Rpi 4 and two monitors

NathTheDude

Thank you for this although it is still producing 2 x MM’s on the first screen (MM and MM2), not sure what could be wrong. If you have it working it obviously must me something I have done wrong…hmmmmm.

I will review all the files and let you know if I find anything.

NathTheDude

@sdetweil . I know it is a bit extreme but thought I would just start again and burn another image to the SD card. I am in the same position though

burnt image to sd card, booted rpi and did an update, enabled SSH and VNC
installed MM with your automation script
copied the ‘MagicMirror’ Folder to ‘MagicMirror2’, in the new folder I updated:
– config.js - just updated port to 8082
– run-start.sh - updated with window position and profile
– mm.sh - new location
– pm2_MagicMirror.json - updated with new locations
within the MagicMirror2 folder,
– pm2 start ./installers/pm2_MagicMirror.json
– pm2 save
This then started another MM from the MM2 folder on to screen 1
htop confirms that processes are running from both MagicMirror and MagicMirror2
pm2 status confirms that both are up

In your setup, if you update the chromium line within run-start.sh with bad entries does that break your setup. Does not seem to be running this command from what I can see in my setup

sdetweil

well, I finally got it to work , note I have two displays that support 4k, 3840x2160, so my screen pos is double yours

in /boot/config.txt

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=4

and in /boot/cmdline.txt
add cma=384M to the end of the line, like this…

plymouth.ignore-serial-consoles cma=384M

then you must power down and back up for these changes to be applied

found here
https://retropie.org.uk/forum/topic/24436/drm_ioctl_mode_create_dumb-failed-cannot-allocate-memory/9

I was getting the DRM cannot allocate memory error

MagicMirror/run-start.sh line for chromium

chromium-browser -noerrdialogs -kiosk --user-data-dir='Default' --window-position=0,0 -start_maximized  --disable-infobars --app=http://localhost:$port  --ignore-certificate-errors-spki-list --ignore-ssl-errors --ignore-certificate-errors 2>/dev/null

MagicMirror2/run-start.sh line for chromium

chromium-browser --disable-bundled-ppapi-flash -noerrdialogs -kiosk -start_maximized  --window-position="3840,0" --disable-infobars --app=http://localhost:$port  --ignore-certificate-errors-spki-list --ignore-ssl-errors --ignore-certificate-errors  --user-data-dir='Test2'  # 2>/dev/null

this boots up and both MM start via pm2 and display on separate screens, with different content (modules in different positions)

here is a screenshot of my dev system connected to both MM servers at the same time
(the displays are two hdmi ports on the same TV, so I can’t show them physically at the same time)
alt text

NathTheDude

@sdetweil - nice 2 x 4k’s.

So, I did what you mentioned in your last post but unfortunetly I am in the same issue. I wonder if your problem was more to do with 2 x 4k’s which is perhaps different to mine? I am not sure.

NathTheDude

@sdetweil - if you comment out the chromium line in the run-start.sh does this cause you any issues/errors?

sdetweil

@NathTheDude no… you could just change config.js to serverOnly:true, then it won’t try to start chrome

sdetweil

@NathTheDude I started by doing

cd MagicMirror
node serveronly

note no npm start needed, will run til you ctrl-break out

then tried multiple tries to get chrome on the second display…
(it works manually if the position is mispelled!)

then once it worked reliably,
i killed the server instance
then I used pm2 to stop/start that instance til I got that to work.

note that I had to use
–disable-bundled-ppapi-flash
on the second instance as it collided with the 1st…

krocaq

@sdetweil

@saljoke
Hi. Thats right. i only use 1 Pi4 to serve both displays via 2 MM instances. first the originally MagicMirror directory and the second in a MagicMirror2 directory. Both powered up via PM2 and turned off and on via PIR sensor.

The config looks like this:

language: “de”,
logLevel: [“INFO”, “LOG”, “WARN”, “ERROR”],
timeFormat: 24,
units: “metric”,
electronOptions: {fullscreen:true, x:1920},

1920 is the resolution witdh of the main display.

Very easy to handle and good for the electrical consumption

sdetweil

@krocaq see my comment here , you can do it with ONE directory
https://forum.magicmirror.builders/topic/17239/two-display/2?_=1663555322286