Lock Screen Hangs

[bigdan]

I have been on 20.4 for a few months. My current rev's are plasma version 5.18. I love Kubuntu and have become a supporter. One problem that I am having is my lock screen will not work. Whenever I lock the screen. It will not unlock, or give me a password. CNTL F2 wont work. I am in reset land. I am using NVIDIA drivers 470. My Card is a Quadro Pro 5000. I am using an old server. 32 Cores, 264 Gigs of Ram and multiple T's of disk. Any ideas?

[Snowhog]

Welcome to KFN.

As a starting point, let's see if the issue might be within your user account. Create a new user. Logout and log back in with the new user. Lock the screen and see if it behaves as expected when unlocking. If it does, then we need to start looking at setting/configuration files in your normal users account.

[bigdan]

Thank you Snowhog, the new test user's lock screen worked as expected. So the problem is within my profile. Is this is the problem where all the styles have to match?

[Snowhog]

Now that we know, or have good reason to believe, that your issue is associated specifically with your user (some configuration setting/file in your user /home directory), we now have to figure out what that is. There is the finesse way, and the brute force way. I'll let more experienced members chime in on that.

Just know that this is fixable.

[bigdan]

Awesome! Thank you

[Snowhog]

One of the possibilities could be a cached configuration that is not playing nice with current conditions. Testing that is the least risky approach (in fact, there is no risk).

Open a konsole. Ensure that you are in your logged in users /home directory. Type pwd and press Enter and you should see /home/yourusername. (Mine is /home/paul) If you aren't in that directory, change into it and then type rm -r .cache and press Enter. This action removes the .cache directory and all content it contains. Logout and reboot. Rebooting isn't actually necessary, but it doesn't hurt either, and it ensures you are starting with a clean session.

When you log in the .cache directory will be rebuilt. Now observe whether the undesired behavior continues or not.

[bigdan]

Snowhog

Thanks, I removed the .cache file and rebooted. I saw another Redhat bug that said the session was slow and eventually gave you a prompt. So I waited. However, it was just hung. I am able to do opt/alt F2 and log in to reboot.

Also I use JACK and Zero Delay kernel. I did notice after clearing the cache. My JACK interface hung after reboot.

Thanks, one step closer...

[Snowhog]

As you aren't reaching the Desktop session login dialog (SDDM), you can safely just power off the PC. Power it back on and try again to get logged in.

[bigdan]

Snowhog -

Tried it a couple of times. Lock Screen still hangs.

[Snowhog]

So I'm clear. You can successfully boot. You reach the SDDM Login screen and can type in your pwd and you are logged in to your Desktop session. Applications work. But when you lock your screen; I'm assuming you manually do this?; you then can't get SDDM Login screen to reappear at all. Is that correct?

[bigdan]

Yes, Sir. I successfully boot. I am all logged in. I want to leave my pc. I lock the screen. When I depress the keyboard or move the mouse. SDDM does not come back. I have to use CTRL ALT F2 to reboot the machine.

In fact, I can't logout or leave my machine without hit hanging up.

[Snowhog]

Thank you. Given that a 'new user' isn't experiencing this issue means that the actual package(s) that provide locking/unlocking of the screen are functional. That still points us to a user (you) configuration issue that is housed in your /home/yoursusername directory.

Was screen locking/unlocking ever working with this installation of 20.04, or was it working, but at some point it stopped?

[bigdan]

Right, good question. This partition was a scratch install. (Loved the Kubuntu features combined with Studio). However, this install has never locked I am trying to make it my main partition.

Additional info --
I have another partition with studio and plasma installed under the original Ubuntu branch. That lock screen works.

So it is something with my configuration. I just can't seem to figure our what.

[Snowhog]

Let's try to eliminate some of the obscure possibilities. What Themes (Desktop, Cursor, Color, etc) are you using on the login session that isn't working? What are those same Themes on the new user login you created? Is the partition encrypted?

[Snowhog]

There is also another possibility: the Desktop Session isn't running on the expected tty. See https://ostechnix.com/how-to-switch-...keys-in-linux/

That's a wild guess, but is easy enough to check. By default (?) Ubuntu/Kubuntu use tty1 for the graphical session. From your Desktop press Ctrl+alt+F2 and you should be switched to non-graphical tty2. Press Ctrl+alt+F1. You should be switched to the Desktop Session. If instead, you are switched to another tty (tty1), then the Desktop Session is probably on tty7 (Ctrl+alt+F7).