Using a Dell laptop and an Ubuntu computer via the same Dell monitor

Anoth­er ques­tion that I unfor­tu­nate­ly had to answer myself sev­er­al times because I am so for­get­ful: How do I con­nect my Dell lap­top XPS 129240 (WIN11), an Ubun­tu machine (24.04), and my Dell curved mon­i­tor S3423DWC in a way, that I can use both machines with the same key­board and mon­i­tor via the KVM switch inte­grat­ed in the Dell mon­i­tor?

Solution

• Prepar­ing the WIN11 com­put­er (Dell lap­top):
  • Con­nect the key­board to the Dell mon­i­tor via USB‑2/Bluetooth.
  • Con­nect the Dell lap­top to the Dell mon­i­tor via USB‑C cable and start it (WIN11).
  • Down­load the setup/installation file for the Dell Dis­play Man­ag­er (ddmsetup.exe) from https://www.dell.com/support/home/de-de/drivers/driversdetails?driverid=g0v75 (ver­sion 2.3) and run it as admin­is­tra­tor (and save a link in the menu dur­ing instal­la­tion).

• Prepar­ing the Ubun­tu com­put­er:
  • Con­nect the Ubun­tu com­put­er to the Dell mon­i­tor using a USB‑2 / HDMI cable.
  • Start the Ubun­tu machine.
  • sudo apt-get install ddcutil ddcui
  • Start ddui, select View/Capabilities and select input source VCP/Feature 0x60.
    • Ver­i­fy 0x1b: Unrec­og­nized fea­ture = USB‑C port for the Dell lap­top with WIN
    • Ver­i­fy 0x11: HDMI 1 = HDMI port of the Ubun­tu com­put­er
    • Check Del­l’s own man­u­al
  • Gen­er­ate the fol­low­ing Bash script, save it as ~/bin/2dell.sh and make it exe­cutable.

#!/bin/bash

sudo ddcutil setvcp 60 0x1b

• Switch from WIN11 to UBUNTU-24.04:
  • On the Dell-Lap­top (WIN11), start ddm, click Burg­er Menu/KVM-Rubrik
  • Define your own Hotkey and use it
  • Oth­er­wise start the switch graph­i­cal­ly.

• Switch from UBUNTU-24.04 to WIN11:
  • > ~/bin/2dell.sh