Comment 0 for bug 1305440

It might be desirable to have a distinct pam config file when logging in and when unlocking the screen. Specifically, using a fingerprint reader is fine for sudo or for unlocking, but you want to use your password when logging in, to provide a secret and be able to unlock the gnome-keyring for example.

See http://askubuntu.com/questions/445131/how-do-i-enable-a-specific-pam-config-in-the-lockscreen

So this feature request is about allowing for a (optional) pam config file for the lock-screen, distinct from the /etc/pam.d/lightdm currently used and shared with the greeter.