Thunderbolt 3 Software Connection Manager Support Coming In Linux 5.5 For Apple Hardware

The Thunderbolt changes have been merged to char-misc ahead of the upcoming Linux 5.5 merge window.

The principal Thunderbolt changes for this next version of the Linux kernel is introducing software connection manager support for Thunderbolt 3 hardware -- initially just Apple systems. Up to now the Thunderbolt 3 controllers on Apple systems have just relied upon the firmware connection manager but now Linux's in-kernel connection manager can be used in place of the firmware implementation. The Thunderbolt connection manager is responsible for creating PCIe tunnels and other operations when Thunderbolt devices are connected.

This Thunderbolt pull consists of supporting lane bonding / DisplayPort bandwidth manager / DP pairing, DP handshakes for Titan Ridge controllers, and other updates.

The Thunderbolt code has also begun seeing updates so the register names match the USB 4.0 specification. Intel has begun working on USB 4.0 support for the Linux kernel though those USB4 patches have yet to be merged into any "-next" branch so likely will not end up making it for the Linux 5.5 merge window opening later this month.

The list of Thunderbolt changes now in char-misc can be found via this Git merge to Greg KH's char-misc tree.