How to enable integrated fingerprint reader with fprint
Ubuntu 11.04
The integrated fingerprint reader on the ThinkPad X220 (at least) is well supported in Template:Ubuntu 11.04 (natty).
Install the necessary packages if they aren't already present.
aptitude install libpam-fprintd
Confirm that the needed lines in common-auth are already present.
$ grep fprint /etc/pam.d/common-auth auth [success=2 default=ignore] pam_fprintd.so
Log in to the desktop using your password. Open a terminal. In the terminal run fprintd-enroll and swipe your right index finger five times.
Now you should be able to log in by swiping your right index finger.