02 · How USB devices receive a physical port

02 · How USB devices receive a physical port A workflow diagram generated by Archify. 01 / IOKit topology 02 / Directly on the Mac 03 / On an external router 04 / Missing / ambiguous Native port occupation · TB router + direct attachments · IOKit topology Native port occupation TB router + direct attachments Check host USB · UsbCPortNumber on the direct parent · Directly on the Mac Check host USB UsbCPortNumber on the direct parent Uniquely assignable? · One port and one USB candidate · Directly on the Mac Uniquely assignable? One port and one USB candidate Occupy host port · USB transport and speed remain · Directly on the Mac Occupy host port USB transport and speed remain Check dock evidence · Host binding + controller + tunnel · On an external router Check dock evidence Host binding + controller + tunnel DROM mapping unambiguous? · USB 2/3 companion → one candidate · On an external router DROM mapping unambiguous? USB 2/3 companion → one candidate Occupy dock port · Only ports not occupied yet · On an external router Occupy dock port Only ports not occupied yet USB remains in the remaining list · Do not claim a physical assignment · Missing / ambiguous USB remains in the remaining list Do not claim a physical assignment including USB Port Map allowed yes no Dock Host yes no Legend Evaluation Decision rule / status

Host: direct peripherals only

  • • External, countable, USB; no hub parent.
  • • No Billboard, tunnel, or Thunderbolt owner.

Dock: combine several pieces of evidence

  • • Same controller, hub parent, and hub port.
  • • DROM connects companion hub ports to sockets.

Evidence takes priority

  • • Native Thunderbolt assignments are never overwritten.
  • • Without prior evidence, USB remains unassigned too.