ddcutil commands to control dell U2520D

ddcutil_dell_U2520D.sh

#!/bin/bash

# Get Display Mode
# sudo ddcutil getvcp 0xdc --bus=9 --verbose

# Set Display Mode to movie
# sudo ddcutil setvcp 0xdc 0x03 --bus=9 --verbose

# Set Display Mode to standard
# sudo ddcutil setvcp 0xdc 0x00 --bus=9 --verbose

# Set Display Mode to comfortview
# sudo ddcutil setvcp 0xf0 0x0c --bus=7 --verbose

# Set Display Mode to game preset
# sudo ddcutil setvcp 0xdc 0x05 --bus=7 --verbose

# Get Display Brightness
# sudo ddcutil getvcp 0x10 --bus=9 --verbose

# Set Display Brightness
# sudo ddcutil setvcp 0x10 25 --bus=9 --verbose

# Set Display input to usb-c
# sudo ddcutil setvcp 60 0x1b --bus=8 --verbose

# Set Display input to DP
# sudo ddcutil setvcp 60 0x0f --bus=8 --verbose

# Set Display input to HDMI
# sudo ddcutil setvcp 60 0x11 --bus=8 --verbose

# Get serial numbers
# sudo ddcutil detect | grep 'Serial number'

dell_monitors=("YOUR_SERIAL_NUMBER" "ANOTHER_SERIAL_NUMBER")

dell_brightness () {
    for sn in "${dell_monitors[@]}"; do
      sudo ddcutil setvcp 0x10 "$1" --sn="${sn}"
    done
}

dell_both_mode () {
  case $1 in
    standard)
      for sn in "${dell_monitors[@]}"; do
        sudo ddcutil setvcp 0xdc 0x00 --sn="${sn}"
      done
      ;;
    comfort)
      for sn in "${dell_monitors[@]}"; do
        sudo ddcutil setvcp 0xf0 0x0c --sn="${sn}"
      done
      ;;
    game)
      for sn in "${dell_monitors[@]}"; do
        sudo ddcutil setvcp 0xdc 0x05 --sn="${sn}"
      done
      ;;
    movie)
      for sn in "${dell_monitors[@]}"; do
        sudo ddcutil setvcp 0xdc 0x03 --sn="${sn}"
      done
      ;;
  esac
}

https://www.dell.com/community/Monitors/DDM-Linux-standard-command-to-switch-Preset-Modes/td-p/7840333