I did a significant amount of testing on this over the last week or so
(and a few hours tonight), as there are two nearly-identical issues that
have been reported; one running 24.04 under Hyper-V, and accessing it
via RDP, resulting in a black/blank screen after a number of idle
minutes, and another using a 24.04 VM on ESXi, where the VMRC/console
will go blank/gray, and never return.

While these machines are inaccessible via their graphical consoles, they
can be used via SSH and other means, just not graphically.

The Hyper-V/RDP issue is almost entirely mitigated by _disabling_ the
Screen Blank under Settings -> Power, and I'm confident that this either
solves it, or works around it. I personally tested setting that blank
value to 5 minutes, 10 minutes, etc. and confirmed the blank/black
screen follows 1 minute _after_ the screen is blanked. That is,
attaching at 4-5 minutes works when it's set to 5 minutes, but attaching
at 6 minutes does not. When moving that to 10 minutes, attaching at 4,
5, 6 minutes works, but 11 minutes does not, and so on.

The VMware issue is subtly different. I tested the same screen blank
setting (set to 'Never'), which stops the console from being
lost/blanked, but I don't believe this is the root cause.

I also tried setting 'org.gnome.settings-daemon.plugins.power idle-dim
false', in an attempt to chase down the same line of reasoning, which
did _not_ resolve the issue (after restoring the Screen Blanking back to
the default 5 minutes).

However, setting 'MUTTER_DEBUG_FORCE_KMS_MODE=simple' _does_ positively
influence the issue, although with this set, the screen _never_ blanks,
even when Settings -> Power is set to blank the screen at 5 minutes. I'm
not clear why that isn't blanking, but I'll chase that down next.

So this looks to be mutter-related, or at the very least, gnome-shell,
but I don't yet have a definitive smoking gun. It's absolutely related
to screen blanking, that much is clear, and all of my tests confirm
that.

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https://bugs.launchpad.net/bugs/2089709

Title:
  Ubuntu 24.04 sometimes logs in to a black screen if the mouse is moved
  during login

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