Linux Prepares For New USB-C Security Feature On Lenovo ThinkPads

Newer Lenovo ThinkPad systems feature a security feature called USB-C Security Restricted Mode that is in the process of being wired up for reporting under Linux.

When USB-C Security Restricted Mode is enabled, power delivery is enabled but the USB-C data connections are disabled. Thus preserving USB charging capabilities while not allowing any USB data transfers to take place. The intent here is for kiosk-type deployments or physically-secured environments where not wanting to permit any USB data transfers or protecting against potential malicious USB-C devices.

The USB-C Security "USCS" feature is being enabled under Linux for toggling by the ThinkPad ACPI driver. On capable newer ThinkPads with this security feature, the support can be enabled by Fn+U and Fn+S key sequences.

With this Linux enablement, on capable Linux systems the current state of this USB-C security feature will be exposed via /sys/devices/platform/thinkpad_acpi/usb_c_security for reflecting whether it's enabled or disabled -- or checking the presence of the file to see if the feature is available on your particular Lenovo system.

This patch series has that latest Lenovo ThinkPad ACPI driver work for this USB-C security feature.