Sometimes, when the monitor's energy saving is activated, the screen no longer responds to mouse or keyboard actions. Only disconnecting the computer from the network helps. Not often, but sometimes I encounter this.

(In reply to gigastarcraft2 from comment #0)
> SUMMARY
> System does not go back up after a screen turns off. 
> 
> STEPS TO REPRODUCE
> 1. Log out.
> 2. Wait for a screen to turn off.
> 3. Move a mouse or type any key on a keyboard.
> 
> OBSERVED RESULT
> Black screen, monitor shows a message: "No Signal."

After trying to figure it out, I managed to fix it
after deleting the maliit-keyboard package and the file
/etc/sddm.conf.d/plasma-wayland.conf.
If the system uses only a wayland session,
then there are no crashes or black screen issues at all
after exiting the session.
But if the system uses a wayland session and an x11 session,
then when exiting the session, it happens that instead of
the login screen, there is just a black screen.
The problems started after the release of plasma-6.3.x.
After deleting maliit-keyboard and maliit,
as well as the file /etc/sddm.conf.d/plasma-wayland.conf,
I no longer see a black screen after exiting the session.

Hi - just to check, is this issue happening at the SDDM screen, where you're sent immediately after logging out and where you'd choose which user to log in as next?

I'm double-checking that it's related to that screen, and not the "lockscreen" that's used when you haven't actually logged out of your user session, but either enough time has passed or you've manually locked your device.

Thanks!

(In reply to John Kizer from comment #3)
> Hi - just to check, is this issue happening at the SDDM screen, where you're
> sent immediately after logging out and where you'd choose which user to log
> in as next?

Yes, exactly on the SDDM screen, immediately after logging out.
In my case, there is also nvidia-570.
But it seems the error was fixed with the latest commits in https://invent.kde.org/plasma/kwin.
I don't encounter this error anymore.
At first I switched completely to wayland and did not receive this error, since it only 
appeared for me if two sessions were available, wayland and x11.
Recently, I installed the package again for testing, which contains files
/usr/bin/startplasma-x11
and
/usr/share/xsessions/plasmax11.desktop.
But I was never able to recreate the error again.
The black screen never appeared.

Glad it's working for you now!

I still have the same issue but it looks like time required for the bug to show up takes more minutes.

Please get the output of drm_info when the display wrongly doesn't turn on. You can run it from ssh

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

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Since 6.5.0 update I haven't noticed this bug, however I tested only once since I disabled the option. I turned it on and I will inform in a few days/weeks.

(In reply to gigastarcraft2 from comment #9)
> Since 6.5.0 update I haven't noticed this bug, however I tested only once
> since I disabled the option. I turned it on and I will inform in a few
> days/weeks.

The bug still persists. Immediately and about 1 minute after screen turns off I am able to 'recover' screen but approximately after 5 minutes I am unable to 'recover' a screen. This is irrelevant of the "Turn off screen" setting. I cannot issue any command (even tty) when a monitor blacks out.

(In reply to gigastarcraft2 from comment #10)
> The bug still persists. Immediately and about 1 minute after screen turns
> off I am able to 'recover' screen but approximately after 5 minutes I am
> unable to 'recover' a screen. This is irrelevant of the "Turn off screen"
> setting. I cannot issue any command (even tty) when a monitor blacks out.

Can you send us the information that Zamundaaa asked for? Please get the output of drm_info when the bug prevents the display from turning on.

(In reply to TraceyC from comment #11)
> (In reply to gigastarcraft2 from comment #10)
> > The bug still persists. Immediately and about 1 minute after screen turns
> > off I am able to 'recover' screen but approximately after 5 minutes I am
> > unable to 'recover' a screen. This is irrelevant of the "Turn off screen"
> > setting. I cannot issue any command (even tty) when a monitor blacks out.
> 
> Can you send us the information that Zamundaaa asked for? Please get the
> output of drm_info when the bug prevents the display from turning on.

> I cannot issue any command (even tty) when a monitor blacks out.
I tried and it looks like this bug prevents from issuing any command.

You can log in through ssh and get it that way.