Rpi 4 and two monitors

NathTheDude

@sdetweil na, no joy. I did try this yesterday also but was not sure I was looking in the right place. For the sake of it I tried using numbers 0 to 9, all with the same result. This for example:

npm ERR! code ENOENT
npm ERR! syscall open
npm ERR! path /home/pi/package.json
npm ERR! errno -2
npm ERR! enoent ENOENT: no such file or directory, open '/home/pi/package.json'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent 

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/pi/.npm/_logs/2020-02-04T21_33_32_894Z-debug.log

However if I reboot the RPI with run-start having the different value it will still display the MM on the first screen, this made me think that this script was not being used at the startup as I would expect it to fail and not display the MM - perhaps I am wrong.

bhepler

I wonder if we’re looking in the wrong place? Perhaps it’s how the MM process is calling Electron that determines where on the desktop the app appears.

sdetweil

@NathTheDude said in Rpi 4 and two monitors:

npm ERR! code ENOENT
npm ERR! syscall open
npm ERR! path /home/pi/package.json
npm ERR! errno -2

you are doing npm start in the root, not in the MagicMirror folder…

sdetweil

@bhepler that is run-start.sh

~/MagicMirror/package.json

{
  "name": "magicmirror",
  "version": "2.10.1",
  "description": "The open source modular smart mirror platform.",
  "main": "js/electron.js",
  "scripts": {
    "start": "./run-start.sh",     // < ------   when u do npm start this happens

sdetweil

@NathTheDude run-start.sh is in the MagicMirror folder

actually the pm2 only on the 1st screen is understandable
as the script used by pm2 is installers/mm.sh

which does

DISPLAY=:0 npm start

and run-start does

# if DISPLAY is not set then set it
if [ -z "$DISPLAY" ]; then #If not set DISPLAY is SSH remote or tty
	export DISPLAY=:0 # Set by default display
fi

so I would just set export DISPLAY=:0
and the execute run-start.sh

bhepler

I have to head home, so I can’t investigate any more for some time. But I did find this link on StackOverflow that seems to address the issue. Aren’t we using an X11 based desktop manager?
Anyway, this may help.

sdetweil

@bhepler correct, that is DISPLAY

NathTheDude

thanks @sdetweil , right you are - I was not running npm from within the MagicMirror directory.

When I update ‘Display’ to 1 I still get an error when trying to manually run NPM, however when ‘Display’ is set to 0 and then I run NPM there are no errors with it. The error is:

pi@MagicMirrors:~/MagicMirror $ npm start

> magicmirror@2.10.1 start /home/pi/MagicMirror
> ./run-start.sh

(electron:11918): Gtk-WARNING **: 22:18:00.088: cannot open display: :1
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! magicmirror@2.10.1 start: `./run-start.sh`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the magicmirror@2.10.1 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/pi/.npm/_logs/2020-02-04T22_18_00_154Z-debug.log
pi@MagicMirrors:~/MagicMirror $

@bhepler thanks for the link, it is a bit beyond my understanding at the moment. I will have to read up on it a bit more. I tried to run xrandr to see what kind of status it gives on the monitors but it currently comes back with ‘Can’t open display’, I assume it is because another service/application is utilising them?

Anyway, thanks for your help.

sdetweil

@NathTheDude said in Rpi 4 and two monitors:

When I update ‘Display’ to 1 I still get an error

Yes, we just need to find out what the other Display number is.

tvservice is wrong cause it reports display 2 for HDMI 0, and we know it’s really Display 0

NathTheDude

@sdetweil , so using ‘0’ or ‘0.0’ give the same result and start MM on the first monitor.

So far I have tried 1,2,3,4,5,6,7,8,9 and 0.1, 0.2, 0.3, 0.4, 0.5

How far do I go? :)