yes media keys do work.

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Good to hear!

As for the nightlight, I do not know… I don’t use Gnome and that is more of a specific issue to Gnome. Maybe mark this issue as solved and open a new issue or search if there is already a fix.

Cheers

Thanks for your help, even the nightlight seems to have fixed itself after another reboot.

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