Left monitor display becomes garbled

[Liam Proven]

On Mon, 7 Mar 2022 at 19:36, Jay Ridgley <jridgley2 at austin.rr.com> wrote:
>
> Good afternoon,
>
> Thanks ALL, here is an update..
>
> In addition, and as requested a bit more information (OK, more than a
> little).

Good stuff!

> I have not tried re-seating the Graphics card, yet. I am not a hardware
> type guy and it is not easy for me to get to the box to disconnect it.

Understandable. It may be worth doing anyway, though...

This is a desktop computer, right?

Are you able to get round the back of the main computer and check that
the cables are both securely connected?

It might also help if you could tell us what connectors they're using.
If they are not both the same then the excellent troubleshooting tip
from "Jonesy" might not be feasible.

> Have not swapped the monitors, yet. The cables are wrapped and I do not
> have a set of spares handy.

Hmmm.  Again this depends in part upon the connectors in use.

For example, HDMI cables are used in TV sets now, meaning they're
commodity parts. I haven't bought one in about 4-5 years but it was
under $5 when I last did, and maybe cheaper now.

So you could buy a spare, or 2 spares, and leave the "wrapped" cables
_in situ_ and try other ones for very little expense.

> The problem has not manifested itself since my first report. So I have
> not tried the ctl-alt-fn.

OK.

Often the way. ;-)


> Liam, I will eventually get it through my thick skull that I need to
> supply as much info about my s/w and h/w as I can when asking for help.

:-D

> Yes, I am running Gnome 3 and also X11.

OK.

> I know nothing about Wayland and really do not want to learn it, sorry.

It's an alternative display server. It's not a separate desktop or
anything. You may already have it and not know.

You can pick it from the login screen by clicking the little gearwheel
symbol. Click your username, type your password but *do not hit Enter
at the end!*

Down at the bottom right of your login screen, there's a cogwheel.
Click that. Then you can pick between plain unmodified GNOME on X.11
or Wayland, or Ubuntu's tweaked GNOME on X.11 or Wayland.

(And maybe others if you have them installed; I have recently added
GNOME Flashback for experimental purposes. It's actually quite usable
and makes me wonder why Cinnamon and indeed MATE exist, TBH.)

If your PC is set to auto-log-in and you don't normally see the login
screen, no problem: just log out.

> Below is the hardware info, I have found so far...
>
> jay at polar:~$ inxi -F
> System:    Host: polar Kernel: 5.4.0-100-generic x86_64 bits: 64

OK, so you are on the original shipped kernel. If the problem is with
drivers, you may find the free easy HWE kernel upgrade helps. Here's
how:
https://wiki.ubuntu.com/Kernel/LTSEnablementStack


> Graphics:  Device-1: Intel Xeon E3-1200 v3/4th Gen Core Processor
> Integrated Graphics driver: i915 v: kernel

OK, so it looks like 1 screen is using the CPU's built-in graphics.

>             Device-2: NVIDIA GK208B [GeForce GT 710] driver: nouveau v:
>             kernel

That's a ~8YO 3rd party add-in card.

https://www.techpowerup.com/gpu-specs/geforce-gt-710.c1990

>             Display: x11 server: X.Org 1.20.13 driver: nouveau

As you said, using X.org.

TBH I am not sure Wayland will drive 2 dissimilar displays, but I
suspect it would.

Worth a try!

> The next time it fails I will do what I can to isolate the problem.

The next thing we need to know is which screen is on which GPU.

The nVidia card has all 3 of the most common types: VGA, DVI and HDMI.

We don't know what your motherboard has.

If you can, you may be able to drive 2 screens off the nVidia card,
for instance. If the m/b one is the one that's going blank, that may
help. And if so, and you can, then installing nVidia's drivers may
improve performance.

-- 
Liam Proven ~ Profile: https://about.me/liamproven
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