Use Balena Dash in a HDMI Dual-Screen Setup

Project help balenaDash
1

Hello,

is there any possibility to use both screens of a RPi4 with balena dash?
I tried cloning the kiosk container and setting DISPLAY_NUM=1 on the second, but that does not seem to work.

And suggestions?

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7

Hello @ich5003 thank you for your message and apologizes for the delay with the answer!

We think that this is related to the x11 configuration. We recall this X11 With Multiple Displays - #14 by csuich2 but we haven’t tested it yet.

Do you think you can try?

8

Hi @ich5003 just checking to see if you had seen my colleagues message above? :smile:

11

I’ve not tried this with balena dash yet, but I’ve gotten the browser block to span two screens.

Here’s my Configuration:
Define DT overlays: vc4-fkms-v3d
Define device GPU memory in megabytes.: 512
Force the HDMI hotplug signal: 1
Define the HDMI output group: 2
Define the HDMI output format: 82
Force the HDMI hotplug signal on HDMI port 2 Only supported by supervisor versions >= v14.6.0.: 1
Define the HDMI output group on HDMI port 2 Only supported by supervisor versions >= v14.6.0.: 2
Define the HDMI output format on HDMI port 2 Only supported by supervisor versions >= v14.6.0.: 82

BALENA_HOST_CONFIG_disable_overscan: 1
BALENA_HOST_CONFIG_max_framebuffers: 2

Variables:
WINDOW_SIZE: 3840,1080

This allows me to have one browser window that spans 2 1920x1080 screens. My web app displays content in two 1920x1080 regions side by side. The result is different content on each screen.
If you want to show two different websites, I suppose you could point it to a webpage with two 1920x1080 iframes.

I’m still doing some testing and I’m actually using a fork of this block for my application, but I thought I’d share in case anyone else wants to try it out.

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