Xiaomi Fingerprint
Solution 1:
Had the same issue solved by installing fingerprint+gui package. After adding this package Ubuntu recognised the fingerprint HW.
Add ppa source:
sudo apt-add-repository ppa:fingerprint/fingerprint-gui
Update source list:
sudo apt-get update
Install necessary packages:
sudo apt-get install libbsapi policykit-1-fingerprint-gui fingerprint-gui
Installing this packages will overwrite/remove default package "policykit-gnome" In case you decide to remove this PPA, reinstall default policykit.