Rpi 4 and two monitors

[NathTheDude]

Hey @sdetweil and @chassain-0 , so my kit for my v2 project has arrived. I have two 21.5 inch (same model) monitors connected up to an RPI4.

I have had a look around the forum but not been able to see what the best method is for this. When we start pm2 or when the RPI reboots it will boot up with the MM on the first screen and the normal desktop seen on the 2nd screen.

I think I would prefer to have two MM’s installed (one for each monitor), I assume this is ok todo or is the best approach to have the one MM on both screens?

Thanks

Nathan

[NathTheDude]

I wondered if I needed to update the ‘mm.sh’ file within the ‘installers’ folder, I tried changing this from ‘0’ to ‘1’ - reboot the RPI but on reboot MM does not get started on either monitor.

---

pi@MagicMirrors:~/MagicMirror/installers $ tvservice --list
2 attached device(s), display ID’s are :
Display Number 2, type HDMI 0
Display Number 7, type HDMI 1

[bhepler]

@NathTheDude - I tried that one-pi-two-instances thing a couple years ago. I wasn’t using an RPI but rather a tiny Ubuntu box. My problem was that I couldn’t find a way to guarantee which instance would appear on which monitor at start. They usually both ended up in the same monitor on top of each other.

You may have more luck than I did. If you do figure it out, please let me know how you did it!

[sdetweil]

@NathTheDude said in Rpi 4 and two monitors:

think I would prefer to have two MM’s installed (one for each monitor), I assume this is ok todo or is the best approach to have the one MM on both screens?

the answer is yes, … depends on what you want to do…

to use two MM on the same full width display you will have to modify custom.css on the one to the right
and make its starting position 1/2 way across the screen

when MM is on the left, is the desktop a full image, or just the right side of the full image?

[NathTheDude]

Hey @sdetweil , I started with stopping MM (pm2 stop all). This then allowed me to use VNC to change the screen settings, as in just rotate the screen’s display.

The screens are showing as two seperate desktops and from VNC the mouse smoothly goes from one display to the other.

When MM is started this completly fills the first screen and a raspbian windows desktop is seen on the 2nd screen.

[sdetweil]

@NathTheDude try the raspian, preferences, appracne settings, desktop stretch across

[NathTheDude]

Thanks @sdetweil , I have just played with those settings again. These seem to only effect the desktop and the desktop background and not the MM site. Always appears on the first screen.

[sdetweil]

@NathTheDude but is the desktop all the way across as a single desktop, or two separate instances?

[NathTheDude]

@sdetweil , it is seen as two separate monitors. There is not a setting to scretch one screen to the other with the settings. The closest is ‘Strectch to cover screen’ but that does not seem to help.

[bhepler]

@sdetweil - I don’t know if that capability is in the Raspi display drivers. It’s always going to see the two monitors as two separate devices with unique desktops. If you click on the Identify button, it should show you a different number on each monitor.

The only thing I can think of that would treat two monitors as a single continuous desktop is the AMD Eyefinity tech.