Phase 1 of the gyro program (design/gyro-program.md, G1-G5) — the five
correctness fixes under it. Gyro aim integrates angular velocity over time, so
each of these is not a cosmetic wrongness: a wrong scale is every rotation being
the wrong size, a wrong clock is every rotation being integrated against a
fictional dt, and a stale sample is rotation that never happened.
G1 — the DualShock 4 calibration blob. A Sony pad does not assume a motion
scale, it reads one out of a fixed calibration feature report. Ours declared
0.5 LSB per °/s and 8192 LSB/g while the wire delivers 20 and 10000, so every
DS4-type session decoded gyro 40× too fast and acceleration 1.22× hot — since
the backend shipped. The blob now states the wire's own units (the DualSense
blob's numbers, deliberately: both pads consume the identical wire sample). Its
interleaved per-axis order is NOT a bug and stays: the virtual pad declares
BUS_USB, where interleaved is the correct layout; grouped is Bluetooth's.
The same blob lives a second time in the UMDF driver, which is a separate WDK
workspace that cannot depend on pf-inject — one wrong table in two files, where
fixing one reads as fixing it. Both are fixed, and the DS4 feature reports now
live in dualshock4_proto beside the DualSense's rather than in the Linux
backend, so there is one canonical copy to point at.
Field hosts keep the old blob until they update the host package.
G2 — the gate that would have caught it. Nothing pinned any backend's
declaration against the wire, so tests/motion_contract.rs now applies the
CONSUMER's arithmetic (the kernel's, and SDL's, which differ) to each backend
and asserts the result lands back on the wire constants — for the DualSense and
DS4 blobs, and for the Deck and Switch Pro rescales. It also parses the driver's
Rust source and re-derives the units from THAT, so the two copies cannot drift.
Verified non-vacuous both ways: re-introducing the old blob fails with "declares
a fractional 32/64 LSB per °/s", and reverting only the driver's copy fails with
"the UMDF driver's DS4_FEATURE_CALIBRATION has drifted from pf-inject's".
The wire units themselves move to punktfunk_core::input::gamepad, referenced by
the client's capture scale, the Deck/Switch rescales, and the probe — whose
at-rest vector said 16384 (a driver's number, not the wire's) and now says 1 g.
G3 — real sensor clocks. The DualSense advanced its sensor timestamp by +1 raw
unit per report (0.33 µs — a frozen clock) and the DS4 by a flat +188 (~1 ms)
regardless of the real 4-8 ms cadence. Anything integrating rate × dt off that
field got nonsense. All four backends now stamp elapsed monotonic time in their
own units via a shared SensorClock, anchored to the pad's first report so an
irregular publish loop cannot make it drift, and truncated to the field width —
which reproduces the wrap real hardware does.
G4 — motion is level-triggered and had no watchdog. merge_frame preserves the
last sample and the heartbeat re-emits it, so a feed that stops leaves the pad
rotating forever — and with G3's honest clock, at a dt that keeps growing.
Rumble and the pen plane each have an idle timeout; motion now has one too, at
100 ms. Angular velocity only: acceleration is kept, because gravity is
legitimately persistent and blanking it reads as free-fall. The SDL client
parks its gyro at zero when a slot closes, which is the case we can flush
rather than wait out. (The Apple half of this rides in PR #88.)
G5 — a pad returning inside the 300 ms replug grace keeps the same device and
skips the create path, so a different controller inherits the previous one's
touch contact and rotation — and a pad with no gyro never sends a sample to
correct it. sweep() now reports re-claims separately from drops, and the manager
clears the rich plane on one. Rich fields only: rumble and hidout dedup
deliberately survive a removal.
Gates (Linux, CI image): fmt, build, clippy --all-targets -D warnings over
pf-inject/punktfunk-core/punktfunk-probe/pf-client-core, and the test suites —
110 pf-inject unit + 6 contract + 29 pf-client-core gamepad, all green.
Not yet verified on glass; the on-glass sign/scale session is G16.
enricobuehler
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