THUNDERBOLT(4)          FreeBSD Kernel Interfaces Manual          THUNDERBOLT(4)

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.

FreeBSD 16.0-CURRENT              June 19, 2026                   THUNDERBOLT(4)