Bug 500357

Summary: Fingerprint authentication doesn't work in lock screen
Product: [Plasma] plasmashell Reporter: Foxe Chen <foxeproger>
Component: Screen lockingAssignee: Plasma Bugs List <plasma-bugs>
Status: RESOLVED DUPLICATE    
Severity: normal CC: nate
Priority: NOR    
Version First Reported In: 6.3.0   
Target Milestone: 1.0   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Foxe Chen 2025-02-18 22:49:15 UTC
SUMMARY
After upgrading to plasma 6.3, fingerprint authentication stopped working in the lock screen when the session is locked indirectly. My fingerprint authentication works properly in other applications such as sudo or polkit.

STEPS TO REPRODUCE
1. Enroll fingerprint
2. Do something such as suspending or closing laptop lid
3. Open back to lock screen

OBSERVED RESULT
When the fprintd daemon is not running, the screen locker still shows the prompt "or scan your fingerprint on the reader". However, if I try doing that, it shortly disappears right after without ever unlocking the session. If the fprintd daemon is running, I never get the prompt to use my fingerprint in the first place. Weird thing is that if I directly lock the current session using the button in the application launcher, the prompt appears and fingerprint authentication works fine.

EXPECTED RESULT
Fingerprint authentication should work consistently

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 6.3.1
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2
Kernel Version: 6.13.3-2-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 7640U w/ Radeon 760M Graphics
Memory: 27.2 GiB of RAM
Graphics Processor: AMD Radeon 760M

ADDITIONAL INFORMATION
These are the fprintd systemd service logs if it is not running before attempting to unlock the session:
```
Feb 18 17:44:09 archlinux systemd[1]: Starting Fingerprint Authentication Daemon...
Feb 18 17:44:10 archlinux fprintd[8107]: Failed to install a sleep delay inhibitor: GDBus.Error:org.freedesktop.login1.OperationInProgres>
Feb 18 17:44:10 archlinux systemd[1]: Started Fingerprint Authentication Daemon.
Feb 18 17:44:15 archlinux fprintd[8107]: Device reported an error during verify: device was disconnected
Feb 18 17:45:01 archlinux systemd[1]: fprintd.service: Deactivated successfully.
```
Comment 1 Foxe Chen 2025-02-18 22:51:26 UTC
* When I mean the fprintd daemon is running or not, I mean if it was running or not before the screenlocker appeared
Comment 2 Nate Graham 2025-02-18 22:55:49 UTC

*** This bug has been marked as a duplicate of bug 499893 ***
Comment 3 Nate Graham 2025-04-18 17:28:36 UTC

*** This bug has been marked as a duplicate of bug 499637 ***