Linux Nears USB4 Support for Apple Silicon

Asahi Linux developers have submitted a comprehensive patch to upstream the Apple-specific USB4/Thunderbolt drivers for M1, M2, and M3 chips; the article explains Apple’s ACIO/NHI hardware design and the driver complexities (power sequencing, RTKit boot, DART/IOMMU handling, and per-ring interrupts), notes enhanced isolation in M3 hardware and added quirks, and clarifies that current upstream code supports only basic XDomain and USB3-over-USB4 tunneling while PCIe and DisplayPort tunneling remain unsupported as the patch is still under review.