login screen is incorrect with multiple monitors

pjlbyrne · 2015-10-04 11:31:38

Hi,

I am using xfce on debian testing (stretch).

I have a laptop plugged into a docking station - the laptop screen is closed and there are two monitors plugged in. The monitor configuration layout is incorrect on the login screen. My two monitors are of different resolutions and one is rotated 90 degrees, On the login screen the displays are mirrored, and the screen rotation is not recognised.

I understand that this is not a problem with xfce. The login screen would seem to be displayed by 'lightdm', and is probably affected by configuration in /etc/lightdm/lightdm-gtk-greeter.conf. I have been trying to find out if it can be fixed at this level but it is taking some time and there does not appear to be good help in this area.

Could the xfce display configuration panel code not be changed so that it sets the correct configuration for lightdm monitor layout? From the user point-of-view (me!) this would be by far the most convenient way of fixing the problem: I mean for the window manager (xfce) to configure the greeter monitor layout.

So, I guess this is a feature request for xfce. Good idea?

ToZ · 2015-10-04 13:05:22

The problem is that there are numerous different display managers that can be used outside of lightdm. Personally, I don't think its realistic to ask Xfce to manage something that it has no control over and that there can potentially be a huge variety of options and configurations.

I know that the Xubuntu devs use something called lightdm-gtk-greeter-settings to set up the greeter. Perhaps they can be petitioned to add some sort of multi-display management functionality to that app.

I don't use a display manager, but I do recall that you can use lightdm's display-setup-script configuration option to setup mutliple monitor layouts using xrandr. Have you tried this?

pjlbyrne · 2015-10-04 18:23:07

Thanks for your reply, and especially the reference to the greeter settings app.

I understand your objections, but I still think from the user point of view it would be highly desirable for the xfce display settings to be applied back to the greeter.

Yes thanks, I have spent several hours fiddling with xrandr and the lightdm configuration, so far to no effect!

pjlbyrne · 2015-10-04 20:43:05

I have managed to install lightdm-gtk-greeter-settings, but sadly it does not allow for multiple monitor configuration :-(

ToZ · 2015-10-04 21:52:01

pjlbyrne wrote:

I have managed to install lightdm-gtk-greeter-settings, but sadly it does not allow for multiple monitor configuration :-(

No it doesn't. I was thinking that maybe this app might be a better place for monitor configuration as you are suggesting because it is in some way related to lightdm whereas Xfce is not. You could suggest it to the developers and see what they say.

RushTac · 2015-11-08 12:35:20

In the System menu there is a program named 'Login Window' that let you change the login window preference.
In it you can set the Primary monitor..

or if you like command prompt type 'sudo mdmsetup'.

pjlbyrne · 2015-11-08 12:47:35

> No it doesn't. I was thinking that maybe this app might be a better place for monitor configuration
> as you are suggesting because it is in some way related to lightdm whereas Xfce is not.
> You could suggest it to the developers and see what they say.

I did! But "answer came there none".

> In the System menu there is a program named 'Login Window' that let you change the login window preference.
> In it you can set the Primary monitor..
> or if you like command prompt type 'sudo mdmsetup'.

Thanks. Unfortunately it looks as though MDM is a feature of Linux Mint which is not in the main debian archives.

This thread:
http://www.linuxquestions.org/questions … 175448740/
indicates that it may not be easy to just add the mint repos to get this. Oh well.

sixsixfive · 2015-11-08 17:27:49

you need to edit you lightdm config there must be a line with something like:

display-setup-script=

just add your desired xrandr command to it eg:

xrandr --output DVI-0 --mode 1440x900 --right-of DVI-1

see also:
http://www.x.org/archive/X11R7.5/doc/ma … ndr.1.html
http://www.thinkwiki.org/wiki/Xorg_Rand … .24_xrandr
https://wiki.ubuntu.com/X/Config/Resolution

pjlbyrne · 2015-11-09 21:27:11

Thanks. I tried adapting the lightdm config line but it did not make a difference to the login screen.

display-setup-script=xrandr --output HDMI3 --mode 1680x1050 --primary --right-of VGA1

sixsixfive · 2015-11-09 21:40:54

ok it seems to have changed since the last time i used lightdm:(you need a real script now)

http://askubuntu.com/questions/408302/r … s-rotation

edit: make sure the command works(you can test this anytime in a terminal even if logged into xfce)

Last edited by sixsixfive (2015-11-09 21:45:59)

pjlbyrne · 2015-11-09 22:01:58

Thanks for your persistence in following this up. I haven't gotten the correct configuration yet but it is certainly affecting the layout of my greeter screen!

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#1 2015-10-04 11:31:38

login screen is incorrect with multiple monitors

#2 2015-10-04 13:05:22

Re: login screen is incorrect with multiple monitors

#3 2015-10-04 18:23:07

Re: login screen is incorrect with multiple monitors

#4 2015-10-04 20:43:05

Re: login screen is incorrect with multiple monitors

#5 2015-10-04 21:52:01

Re: login screen is incorrect with multiple monitors

#6 2015-11-08 12:35:20

Re: login screen is incorrect with multiple monitors

#7 2015-11-08 12:47:35

Re: login screen is incorrect with multiple monitors

#8 2015-11-08 17:27:49

Re: login screen is incorrect with multiple monitors

#9 2015-11-09 21:27:11

Re: login screen is incorrect with multiple monitors

#10 2015-11-09 21:40:54

Re: login screen is incorrect with multiple monitors

#11 2015-11-09 22:01:58

Re: login screen is incorrect with multiple monitors

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