enricobuehler
ce5047f3ad
G6 + G15 of the gyro program. G6 — the UMDF gamepad driver's input path. Its timer ran at 8 ms and completed one pended READ_REPORT per tick, so a game could observe at most ~125 Hz while clients stream motion at ~250 Hz: every other sample was overwritten in the slot before anything read it, and the ones that survived carried up to 8 ms of extra latency. For gyro, a dropped sample is not a dropped frame — it is rotation that never reaches the game. The timer now ticks at 2 ms (about a real DualShock 4's Bluetooth cadence). Only the cheap half runs on every tick: read the input slot, complete one pended read. The channel handshake and the health marks stay on their historical ~8 ms, because they cost more, nothing wants them faster, and `driver_heartbeat`'s documented "+1 per ~8 ms tick" is what the host reads as liveness. The same slot is a single unqueued buffer that both sides touch without a lock, so a driver read landing mid-copy handed the game a report that was half the previous frame and half the next. For a button that is a one-tick glitch; for motion it is a spike in angular velocity, which an integrator turns into aim movement. `PadShm` gains an `input_gen` seqlock (v2.3, carved from reserved space inside the v2 legacy region): the host takes it odd, fences, writes the 64 bytes, and stores it even; the driver samples it either side of its read and retries once. The old code's own comment called this out as a known residual — it is now closed rather than documented. Version posture matches the ring's, with one simplification: no capability stamp is needed, because an old host never writes the field and a constant 0 is indistinguishable from "no write in flight", so a new driver against an old host behaves exactly as it does today, and an old driver ignores the field entirely. The Steam Deck write path had neither the seqlock nor even the trailing Release its DualSense sibling carried; all three Windows backends now publish through one `publish_input`. G15 — motion-cadence observability. The host already computed the measurement a "gyro feels floaty" report needs (client inter-arrival percentiles), but kept ONE global accumulator, so two motion-capable pads in a session interleaved into each other's gaps and produced a number describing neither. It also sat at `debug` behind a `tracing::enabled!` check, so a field log arrived with nothing in it and the only way to get the measurement was to ask for a re-run. Now per-pad and always on, summarized at `info` when the session ends — the moment a field report is being written. It costs one subtraction and one array increment per sample: percentiles come from a fixed log2 histogram instead of a growing sorted Vec, so there is no allocation, no per-window sort, and no way for a client streaming as fast as the link allows to make the instrument expensive. Percentiles are reported as bucket upper bounds (`_le`), which is a factor-of-two answer to a question whose answers are orders of magnitude apart. Gaps of 500 ms or more are counted as stalls rather than folded into the percentiles — an interruption is not a cadence, and averaging it in would report a healthy feed as a terrible one. Gates. Windows CI runner .133, the drivers workspace on the real WDK: cargo build, clippy -D warnings (which enforces the unsafe-audit lints), and fmt — all green, against a source whose SHA-256 matches this commit's. Linux CI image: fmt, build, clippy --all-targets -D warnings over pf-inject / punktfunk-core / punktfunk-probe / pf-client-core / pf-driver-proto / punktfunk-host, and the test suites including the 5 new motion-cadence tests — all green. Not measured on glass. G6's stated gate is a sensor-rate reading (SDL testcontroller or Steam's calibration screen) that matches the client's send rate; that is still owed, and a driver change only a compile has seen deserves it before anyone trusts the number.
pf-driver-proto
The shared host ↔ driver binary contract for punktfunk's Windows pf-vdisplay virtual display — the control IOCTLs and the IDD-push frame transport, defined exactly once.
It's a path dependency of both the host workspace (crates/punktfunk-host)
and the out-of-workspace driver workspace (packaging/windows/drivers/),
so it must resolve identically from either build graph. That's why it's deliberately self-contained:
no_std (+ alloc), platform-neutral (GUID/LUID are plain integers each side converts to its own OS
type), and free of *.workspace = true inheritance.
Defining every wire struct here — with const size/offset asserts and bytemuck round-trips — turns
host↔driver ABI drift into a compile error instead of a silent frame or IOCTL corruption.
See the crate root (src/) for the wire types; the Windows virtual-display design is in
the internal planning repo (punktfunk-planning: windows-virtual-display-rust-port.md).