Comment 11 for bug 1881380

OK, I am out of ideas.

I think we'll need a trace of a working enroll. Which hopefully does still work with the old packages from F31 or F30 (fprintd and libfprint).

Note, there are two things that you can do here:
 1. Run the exact same test with debug output. Luckily the driver prints quite a lot of information, so this might be enough to learn more.
 2. Run the test in umockdev-record to trace the USB transfers

For 2. you would need to install umockdev. Then wrap the fprintd binary with umockdev-record, something like:

  umockdev-record -i /dev/bus/usb/001/005=capture.ioctl -- fprintd

You can also build an old version of libfprint (the V_1_0 tag) from git and run the smaller enroll test in the repository. Replace 001/005 with the actual device path (these numbers match the bus and device number listed by lsusb).