Read the statement by Michael Teeuw here.
Rpi 4 and two monitors
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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.
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@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
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@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? :)
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@NathTheDude The 2nd monitor should be display 0, screen 1. Use this:
DISPLAY=:0.1 -
Hey @OldSunGuy , thanks. ‘0’ and ‘0.0’ seem to be the first monitor however I get an error when I try anything else. So far I have tried using each of the following: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9
Each time I try to start npm (npm start) apart from when I use 0 or 0.0 I get the following (with the value reflecting the number I changed in ‘run-start.sh’):
(electron:2238): Gtk-WARNING **: 06:14:02.236: cannot open display: :0.1@sdetweil - not sure if this is relevant but it does not seem to matter what value I set in ‘run-start.sh’, when I reboot the pi it will always start MM on the first screen. Should it not fail if it is using ‘run-start.sh’?
Also with an incorrect value being added to ‘run-start.sh’, when I run ‘mm.sh’ this always works and displays MM on the first screen.
okay, I think I understand it now. When I reboot it is using ‘mm.sh’, within mm.sh is the following:
cd ~/MagicMirror DISPLAY=:0 npm startWhich I assume means that the ‘run-start.sh’ is not used during boot up?
When I change this value to anything other than 0, this will also fail with the same error seen when trying to run npm previously.
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@NathTheDude If you start a terminal on one desktop and run:
echo $DISPLAYThen start a terminal on the other desktop and run:
echo $DISPLAYdo you get the same results?
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@OldSunGuy - I get :0.0
I wonder if both screens are being seen as 0.0, if that is the case I guess I would expect the MM screen to cover both screens and not just the first :-/
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@OldSunGuy , sorry mis read your comment. Not sure how I would start a terminal on one screen and a different terminal on another.
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@NathTheDude if they are two independent desktops, then you should have a menu on the second desktop, just like the first…
also, you can move the mouse to the second desktop and do ctrl-alt-t to open a terminal there
I have an micro hdmi adapter coming later today so I can put up a second physical display on my pi4…
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@sdetweil , I opened up a terminal session on each screen and both indicated the same display was being used (:0).
From the ‘Appearance Settings’ window (‘Prefences’ > ‘Apprearance Settings’, there is a ‘Taskbar’ tab and in this tab you select which hdmi output you want the taskbar to be on. You can choose both.
