USB4 Support Being Introduced With Linux 5.6 Kernel
Following the USB4 specification being published in September and based on Intel Thunderbolt, the open-source folks at Intel in early October published the initial USB4 Linux kernel support and now that refined code will be included come Linux 5.6.
Queued this week into USB-next is the initial support for USB4 as well as adding USB 3.x tunnels support to Thunderbolt and the other USB/Thunderbolt changes as a result of USB4. USB4 is backwards compatible with Thunderbolt 3 and USB 3/2. The initial kernel support for Linux 5.6 has both host and device support while thanks to leveraging the existing Thunderbolt kernel code allows for the PCIe tunneling, DisplayPort tunneling, P2P networking, host/device NVM firmware upgrading, and other features.
This roughly two thousand lines of new kernel code is all that was required thanks to leveraging the kernel's existing USB/Thunderbolt code and was authored by Intel's open-source department.
Linux 5.6 should debut with this USB4 support as stable likely around the end of March or early April, however, it likely will be too late for making it into Ubuntu 20.04 considering it's an LTS release. But at least Linux 5.6 should make it into Fedora 32 and others.
USB4 is rated to provide 40 Gbit/s throughput and we should begin seeing USB4 devices in 2020.