The xHCI driver scans its root-hub ports and reports the tree (M18.2)

child_added/child_removed join the device-manager protocol. The driver
maps its register BAR (resource 0 is the ECAM config space; the walk
starts at 1), reads CAPLENGTH and HCSPARAMS1, and reads one PORTSC per
port: the connect bit and speed class come straight from hardware, no
rings needed to see the devices. The manager mirrors reported children
keyed by (parent, port), remembers which instance reported each, and
prunes a dead reporter's children before deciding the restart — the
children describe protocol state that died with the process. The
usb-report scenario drives the whole loop: two QEMU devices reported,
reporter killed, children pruned, driver respawned with backoff, and the
new instance re-claims, re-scans, and re-reports.

docs/device-manager.md

@@ -4,8 +4,11 @@
 with its deadline, supervised spawn, restart with backoff, and the crash-loop
 cap are in — usb-xhci-bus is the first conforming driver, and the
 `driver-restart` scenario proves fault → backoff → re-claim → cap end to end.
-Tree reports (M18.2) and the application surface (M18.3) remain design. The
-primitives underneath are real ([process-management.md](process-management.md):
+Tree reports are built too (M18.2, 2026-07-13): the xHCI driver scans its
+root-hub ports and reports each connected device (`child_added`); the manager
+mirrors them and prunes a dead reporter's children, and the `usb-report`
+scenario proves report → prune → respawn → re-report. The application surface
+(M18.3) remains design. The primitives underneath are real ([process-management.md](process-management.md):
 spawn/supervise/kill/exit-notification; [driver-model.md](driver-model.md): the device
 table as a capability system; [drivers.md](drivers.md): claim/map/IRQ), and the first
 per-device driver spawn works (the device manager matches the xHCI controller by PCI

docs/m17-m18-plan.md

@@ -53,7 +53,11 @@ only when its definition of green holds.
       re-proving claim release each respawn; `driver-restart` scenario;
       maximum_tasks 16→32 — the sweep was overflowing the pool; suite 52/52)
 - [x] **merge** `feat/device-manager` → main, push (merged 2026-07-13)
-- [ ] **M18.2** — xHCI port scan + tree reports (branch `feat/usb-xhci-bus`)
+- [x] **M18.2** — xHCI port scan + tree reports (child_added/child_removed in
+      the protocol; the manager's child mirror with death-pruning; xHCI maps the
+      register BAR — resource 0 is ECAM — reads CAPLENGTH/HCSPARAMS1, scans
+      PORTSC, reports connected ports with speed-class identity; `usb-report`
+      scenario proves report → prune → respawn → re-report; suite 53/53)
 - [ ] **M18.3** — app surface: enumerate/subscribe + device-list
 - [ ] **merge** `feat/usb-xhci-bus` → main, push — **loop ends here**