Possibly a race on boot: fingerprint not operational

REPRODUCIBILITY (% or how often): high
BUILD ID = OS VERSION (Settings > About product): noticed on 4.0, tested on 4.1, confirmed on 4.2
HARDWARE (XA2, X10, X10 II, …): XA2
UI LANGUAGE: na
REGRESSION: (compared to previous public release: Yes, No, ?): unknown

DESCRIPTION:

Fingerprint doesn’t always work after boot

PRECONDITIONS:

Might be necesssary to have it on for some time and battery saving mode active (not too low value??)

STEPS TO REPRODUCE:

  1. Let the device run out of battery
  2. Connect to powersupply, boot it up,
  3. Unlock it promptly

EXPECTED RESULT:

Fingerprint is operational

ACTUAL RESULT:

Fingerprint is not always operational

ADDITIONAL INFORMATION:

(Please ALWAYS attach relevant data such as logs, screenshots, etc…)
I tested this on 4.1, more than 20 times…
The device, XA2, was encrypted, with “defaultuser”. I saw this once or twice on an XA2plus, unencrypted, “nemo”.
After the first PIN prompt, the spinner stutters.

Workaround:
Set DefaultStartLimitInterval to 180 s (/etc/systemd/system.conf).
At least, I couldn’t reproduce it then…

Additionally:
Quite often, this was acompanied by the SIM PIN entry misbehaving. The UI claimed that the SIM PIN was incorrect, when it was correct. SIM PIN not re-entered a second time, continued without unlocking the SIM. Then, the network icon was grayed out, calling out was not possible, but, receiving calls worked, “unlocking” the SIM in settings by tapping on it, disabling and enabling was possible without entering the SIM PIN.

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