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By Zayden R., August 3, 2026
Linux 7.3 is set to include support for MCTP-Over-USB v1.1, improving packet transfers. This update introduces packet spanning, allowing larger packet sizes and better error handling, crucial for tasks like crash dumps and firmware updates.
Linux 7.3 is gearing up to include support for MCTP-Over-USB v1.1, marking a significant update for engineers focused on networking tasks such as crash dumps, logging, and firmware updates. This comes as the net-next Git branch has queued up the necessary changes, aiming for inclusion in the upcoming release.
The Management Component Transport Protocol (MCTP) has been a staple for USB communications, but the new v1.1 specification, announced earlier this year by DMTF, brings notable improvements. The standout feature is the introduction of 'packet spanning' mode, which allows a single MCTP packet to be distributed over multiple USB packets. This is particularly useful as it eliminates the need for USB high-speed mode, making it possible to send MCTP packets in multiple 64-byte full-speed USB bulk transfers.
Engineers will appreciate the increased maximum MCTP packet size, thanks to the expanded 13-bit packet length in the transport header, up from the previous 8 bits. While this introduces some complexity in the transmit and receive paths, the development of a new library, 'mctp-usblib', helps manage this by providing packing and unpacking implementations. The host driver leverages this library, and it lays the groundwork for future gadget drivers.
This update doesn't just bring new features; it enhances error resiliency and ensures better handling of packet transfers, which is crucial for maintaining robust system operations. With the code now in net-next, Linux 7.3 is expected to officially integrate these changes when the merge window opens later this month. Engineers keen on testing and implementation should look forward to these improvements, as they promise to streamline and enhance their workflows.
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