punktfunk/docs/windows-host-rewrite.md

Windows Host — Architecture, Status & Roadmap

Single source of truth for the punktfunk Windows streaming host: the all-Rust pf-vdisplay IddCx virtual-display driver + IDD-push zero-copy capture + NVENC/AMF/QSV encode, shipped as a signed Inno Setup installer with a LocalSystem SCM service. Live-validated on the RTX box through 5120×1440@240 HDR, the secure desktop (lock/UAC), and a fullscreen game.

This file consolidates and replaces five earlier docs (now retired into it): the rewrite design plan, the Goal-1 staged-refactor plan, the audit, the audit-remediation tracker, and the fullscreen-game capture-bug analysis. See the consolidation note for what moved where. Last updated 2026-06-25. Work lives on branch windows-host-goal1 (off main, not yet merged).

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1. Status at a glance

The Windows host is functionally complete and validated on glass. The hard, high-risk proofs are done: a clean all-Rust IddCx driver on the unified windows-drivers-rs stack (the /INTEGRITYCHECK answer + the iddcx wdk-sys binding), IDD-push zero-copy capture at 5K@240 HDR, the secure desktop (Winlogon / UAC / lock), and the host re-architected into a clean, typed, layered shape. What remains is non-blocking: hygiene (host unsafe lints, a few OwnedHandle rollouts), the SudoVDA backend deletion (decoupled, not yet removed), a driver robustness gap (slot reclaim), the gamepad-driver unification (M4), and old-monolith cleanup (M6) — plus the merge to main.

One framing correction baked into this doc: the host was not greenfield-rebuilt as the original plan imagined. It was refactored in place via a staged, behavior-preserving sequence (the "Goal-1" plan), which kept the live-validated host working at every step. The driver, by contrast, was rebuilt fresh (the new packaging/windows/drivers/pf-vdisplay/ tree).

Scorecard (verified against windows-host-goal1 HEAD, 2026-06-25)

Item	Status	Evidence
Goal 1 — clean, layered host architecture	✅ DONE	config.rs (HostConfig), session_plan.rs (SessionPlan), SessionContext, windows/+linux/ confinement (38c68c3), VirtualDisplayManager (§2.5), EncoderCaps (0ccd0fe)
Goal 2 — drop every trace of SudoVDA	🟡 PARTIAL	reach-in decoupled (F1: d638a93/e60cda3 → win_adapter/win_display); sudovda.rs still present as a fallback backend — deletable now, not yet deleted
Goal 3 — minimize unsafe + P0 lints	🟡 PARTIAL	driver deny(unsafe_op_in_unsafe_fn) (a755d6e); host crate has no P0 lints yet; OwnedHandle adopted in manager.rs/pf_vdisplay.rs/sudovda.rs, not idd_push.rs
M0 — proto ABI + driver toolchain + /INTEGRITYCHECK + iddcx	✅ DONE	pf-vdisplay-proto; vendored windows-drivers-rs 0.5.1; clear-force-integrity.ps1; CI-green
M1 — new IddCx driver, first light + HDR	✅ DONE (on-glass)	STEP 0–8 (d7a9fbf…cd59151); HDR live ("Mac connects WITH HDR", 6399d28)
M2 — IDD-push capture + NVENC, glass-to-glass	✅ DONE (on-glass)	5120×1440@240 HDR zero-copy; integrated into the host path
M3 — service / input / audio / secure desktop	✅ DONE (on-glass)	secure desktop (lock/UAC) owner-confirmed 2026-06-25 — IDD-push captures it + input reaches it
M4 — gamepad drivers onto the unified stack	❌ OPEN	pf_dualsense/pf_xusb still standalone (packaging/windows/{dualsense,xusb}-driver/), not in drivers/ workspace
M5 — WGC/DDA fallback reshape + GameStream-on-pipeline + AMF/QSV	🟡 PARTIAL	fallbacks exist (wgc.rs/wgc_relay.rs/dxgi.rs), not reshaped onto the new seams; AMF/QSV CI-only (no lab hw)
M6 — cut over + delete the old monoliths	🟡 PARTIAL	old vdisplay-driver/ tree deleted (a2bd0cd); host monoliths + bring-up scaffolding (spawn_observer/DebugBlock) remain
Game-capture bug (GB1) — fullscreen game breaks IDD-push	✅ FIXED	resolution-listening recovery (c87bfe0) + open-time DDA failover (f98ab07) + driver guard/log (789ad49)
Audit P0/P1/P2	✅ mostly RESOLVED	watchdog, SET_RENDER_ADAPTER, log gate, mode bounds, IDD-push fallback, F1, out-ring/HDR-ring, proto asserts — all landed; open: host hygiene (§8), E1 completion, slot-reclaim

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2. Architecture (what is on disk)

2.1 Layering & crates

• crates/punktfunk-host — one shared host crate (Linux + Windows; not split). Platform code is confined under per-module windows/+linux/ folders behind #[cfg] seams (capture/{windows,linux}/, encode/{windows,linux}/, inject/{windows,linux}/, audio/{windows,linux}/, vdisplay/{windows,linux}/, and top-level src/windows/+src/linux/). Module names stay flat (#[path]), so caller paths are platform-agnostic.
• crates/punktfunk-core — the one linked protocol/FEC/crypto/QUIC core (unchanged here).
• crates/pf-vdisplay-proto — the owned, no_std host↔driver ABI (frame ring + control plane + gamepad SHM), consumed by both the host crate and the driver workspace (§2.7).
• packaging/windows/drivers/ — the unified driver workspace on microsoft/windows-drivers-rs (vendored 0.5.1 + an iddcx subset): members pf-vdisplay (the IddCx display driver), wdk-iddcx (the typed IddCx DDI wrappers), wdk-probe (the CI link/surface gate), vendor/{wdk-build,wdk-sys}.

2.2 Session resolution — HostConfig → SessionPlan → SessionContext (Goal-1 realized)

The old ~40-knob PUNKTFUNK_* env soup, re-read and recomputed in three places, is replaced by a resolve-once pipeline:

• config.rs HostConfig — typed config parsed once from host.env/env/flags (idd_push/encoder_pref/no_wgc/capture_backend/render_adapter/secure_dda/ten_bit/zerocopy/…). Each field's parser is byte-identical to the read it replaced. (Runtime-mutated Linux session vars from vdisplay::apply_session_env, and single-use local tuning knobs, are deliberately kept live — see the config.rs header.)
• session_plan.rs SessionPlan { display, capture, topology, encoder, input_format, bit_depth, hdr, pipeline_depth } — a Copy plan resolved once per session from HostConfig + the negotiated bit-depth, logged, and threaded through build_pipeline. CaptureBackend::resolve() is the one resolver (IddPush | Dda | Wgc); resolve_topology decides SingleProcess | TwoProcessRelay. This killed the latent capture/encode backend-disagreement bug.
• SessionContext — bundles the session entry's ~13 args (was #[allow(too_many_arguments)]) and the plane receivers into one owned struct moved into the stream thread.

2.3 Ownership model — VirtualDisplayManager + MonitorLease (§2.5 realized)

A single OnceLock VirtualDisplayManager (vdisplay/windows/manager.rs) owns a typed Arc<OwnedHandle> control-device handle (no raw-isize cross-thread smuggle), the refcounted Idle/Active/Lingering state machine, and the monitor generation (AtomicU64). Both Windows backends (pf_vdisplay, sudovda) shrank to thin VdisplayDriver impls (open/add_monitor/remove_monitor/ ping) behind it; MonitorKey = Guid | Session(u64). A per-session MonitorLease's Drop releases the refcount (a stale lease can't tear down a fresh monitor). This deleted the old CURRENT_MON_GEN/MON_GEN/ two-MGR/IDD_PERSIST/IDD_SETUP_LOCK/IDD_SESSION_STOP globals. Validated on glass: 0 leaked active monitors across a reconnect storm, A/B-equivalent to the shipping host. (The 5-agent map found CURRENT_MON_GEN had been write-only — the per-frame "monitor-gen bail" was never wired — so the gen lives on the manager + lease only.)

2.4 The seam traits

VirtualDisplay/VirtualOutput/VirtualLease (RAII keepalive = release), Capturer (next_frame/try_latest/set_active/hdr_meta/pipeline_depth), Encoder (submit/caps/request_keyframe/set_hdr_meta/invalidate_ref_frames/poll/flush), AudioCapturer/VirtualMic/InputInjector/PadManager. Realized tightenings: the capturer takes the desired OutputFormat { gpu, hdr } in (killed the capture → encode::windows_resolved_backend() back-reference recomputed in dxgi.rs); and Encoder::caps() -> EncoderCaps { supports_rfi, supports_hdr_metadata } lets the session glue route loss-recovery by query (only Windows direct-NVENC overrides it; the GameStream loop gates the RFI path on supports_rfi).

2.5 Capture — IDD-push primary (normal and secure desktop), WGC/DDA fallback, GB1 recovery

IDD-push is the universal primary path. Capture comes straight from the driver's shared keyed-mutex texture ring (capture/windows/idd_push.rs) — no Desktop Duplication, no win32u reparenting hook. The host creates the ring; the driver opens it (permissive D:(A;;GA;;;WD) SDDL). The generation-tagged latest = gen<<40 | seq<<8 | slot stale-ring reject kills the HDR-flip garbage frame; a host-owned 3-slot OUT_RING rotated per frame is the texture-ownership contract that enables pipeline_depth=2 (convert/copy on the 3D engine overlapping NVENC on the ASIC). It captures the secure desktop (Winlogon/UAC/lock) directly (validated 2026-06-25), so there is no separate secure capturer in the primary path.

• Open-time fallback: IddPushCapturer::open waits a bounded ~4 s for a first frame (not just DRV_STATUS_OPENED); on attach failure it returns the keepalive back so capture.rs opens DDA on the same WinCaptureTarget — never a 20 s black bail (audit §5.1, ed58365/f98ab07).
• Mid-session game mode-set recovery (GB1, fixed): the 250 ms poll follows the display's actual resolution (win_display::active_resolution, CCD/GDI) and recreates the ring on any descriptor change (size or HDR) → the driver re-attaches → frames resume at the game's mode, no reconnect. If a change is unrecoverable (e.g. an exclusive flip), a recovering_since clock drops the session after 3 s so the client reconnects cleanly. No protocol bump was needed — the host reads the resolution straight from Windows (c87bfe0; the driver's publish() width/height guard + flushed log is 789ad49).
• WGC + DDA stay as demoted fallbacks for non-IddCx hardware (wgc.rs/dxgi.rs). The two-process WGC secure-desktop relay (wgc_relay.rs) is no longer load-bearing now that IDD-push handles the secure desktop; it is kept recoverable but slated for M5/M6 cleanup.

2.6 Encode — NVENC / AMF / QSV / software; EncoderCaps; HDR

encode/windows/ dispatches per DXGI adapter vendor (open_video): NVENC (NVIDIA, direct SDK, nvenc.rs — caps-probe-before-configure, bitrate-clamp binary search, true RFI over the DPB, in-band ST.2086/CLL SEI), AMF/QSV (AMD/Intel via libavcodec, ffmpeg_win.rs — system-readback default, opt-in zero-copy D3D11; CI-only, no lab hardware), or software H.264 (sw.rs). HDR (10-bit) forces HEVC Main10 + BT.2020 PQ; the client auto-detects PQ from the VUI. The encoder adapts to a mid-session size/format/HDR change per frame (tears down + re-inits), so the GB1 capturer's resolution changes are handled downstream with no API change.

2.7 Host↔driver ABI — pf-vdisplay-proto

One no_std crate, both build graphs. Owns the frame plane (SharedHeader, FrameToken { generation, seq, slot } with pack/unpack, Global\pfvd-* name helpers), the control plane (fresh interface GUID — not SudoVDA's e5bcc234; contiguous 0x900 IOCTL ops; u64 session id; a real GET_INFO version handshake the host asserts + bails on mismatch), and the gamepad SHM (XusbShm 64 B, PadShm 256 B incl. device_type). bytemuck-Pod + size_of and offset_of! asserts make ABI drift a compile error (95dcef3). The host-side gamepad consumers derive their layouts from here; the driver-side gamepad drivers do not yet (M4).

2.8 The pf-vdisplay IddCx driver

All-Rust UMDF IddCx driver on windows-drivers-rs + the iddcx wdk-sys subset. STEP 0–8 landed (packaging/windows/drivers/pf-vdisplay/src/): entry.rs (DriverEntry + IDD_CX_CLIENT_CONFIG, 15 callbacks), adapter.rs (caps + FP16 + SET_RENDER_ADAPTER), monitor.rs/callbacks.rs (the *2 HDR mode DDIs, EDID verbatim), swap_chain_processor.rs (the worker, SetDevice-retry + top-of-loop terminate), frame_transport.rs (the FramePublisher on pf_vdisplay_proto::frame), control.rs (the typed IOCTL dispatch + host-gone watchdog + mode bounds). Self-signed-loadable under Secure Boot (FORCE_INTEGRITY cleared post-link). Known gaps: ownership state is still partly process-global (MONITOR_MODES/NEXT_ID/ADAPTER/DEVICE_POOL) with EvtCleanupCallback on the WDFDEVICE (not per-IDDCX_MONITOR) — see E1 in §4; and it does not reclaim IddCx monitor slots on REMOVE (the ghost-monitor wedge, §4).

2.9 Service, packaging, installer

A LocalSystem SCM supervisor (service.rs) token-retargets and CreateProcessAsUserWs serve into the console session (so SendInput reaches the streamed desktop + the secure desktop), relaunches on session-change, and kills-on-close via a Job Object. Shipped as a signed Inno Setup setup.exe (packaging/windows/, windows-host.yml) that bundles the new pf-vdisplay driver (pf_vdisplay.inx in-tree, old vdisplay-driver/ tree deleted) + FFmpeg DLLs and delegates to service install. GameStream (Moonlight) is kept but the installer/service default to secure serve (GameStream opt-in).

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3. Validated invariants — preserve, do not regress

These are expensive empirical wins; keep them intact when touching the code:

• Frame transport: host-creates/driver-opens keyed-mutex ring; generation-tagged stale-ring reject; 0 ms try-acquire / drop-on-full publish (never block the swap-chain thread); the OUT_RING rotation + pipeline_depth=2 overlap; repeat_last rotates into a fresh out-ring slot (depth-safe).
• Driver internals: edid.rs (128-byte EDID + CTA-861.3 HDR block, dual checksums); the FP16 HDR recipe (CAN_PROCESS_FP16 + the *2 DDIs + gamma/HDR accept-stubs + HIGH_COLOR_SPACE); DEVICE_POOL per render-LUID (NVIDIA UMD/VRAM leak fix); target-id stamped on the monitor context; the two swap-chain leak fixes (borrow IDXGIDevice across SetDevice retries; check terminate at the loop top).
• Monitor lifecycle: serialized ADD/REMOVE/teardown; restore CCD topology before REMOVE; the generation-stamped lease (a stale lease can't tear down a fresh monitor); 0-leak across reconnects.
• HDR color math: hdr.rs (pure, unit-tested, ST.2086 + big-endian SEI); the FP16→P010/Rgb10a2 converters + hdr_p010_selftest; the cursor decomposition.
• NVENC tuning: caps-probe-before-configure (10-bit→8-bit graceful downgrade); bitrate-clamp binary search (each GPU's real ceiling); true RFI over the DPB; CBR / infinite-GOP / P-only / ~1-frame VBV.
• Gamepad recipe: the SwDeviceCreate identity (enumerator with no _; mandatory completion callback; synthesized DS5 compat-ids; non-null per-pad ContainerId); one pf_dualsense serving DualSense+DS4 via a device_type byte; XUSB declining WAIT_*; per-pad index via pszDeviceLocation.
• Session glue: the trait seam + RAII keepalive teardown; host-lifetime shared services + per-session gamepads; the encode|send split + microburst pacing; build_pipeline_with_retry permanent-vs-transient classification; the GameStream VideoPacketizer (GF8 Cauchy, Moonlight byte-exact); the pairing/trust handshake.
• Core discipline: no async on the per-frame path; pf-vdisplay-proto is the single ABI source (drift = compile error); the version handshake the host asserts.

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4. Open work / next tasks (prioritized)

P1 — ship-readiness / correctness

1. Merge windows-host-goal1 → main + push (outward-facing → confirm first). Pushing also runs the full Windows CI matrix incl. the amf-qsv encode path, which local checks skip.
2. Make IDD-push the default — today it is gated behind PUNKTFUNK_IDD_PUSH (config.rs default false); deployment sets it in host.env. Flip the code default (with the WGC/DDA fallback already in place) so a fresh install runs the validated path, or document the host.env requirement explicitly.
3. pf-vdisplay slot reclaim on REMOVE (driver robustness) — 🟡 fix landed, on-glass-validation pending. Sustained ADD/REMOVE churn wedged the driver (ADD → 0x80070490 ERROR_NOT_FOUND) because the monitor id (EDID serial / ConnectorIndex / container GUID) was a monotonic NEXT_ID, never reclaimed → IddCx accumulated a new OS target slot per cycle until exhaustion. monitor.rs now allocates the lowest free id (alloc_monitor_id), reused on REMOVE, so a fresh ADD reuses the departed monitor's target slot instead of orphaning it. CI-compile-gated; the wedge only reproduces under sustained churn on the RTX box, so this needs an on-glass reconnect-storm A/B to confirm (the box is ephemeral). Keep packaging/windows/reset-pf-vdisplay.ps1 as the recovery until validated.

P2 — hygiene / architecture completion 4. D1-host — host-crate P0 lints. Add #![deny(unsafe_op_in_unsafe_fn)] + #![warn(clippy::undocumented_unsafe_blocks)] to the host crate and fix the fallout (large, mechanical, touches Linux + Windows unsafe). Do it incrementally per-subsystem. The driver already has the deny. 5. D2 — OwnedHandle in idd_push.rs. map/event/dbg_map are still raw HANDLE closed in Drop; wrap in std::os::windows::io::OwnedHandle (RAII close, fixes leak-on-error). manager.rs already shows the pattern. 6. Goal 2 — delete sudovda.rs. The reach-in is fully decoupled (F1); the backend is now a thin, deletable fallback. Retire it (and the PUNKTFUNK_VDISPLAY=sudovda path) to finish "drop SudoVDA." 7. E1 — finish the driver ownership refactor. Move the process-globals (MONITOR_MODES/NEXT_ID/ADAPTER/DEVICE_POOL) into a DeviceContext; wire EvtCleanupCallback on the IDDCX_MONITOR object (today only the WDFDEVICE has it); collapse the 3-key monitor identity. This is the prerequisite to max_concurrent>1 on Windows + removes the host-side preempt dance. On-glass gated (must instrument that MonitorContext::Drop actually fires on this UMDF/IddCx stack; keep the explicit REMOVE path as fallback if it doesn't). 8. M6 scaffolding cleanup — delete the bring-up diagnostics (spawn_observer/DebugBlock in idd_push.rs) and, once full parity is proven on glass, the host monoliths.

P3 — larger, mostly hardware-gated 9. M4 — gamepad-driver unification. Fold pf_dualsense + pf_xusb (standalone packaging/windows/{dualsense,xusb}-driver/ on the old WDF stack) into the unified drivers/ workspace on windows-drivers-rs with WDF device contexts (true multi-pad), and point the driver side at pf_vdisplay_proto::gamepad::{PadShm,XusbShm} (host side already does — the device_type-at-offset-140 hand-duplication is the last ABI-drift hazard). Largest item. 10. M5 — reshape WGC/DDA + GameStream onto session/pipeline, then delete the old relay/monoliths. AMF/QSV stays CI-only (no lab hardware). 11. On-glass behavioral validation of the committed-but-unexercised fixes: the watchdog reaping on host-kill, SET_RENDER_ADAPTER on a hybrid box (the lab box is single-dGPU), the IDD-push→DDA fallback trigger, HDR-ring sizing + out-ring repeat under real HDR/static-desktop pipelining.

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5. Operations

5.1 RTX box on-glass recipe

The persistent on-glass validator is the RTX box (ssh "Enrico Bühler"@<ip>, ENRICOS-DESKTOP, RTX 4090, PS shell). The IP FLOATS (DHCP; boots to Proxmox on reboot → ephemeral, unreachable after a reboot; recently .173/.158 — confirm current first; never reboot it, never depend on it surviving). It has WDK 26100 + LLVM 21.1.2 + the Rust toolchain; build clone at C:\Users\Public\pf-rewrite (the user's active driver-dev tree — don't clobber uncommitted WIP; use a worktree). Username has a ü → quote it; it only breaks SDL3/client builds, not the host. To validate a host branch: worktree-checkout, build with CARGO_TARGET_DIR=C:\t-goal1, then stop the PunktfunkHost service, back up the binary + %ProgramData%\punktfunk\host.env, copy your build in, restart, drive punktfunk-probe.exe loopback, then restore + git worktree remove. Drive over ssh via powershell -EncodedCommand <base64 UTF-16LE> (plain quoting mangles; prefer Write-Output/file-redirect for clean output). Driver redeploy: packaging/windows/redeploy-pf-vdisplay.ps1; ghost-monitor recovery: reset-pf-vdisplay.ps1.

5.2 CI / validation

The persistent build validator is the windows-amd64 CI runner (no GPU — fine for builds / iddcx link / /INTEGRITYCHECK self-sign / the surface-asserts; live NVENC encode + on-glass defers to the RTX box). Workflows: windows-host.yml (the host installer), windows-drivers.yml (the driver workspace build + FORCE_INTEGRITY clear), windows-drivers-provision.yml (WDK/LLVM toolchain), windows-msix.yml (the client). A single Windows runner serializes the whole fleet; a Cargo.toml touch costs ~25 min of queue, so driver pushes that avoid Cargo.toml skip the fleet serialization.

Local pre-push checks (this Linux box can't compile the Windows paths):

cargo test  -p pf-vdisplay-proto                 # the ABI crate (cross-platform)
cargo check -p punktfunk-host                     # Linux paths; win_* mods are #[cfg(windows)]
cargo clippy -p punktfunk-host --all-targets -- -D warnings
# Windows host clippy (on the box): PUNKTFUNK_NVENC_LIB_DIR=C:\t\nvenc;
#   cargo clippy -p punktfunk-host --features nvenc --target x86_64-pc-windows-msvc -- -D warnings
# Driver build (on the box): cd packaging/windows/drivers; Version_Number=10.0.26100.0;
#   LIBCLANG_PATH='C:\Program Files\LLVM\bin'; cargo build

Note: a pre-existing rustfmt-version drift exists in some Windows-only files (this box's rustfmt 1.9.0 wraps offset_of!/unsafe fn differently than the runner's) — don't reformat unrelated files to chase it.

5.3 Env knobs (Windows host)

PUNKTFUNK_IDD_PUSH=1 (capture from the driver ring; default off), PUNKTFUNK_VDISPLAY=pf|sudovda, PUNKTFUNK_ENCODER=auto|nvenc (auto → vendor-detect), PUNKTFUNK_10BIT=1 + PUNKTFUNK_HDR_SHADER_P010=1 (HDR), PUNKTFUNK_SECURE_DDA=1, PUNKTFUNK_NO_WGC=1 (pure DDA), PUNKTFUNK_ZEROCOPY=1, PUNKTFUNK_MONITOR_LINGER_MS, PFVD_DEBUG_LOG=1 (driver file log — release builds are silent without it). Config lives in %ProgramData%\punktfunk\host.env; logs in %ProgramData%\punktfunk\logs\host.log.

5.4 Build / deploy / packaging

x64-only by design (no ARM64 NVIDIA driver / SudoVDA). The installer is the thin-.iss / fat-binary model delegating to service install; tag host-win-vX.Y.Z. The driver is built + FORCE_INTEGRITY-cleared + signed + Inf2Cat'd in CI from source. DriverVer must bump on any driver change; create the ROOT devnode via nefcon (devgen is forbidden).

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6. Reference (hard-won — keep)

6.1 The /INTEGRITYCHECK answer

wdk-build emits cargo::rustc-cdylib-link-arg=/INTEGRITYCHECK unconditionally (no cfg/env/Config opt-out), so a self-signed driver can't load (CodeIntegrity 3004/3089). The fix: a deterministic, idempotent post-link step packaging/windows/clear-force-integrity.ps1 clears the PE FORCE_INTEGRITY bit (0x0080 @ e_lfanew+0x5e) + verifies (CI-proven 0x01E0 → 0x0160), before signing. Packaging order: cargo build → clear-force-integrity → sign .dll → Inf2Cat → sign .cat. (A public build would use real attestation signing, which satisfies /INTEGRITYCHECK legitimately.)

6.2 The iddcx binding on wdk-sys (the make-or-break — proven, the 6 bindgen knobs)

IddCx DDIs are function-table dispatched (IddFunctions[] indexed by _IDDFUNCENUM::<Name>TableIndex, IddDriverGlobals implicit arg 1) — the same model wdk-sys already implements for WDF. The vendored windows-drivers-rs 0.5.1 (packaging/windows/drivers/vendor/, [patch.crates-io]'d) gets a first-class ApiSubset::Iddcx that bindgens iddcx/1.10/IddCx.h reusing the identical wdk_default(config) baseline (so WDF/DXGI types resolve to, not redefine, wdk-sys's — type-identity by construction). The six knobs generate_iddcx needed (each a real gotcha, all CI-proven):

1. --language=c++ — wdk_default parses C; IddCx.h's IDARG_* typedefs need C++ (else a "must use 'struct' tag" cascade).
2. -DIDD_STUB — table-dispatch mode; skips IddCxFuncEnum.h's #error IDDCX_VERSION_MAJOR not defined. Do NOT add WDF_STUB (would desync the shared WDF type-identity).
3. allowlist_recursively(false) + allowlist_file("(?i).*iddcx.*"), full codegen (no .complement()) — emit ONLY IddCx items; WDF/Win types resolve via use crate::types::*.
4. allowlist_type("_?DXGI_.*" / "IDXGI.*" / "_?OPM_.*" / "_?D3DCOLORVALUE") — emit the non-WDF types wdk-sys doesn't bindgen, locally. The _? is load-bearing (typedef struct _OPM_X {} OPM_X needs the tag AND the alias).
5. pub type UINT = ::core::ffi::c_uint; in src/iddcx.rs — UINT is absent from crate::types.
6. translate_enum_integer_types(true) — emit native u32 reprs for the DXGI/OPM ModuleConsts enums (nested modules can't see a parent UINT).

Wrapper note: table dispatch via _IDDFUNCENUM::<Name>TableIndex as usize (the ModuleConsts const, not a NewType .0); NTSTATUS is plain i32 (wdk_sys::NT_SUCCESS). The driver build.rs adds the IddCxStub link-search (the import lib is under iddcx\1.0\ even though headers are 1.10) + #[no_mangle] pub static IddMinimumVersionRequired: ULONG = 4. The versioned IDD_STRUCTURE_SIZE! path is dropped — the WDK links the iddcx 1.0 stub (lacks the version table); we target 1.10 vs a current framework, so size_of is exactly correct.

6.3 Driver port checklist (STEP 0–8, as landed)

0. workspace pf-vdisplay(cdylib)+wdk-iddcx; prove std::thread+OwnedHandle link under UMDF (done).
1. wdk-iddcx: 11 typed DDI wrappers via one dispatch macro + re-export the inbound PFN_* types.
2. DriverEntry + IDD_CX_CLIENT_CONFIG (15 callbacks) + DeviceInitConfig + WdfDeviceCreate + CreateDeviceInterface (the owned pf GUID) + DeviceInitialize; edid.rs salvaged verbatim.
3. DeviceContext + WDF_DECLARE_CONTEXT_TYPE blob; init_adapter in D0Entry (caps + FP16) → AdapterInitAsync; the *2 mode DDIs + query_target_info + gamma/HDR accept-stubs. (Box gate: loads under Secure Boot, enumerates as an IddCx adapter, Status OK.)
4. control plane (GET_INFO version handshake the host asserts, ADD/REMOVE/SET_RENDER_ADAPTER/PING/ CLEAR_ALL) + create_monitor + real mode DDIs + watchdog + mode bounds; host switched to pf_vdisplay_proto.
5. Direct3DDevice + assign/unassign + SwapChainProcessor (worker, SetDevice 60×@50 ms single-borrow retry, top-of-loop terminate, ReleaseAndAcquireBuffer2, from_raw_borrowed).
6. FramePublisher on pf_vdisplay_proto::frame + keyed-mutex RAII guard; wire into run_core. (Box: full IDD-push glass-to-glass + the secure-desktop gate — validated 2026-06-25.)
7. HDR / FP16 ring (validated: Mac connects WITH HDR).
8. its own .inx + an unsafe-reduction pass (deny(unsafe_op_in_unsafe_fn), per-site // SAFETY:).

Remaining driver work beyond STEP 8: E1 (DeviceContext-owned state + per-IDDCX_MONITOR EvtCleanupCallback → unblock max_concurrent>1), the slot-reclaim-on-REMOVE fix, and M4 (fold the gamepad drivers in). See §4.

6.4 Resolved product decisions (the five forks)

A the host was refactored in place (staged, behavior-preserving), not greenfield-rebuilt — the driver was rebuilt fresh. B IDD-push primary for everything incl. the secure desktop (validated); WGC+DDA demoted to non-IddCx fallbacks. C all drivers on microsoft/windows-drivers-rs (+ the iddcx subset; /INTEGRITYCHECK solved) — done for pf-vdisplay, pending for the gamepad drivers (M4). D keep GameStream (Moonlight), default to secure serve. E concurrent sessions: the host-side preempt dance was removed by §2.5, but true max_concurrent>1 on Windows stays blocked on the E1 driver swap-chain-reuse work.

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Appendix — consolidation note

This file replaces five docs (recoverable from git history):

• windows-host-rewrite.md (the original design + plan, §0–§15) — its current status, architecture, the jewels, the seam traits, and the deep reference (§6) are folded in here.
• windows-host-goal1-plan.md (the 6-stage in-place host refactor) — complete; its outcome is §2.2–2.4 and the Goal-1 scorecard row.
• windows-host-rewrite-audit.md (the 2026-06-25 audit) — its findings are reconciled to current reality in §1 (scorecard) and §4 (only the still-open items survive: host hygiene, E1, slot-reclaim).
• windows-host-rewrite-remediation.md (the audit-remediation tracker) — its landed items are in §1; its remaining items (D1-host, D2, E1, G) are §4 P2/P3.
• windows-host-rewrite-game-capture-bug.md (the GB1 investigation + fix) — fixed; the resolution is §2.5 (capture). The full investigation narrative is in git history.

(The older docs/windows-host.md, a pre-rewrite implementation plan from 2026-06-22, is a separate lineage and is left as-is.)