Ubuntu 20.4.6 LTS Nvidia legacy 340 driver and external monitor

[Richmond]

Sorin Srbu via ubuntu-users wrote:
> 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 chose 20.04 because had read that the driver I am using, legacy 340,
is not supported with kernels after version 5.4. (And even 5.4 support
is an unofficial patch maybe?).


>
> 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...
>
What I actually did was install 18 with Gnome, because I thought it was
still supported, and because kernel 4 was more likely to work with
nvidia because that's what I had been using on Debian, but then found it
was only supported for paying subscribers, so I upgraded to 20.04 by
pressing the upgrade button, which isn't going to fill anyone with
confidence but it seemed to work.

If I try 22 it will be in April when LTS for 20 runs out, as I have too
much to lose at the moment, I can it to work with xdm/ctwm, I just can't
use gnome properly.