Unable to set up Fingerprint Scanner on Lenovo Thinkpad x270 & Linux Mint 20.2

Hi,

I have a Lenovo Thinkpad x270 with Linux Mint 20.2. The fingerprint scanner shows up in lsusb as so:

Bus 001 Device 004: ID 138a:0097 Validity Sensors, Inc.

I have fprintd, libpam-fprintd, installed.

I have used this tool: https://snapcraft.io/validity-sensors-tools
and validated it using the 'sudo validity-sensors-tools.led-test' command. (However, it does give me this semi-erroneous output):

Found device <DEVICE ID 138a:0097 on Bus 001 Address 006>
Opening device 0x97
Sleeping...
Try 1 failed with error: Failed: 0315
Let's glow the led!

I am able to use 'validity-sensors-tools.enroll --finger-id 1' to enroll a fingerprint using this tool as so (other times ive tried this i've had no errors, but on this try I did get a few, still finished successfully)

Found device <DEVICE ID 138a:0097 on Bus 001 Address 006>
Opening device 0x97
Sleeping...
Try 1 failed with error: Failed: 0315
Waiting for a finger...
Progress: 14 % done
Progress: 28 % done
Progress: 42 % done
Progress: 57 % done
Progress: 71 % done
Error 00080000, try again
Error 00080000, try again
Progress: 85 % done
Progress: 100 % done
All done

I'm guessing this error 00080000 is nothing major, just fingerprint scanning happened to fail. I had to press the fingerprint scanner between every 'progress' line.

So, according to the snapcraft website for this tool (link above), once I have installed the drivers here: https://github.com/3v1n0/libfprint/ then I should be good to go with fprintd-enroll.

However, the first time I run it, i'm given an error with device protocol, followed by a 'device is already open' error on the next attempt:

bcsm@thinkpad-x270:/tmp$ fprintd-enroll
Using device /net/reactivated/Fprint/Device/0
failed to claim device: GDBus.Error:net.reactivated.Fprint.Error.Internal: Open failed with error: The driver encountered a protocol error with the device.

bcsm@thinkpad-x270:/tmp$ fprintd-enroll
Using device /net/reactivated/Fprint/Device/0
failed to claim device: GDBus.Error:net.reactivated.Fprint.Error.Internal: Open failed with error: Device 138a:0097 is already open

Every subsequent attempt gives the second error message.

I've got fingerprint stuff set up in pam, but i think that's irrelevant at this stage.

I believe i've provided all info, but this is the second time I've given getting this set up a go, so there may be some installation of libraries etc i've forgotten.

I've also tried:

• fwupdmgr - fingerprint scanner not present as a device that could be updated, there was some updates available for other devices, did so but did not aid this
• stopping & restarting fprintd - same pattern of error output still occurred. Still present after reinstalling it
• Redoing firmware initialisation and setting up enrolling using that first snap tool

I'm confident it must be possible as people seem to be able to get it working with an x270 and other distros, e.g Ubuntu (which further makes me think it should be possible given I'm on Mint)

Thank you very much for your time