034ec8b47f
Ours' GPU never drained the D3D driver's system command buffer past the first 11-dword indirect buffer, so DRAW_INDX / reg-0x57C-arm packets never executed and draws stayed 0 (the long-hunted render gate; see UPDATE-18). Runtime tracing (temporary, removed) showed the guest submits 6 INDIRECT_BUFFER packets at boot (CP_RB_WPTR 22→37) but ours executed exactly ONE IB and then spun 15.7M packets inside it. Three coupled command-processor bugs, all corrected to match canary: 1. `sync_with_mmio` applied the primary CP_RB_WPTR to whichever ring was active, including an executing indirect buffer — `37 % 11 = 3` clobbered the IB's write pointer so its read pointer looped 0→2→5→0 forever and never popped back to the primary ring. CP_RB_WPTR governs ONLY the primary ring; while an IB executes, the primary is the bottom of the IB stack. Canary executes each IB through a separate `RingBuffer reader_` (command_processor.cc), so the primary write pointer is structurally inapplicable to an IB. 2. Indirect buffers were treated as circular rings: read wrapped at `size_dwords` (`11 % 11 = 0`) and never reached the fixed write pointer, so even without the clobber the IB could not terminate. An IB is a fixed *linear* sub-stream; add `RingBufferView.indirect` and drain `[0, ib_size)` monotonically, then pop. 3. `is_ready` only checked the active ring, so an IB that now correctly exhausts would never get `execute_one` called again to pop back to the primary ring (whose WPTR may have advanced). Check the whole IB stack. Also: the ring was sized `1 << size_log2` bytes (1024 dwords) vs canary's `1 << (size_log2 + 3)` (8192 dwords) — an 8× undersize that desynced WPTR-wrap math from the guest. Fixed in `GpuSystem::initialize_ring_buffer` (and the dead bookkeeping copy in `vd_initialize_ring_buffer`). Cascade (deterministic; threaded-default backend, byte-identical across runs): reg 0x57C now written, IB jumps 1→12, packets 15.7M→9,825, and the splash renders — draws 0→78, shaders 0→3, render_targets 0→2, swaps 2→3 — stable at 50M / 200M / 1B. Boot then reaches a new downstream gate (draws plateau at 78, interrupts keep climbing → engine alive, not deadlocked). golden `sylpheed_n50m.json` re-baselined (draws 78). `cargo test --workspace` green (674; +2 ring_view regression tests). vd_swap's synthetic-swap short-circuit is now redundant but left untouched (cascade works without changing it); cleaning it up is a separate follow-up. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Sylpheed regression goldens
These JSON files anchor xenia-rs check digest output for Project Sylpheed.
Files
| File | -n | Mode | Captures |
|---|---|---|---|
sylpheed_n2m.json |
2_000_000 | full digest | early boot (swaps=0, no rendering) |
sylpheed_n50m.json |
50_000_000 | stable-digest | first VdSwap pair (swaps=2 post-Phase-A) |
Stable-digest mode
sylpheed_n50m.json is captured with --stable-digest, which omits
timing-sensitive counters: packets (±2–8% lockstep noise from a GPU thread
race), resolves, interrupts_delivered, interrupts_dropped,
texture_decodes. The remaining fields are byte-identical across repeated
lockstep runs at a fixed -n.
sylpheed_n2m.json predates the stable-digest flag and uses full-digest
compare. It still works because at -n 2M the GPU pipeline has not produced any
packets yet — packets=0 is trivially deterministic.
Circularity hazard
Per ORACBUG-001/002/003, these goldens were captured by running the same code
they validate. They detect regression from a known-good snapshot, not
correctness. When a planned fix intentionally moves the digest (e.g. a
shader fix landing draws > 0 for the first time), re-baseline the golden as
a separate commit and reference the audit ID in the message.
Re-baselining
cargo build --release -p xenia-app
target/release/xenia-rs check \
"$SYLPHEED_ISO" \
-n 50000000 \
--stable-digest \
--out crates/xenia-app/tests/golden/sylpheed_n50m.json
Running the goldens
cargo test --release -p xenia-app --test sylpheed_oracles -- --ignored --nocapture
The tests are #[ignore]-gated because each run takes a few seconds, which is
unacceptable in the default cargo test cycle. The ISO path defaults to the
contributor's local ~/RE Project Sylpheed/Project Sylpheed*.iso and can be
overridden via SYLPHEED_ISO=/path/to/sylpheed.iso.
n4b canonical-invocation regression anchor (deferred)
The audit's recommended next sprint also called for a sylpheed_n4b.json
golden capturing the canonical reference invocation
xenia-rs check sylpheed.iso -n 4_000_000_000 --parallel --reservations-table.
This is deferred because:
- The
--parallel --reservations-tablecombination is empirically pathologically slow at -n 100M (>32 min per run per the audit memory). At -n 4B the run cost is many hours, not the single-session-friendly 5–15 min the original plan estimated. - Each phase that intentionally moves rendering counters (C, D, E, F) would need a re-baseline of n4b — a significant time cost compounding over the sprint.
Once the renderer-unblock phases (C+D+E) land and draws > 0 is confirmed at
-n 100M lockstep, an n4b artifact may be captured one-shot and stored under
audit-runs/post-fix/ (not as a test golden) as a manual regression anchor for
the canonical invocation.