Touchscreen (DSI) + HDMI simultaneously?

I have Volumio on a Raspberry Pi 4 with the official 7" touchscreen connected via the DSI ribbon cable port. I would like to add the ability to also view the album art etc on my 4k TV via HDMI, but I’m unable to get a signal from the HDMI port 0. Is it possible to have the video output from both the DSI and the HDMI simultaneously? I guess there may be issues around resolution so a simple screen duplication may not be possible.

Volumio 3.661
Touch Display plugin 3.4.0

Hi, I have posted the same question few days ago, same request for me… no answer so far

@Hypermale, @fxn,

It is possible to have multiple X11 session outputs. For this to work, you will need address each display’s port in the /boot/cmdline.txt

video=<PORT>:<x-res>x<y-res>@<fr>

Set max_framebuffers=x (number of screens) in /boot/userconfig.txt

In addition, X11 will need to have individual vc4 config in the /etc/X11/xorg.conf.d/ with “Screen” and “modesetting” parameters.

Kind Regards,