Ubuntu 20.4.6 LTS Nvidia legacy 340 driver and external monitor

[Richmond]

Sorin Srbu via ubuntu-users wrote:
> On Sun, 2024-08-25 at 00:07 +0100, Richmond via ubuntu-users wrote:
>> Liam Proven wrote:
>>> On Sat, 24 Aug 2024 at 20:21, Richmond via ubuntu-users
>>> <ubuntu-users at lists.ubuntu.com> wrote:
>>>> when gdm3 starts up the graphics card is reset to its default
>>>> settings, which are not quite right. I tried to change these
>>>> settings in
>>>> the gnome preferences - displays, but it doesn't quite work the
>>>> same and
>>>> sets the virtual screen bigger than the screen.
>>> Are you using GNOME on Wayland or on X.org?
>>>
>>> Settings in `/etc/X11/xorg.conf` won't affect Wayland.
>>>
>>>
>> I would ask how to tell, but if xorg.conf doesn't affect Wayland, then
>> I
>> must be using xorg, because it clearly works until gdm or gnome resets
>> the card.
>>
>> I think on Debian there was an option on the login screen to choose
>> between Wayland and Xorg, but I don't see that with Ubuntu.
>>
>>
> Hello!
>
> What's the output from the below command in a terminal?
>
> echo $XDG_SESSION_TYPE
>
>
> Just making sure we're on the same track. :-)
Hi,

The output is:

x11

According to the ever dependable chatgpt, this variable is set by the
display manager. So x11 is what I would expect as I currently have the
display manager set to xdm. Then, depending on which user I log in as,
either the window manager ctwm is called from .xsession, or the default
gnome desktop is started if there is no .xsession file.

So the case I am considering is the latter where no .xsession file
exists and I am using the default desktop environment, gnome.

This gave me an idea to check /etc/gdm3/config and set
WaylandEnable=false the dpkg-reconfigure gdm3 but the display was still
not set correctly so I changed the display manager back to xdm.