Bug 462041

Summary:	Fingerprint unlock gets stuck after lock-then-sleep
Product:	[Unmaintained] kscreenlocker	Reporter:	me
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED FIXED
Severity:	major	CC:	boredsquirrel, nate, postix
Priority:	HI
Version First Reported In:	5.26.3
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:	6.0
Sentry Crash Report:

Description me 2022-11-19 23:42:17 UTC

SUMMARY
On my ThinkPad X220 Tablet with EndeavourOS, when I put to standby multiple times the computer and resume I can't unlock the computer anymore: it gets stuck saying that the fingerprint verification failed and inputting the password or the fingerprint won't do anything until I wait a minute or so for the fingerprint verification to actually fail. In that moment I can only unlock the computer with the password even if I lock it again until the next boot.

STEPS TO REPRODUCE
1. Standby and unlock a bunch of times

OBSERVED RESULT
I can't unlock for a minute and then I can only unlock with the password until the next boot.

EXPECTED RESULT
It should always be ready to unlock with either the fingerprint or the password without waiting for any phantom verification to fail.

SOFTWARE/OS VERSIONS
Linux: EndeavourOS
KDE Plasma Version: 5.26.3
KDE Frameworks Version: 5.100.0
Qt Version: 5.15.7

ADDITIONAL INFORMATION
The fingerprint sensor is called "Upek TouchChip Fingerprint Coprocessor" by the system.

Comment 1 Nate Graham 2022-11-29 22:35:55 UTC

I can confirm this on my system.

Comment 2 postix 2023-08-17 19:34:41 UTC

Can you still reproduce it? Seems to work for on Fedora 38. Though, bug #455578 bothers me, which shows a password field without function additional to the fingerprint auth.

Comment 3 Bug Janitor Service 2023-09-01 03:45:30 UTC

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

Comment 4 postix 2023-09-06 11:10:06 UTC

The following way I can always reproduce it:

1) Lock the screen with Meta+L
2) Click on the StandBy-Button
3) Wake up the laptop

The fingerprint unlocking no longer works. If I don't lock the screen in beforehand but go straight to standby, unlocking via fingerprint works.

Comment 5 Nate Graham 2023-09-14 19:28:06 UTC

*** Bug 474528 has been marked as a duplicate of this bug. ***

Comment 6 postix 2023-09-29 12:29:53 UTC

Sorry, I had referenced the wrong issue in comment 2: it's correctly described now with bug #475024
(When not going to standby, but simply unlocking with Meta+L, unlocking by password instead of the fingerprint takes >20 seconds for me.)

Comment 7 postix 2023-09-29 12:58:48 UTC

I've logged in into my laptop via ssh and observed the journalctl output:

After step 3) in comment 4 I have put my finger on the finger print read serveral times: A single time, after the first or second try the following was logged:

```
kscreenlocker_greet: pam_fprintd(kde:auth): ReleaseDevice failed: Release failed with error: The device is still busy with another operation, please try again later.
```

Comment 8 Nate Graham 2023-11-03 03:53:03 UTC

This should be fixed in Plasma 6 now with a new authentication architecture used for the lock screen.