Brightness slider not working on Fedora Workstation 42 (GNOME 48)

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Hi everyone,

I’m using Fedora Workstation 42 (GNOME 48) on a laptop with Intel + NVIDIA hybrid graphics (RTX 4050).
The brightness slider in the top panel moves, but it doesn’t actually change the screen brightness.

Here’s what I’ve observed:

  • I can manually change brightness with:
brightnessctl set 100%
brightnessctl set 50%

or directly with:

sudo sh -c 'echo 1 > /sys/class/backlight/acpi_video1/brightness'
sudo sh -c 'echo 10 > /sys/class/backlight/acpi_video1/brightness'
  • and the screen brightness really changes.
  • /sys/class/backlight/ shows: acpi_video0, acpi_video1, and acpi_video2.
    Only acpi_video1 affects brightness.
  • gnome-settings-daemon version is 48.1.

The brightness slider still doesn’t work even though hardware control works fine via terminal commands.
Any idea how to fix this on Fedora 42 / GNOME 48?

Output of inxi -Gxx:

Graphics:
  Device-1: Intel Alder Lake-P Integrated Graphics
    vendor: Acer Incorporated ALI driver: i915 v: kernel arch: Xe ports:
    active: eDP-1 empty: DP-1,DP-2 bus-ID: 00:02.0 chip-ID: 8086:4626
  Device-2: NVIDIA AD107M [GeForce RTX 4050 Max-Q / Mobile]
    vendor: Acer Incorporated ALI driver: nvidia v: 580.95.05 arch: Lovelace
    pcie: speed: 16 GT/s lanes: 8 ports: active: none
    empty: DP-3,HDMI-A-1,eDP-2 bus-ID: 01:00.0 chip-ID: 10de:28a1
  Device-3: Chicony ACER HD User Facing driver: uvcvideo type: USB rev: 2.0
    speed: 480 Mb/s lanes: 1 bus-ID: 3-6:4 chip-ID: 04f2:b76f
  Display: wayland server: Xwayland v: 24.1.8 compositor: gnome-shell
    v: 48.5 driver: gpu: i915 display-ID: 0
  Monitor-1: eDP-1 model: ChiMei InnoLux 0x1521 res: 1920x1080 dpi: 142
    diag: 394mm (15.5")
  API: OpenGL v: 4.6 vendor: intel mesa v: 25.1.9 glx-v: 1.4 es-v: 3.2
    direct-render: yes renderer: Mesa Intel Graphics (ADL GT2)
    device-ID: 8086:4626 display-ID: :0.0
  API: Vulkan v: 1.4.313 surfaces: N/A device: 0 type: integrated-gpu
    driver: mesa intel device-ID: 8086:4626 device: 1 type: discrete-gpu
    driver: nvidia device-ID: 10de:28a1 device: 2 type: cpu
    driver: mesa llvmpipe device-ID: 10005:0000
  API: EGL Message: EGL data requires eglinfo. Check --recommends.
  Info: Tools: api: glxinfo,vulkaninfo gpu: nvidia-settings,nvidia-smi
    x11: xdriinfo, xdpyinfo, xprop, xrandr

Thanks in advance!

1 Like
2

Hey everyone,

I managed to fix the issue. It seems the system was defaulting to the wrong backlight interface.

Forcing the kernel to use the native backlight driver solved the problem completely. If you’re having the same issue, this command might work for you too:

sudo grubby --update-kernel=ALL --args="acpi_backlight=native"

Just run that in the terminal and then reboot.

Hope this helps someone else!