In early October of this year, Intel engineers submitted 22 open source Linux kernel mailing list USB4 patch , with the Linux kernel that provides basic USB4 support. This support will be formally introduced in the 5.6 version of the Linux kernel.
Initially supported on Linux 5.6 kernel includes both host and device support, and tunneling PCIe, DisplayPort tunnel, USB 3.x tunnel, P2P network and host / device NVM firmware upgrades.
As the use of existing core USB / Thunderbolt code, so only need about 2000 lines of the new kernel code, which was written by Intel open source sector.
Linux 5.6 is expected to debut around the end of March or early April next year steady USB4 support, which is incorporated Ubuntu 20.04 may be too late, but at least should be included in Fedora 32 and other versions.
USB4 standard announced in September this year , due to the use of Intel's Thunderbolt 3 authorization agreement, the speed has increased substantially, the new version is twice the bandwidth of USB 3.2, while expanding USB Type-C performance. USB4 rated throughput of 40 Gbit / s, began in 2020, should continue to be some USB4 equipment.
Source: https://www.phoronix.com/scan.php?page=news_item&px=USB4-In-Linux-5.6