I have 2 HDMI touchscreens that I'd like to have with identical vertical displays. By identical, I mean I'd like the screens to be mirrored and show exactly the same image.
The Screen Layout Editor is not working for this. I am able to rotate the screens. I am able to drag them around as long as they don't overlap. I am asked to reboot each time I make a change.
As soon as I stack them on top of each other in the layout editor and reboot, they default back to the default horizontal side-by-side configuration. What am I missing to make them display the same thing?
I have an older Pi 4 that I've done this successfully with so I know its do-able. It is also what is recommended all over the internets. Any help is appreciated.
Lastly, I attempted to install a new OS and was able to reproduce this problem on a fresh OS install.
Edit: I dug up an old image that I have that works with same hardware. Working one is running
buster and the one that is not working is on
bullseye. Can someone please point me to some config that I should look at that may be different?
/boot/config.txt the only difference seems to be
dtoverlay=vc4-fkms-v3d(working), but changing this property does not fix the issues.