Asahi Linux posts initial USB4 and Thunderbolt support for Apple M1, M2 and M3 to the kernel list

Sources: patch series, author post, discussion
Summary: The series, posted on 2026-08-30, adds 3872 lines including a 1028-line drivers/thunderbolt/apple.c. Each USB4-capable Type-C port carries an Apple Converged I/O block with a Cortex-M3 co-processor, and the main SoC bus sees only a 16 MiB window into its MMIO space while that co-processor runs, so the NHI and the DART IOMMU are modelled as device-tree children populated after boot and removed before power-down. The stated scope is bounded: only XDomain connections and USB3-over-USB4 tunnels work, PCIe and DisplayPort tunneling need reverse engineering that is not done, and suspend is blocked whenever a connection is active because resume hits an SError.
Why it matters: Apple Silicon laptops running Linux gain a path to their USB4 ports, though the series is posted for review, depends on five other in-flight series, and lands nothing today.
Follow-up: Track whether the series is taken through the thunderbolt tree and whether PCIe and DisplayPort tunneling follow.