Commit Graph
2 Commits
Author SHA1 Message Date
enricobuehler 94c2f62490 test(tools): a GameInput probe — and it cannot see our promoted Xbox pad
`win-input-matrix` covered four of the five rows and said so; GameInput was the gap, because it has
no binding in the `windows` crate and needs hand-written COM. This adds it: `--gameinput` reports
whether GameInput has a reading, and `--gi-rumble l,h,lt,rt [--gi-pid PID]` drives
`SetRumbleState`. Every vtable slot is taken from the SDK header, not guessed — a COM vtable is
positional, so a wrong slot calls a different method with the wrong signature.

WHY RUMBLE AND NOT JUST ENUMERATION. `XINPUT_VIBRATION` has two members, so classic XInput can never
exercise an Xbox pad's two IMPULSE-TRIGGER motors. `GameInputRumbleParams` has four
(`lowFrequency`, `highFrequency`, `leftTrigger`, `rightTrigger`), which makes GameInput the only API
that can settle `design/trigger-rumble-plane.md` §2.1's open question — the `enable`-mask bit
assignment for the two trigger actuators, where bits 2/3 (the handles) are measured and bits 0/1
(the triggers) are inferred from field order and nothing else.

TWO THINGS MEASURED ON .173, 2026-08-09:

1.  GameInput's device enumeration is ASYNCHRONOUS, and the first `GetCurrentReading` reliably
   returns nothing even with pads actively reporting. This is the GameInput analogue of `wake_wgi`:
   the API looks like a query and is really a cache someone else fills. A bounded poll fixes it.
   ⚠️ Focus is NOT the cause, and the header rules it out rather than my guessing:
   `GameInputDefaultFocusPolicy` is 0 and every `GameInputFocusPolicy` flag is a RESTRICTION, so the
   default already admits background input. Do not "fix" this with `SetFocusPolicy`.

2. 🛑 **GameInput never sees our pad.** Hunting by product id for six seconds with the pad live and
   sweeping, it enumerated `054C:0CE6` (DualSense) and `3434:D031` (8BitDo) — both plain HID pads —
   and never `045E:02FD`, ours, while classic XInput was reading ours live in the same moment.

⇒ THE TRIGGER ENABLE BITS REMAIN CONJECTURE, but for a better reason than before: it is not that
nobody has tried, it is that on this box NOTHING CAN DELIVER a four-motor rumble to our pad. XInput
structurally cannot; GameInput can but does not see it.

⚠️ The obvious suspicion is that `xinputhid` claiming the HID collection exclusively is what hides
the pad from GameInput — which would mean promotion costs us the API most Game-Pass-era titles use,
a trade we have shipped by default. **That is NOT established here.** The decisive control is cheap
and has not been run: power on the REAL Xbox Elite, which Microsoft's own driver promotes the same
way, and see whether GameInput enumerates it. If a real promoted Xbox pad is also absent, this is a
property of GameInput in a non-interactive session and not our defect — the same shape as the WGI
`ts=0` row, which a real Elite reproduced.

VERIFIED
  * `cargo fmt --check` clean; `cargo clippy --target x86_64-pc-windows-msvc --all-targets
    -- -D warnings` clean (cross-checked from macOS).
  * Builds and runs on .173; `GameInputCreate` succeeds, readings arrive after the poll, and
    `SetRumbleState` is accepted.
  * The runtime is loaded by name, so a box without GameInput reports "unavailable" rather than
    failing to link or crashing.

NOT VERIFIED
  * That `SetRumbleState` reaches ANY pad's motors — it was accepted for the DualSense but nothing
    observable was checked on that device, and it never reached ours.
  * `GameInputDeviceInfo` is read only for `vendorId`/`productId` (offsets 4 and 6). The rest of the
    struct has variable-size members whose layout would have to be mirrored exactly; nothing here
    needs them. `supportedRumbleMotors` is in there and would answer "does GameInput think this pad
    has trigger motors" — worth adding if this line of enquiry continues.
2026-08-09 22:55:17 +02:00
enricobuehler 13438b1287 test(tools): ask Windows which input APIs can see the pad, and find what promotes it
The Xbox-pad-on-Windows programme is a five-row matrix — classic XInput, WGI `Gamepad`, WGI
`RawGameController`, GameInput, and the HID/DirectInput/Steam family — and nothing in this tree
measured any of it. Every reading in the handoff came from ad-hoc off-tree tools, which is why
several could not be reproduced later and why one was a false positive. `win-input-matrix` makes
the matrix a command you can run twice and diff.

Two traps are baked into it because both have already cost this programme a wrong conclusion.
`--watch` samples repeatedly and reports LIVE vs MUTE per device, because an API listing a pad that
never reports is the exact failure mode here — worse than not listing it, since a title that binds
the first gamepad latches a dead one. And the doc comment insists on a baseline with the virtual pad
STOPPED: a real Xbox pad owns XInput slot 0, which is how `rc=0 LX=-885` was once read as success
with our pad already killed.

 `wake_wgi()` is not optional and is commented as such. `Gamepad::Gamepads()` and
`RawGameController::RawGameControllers()` return a cache filled by WGI's device-watcher, which a
GUI app has already started and a console app has not. Without subscribing to the Added events
first, BOTH collections come back empty with real controllers attached — measured here: a DualSense
sitting in the HID interface class, `RawGameControllers` count=0. A probe missing this reports "WGI
cannot see the pad" when WGI could not see anything.

WHAT IT FOUND (full record in measurements/2026-08-09-xbox-hid-xinputhid-busfilter.md): with
`UpperFilters=xinputhid` on the pad's PARENT devnode AND `DevicePropertyFlags=1` in that parent's
SOFTWARE key, the HID Xbox pad is promoted for the first time — the child gains the `IG_00` token,
an XUSB interface appears, classic XInput admits it, and WGI `Gamepad` lists it. All four had never
happened on this backend. A one-value A/B proves `DevicePropertyFlags` is the decisive half:
removing it alone reverts all four. That retro-explains the earlier "the filter installs fine and
produces nothing" result — the filter was loading without ever being put in bus-filter mode, which
is what `BusDevice = 0x1` means in Microsoft's own comment in `xinputhid.inf`.

Not a workspace member, for the same reason as `hid-descriptor-dump`: it is a Windows-only
bring-your-own-hardware tool with no business on a CI leg.

VERIFIED
  * `cargo fmt --check` clean; `cargo clippy --target x86_64-pc-windows-msvc --all-targets
    -- -D warnings` clean (cross-checked from macOS; the target is installed).
  * Builds and runs on .173 (Win11 26200).
  * Self-checked against known-good hardware before any conclusion was drawn from it: baseline
    reads the USB DualSense as LIVE in both WGI collections and the resting 8BitDo as MUTE.
  * The A/B was run in both directions on the same box in one session.
  * `cargo metadata` on the root workspace resolves and does NOT list this crate.
  * .173 fully reverted: registry values removed, devnodes removed, oem100.inf deleted, both certs
    delstored, 6 pre-existing pf_gamepad packages and the production service untouched.

NOT VERIFIED
  * GameInput — no binding in the `windows` crate, needs hand-written COM vtables. Not covered;
    the doc comment says so.
  * That the promotion survives a reboot or a devnode re-create from a shipped INF `AddReg` rather
    than a hand-written registry value. Nothing is shipped: `pf_gamepad.inx` is UNCHANGED and still
    contains no AddReg of any kind.
  * WHY the promoted pad still translates no data. Enumeration is fixed; translation is not. The
    evidence points at the report descriptor, which is gated on the §3.3 decision.
2026-08-09 19:24:28 +02:00