From 233ccc41f4a172c7d36496927d48006bec2bf486 Mon Sep 17 00:00:00 2001
From: vasilito <adminpupkin@gmail.com>
Date: Mon, 20 Jul 2026 21:10:19 +0900
Subject: [PATCH] docs: record P6-A completion + endpoint-indexing bug-class
 audit (2026-07-20)

acmd global-index fix + serial-state/SEND_BREAK (f505d18a89), ecmd/usbaudiod
address-vs-index fix (08097d5a2d), usbhidd per-config reset (94a99f02).
bot.rs assigned to UAS workstream. Multi-port IAD remains open.
---
 local/docs/USB-IMPLEMENTATION-PLAN.md | 37 ++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/local/docs/USB-IMPLEMENTATION-PLAN.md b/local/docs/USB-IMPLEMENTATION-PLAN.md
index 80a129ced3..c5adeb9dd7 100644
--- a/local/docs/USB-IMPLEMENTATION-PLAN.md
+++ b/local/docs/USB-IMPLEMENTATION-PLAN.md
@@ -580,16 +580,39 @@ UAS uses 4 endpoints (cmd BULK OUT, status BULK IN, data-in BULK IN, data-out BU
 
 **Reference:** `local/reference/linux-7.1/drivers/usb/class/cdc-acm.c` (2,186 lines).
 
-**Files:** `local/recipes/system/redbear-acmd/` (currently stub).
+**Files:** `local/recipes/system/redbear-acmd/`.
+
+**Status (2026-07-20):** substantially complete (`f505d18a89`). **Bug-class
+fix:** acmd used per-interface endpoint positions while xhcid keys endpoints
+by global enumeration index — on two-interface ACM devices it opened the
+wrong endpoints entirely. Same latent class fixed in redbear-ecmd and
+redbear-usbaudiod (`08097d5a2d`, endpoint-address ≠ enumeration index) and
+usbhidd multi-config counting (base `94a99f02`). usbhidd/ecmd/usbaudiod were
+correct-by-coincidence on single-interface/sequential-address devices;
+acmd was outright broken. Line coding, DTR/RTS, SEND_BREAK, and SERIAL_STATE
+monitoring (interrupt-IN thread → scheme `state` file) implemented.
+
+**Remaining:** multi-port modems (IAD interface grouping — structural);
+runtime validation needs an ACM device (QEMU has no CDC ACM emulation).
+
+**Endpoint-indexing bug class — audit result (2026-07-20):**
+
+| Driver | Was | Status |
+|---|---|---|
+| redbear-acmd | per-interface position → wrong endpoints | ✅ fixed `f505d18a89` |
+| redbear-ecmd | `ep.address & 0x0F` (coincides when sequential) | ✅ fixed `08097d5a2d` |
+| redbear-usbaudiod | `ep.address & 0x0F` | ✅ fixed `08097d5a2d` |
+| usbhidd | global but no per-config reset | ✅ fixed base `94a99f02` |
+| usbscsid/bot.rs | per-interface `position()+1` (single-interface devices coincide) | **open — assigned to UAS workstream (C1) for bot.rs + uas.rs pipe discovery** |
 
 **Tasks:**
 
-1. Implement a real CDC ACM class driver (`redbear-cdc-acmd` or just keep the name and add code).
-2. Line coding: baud rate, parity, stop bits, data bits.
-3. Flow control: RTS/CTS, DTR/DSR via control transfers.
-4. Break signaling.
-5. Multi-port modems (data + control + notification interfaces).
-6. Expose `/scheme/tty` for userspace clients (replacing the stub `redbear-acmd` admin CLI).
+1. ~~Implement a real CDC ACM class driver~~ ✅ (2026-07-08, P1-D)
+2. ~~Line coding: baud rate, parity, stop bits, data bits~~ ✅
+3. ~~Flow control: RTS/CTS, DTR/DSR via control transfers~~ ✅ (RTS/DTR via SET_CONTROL_LINE_STATE; CTS/DSR via SERIAL_STATE monitor)
+4. ~~Break signaling~~ ✅ (SEND_BREAK 0x23)
+5. Multi-port modems (data + control + notification interfaces) — **open**
+6. ~~Expose `/scheme/tty` for userspace clients~~ ✅ (`/scheme/ttys/usbACM_<N>` + `state` file)
 
 **Exit:** an FTDI USB-serial adapter or Arduino appears as a TTY device.