How to change the brightness and contrast on Fedora32 with wayland?

xgamma and xrandr only work in xorg, is there a command or program to adjust the brightness and contrast in gnome wayland ?
My computer is a desktop and monitor is a 2K LCD monitor, without backlight feature.

$ ls /sys/class/backlight/   # The output is empty.


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Changing the color temperature may temporarily solve my issue.

This is a temporary solution, not a final one.
By default, Windows10 has very good brightness and colors, while Fedora32 colors look pale and the white is especially harsh.
Guess the amdgpu open source driver still not good enough for Radeon RX 480.

Any idea is appreciated.


Usually, desktop monitors don’t provide the kernel a backlight interface directly, instead, you need to communicate via ddc protocol.

There is already a tool to do this GitHub - rockowitz/ddcutil: Control monitor settings using DDC/CI and USB

And for colors, this may relate to color management, you can try a color calibration.


Thanks for taking the time to help me.

Unfortunately, so far I can’t get this software to work properly.

I installed ddcuil from this repository:
dnf copr enable rockowitz/ddcutil

When I run ddcutil detect, I get an error message DDC communication failed.

Invalid display
   I2C bus:             /dev/i2c-3
   EDID synopsis:
      Mfg id:           CGC
      Model:            32CL36
      Serial number:    32CL36R2W0001
      Manufacture year: 2016
      EDID version:     1.3
   DDC communication failed

DDC communication failed over HDMI :