[BUG] Brightness control not working on V5 with hybrid graphics, used to work on V4

[MathisP75]

Submission checklist

• I have searched existing issues and confirmed this is not a duplicate.
• I am using the latest available version of Noctalia.

Bug description

The backlight controls now adjust backlight device nvidia_0 instead of intel_backlight, and there seems to be no way of changing it. It used to work fine in V4.

Steps to reproduce

1. Adjust backlight, either through IPC or GUI, on Nvidia + Intel laptop

Expected behavior

Internal screen backlight should change

Actual behavior

Internal screen backlight does not change

Logs / error output

Noctalia version

5.0.0.r2793.g8346d3ce5-1

Compositor

Hyprland

Distribution

Arch-based

Environment information

Installed from AUR

Hybrid Nvidia + Intel system

Additional context

It seems like #1899 fixed it in V4, but it does not seem to have been ported yet.

[MathisP75]

Oh, I see this is on the roadmap.

Feel free to close this in case it's tracked elsewhere.

[Ly-sec]

As mentioned in discord this commit hopefully solves that issue f616e7d. Sadly I am unable to test it at all.

[MathisP75]

Just tested, it works now!

[ppenguin]

It doesn't work on devices which somehow report the wrong default, such as Asahi on MBP M1, which resolves to the touchbar instead of the display.

In V4 this was solved by #1899, with the following (nix) config:

    programs = {
        noctalia.settings.brightness.backlightDeviceMappings = [
          {
            output = "eDP-1";
            device = "/sys/class/backlight/apple-panel-bl";
          }
          {
            output = "touchbar"; # dummy output, not actually reported by niri
            device = "/sys/class/backlight/228600000.dsi.0"; # touchbar
          }
        ];
    };

Probably that solution should be carried over to V5.

EDIT: PR here #3160