Fingerprint support under Linux is spotty at best. For many laptops one will never be able to use it. Fortunately, somebody went through the effort to make drivers for VFS7500 Touch Fingerprint Sensor used on P70.
Unfortunately instructions to install it on Ubuntu 20.04 are not really complete so I here is what worked for me. Newer Ubuntu steps should be reasonably similar if not same but I haven't checked them from scratch.
First I installed a few packages. Since drivers use combination of snap and python, we obviously need them. GMP library is needed to as it's dependency of pyfast library.
Terminalsudo apt-get install --yes snapd python3-pip libgmp-dev
sudo pip install pyusb pycrypto pyfast
Then we can follow original install procedure:
Terminalsudo snap install validity-sensors-tools
sudo snap connect validity-sensors-tools:raw-usb
sudo snap connect validity-sensors-tools:hardware-observe
With all in place we can finally initialize reader:
Lastly, install libfprint TOD driver.
Terminalsudo add-apt-repository -u ppa:3v1n0/libfprint-vfs0090
sudo apt-get install --yes libfprint-2-tod-vfs0090
Now you should see Fingerprint Login in system's Users applet. Once you enroll your one or more finger, you should be able to use it for login.