Ubuntu 20.4.6 LTS Nvidia legacy 340 driver and external monitor

[Sorin Srbu]

On Tue, 2024-08-27 at 14:33 +0100, Richmond via ubuntu-users wrote:
> Sorin Srbu via ubuntu-users wrote:
> > On Mon, 2024-08-26 at 12:58 +0100, Richmond via ubuntu-users wrote:
> > > 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.
> > Ok, thanks.
> > 
> > But isn't gdm3 the default with Gnome?
> > Why is xdm being used, or is this a recent change with Ubuntu?
> I changed it to xdm because gdm3 resets the graphics card losing the
> changes from xorg.conf.
>
> > Anyway, when I've had weirdish graphic problems I've used xrandr to
> > hard-set resolutions, screen setups etc. Those setting are
> > remembered between reboots and logoffs in my experience.
> > 
> > Would that maybe be of help for you too?
>
> Thanks, I managed to improve it a bit with that. But there is still
> some strange thing happening with the virtual screen/physical screen
> not being the same. I admit defeat with nvidia-settings as it does
> not even accept its own output configuration file as valid.




I confess I'm a little out of my depth with Gnome DE, as KDE is my
preferred poison. Nvidia-settings isn't too helpful at the best of
times as well. Xrandr has fixed all my gfx problems when they've arisen
though.

You mention you installed Ubuntu 20.04.6, which is rather old.
I've a hunch that updating and upgrading to the latest available LTS
version might fix things with Gnome for you. You'd also get newer
nvidia drivers.

Is this a possible way forward?
If you decide to try that, make sure you have backups of the important
stuff like /home and any settings you care about from /etc.

I'm using the proprietary 350 (IIRC) nvidia driver with my 22.04-
install on WFH-computer. 
Had the best results with that one.
You could try other nvidia drivers on your computer and see if any of
them is better.

A sidetrack:
Was the 20.04.6 installation a plain vanilla thing? Ie you chose Gnome
as the desktop and so on?
I'm thinking maybe some Gnome components _may_ be missing for you (yes,
farfetched, but still) if you chose a light installation or some such.
Or maybe light installs are only available for Ubuntu server installs,
I don't quite recall that...





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