---
name: "thunderbolt"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/thunderbolt"
---

# thunderbolt(4)

Thunderbolt / USB4 Native Host Interface driver

## NAME

**thunderbolt** – Thunderbolt / USB4 Native Host Interface driver

## SYNOPSIS

**device** **thunderbolt**

## DESCRIPTION

The **thunderbolt** driver attaches to the Thunderbolt and Generic USB4 Native Host Interface (NHI) found on Intel and AMD platforms. The NHI is the host-side controller that manages communication with Thunderbolt and USB4 routers.

The driver initializes the NHI hardware and can read from and write to its configuration space in order to suspend or resume it.

*This* *driver* *does* *not* *provide* *working* *Thunderbolt* *or* *USB4* *support*. The primary purpose of loading this driver is to allow the system to assert ownership of the NHI device so that PCI power management can place it into a low-power state. On platforms that support S0ix (such as S0i3), an unsuspended NHI will block entry into the deepest idle states, and the NHI is put in an active state by the pre-OS connection manager at boot. Loading **thunderbolt** prevents that blockage. Users who do not require S0ix idle states have no need to load this driver for the time being.

## HARDWARE

The **thunderbolt** driver only attaches to generic USB4 controllers, that is devices matching PCI class PCIC\_SERIALBUS, subclass PCIS\_SERIALBUS\_USB, and programming interface PCIP\_SERIALBUS\_USB\_USB4.

## HISTORY

The **thunderbolt** driver appeared in FreeBSD 16.0.

## CAVEATS

This driver is under active development and is not feature-complete. The interface and behaviour are subject to change without notice. Do not rely on this driver for Thunderbolt or USB4 device connectivity.