Can't mirror my screen over HDMI on Pop!_OS 21.04

Hello everyone,
I’ve recently migrated to Linux, and thanks to so much help from you guys in the community and other random forums I’ve come across, it’s become quite the smooth experience.

However, I am running into some trouble with my HDMI expansion card. I can get the laptop to display to my TV in 16:9, but only while my laptop screen is blacked out. I cannot have my laptop screen change to 16:9 and then have that image mirrored to the TV like I do on Windows. When I try to select the “Mirror” option, the settings app tells me that there could be some hardware limitations.

How can I go about fixing this?

Have you tried doing the same thing with other screens? Is the problem only with you TV? What resolution is the TV in? When mirroring, both screens needs to display the same resolution, maybe this is the problem?

I can’t recall if the fix was posted to these forums, but I believe you can “force” a 16:9 resolution in the Displays app, as long as it actually works on your hardware (xrandr might help with all possibilities). You need to add a new modeline to your Xorg config if I remember correctly and then you can select it from Displays and that should enable mirroring if you have the 16:9 resolution selected for the internal display.


Would I need xrandr for this?

hi, sorry to bump this thread, but I am having a similar problem… however, for me the problem exists no matter if I’m using usb-c, the original HDMI expansion card, or a VGA adapter. The Display settings window just crashes when I click on mirror. I tried messing around with xrandr and got it to mirror but only at a (way too) large scale… trying to change this brings about crashes.

Anybody here have any luck with mirroring in Pop? I’m using an 11th gen. I’ve tried it on a variety of projectors / monitors and it’s always the same results. Thanks!