The Raspberry Pi 4 and Raspberry Pi 400 have the option to connect a second monitor as they both come with two micro-HDMI ports.
In most cases, when you attach a second monitor it will 'just work' and your desktop will display across both screens.
Some monitors/TVs can be a little stubborn and won't work out of the box. We have a few suggestions to help when this happens:
Does the screen work on its own - Plug the second monitor into the left micro-HDMI port and see if it works on its own without any other monitors plugged in. If it does, we know it isn't an issue with the monitor or cable.
Force Dual-screen mode - A little tweak of the Raspberry Pi's configuration can help to 'force' the second display to work. Taken from a discussion on the Raspberry Pi forum, try the following fix:
- Open a new terminal window and edit the config file by using the following command:
- sudo nano /boot/config.txt
- Now and add the following lines to the file:
- hdmi_edid_file:1=1
- hdmi_edid_filename:1=edid.dat
- hdmi_force_hotplug:1=1
- Save the file by pressing Ctrl+X then selecting 'Y' to save
Post your own question - If the fix above didn't work, we suggest posting your own question on the Raspberry Pi forum with your exact setup. Remember to include the OS you're using, monitor model numbers and any other relevant detail such as cable type or power supply.