forked from unom/punktfunk
enricobuehler
b5f91d50bb
The Android twin of `pf-client-core`'s pad_audio: drain the host's per-pad DualSense streams, Opus-decode haptics (kind 0) and speaker (kind 1), interleave into the pad's own 4-channel layout, and render on the pad itself. Every other client hands that stream to the platform's audio graph. Android cannot: AOSP's UsbAlsaManager denylists the DualSense's output by VID/PID, so the kernel enumerates the pad's playback node and the framework discards it — `hasOutput: false`, nothing for setPreferredDevice to target, /dev/snd closed by SELinux, and UsbRequest rejects non-bulk/interrupt endpoints. So this drives the pad's isochronous endpoint directly via uac-host on the descriptor Java owns. That is measured, not assumed. On a Nothing Phone (3): the claim succeeds unprivileged, the gamepad and the pad's microphone both keep working, and the underrun-free floor is 4 ms — holding under eight-core load with the SoC in severe thermal throttling. The renderer runs at 6 ms, one step of headroom, because the same measurement found transient events that are not depth-dependent. Structured to the crate's own convention: the mixer and PLC are ungated so they compile and unit-test in the host workspace (8 tests), while everything touching an Android-only dependency is cfg'd to android. Two details worth review: - The kinds arrive on different cadences (5 ms vs 10 ms), so each has its own write cursor and both shift together on overflow — a haptics-only session renders with a silent speaker pair instead of stalling on a kind that will never arrive, and the two can never skew. - An unrecognised kind is dropped rather than folded into the coil pair. A `min(1)` clamp would have rendered a future kind straight into the actuators. Lifecycle mirrors MicCapture: dropping the handle joins the thread, and nativeStopPadAudio returns only once it has, so Kotlin may close the UsbDeviceConnection as soon as it returns and not before. usbfs-iso/uac-host enter as git dependencies pinned by revision — a transport under a real-time deadline should move when we choose. They become version dependencies once published to crates.io.