A new Linux driver developed by Intel maintainer, Mika Westerberg, has been revealed to be merging in the Linux kernel version 7.2, which is slated to launch in June 2026. The new driver will enable users to more easily share files over USB4 while bypassing the network driver. The developer pitches the new protocol as a way to easily back up, transfer, and access files across two or more connected systems, or even share hardware, like a webcam or input peripherals. For now, the protocol requires some setup, currently requiring users to set up devices using the ConfigFS interface, and the developer details a number of examples and commands to configure them. More importantly, because the stream is controlled by the receiving side, it seems as though after a little setup, the protocol could be used by app developers to create apps with similar functionality to LocalSend without the need for a network connection. The upstream request reads:

Introduce USB4STREAM protocol and Linux implementation. This allows two (or more) hosts to transfer data directly over Thunderbolt/USB4 cable through a character device without need to go through the network stack.

Any application that supports read(2) and write(2) in some form should be able to use the device without changes. The data is sent out to the other side over a tunnel inside Thunderbolt/USB4 fabric. The character device is called /dev/tbstreamX where X is the minor number starting from 0.