setup-fingerprint-thinkpad-linux.md

Fingerprint Reader Setup on Linux - Synaptics Sensors

Complete guide for configuring Synaptics fingerprint readers (including Metallica MIS Touch) on Linux distributions using python-validity and fprintd.

Device Compatibility

This guide specifically covers Synaptics fingerprint sensors that require proprietary drivers:

• Synaptics Metallica MIS Touch (06cb:009a)
• Synaptics Prometheus (06cb:0081)
• Synaptics VFS series (various IDs)

Check your device:

lsusb | grep -i synaptics
# Example output: Bus 001 Device 011: ID 06cb:009a Synaptics, Inc. Metallica MIS Touch Fingerprint Reader

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Table of Contents

1. Arch/Manjaro Installation
2. Ubuntu/Debian Installation
3. Fedora Installation
4. Fingerprint Enrollment
5. PAM Configuration
6. GNOME Integration
7. KDE Plasma Integration
8. Troubleshooting
9. Uninstallation

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Arch/Manjaro

Installation

# Install required packages
yay -S python-validity fprintd

# Enable and start python-validity service
sudo systemctl enable --now python3-validity.service

# Download firmware (if prompted)
sudo validity-sensors-firmware

Verification

# Check service status
systemctl status python3-validity.service

# Verify device detection
fprintd-list $USER

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Ubuntu/Debian

Installation

# Update package list
sudo apt update

# Install dependencies
sudo apt install -y fprintd libfprint-2-2 python3-pip python3-dev \
    libssl-dev libusb-1.0-0-dev git build-essential

# Clone python-validity repository
cd /tmp
git clone https://github.com/uunicorn/python-validity.git
cd python-validity

# Install python-validity
sudo pip3 install .

# Install systemd service
sudo python3 validity-sensors-firmware
sudo systemctl enable --now python3-validity.service

Alternative: PPA Method (Ubuntu 20.04+)

# Add PPA (community-maintained)
sudo add-apt-repository ppa:uunicorn/open-fprintd
sudo apt update

# Install packages
sudo apt install -y python3-validity fprintd

# Enable service
sudo systemctl enable --now python3-validity.service

Verification

systemctl status python3-validity.service
fprintd-list $USER

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Fedora

Installation

# Install dependencies
sudo dnf install -y fprintd fprintd-pam python3-pip python3-devel \
    openssl-devel libusbx-devel git gcc

# Clone python-validity repository
cd /tmp
git clone https://github.com/uunicorn/python-validity.git
cd python-validity

# Install python-validity
sudo pip3 install .

# Download firmware and install service
sudo python3 validity-sensors-firmware
sudo systemctl enable --now python3-validity.service

SELinux Configuration (if enabled)

# Check SELinux status
sestatus

# If enforcing, create policy for python-validity
sudo ausearch -c 'python3' --raw | audit2allow -M python-validity-policy
sudo semodule -i python-validity-policy.pp

# Restart service
sudo systemctl restart python3-validity.service

Verification

systemctl status python3-validity.service
journalctl -u python3-validity.service -f

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Fingerprint Enrollment

Command Line Enrollment

# Enroll default finger (right index)
fprintd-enroll

# Enroll specific finger
fprintd-enroll -f left-index-finger

# Available fingers:
# left-thumb, left-index-finger, left-middle-finger, left-ring-finger, left-little-finger
# right-thumb, right-index-finger, right-middle-finger, right-ring-finger, right-little-finger

Process:

1. Follow prompts to scan the same finger 5 times
2. Vary finger placement slightly for better recognition
3. Ensure finger is clean and dry

List Enrolled Fingerprints

# Show enrolled fingerprints for current user
fprintd-list $USER

# Delete specific fingerprint
fprintd-delete $USER

# Delete and re-enroll
fprintd-delete $USER && fprintd-enroll

Test Authentication

# Verify fingerprint authentication
fprintd-verify

# Expected output:
# Using device /net/reactivated/Fprint/Device/0
# Verify result: verify-match (or verify-no-match)

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PAM Configuration

Sudo Authentication

sudo nano /etc/pam.d/sudo

Add before the first auth line:

auth sufficient pam_fprintd.so

Result: Fingerprint prompt for sudo commands, password fallback.

System Login

GDM (GNOME Display Manager):

sudo nano /etc/pam.d/gdm-password

SDDM (KDE Plasma):

sudo nano /etc/pam.d/sddm

LightDM:

sudo nano /etc/pam.d/lightdm

Add:

auth sufficient pam_fprintd.so

Lock Screen

GNOME:

sudo nano /etc/pam.d/gnome-screensaver

KDE:

sudo nano /etc/pam.d/kde

Add:

auth sufficient pam_fprintd.so

Polkit (Administrative Actions)

sudo nano /etc/pam.d/polkit-1

Add:

auth sufficient pam_fprintd.so

Result: Use fingerprint for privileged GUI operations (software installation, system settings).

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GNOME Integration

Settings GUI

# Open user accounts settings
gnome-control-center user-accounts

Steps:

1. Navigate: Settings → Users
2. Click Unlock (authenticate)
3. Select Fingerprint Login
4. Click + Add Fingerprint
5. Choose finger and scan 5 times

Validation

# Lock screen (Super + L or Ctrl + Alt + L)
# Unlock with fingerprint

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KDE Plasma Integration

Install KCM Module (Arch/Manjaro)

yay -S kcm-fingerprint

Install KCM Module (Ubuntu/Debian)

sudo apt install -y plasma-settings-fingerprint

Install KCM Module (Fedora)

sudo dnf install -y plasma-kcm-fingerprint

Settings GUI

Steps:

1. Open System Settings → Users
2. Navigate to Fingerprint tab
3. Click Add Fingerprint
4. Select finger and enroll

Validation

# Lock screen (Meta + L)
# Unlock with fingerprint

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Troubleshooting

Device Not Detected

# Check service status
systemctl status python3-validity.service

# View logs
journalctl -u python3-validity.service -b

# Restart services
sudo systemctl restart python3-validity.service fprintd.service
sudo killall fprintd

Enrollment Fails

# Clear fprintd data
sudo rm -rf /var/lib/fprint/*

# Re-enroll
fprintd-enroll

USB Device Not Accessible

# Check USB permissions
lsusb | grep -i synaptics
# Note Bus and Device numbers (e.g., Bus 001 Device 011)

ls -la /dev/bus/usb/001/011

# Add user to plugdev group (if exists)
sudo usermod -aG plugdev $USER

# Reboot
sudo reboot

fprintd Debug Mode

# Stop service
sudo systemctl stop fprintd.service
sudo killall fprintd

# Run in debug mode
sudo fprintd -t -d

# In another terminal, test enrollment
fprintd-enroll

PAM Configuration Not Working

# Verify PAM syntax
sudo pam-auth-update --force

# Test PAM stack
pamtester sudo $USER authenticate

# Check logs
journalctl -xe | grep fprintd

Python-validity Installation Issues

# Check Python dependencies
pip3 show python-validity

# Reinstall
sudo pip3 uninstall python-validity
cd /tmp/python-validity
sudo pip3 install --force-reinstall .

# Restart service
sudo systemctl restart python3-validity.service

Firmware Download Fails

# Manual firmware download
sudo validity-sensors-firmware --verbose

# Alternative: Check GitHub releases
# https://github.com/uunicorn/python-validity/releases

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Uninstallation

Arch/Manjaro

# Stop services
sudo systemctl stop python3-validity.service fprintd.service
sudo systemctl disable python3-validity.service

# Remove packages
yay -R python-validity fprintd

# Clean fingerprint data
sudo rm -rf /var/lib/fprint/*

Ubuntu/Debian

# Stop services
sudo systemctl stop python3-validity.service fprintd.service
sudo systemctl disable python3-validity.service

# Uninstall python-validity
sudo pip3 uninstall python-validity

# Remove packages
sudo apt remove --purge fprintd libfprint-2-2
sudo apt autoremove

# Clean data
sudo rm -rf /var/lib/fprint/*

Fedora

# Stop services
sudo systemctl stop python3-validity.service fprintd.service
sudo systemctl disable python3-validity.service

# Uninstall python-validity
sudo pip3 uninstall python-validity

# Remove packages
sudo dnf remove fprintd fprintd-pam

# Clean data
sudo rm -rf /var/lib/fprint/*

Remove PAM Configuration

# Edit PAM files and remove lines containing pam_fprintd.so
sudo nano /etc/pam.d/sudo
sudo nano /etc/pam.d/gdm-password  # or sddm, lightdm
sudo nano /etc/pam.d/gnome-screensaver  # or kde

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Additional Resources

• python-validity GitHub: https://github.com/uunicorn/python-validity
• fprintd Documentation: https://fprint.freedesktop.org/
• Arch Wiki - Fprint: https://wiki.archlinux.org/title/Fprint
• Ubuntu Community Help: https://help.ubuntu.com/community/Fingerprint
• PAM Configuration Guide: https://wiki.archlinux.org/title/PAM

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Credits

• python-validity: @uunicorn
• fprintd: freedesktop.org
• Community Contributors: Arch/Ubuntu/Fedora communities

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License

This documentation is provided under the MIT License. Free to use, modify, and distribute.

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Last Updated: November 2025
Tested On: Manjaro GNOME, Ubuntu 24.04 LTS, Fedora 42