Thinkpad acpi_call not working on Debian Sid

[Apurv J <appjoe.beta@gmail.com>]

Hi,

I've been trying use certain features offered by tlp (like discharging and re-calibration) but getting an error. Did a little digging and found out some clues as to what's going on.

output of "tlp-stat -b":
> tpacpi-bat (acpi_call)  = inactive (kernel error)

searching in the logs using journalctl I got:
> acpi_call: loading out-of-tree module taints kernel.
> 440 kernel: acpi_call: module verification failed: signature and/or required key missing - tainting kernel

I'm using a Thinkpad T440, secureboot disabled. Kernel: 5.15.0-2-amd64.

Is this a bug?

Regards,
Apurv