Bug 494927

(In reply to Airbag from comment #0)

> OBSERVED RESULT
> The field for entering the password is blanked, nothing else is changed, no
> error message, the unlock screen stays on screen.
> You can try to type the password again for the same result.
> 

Little correction : nothing _at all_ happens when pressing enter. (The password field is not blanked)

I believe I have the same issue. For me it seems to occur when I dock or undock my laptop while it's suspended. When I type my password, nothing happens. It seems to fix itself sometimes if I suspend and unsuspend a few times.

OS:
Arch Linux
kernel 6.11.3-arch1-1
kscreenlocker 6.2.1-1
Plasma 6.2.1
KDE Frameworks 6.7.0
Qt Version 6.8.0
Graphics Platform Wayland

AMD cpu and gpu

Logs:
Oct 18 23:52:31 host kscreenlocker_greet[7107]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Oct 18 23:52:39 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object TypeError: Type error is not a function
Oct 18 23:52:40 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:42 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:42 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:42 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:42 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:42 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:42 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:43 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:43 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:43 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:43 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:43 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:44 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:44 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:44 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:44 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:52:44 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:01 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:07 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:09 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:11 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:11 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:11 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:11 host kscreenlocker_greet[7107]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.003385616941083,-0.0009141251735766687,-0.0009141251735766687,0,0,1.0042997421146598,0,0,0,0,1.0042997421146598,0,0,0,0,1 is not a function
Oct 18 23:53:11 host kernel: kscreenlocker_g[7107]: segfault at 76f01b6dcb48 ip 000076f047bb7490 sp 00007ffc755fb258 error 4 in libQt6Qml.so.6.8.0[1b7490,76f047aa7000+3de000] likely on CPU 2 (core 1, socket 0)
Oct 18 23:53:12 host kscreenlocker_greet[7530]: pam_systemd_home(kde:auth): New sd-bus connection (system-bus-pam-systemd-home-7530) opened.
Oct 18 23:53:18 host kscreenlocker_greet[7530]: Failed to write to the pipe: Bad file descriptor.

I also have the same behavior where the password is not cleared

Perhaps it's an issue with arch's package?

I had the bug reproduced without the 2nd screen, so I edit the title.

Like the previous comments, I have the repetition of "LockScreenUi.qml:280: TypeError: Property 'respond' of object ". 
It happens each time I try to unlock (by pressing enter or clicking on the 'submit' button)

If I open a virtual terminal (with Control Alt F3) to read the log, I see that after toggling between the KDE session and the virtual terminal a few times (and spamming attempts to unlock the session), kscreenlocker eventually segfaults.

After that I can unlock normally the session (with the new "autospawned" kscreenlocker)

> If I open a virtual terminal (with Control Alt F3) to read the log, I see
> that after toggling between the KDE session and the virtual terminal a few
> times (and spamming attempts to unlock the session), kscreenlocker
> eventually segfaults.
> 
> After that I can unlock normally the session (with the new "autospawned"
> kscreenlocker)

I found similar behavior when sleeping and waking over and over again. Eventually kscreenlocker would segfault, and the restarted version worked fine.

I also experience the same behavior after suspend.
using loginctl session-unlock from different terminal I can unlock the session.

This bug might be a duplicate of this 7 months old bug : https://bugs.kde.org/show_bug.cgi?id=483094

(In reply to Airbag from comment #8)
> This bug might be a duplicate of this 7 months old bug :
> https://bugs.kde.org/show_bug.cgi?id=483094

These look like different bugs. The error messages are different. The symptoms are also subtly different.

The error messages are probably not related, but what subtle differences in symptoms between the two bugs do you see?

Cannot reproduce the failure to unlock, FWIW.

(In reply to Nate Graham from comment #10)
> The error messages are probably not related, but what subtle differences in
> symptoms between the two bugs do you see?

For me, kscreenlocker does not become completely unresponsive, only the password field. For example, I can press the sleep button, which will correctly cause the laptop to sleep.

I wonder if there are some specific triggering conditions. That will explain that a majority of people are not affected.
For me : my monitor is in 3840x2160 and I use 200% scaling, and an ICC profile.
Do you have any of these unusual settings ?

Nope, but my laptop screen is 1920x1200, and my external monitor is 1920x1080. I must note that for me the issue ONLY occurs when I'm switching between using the external monitor and laptop screen. Once I unlock the screen using the loginctl trick, it works fine until I switch displays again.

I wonder if this is an arch exclusive issue? Do we have any reproductions that aren't on arch

Operating System: Manjaro Linux 
KDE Plasma Version: 6.2.1
KDE Frameworks Version: 6.7.0
Qt Version: 6.8.0
Kernel Version: 6.11.4-1-MANJARO (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 PRO 6850H with Radeon Graphics
Memory: 30.6 GiB of RAM
Graphics Processor: AMD Radeon Graphics
Manufacturer: LENOVO
Product Name: 21D4CTO1WW
System Version: ThinkPad Z16 Gen 1

> paź 23 07:59:20 kamil-thinkpad-z16 kscreenlocker_greet[16522]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 1.000377952,-0.00010204800000000765,-0.00010204800000000765,0,0,1.00048,0,0,0,0,1.00048,0,0,0,0,1 is not a function
> paź 23 07:59:20 kamil-thinkpad-z16 kscreenlocker_greet[16522]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object 1.000377952,-0.00010204800000000765,-0.00010204800000000765,0,0,1.00048,0,0,0,0,1.00048,0,0,0,0,1 is not a function
> paź 23 07:59:23 kamil-thinkpad-z16 kernel: kscreenlocker_g[16522]: segfault at 74bbb4d3d088 ip 000074bbdd9b7490 sp 00007ffd373c3198 error 4 in libQt6Qml.so.6.8.0[1b7490,74bbdd8a7000+3de000] likely on CPU 14 (core 7, socket 0)

I can log in only if I try on second screen, kscreenlocker crashes and restarts.

Eureka ! On my setup, I found a way to reproduce the problem at will (and a workaround to avoid it completely)

1. Lock the screen manually (or wait for the X min delay you have set up in the settings), and wait for the screen to turn off / go in standby mode
2. Wake up the screen *with the mouse*
3. You can't unlock as previously described

How to avoid the problem => change step 2 :
2. Wake up the screen *with the keyboard* (don't touch the mouse at all) => You can unlock normally.

Interesting. In step 2, you say "wake up  the screen", but  screen locking doesn't automatically put screens to sleep. Is a step missing?  Maybe you have to wait 60 seconds after locking so the screen does go to sleep?

> How to avoid the problem => change step 2 :
> 2. Wake up the screen *with the keyboard* (don't touch the mouse at all) =>
> You can unlock normally.

Interesting... I only wake up my computer with the keyboard when it's docked (bluetooth mouse) or by opening the lid, when it isn't. I consistently experience the issue after docking and undocking, but it only happens once. (After I use the loginctl trick it works like normal until I unplug or plug it in to the monitor again)

This just happened to me as well. Similar excerpts after waking up:

> Oct 24 10:00:58 quint plasmashell[272551]: KCrash: Application 'plasmashell' crashing... crashRecursionCounter = 2
> Oct 24 10:00:58 quint plasmashell[272551]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
> Oct 24 10:00:58 quint systemd-coredump[374611]: Process 272551 (plasmashell) of user 2001 terminated abnormally with signal 11/SEGV, processing...
> Oct 24 10:00:58 quint kscreenlocker_greet[330970]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
> Oct 24 10:01:16 quint kscreenlocker_greet[330970]: file:///home/kpetso/build/prefix/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object TypeError: Type error is not a function
> Oct 24 10:01:16 quint systemd[2335]: plasma-plasmashell.service: Scheduled restart job, restart counter is at 2.
> Oct 24 10:01:16 quint systemd[2335]: Starting KDE Plasma Workspace...
> Oct 24 10:01:17 quint systemd[2335]: Started KDE Plasma Workspace.
> Oct 24 10:01:20 quint kscreenlocker_greet[330970]: file:///home/kpetso/build/prefix/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object length is not a function
> Oct 24 10:01:26 quint kscreenlocker_greet[330970]: file:///home/kpetso/build/prefix/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object length is not a function
> Oct 24 10:01:28 quint kscreenlocker_greet[330970]: file:///home/kpetso/build/prefix/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object length is not a function
> Oct 24 10:02:04 quint kscreenlocker_greet[330970]: file:///home/kpetso/build/prefix/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object length is not a function

System info via Info Center:

Operating System: Arch Linux 
KDE Plasma Version: 6.2.80 (a few days before 6.2.2, I think)
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.0
Kernel Version: 6.11.4-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8565U CPU @ 1.80GHz
Memory: 15.3 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620
Manufacturer: LENOVO
Product Name: 20QD001VUS
System Version: ThinkPad X1 Carbon 7th

Possibly related to display configuration changes, as the system went to sleep as I unplugged the monitor/power USB-C cable.

The plasmashell crash may or may not be related.

> The plasmashell crash may or may not be related.

I should add that I did `coredumpctl debug -1` for the plasmashell crash, but it didn't give me any kind of backtrace. Probably stuck in some QML JavaScript interpreter parts when it crashed.

I linked this together with Bug 493145, which I haven't read in full, much less analyzed the differences to tell whether the two are duplicates. Seems very similar to me on first glance, though.

In both bug reports, it seems like all systems are using Qt 6.8 so that's likely relevant here. Personally, I had not hit this issue until I updated to 6.8 a few days ago, even though I had rebuilt all of Plasma once or twice in October.

*** Bug 495031 has been marked as a duplicate of this bug. ***

(In reply to Nate Graham from comment #17)
> Interesting. In step 2, you say "wake up  the screen", but  screen locking
> doesn't automatically put screens to sleep. Is a step missing?  Maybe you
> have to wait 60 seconds after locking so the screen does go to sleep?

It's in step 1 :
1. Lock the screen manually (or wait for the X min delay you have set up in the settings), and wait for the screen to turn off / go in standby mode

(In reply to Nate Graham from comment #17)
> Interesting. In step 2, you say "wake up  the screen", but  screen locking
> doesn't automatically put screens to sleep. Is a step missing?  Maybe you
> have to wait 60 seconds after locking so the screen does go to sleep?

It's in step 1 :
1. Lock the screen manually (or wait for the X min delay you have set up in the settings), and wait for the screen to turn off / go in standby mode(In reply to Nate Graham from comment #17)
> Interesting. In step 2, you say "wake up  the screen", but  screen locking
> doesn't automatically put screens to sleep. Is a step missing?  Maybe you
> have to wait 60 seconds after locking so the screen does go to sleep?

But you are right, I have to be more precise.
Note : I did these additional tests with latest kscreenlocker (6.2.2-1 on archlinux)

1. Lock the screen manually (or wait for the X min delay you have set up in the settings), and wait for the screen to turn off / go in standby mode
2. Wake up the screen (move/clic mouse once or press the keyboard once)
3. Trigger the unlock prompt from  (move/clic mouse once or press the keyboard once)
4. Type the password and press enter

Surprising discovery :
If I use mouse for *both* step 2 and step 3 : I reproduce the problem.
If I use keyboard for step 2, or step 3, or both : I do not reproduce the problem.

I think this is probably the same bug as https://bugs.kde.org/show_bug.cgi?id=493145?

They're both bugs that exclusively appear on Qt 6.8. They both reflect some kind of pointer issue. People reporting the issue in this thread have mostly seen the "Property 'respond' of object 1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1 is not a function" type of error, which results in a freeze in the authentication process and the password field gets stuck.

This doesn't sound like a programming bug in kscreenlocker to me, it looks like in the line

authenticator.respond(password)

The Qt internal pointer to the authenticator object has gotten corrupted, resulting in the nonsensical debugging statement seen here.

People over on the other bug are mostly seeing segfaults, which looks a little different in the logs and sometimes seems to result in kscreenlocker being restarted and it becoming possible to log in, but I think it's probably the same issue?

(In reply to Adam Fontenot from comment #25)
> People over on the other bug are mostly seeing segfaults, which looks a
> little different in the logs and sometimes seems to result in kscreenlocker
> being restarted and it becoming possible to log in, but I think it's
> probably the same issue?

For what it's worth, I've also occasionally seen segfaults in my logs, usually after spamming sleep/wake up.

*** Bug 495404 has been marked as a duplicate of this bug. ***

I'm experiencing this, too...

Whenever I want to unlock my screen after the delay time, I can type my password, but the button click doesn't have any visible result. 
Then, I click on "Switch user" and at the login screen I can type my password and login.

It's independent from mouse or keyboard usage for me.

My configuration:
Operating System: openSUSE Tumbleweed 20241023
KDE Plasma Version: 6.2.1
KDE Frameworks Version: 6.7.0
Qt Version: 6.8.0
Kernel Version: 6.11.3-2-default (64-bit)
Graphics Platform: Wayland
Processors: 32 × AMD Ryzen 9 7950X 16-Core Processor
Memory: 62.0 GiB of RAM
Graphics Processor: AMD Radeon RX 6600
Manufacturer: ASRock
Product Name: B650M PG Riptide

*** Bug 495467 has been marked as a duplicate of this bug. ***

*** Bug 495396 has been marked as a duplicate of this bug. ***

*** Bug 493145 has been marked as a duplicate of this bug. ***

This is happening for me as well, but only with one screen connected, while for others it seems to be two screens.

I have the same problem on Arch Linux (up to date), I also have this problem, it seems that when the lock screen has its own image set the problem is worse, when I changed the regular color it is a bit better

*** Bug 495573 has been marked as a duplicate of this bug. ***

I'm experiencing this issue as well, also on Arch Linux. I don't have an actual second screen plugged in, but the display settings do show me a second "display" which is actually just a strange duplicate of my laptop's screen. I have this erroneous display disabled. My workaround is to select "Switch User" which sends me back to SDDM from where I can log in. I haven't checked for what errors show when I attempt to log in, I'll do that next time it happens. This only happens to me sometimes, I can't tell if it's duration-based or random.

I have the same problem sometimes on my laptop:

1. Close the screen lid -> laptop goes to standby
2. Unplug external screen, go to office and plug external screen there, open lid -> laptop awakens from standby
3. Enter password on external screen (don't know if the password field is always shown there) + enter -> nothing happens
(4. login on different tty and enter `loginctrl unlock-session 1` to successfully unlock)

logs:
Nov 01 12:31:14 myhost kscreenlocker_greet[471716]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
Nov 01 12:31:50 myhost kscreenlocker_greet[471716]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object TypeError: Type error is not a function
Nov 01 12:31:50 myhost kscreenlocker_greet[471716]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object 0.9908571428571429,0,0,0,0,0.9908571428571429,0,0,0,0,0.9908571428571429,0,0.00457142857142856,0.00457142857142856,0.00457142857142856,1 is not a function
Nov 01 12:31:54 myhost kscreenlocker_greet[471716]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 0.9908571428571429,0,0,0,0,0.9908571428571429,0,0,0,0,0.9908571428571429,0,0.00457142857142856,0.00457142857142856,0.00457142857142856,1 is not a function
Nov 01 12:32:00 myhost kscreenlocker_greet[471716]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:128: TypeError: Property 'startAuthenticating' of object 0.9908571428571429,0,0,0,0,0.9908571428571429,0,0,0,0,0.9908571428571429,0,0.00457142857142856,0.00457142857142856,0.00457142857142856,1 is not a function
Nov 01 12:32:01 myhost kscreenlocker_greet[471716]: file:///usr/share/plasma/shells/org.kde.plasma.desktop/contents/lockscreen/LockScreenUi.qml:280: TypeError: Property 'respond' of object 0.9908571428571429,0,0,0,0,0.9908571428571429,0,0,0,0,0.9908571428571429,0,0.00457142857142856,0.00457142857142856,0.00457142857142856,1 is not a function
Nov 01 12:34:30 myhost kscreenlocker_greet[473837]: pam_systemd_home(kde:auth): New sd-bus connection (system-bus-pam-systemd-home-473837) opened.

system:
Operating System: Arch Linux 
KDE Plasma Version: 6.2.2
KDE Frameworks Version: 6.7.0
Qt Version: 6.8.0
Kernel Version: 6.11.5-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 30.9 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620
Manufacturer: LENOVO
Product Name: 20KS0039GE
System Version: ThinkPad E580

I am also experiencing this issue with the latest version of KDE Neon fully updated to KDE desktop 6.2.2

Is this issue maybe connected to https://bugs.kde.org/show_bug.cgi?id=494804? There it seems to be a problem with changed behavior in the QML garbage collector.

*** Bug 495729 has been marked as a duplicate of this bug. ***

(In reply to Marcel Hasler from comment #38)
> Is this issue maybe connected to
> https://bugs.kde.org/show_bug.cgi?id=494804? There it seems to be a problem
> with changed behavior in the QML garbage collector.

I switched away from sddm and i still have this problem, so that link is specific to sddm (the title seems to imply that) it may be unrelated. In fact i've never experienced the problem on the initial login screen. only ever on the lock screen.

(In reply to craig+kde from comment #40)
> (In reply to Marcel Hasler from comment #38)
> > Is this issue maybe connected to
> > https://bugs.kde.org/show_bug.cgi?id=494804? There it seems to be a problem
> > with changed behavior in the QML garbage collector.
> 
> I switched away from sddm and i still have this problem, so that link is
> specific to sddm (the title seems to imply that) it may be unrelated. In
> fact i've never experienced the problem on the initial login screen. only
> ever on the lock screen.

I didn't mean to imply that sddm causes the bug in kscreenlocker – these two are obviously unrelated – but that both issues are caused by the same regression in Qt 6.8 (or a bug in the Breeze theme in combination with the new Qt version).

Seeing the same issue on KDE Neon so it's not just an Arch thing.

Also have the issue on Bazzite, which is based on Fedora 41.  It only started happening after the update to Qt 6.8.  (I'd already been on Plasma 6.2.2 before then, and it was fine.)

I'm using a desktop with only one screen.  I wake the machine by pressing the power button, enter my password, hit enter (or click the arrow) and nothing happens.  I can still click the other buttons on the screen and they work fine, so my workaround is to press the button to switch users, then just type my password there.  (There's only one user on the system.)

The workaround mentioned in https://bugs.kde.org/show_bug.cgi?id=494804#c51 works for me. I've added 'QV4_GC_TIMELIMIT=0' to /etc/environment and haven't had any problems with either kscreenlocker or sddm since. It probably has other side-effects, but as a temporary workaround it seems to be okay.

Today's update to kscreenlocker 6.2.3-1, on Arch, had not effect. Regression is still present.

A report has been filed upstream (https://bugreports.qt.io/browse/QTBUG-130767) for the Qt issue presumably causing this, but I have also seen comments suggesting that this is only occurring on the Breeze theme, which may suggest a bug there as well. Is anyone experiencing this issue with another theme?

*** Bug 495912 has been marked as a duplicate of this bug. ***

(In reply to Torabi from comment #46)
> A report has been filed upstream
> (https://bugreports.qt.io/browse/QTBUG-130767) for the Qt issue presumably
> causing this, but I have also seen comments suggesting that this is only
> occurring on the Breeze theme, which may suggest a bug there as well. Is
> anyone experiencing this issue with another theme?

I just switched to Oxygen theme (in Plasma Style settings), so far it seems this workaround works.

(In reply to Airbag from comment #48)
> (In reply to Torabi from comment #46)
> > A report has been filed upstream
> > (https://bugreports.qt.io/browse/QTBUG-130767) for the Qt issue presumably
> > causing this, but I have also seen comments suggesting that this is only
> > occurring on the Breeze theme, which may suggest a bug there as well. Is
> > anyone experiencing this issue with another theme?
> 
> I just switched to Oxygen theme (in Plasma Style settings), so far it seems
> this workaround works.

I spoke too fast, the problem is still here with Oxygen theme.

*** Bug 495936 has been marked as a duplicate of this bug. ***

*** Bug 495966 has been marked as a duplicate of this bug. ***

I do have the same issue.

Arch Linux
Plasma 6.2.3
Wayland
Kernel LTS

*** Bug 496007 has been marked as a duplicate of this bug. ***

It seems like a very weird and deep issue in Qt. A workaround is in progress with https://invent.kde.org/plasma/kscreenlocker/-/merge_requests/245.

*** Bug 493829 has been marked as a duplicate of this bug. ***

Lowering priority since this works as expected with a single screen, and moving to plasmashell | theme - breeze since it manifests due to an issue with the theme's QML code (though ultimately it's a Qt issue).

Looks like the login screen issue reported in Bug 494804 does have the same root cause. Marking as a duplicate so we can track everything in once place.

*** This bug has been marked as a duplicate of bug 494804 ***

(In reply to Nate Graham from comment #58)
> Lowering priority since this works as expected with a single screen

That is not true. I have experienced this on a single monitor, not multiple monitors, since the beta release. Other reports have confirmed the issue as well on single monitors. But good that it was tracked down to Qt6. I'll be happy to test the patch when it's ready.

Ok, re-raising the priority on the other one, then.

(In reply to Nate Graham from comment #61)
> Ok, re-raising the priority on the other one, then.

I was about to add, I only have one monitor and I am seeing this.

I also have only one screen ...

This issue seems to be resolved for me

After the upgrade to qt-declarative 6.8.0-6 from the Arch official repository, the issue ceased for me. Finally regression free KDE6.