Brightness is not working

Bugs / FRs / Support
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1

Hi,

Recently I installed hyperland on my laptop.

I have a OLED panel. When it boots up the screen brightness is on the full and when I decrease the brightness it is not working I had tried all the way brightnessctl, changed kernel parameter but didn’t worked.

Please help

2

I’m on arch, and have an oled monitor, but had never tried adjusting brightness…
After reading this, I tried adjusting my monitor brightness and have the same issue…
I’ll look into it and if I solve it I’ll post back here.

If you happen to sort it out before I post back, would you mind giving an update on what you did?

3

Ok, after some rabbithole digging, i have found that brightnessctl ddoesn’t support external monitors, without a kernel module for loading ddc/ci protocols, to load the backlight as a system device.

I’m not sure if your issue will be the same, as you are on a laptop, but depending on the interface you’re laptop manufacturer decided on, it may help?

People seemed to have varying degrees of success installing the ddcci-driver-linux-dkmsAUR package.

I noticed issues in the comments of the AUR package, regarding it being out of date, and not working on modern kernels, with the resolution being to use the ddcci-driver-linux-dkms-gitAUR package instead.

I don’t personally like running stuff from the AUR if i can help it, especially git versions (not pinned to a release), so i kept hunting.

After trying a few methods to get it working, i found the ddcutil package, which worked fine for me.

Here is the process i followed on Arch Linux. (If you are on a different distro, im sure it should be the same, except for possibly a slightly differently named package, and obviously a different package manager)

Install brightness support for external monitor

Required packages

  • ddcutil
  • read-edid (optional but allows better hardware detection)

Install (for arch linux)

sudo pacman -S ddcutil read-edid

Note: Needed a reboot to load the i2c-dev kernel module (automatically added by ddcutil)

Detect monitor id

ddcutil detect

output looks like:

Display 1 #<-- This is the ID for your monitor
   I2C bus:  /dev/i2c-4
   DRM_connector:           card1-DP-1
   EDID synopsis:
      Mfg id:               GSM - LG Electronics
      Model:                LG ULTRAGEAR+
      Product code:         23676  (0x5c7c)
      Serial number:        xxxxxxxxxxxx
      Binary serial number: 44407 (0x0000ad77)
      Manufacture year:     2024,  Week: 3
   VCP version:         2.1

Get current monitor brightness

# ddcutil <operation> <featurecode 10 = brightness> --display <diplayId>
ddcutil getvcp 10 --display 1

Outputs:

VCP code 0x10 (Brightness                    ): current value =   100, max value =   100

Set current monitor brightness

Set to 80% brightness

# ddcutil <operation> <featurecode 10 = brightness> <new brightness value> --display <diplayId>
ddcutil setvcp 10 80 --display 1

Set back to 100% brightness

# ddcutil <operation> <featurecode 10 = brightness> <new brightness value> --display <diplayId>
ddcutil setvcp 10 100 --display 1

Decrease brightness by 10%

# ddcutil <operation> <featurecode 10 = brightness> <new brightness value> --display <diplayId>
ddcutil setvcp 10 - 10 --display 1

Increase brightness by 10%

# ddcutil <operation> <featurecode 10 = brightness> <new brightness value> --display <diplayId>
ddcutil setvcp 10 + 10 --display 1