Login Screen Primary Display

I’m on 18.10 and I’m having trouble getting the login screen to appear on my monitor, rather than my livingroom TV. Can anyone point me to where I’m going wrong?

I’ve tried adding entries to the config files in /etc/lightdm, as recommended here:
https://wiki.archlinux.org/index.php/LightDM#LightDM_displaying_in_wrong_monitor
Although the files seem to be called slightly different things here, I tried adding active-monitor=1 (and 0), as well as display-setup-script=xrandr --output DP-0 --primary

I also tried the settings mentioned here:
https://github.com/linuxmint/slick-greeter/blob/master/README.md
I’ve tried only-on-monitor=1 (and 0), as well as active-monitor in the /etc/lightdm/slick-greeter.conf file but they don’t seem to do anything, even after a reboot.

I also found a post somewhere that recommended copying your working monitors.xml from your home directory into /var/lib/lightdm/.config, which I’ve done too.

Does anyone know the precise place where I should set this configuration?
Thanks a lot!

My xrandr output looks like this (HDMI-0 is my TV, DP-0 is my monitor):

Screen 0: minimum 8 x 8, current 2560 x 1440, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected (normal left inverted right x axis y axis)
   1920x1080     60.00 +  59.94    50.00    29.97    23.98    60.05    60.00    50.04  
   1680x1050     59.95  
   1600x900      60.00  
   1280x1024     60.02  
   1280x720      60.00    59.94    50.00    29.97    23.97  
   1152x864      75.00  
   1024x768      60.00  
   800x600       60.32  
   720x576       50.00  
   720x480       59.94  
   640x480       59.94    59.93  
DP-0 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 598mm x 336mm
   2560x1440     59.95 + 144.00*  120.00    99.95    84.98  
DP-1 disconnected (normal left inverted right x axis y axis)
DVI-D-0 disconnected (normal left inverted right x axis y axis)

Looks like from the code that the only-on-monitor value for your slick-greeter.conf file is not a number but a string value - I’m guessing HDMI-0 and DP-0 from your xrandr results

Thanks for the response! That looks promising, but I’ve just tried DP-0 and it doesn’t seem to have had any effect.

My slick-greeter.conf file in /etc/lighdm now looks like this:

[Greeter]
icon-theme-name=Humanity
background=/usr/share/backgrounds/budgie/message-in-a-bottle-3437294cosmic.jpg
only-on-monitor=DP-0

Did I do that right? I tried a full reboot too, but it doesn’t seem to care about it.
Thanks again

Not really an answer but on Ubuntu 16.04 using Unity and Lightdm, on a dual screen setup, the login dialog box automatically « follows » the mouse pointer, if pointer is on screen 0 then login box appears there on 0, if you move it onto screen 1 it appears there…

…isn’t the same expected nowadays ? Or was it another ( good ) Unity feature ?

Unity was simply amazing with multi-monitor support. Better than pretty much anything.

Ah, there is a setting for that, but it didn’t seem to do anything either, since the mouse pointer cannot leave my TV. It’s as if my monitor doesn’t exist until after I successfully log in. Maybe that’s a clue?

It reminds me doing this from time to time on some older Ubuntu installations : https://askubuntu.com/questions/421730/xorg-conf-changes-from-nvidia-setting-have-no-effect-after-reboot/618661#618661