Name the cause when libfprint cannot drive the fingerprint reader

[codeclawd]

omarchy-hw-fingerprint matches readers on vendor ID, and 06cb and 138a are both on its list. Three of those devices — 06cb:009a, 138a:0090 and 138a:0097 — have no libfprint driver at all; only the community's reverse-engineered python-validity daemon talks to them.

So omarchy setup security fingerprint detects a reader, installs libfprint-git, and runs all the way to enrollment before fprintd reports No devices available. That surfaces as:

Enrollment failed. Please try again.

which is indistinguishable from a bad swipe, and sends people into a retry loop that cannot succeed. The script already anticipates this shape of failure — the comment above setup_pam_config notes that an Elan MOC sensor outside the elanmoc table "gets this far and then fails to enroll" — this just names the cause for the three devices where it's knowable up front.

Change

On enrollment failure, check for those three IDs and say what's actually wrong:

Enrollment failed: libfprint has no driver for this reader.
It is a Synaptics/Validity sensor that only the community
python-validity driver can talk to, so retrying will not help:
  https://github.com/uunicorn/python-validity

Only the failure message changes. Nothing new is installed, the supported path is untouched, and the device list is python-validity's own udev match set from 94-validity-sensors.rules rather than a guess.

Verification

Tested on a ThinkPad T480 with 06cb:009a (Synaptics Metallica MIS Touch), where the reader does work once python-validity is driving it — fprintd-list goes from "No devices available" to "found 1 devices", and enrollment and fprintd-verify then succeed.

The helper honours OMARCHY_USB_DEVICES_PATH, so it is testable the same way omarchy-hw-fingerprint is:

• real sysfs on that machine → matches
• device tree containing only an unrelated 1234:5678 → declines
• empty device tree → declines

🤖 Generated with Claude Code

https://claude.ai/code/session_01CqYR76DqmNVGYtGYUpyJmv