Dell Display Manager keyboard shortcuts for KVM switch on Linux / Ubuntu for U3821DW monitor

Up to now I have been using windows machines with my dell monitor / KVM hub.

I rebuilt one of my laptops with Ubuntu 20.4 and then found out that there is no Dell Display manager for Linux.

My requirements are fairly simple, I just want to type Ctl-Shift-S to switch to my other laptop which is the USB-C connection. It works to both laptops so switching is consistent.

Some searching led me to an article on this site it is great and gave me the answer that i needed but the answer is simpler if you are using gnome.

Install the "ddcutil" so from a terminal type:

sudo apt install ddcutil

Then you can see the capabilities of the monitor (change the number to match your monitor)

sudo ddcutil capabilities -d 1

This gives you a bunch of output, I am interested in Feature 60 input sources:

..   Feature: 60 (Input Source)      Values:         1b: Unrecognized value         0f: DisplayPort-1         11: HDMI-1         12: HDMI-2..

Once you have this you can use the values (apparently USB-C is 1b) to switch to your input source from the terminal thus:

ddcutil setvcp 60 0x1b

Try it out, if it works you just need to setup the keyboard shortcut with the exact same command.

The link covers this but here are the instructions just to keep it all together:

1. Open Settings and select Keyboard from the list
2. Scroll down to the Keyboard Shortcuts section and select View and Customize Shortcuts
3. Click on the Custom Shortcuts menu and click Add Shortcut or +
4. Enter the following information in the Add Custom Shortcut window
   1. A Name (mine was SwitchToUsbC)
   2. The command which is exactly as you typed in the terminal above i.e. ddcutil setvcp 60 0x1b
   3. Then click Set Shortcut
   4. Enter your keyboard shortcut i.e. Ctl-Shift-S
   5. Click Add

This is not original, it is all based on other peoples work but it was simpler for me to use the built in functionality than to create scripts or c programs.

If you have more computers attached, you can be slightly more imaginative say Ctl-Shift-W to switch to your work computer or whatever you will remember.