Linux 5.9 Likely To See USB4 Support Improvements

Linux 5.6 brought initial USB4 support that primarily was starting things off by basing things off the existing Thunderbolt 3 support in the kernel for which this latest USB standard is based. For the Linux 5.9 kernel later this summer it's looking like there will be further work on getting Linux's USB4 support into good shape ahead of hardware appearing in the months ahead.

Via the Thunderbolt bleeding-edge branch has been a number of USB4 patches building up over the past week. Intel's Mika Westerberg, Kranthi Kuntala, and Rajmohan Mani have been working on these latest USB4 additions.

One of the areas being worked on is supporting USB4 sideband operations with retimer access as a means of supporting firmware upgrades for USB4 devices. The firmware upgrade approach exposed to user-space is similar to how routers are handled right now in aiming to make it easy to allow Fwupd to be extended for supporting USB4 device firmware upgrades moving forward.

The bleeding-edge branch has also various other low-level improvements for helping the USB4 support get squared away.

Unless anything goes awry with these patches, they should end up making the next (5.9) cycle to their "-next" area rather than "bleeding edge" in the days/weeks ahead. We'll see what more builds up over the next month ahead of the Linux 5.9 merge window.