---
phase: 04-hid-data-pipeline
verified: 2026-03-22T14:10:00Z
status: passed
score: 10/10 must-haves verified
re_verification: false
---

# Phase 4: HID Data Pipeline Verification Report

**Phase Goal:** Reliable reading of periodic proximity reports and calibration parameters
**Verified:** 2026-03-22T14:10:00Z
**Status:** passed
**Re-verification:** No -- initial verification

## Goal Achievement

### Observable Truths

| # | Truth | Status | Evidence |
|---|-------|--------|----------|
| 1 | HidDevice has a background reader thread that reads periodic HID reports | VERIFIED | `hid_device.h:49` declares `std::thread m_readerThread`; `hid_device.cpp:217-261` implements `ReaderThreadFunc` with `hid_read_timeout` loop reading '#' reports |
| 2 | HidDevice extracts prox_distance from '#' header reports (bytes 4-5, big-endian uint16) | VERIFIED | `hid_device.cpp:255-259`: `buf[0] == '#' && ret >= 6` then `prox = (buf[4] << 8) | buf[5]`, stored via atomic |
| 3 | HidDevice reads calibration parameters via TLV+CRC8 from user signature flash | VERIFIED | `hid_device.cpp:141-182` ReadUserSignature reads 16 blocks; `hid_device.cpp:184-213` ReadCalibration calls ParseCalibration; `user_signature.cpp:21-68` implements TLV parser with CRC8 validation |
| 4 | HidDevice sets report rate via 'R' feature report command after connect | VERIFIED | `hid_device.cpp:112-139` SetReportRate sends 'R' command with big-endian rate, validates '$' success / 'E' error responses; called at line 240 after connect |
| 5 | HidDevice survives disconnect and reconnects automatically every 5 seconds | VERIFIED | `hid_device.cpp:246-253` detects ret==-1, closes device, sets state=2; lines 222-241 reconnect with 50ms x 100 sleep loop, re-reads calibration and re-sets rate |
| 6 | CalibrationData struct and TLV parser exist in separate user_signature files | VERIFIED | `user_signature.h` has struct CalibrationData with correct defaults (threshold=1500, hysteresis=100, signed user_trim); `user_signature.cpp` has Crc8 and ParseCalibration implementations |
| 7 | DeviceProvider starts HID reader thread on init and stops on cleanup | VERIFIED | `device_provider.cpp:33` calls `StartReading(0x35BD, 0x0101, 500)`; line 52 calls `StopReading()` before `reset()` |
| 8 | Pipe 'status' command returns connection state and calibration values | VERIFIED | `device_provider.cpp:150-178` status handler returns `proximity=, hid=, prox_raw=, cal=, thresh=, hyst=, trim=` |
| 9 | Verification script confirms build outputs, source structure, and new APIs | VERIFIED | `scripts/verify_hid_pipeline.ps1` exists with 153 lines, 14 Test-Check calls covering all structural requirements |
| 10 | Hardware checkpoint validates real HID data reading on Beyond 2 | VERIFIED | 04-02-SUMMARY.md documents user-confirmed hardware validation: hid=open, non-zero prox_raw, valid calibration, disconnect/reconnect tested |

**Score:** 10/10 truths verified

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `src/hid/user_signature.h` | CRC8, SigTag enum, CalibrationData struct, ParseCalibration | VERIFIED | 31 lines, all exports present: Crc8, SigTag, CalibrationData (correct defaults incl. signed int16_t user_trim), ParseCalibration |
| `src/hid/user_signature.cpp` | TLV parser and CRC8 implementation | VERIFIED | 69 lines (>40 min), CRC8 poly 0x07/init 0xFF, TLV walk with 0xFF end marker, little-endian value read, CRC validation per entry |
| `src/hid/hid_device.h` | Extended HidDevice with StartReading/StopReading, GetProxDistance, GetConnectionState, GetCalibration | VERIFIED | 67 lines, all public methods present, atomic members (m_lastProxDistance, m_connectionState, m_bStopRequested), mutex for calibration |
| `src/hid/hid_device.cpp` | Reader thread, feature report send, calibration read, rate config, reconnect loop | VERIFIED | 262 lines (>150 min), all methods implemented substantively |
| `CMakeLists.txt` | user_signature source files added | VERIFIED | Lines 46-47: `src/hid/user_signature.h` and `src/hid/user_signature.cpp` |
| `src/driver/device_provider.cpp` | Init calls StartReading, Cleanup calls StopReading, status extended | VERIFIED | StartReading at line 33, StopReading at line 52, extended status at lines 150-178 |
| `scripts/verify_hid_pipeline.ps1` | Phase 4 verification script | VERIFIED | 153 lines (>50 min), 14 structural checks, follows project pattern |

### Key Link Verification

| From | To | Via | Status | Details |
|------|----|-----|--------|---------|
| `src/hid/hid_device.cpp` | `src/hid/user_signature.h` | `#include "user_signature.h"` | WIRED | Line 2: includes header; line 189: calls ParseCalibration; line 191: stores CalibrationData |
| `src/hid/hid_device.cpp` | hidapi | hid_read_timeout, hid_send_feature_report | WIRED | Line 97: hid_send_feature_report in SendFeatureReport; line 109: hid_read_timeout in ReadReport; line 245: hid_read_timeout in reader thread; line 225: hid_open in reconnect |
| `src/driver/device_provider.cpp` | `src/hid/hid_device.h` | StartReading/StopReading/GetConnectionState/GetCalibration | WIRED | Line 33: StartReading(0x35BD, 0x0101, 500); line 52: StopReading(); line 155: GetConnectionState(); line 162: GetCalibration(); line 168: GetProxDistance() |
| `src/driver/device_provider.cpp` | `src/hid/user_signature.h` | CalibrationData type used in status | WIRED | Line 4: `#include "../hid/user_signature.h"`; line 162: `CalibrationData cal = m_pHidDevice->GetCalibration()` |

### Requirements Coverage

| Requirement | Source Plan | Description | Status | Evidence |
|-------------|------------|-------------|--------|----------|
| HID-02 | 04-01, 04-02 | Driver reads periodic HID reports (header '#', bytes 4-5 = uint16 big-endian prox_distance) | SATISFIED | hid_device.cpp:255-259 reads '#' reports, extracts big-endian uint16 from bytes 4-5 |
| HID-03 | 04-01, 04-02 | Driver reads calibration parameters from HID feature reports on startup | SATISFIED | hid_device.cpp:184-213 ReadCalibration reads 512-byte user signature via 16-block feature report sequence, parses TLV with CRC8 validation |
| HID-04 | 04-01, 04-02 | Driver adjusts HID report rate via feature report command 'R' | SATISFIED | hid_device.cpp:112-139 SetReportRate sends 'R' with big-endian rate, validates response |
| HID-05 | 04-01, 04-02 | Driver handles HID device disconnection and reconnection gracefully | SATISFIED | hid_device.cpp:246-253 detects disconnect (ret==-1), closes, reconnects with 5s retry, re-reads cal, re-sets rate |

No orphaned requirements found -- all HID-02 through HID-05 are mapped to Phase 4 in REQUIREMENTS.md traceability table and claimed by both plans.

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| (none) | - | - | - | No TODO, FIXME, PLACEHOLDER, stub returns, or empty implementations found in any Phase 4 files |

### Human Verification Required

### 1. Real-time proximity data flow

**Test:** Deploy driver, start SteamVR, run `beyond_prox_ctl.exe "status"` repeatedly while moving hand near/away from sensor
**Expected:** prox_raw value changes reflecting hand distance, hid=open, calibration values non-default
**Why human:** Requires physical Beyond 2 hardware and SteamVR runtime
**Status:** Already validated per 04-02-SUMMARY.md hardware checkpoint (user confirmed)

### 2. USB disconnect/reconnect resilience

**Test:** Unplug Beyond 2 USB cable while driver is running, wait 5+ seconds, replug, run status
**Expected:** hid transitions closed->reconnecting->open, prox_raw resumes, calibration re-read logged
**Why human:** Requires physical USB manipulation
**Status:** Already validated per 04-02-SUMMARY.md (user confirmed disconnect/reconnect test passed)

### Gaps Summary

No gaps found. All 10 observable truths verified with evidence from actual source code. All artifacts exist, are substantive (not stubs), and are properly wired. All 4 requirement IDs (HID-02 through HID-05) are satisfied with concrete implementation evidence. No anti-patterns detected. Hardware validation was completed by the user during plan execution.

---

_Verified: 2026-03-22T14:10:00Z_
_Verifier: Claude (gsd-verifier)_