I have Arch Linux installed with deepin desktop environment and lightdm. Greeter is lightdm-deepin-greeter. I have installed fprintd, configured fingerprint, i can successfully login to sudo with fingerprint, but not login in greeter. I have set files in /etc/pam.d to contain auth sufficient pam_fprintd.so.
Try to set
auth sufficient pam_fprintd.so in
/etc/pam.d/lightdm instead of
lightdm-greeter, it works for me. BUT that's still far away from unlock with finger from resume to suspended state. In case you may ask about it soon, I afford the useful answers that I gathered here: fprint timing out and Fingerprint reader doesn't work after sleep.
I personally don't figure out a workaround yet ╮(╯▽╰)╭.