handoff: VSync/event-wedge fixes + iterate 2.A–2.BC research notes

Source changes (dormant parity infra, retained from iterate 2.AI/2.AO):
- xenia-kernel/exports.rs: nt_create_event manual_reset polarity +
  related event wiring
- xenia-gpu/mmio_region.rs: D1MODE_VBLANK_VLINE_STATUS hardcode parity

Also lands the audit-runs/ analysis notes (.md/.txt/.json digests) for the
iterate 2.x VSync/0x10e8/0x1004 wedge investigation. Raw trace dumps
(.jsonl/.gz/.csv/.stdout) and agent worktrees (.claude/) are gitignored as
regenerable local artifacts — see memory + HANDOFF for the running findings.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

audit-runs/review-a-step2-natural-trigger/extract_canary_worker_tid.py

@@ -0,0 +1,108 @@
+#!/usr/bin/env python3
+"""Find the canary tid that runs the sub_821748F0 worker body and see
+what it does in its 155ms lifetime (host_ns 1.935s to ~2.09s).
+
+The spawn semantic-id is 3bd922fbb385c2c9.
+"""
+import json
+import os
+from collections import Counter
+
+INPUT = "/home/fabi/RE - Project Sylpheed/xenia-canary/build-cross/bin/Windows/Debug/canary-jitter-1.jsonl"
+OUTDIR = os.path.dirname(os.path.abspath(__file__))
+TARGET_HSID = "3bd922fbb385c2c9"
+
+# First pass: locate this thread's tid by matching the spawn handle.
+target_tid = None
+with open(INPUT, "r") as f:
+    for line in f:
+        if '"thread.create"' in line and TARGET_HSID in line:
+            ev = json.loads(line)
+            if ev.get("payload", {}).get("handle_semantic_id") == TARGET_HSID:
+                child_handle = TARGET_HSID
+                print(f"  spawn at host_ns={ev['host_ns']}, entry={ev['payload'].get('entry_pc')}")
+                # The thread's own tid will be in events the thread itself emits.
+                # Look for the FIRST event whose tid is NOT the parent and whose
+                # subsequent guest_pc/handle matches this child handle.
+                break
+
+# We need to find tid by looking at next thread.create's tid_event_idx=0 emission.
+# Simpler: scan events after this point for new tid that emits with this handle.
+# Canary's convention: each new thread emits its first events under its own tid.
+
+# Better approach: find thread.create events with handle_semantic_id=TARGET_HSID,
+# then find the smallest tid > 6 that emits AFTER that timestamp.
+
+T_LO = 1_900_000_000  # 1.9s
+T_HI = 3_000_000_000  # 3.0s
+
+events_by_tid = {}
+with open(INPUT, "r") as f:
+    for line in f:
+        if '"host_ns":' not in line:
+            continue
+        try:
+            i = line.index('"host_ns":') + len('"host_ns":')
+            j = i
+            while j < len(line) and (line[j].isdigit() or line[j] == '-'):
+                j += 1
+            host_ns = int(line[i:j])
+        except (ValueError, IndexError):
+            continue
+        if host_ns < T_LO:
+            continue
+        if host_ns >= T_HI:
+            break
+        try:
+            ev = json.loads(line)
+        except json.JSONDecodeError:
+            continue
+        tid = ev.get("tid")
+        if tid is None:
+            continue
+        events_by_tid.setdefault(tid, []).append(ev)
+
+# tid=6 is parent. Look for new tids that emit between 1.935s and 2.1s.
+print("\n=== tids active in window [1.9..3.0s] ===")
+for tid, evts in sorted(events_by_tid.items()):
+    if not evts:
+        continue
+    first_ns = evts[0]["host_ns"]
+    last_ns = evts[-1]["host_ns"]
+    print(f"  tid={tid}: {len(evts)} events from {first_ns/1e9:.4f}s to {last_ns/1e9:.4f}s")
+
+# Find tid that spawns at ~1.935s and ends at ~2.09s.
+candidate_tid = None
+for tid, evts in events_by_tid.items():
+    if tid == 6:
+        continue
+    first_ns = evts[0]["host_ns"]
+    if first_ns < 1_930_000_000 or first_ns > 1_960_000_000:
+        continue
+    # Check exit time.
+    last_ns = evts[-1]["host_ns"]
+    print(f"  CANDIDATE tid={tid}: first={first_ns/1e9:.4f}s last={last_ns/1e9:.4f}s events={len(evts)}")
+    candidate_tid = tid
+
+if candidate_tid is None:
+    print("\nNo single candidate found.")
+else:
+    print(f"\n=== Worker tid={candidate_tid} timeline (sub_821748F0 body) ===")
+    evts = events_by_tid[candidate_tid]
+    # All kernel.calls and thread.create.
+    summary = Counter()
+    for ev in evts:
+        if ev["kind"] == "kernel.call":
+            summary[ev["payload"].get("name", "?")] += 1
+    print(f"Total events: {len(evts)}")
+    print(f"Top kernel.call names:")
+    for n, c in summary.most_common(40):
+        print(f"  {c:5d}  {n}")
+    # Save full timeline.
+    with open(os.path.join(OUTDIR, f"canary-worker-tid{candidate_tid}-timeline.csv"), "w") as f:
+        f.write("host_ns,tid_event_idx,kind,name,detail\n")
+        for ev in evts:
+            name = ev["payload"].get("name", "")
+            detail = json.dumps(ev["payload"])[:400].replace('"', '""')
+            f.write(f'{ev["host_ns"]},{ev["tid_event_idx"]},{ev["kind"]},{name},"{detail}"\n')
+    print(f"Wrote canary-worker-tid{candidate_tid}-timeline.csv")