The 0xD1 pad-audio plane streams a DualSense's voice-coil haptics (back
channel pair, 5 ms Opus frames) and speaker (front pair, 10 ms) per pad from
a Windows host to the SDL clients, which render them into a USB DualSense's
own 4-channel audio device.
Wire (punktfunk-core, ABI v15): PAD_AUDIO_MAGIC 0xD1 [pad][kind][seq][pts]
[opus]; CLIENT_CAP_PAD_AUDIO 0x04 / HOST_CAP_PAD_AUDIO 0x20; per-pad render
capability rides GamepadArrival flags bits 8/9, sent only toward a host that
advertised its cap so old hosts see byte-identical arrivals; silence is a
frozen seq (mic-mute discipline), loss is a seq gap concealed via
AudioGapTracker. HidOutput::AudioCtl (0xCD kind 0x06) forwards the 0x02
report's audio-control bytes 5..=10 change-only, value-deduped, with a
once-per-pad "title asserted haptics-select" diagnosis log.
Windows host endpoint provider (audio/windows/pad_endpoint.rs): per-pad
render endpoints are additional devnode instances of Valve's Steam Streaming
Speakers driver (SetupDiRegisterDeviceInfo, NOT the class installer - it
needs an interactive window station), stamped with DualSense identity: desc
"Wireless Controller", device name "DualSense Wireless Controller",
ContainerId = the virtual pad's PFDS GUID, 4ch/48k format triplet.
IPropertyStore route first, ACL-repaired registry fallback (the MMDevices
keys deny writes even to SYSTEM; the owner's implicit WRITE_DAC + an ACE for
S-1-5-18 resolved by SID is the way in). Provisioned at host startup
(PUNKTFUNK_PAD_AUDIO, PUNKTFUNK_PAD_AUDIO_SLOTS, default 1), idempotent via
a persisted PunktfunkPadIndex marker; pad endpoints are structurally
ineligible for the mic/loopback wiring plan and guarded against default-
device theft; capture is WASAPI loopback on the stamped endpoint. Devtest:
punktfunk-host pad-endpoint ensure|remove|status.
Host service (native/pad_audio.rs): per-(session,pad) thread, loopback 4ch
-> pair splitter -> per-kind stereo Opus (48k LowDelay CBR 64k) -> per-kind
silence gate (opens at peak>=1e-3, 250 ms hangover, gated = no send + frozen
seq) -> datagrams. Spawned from the native input pump when a DualSense/Edge
arrival carries audio bits and both caps negotiated; idempotent re-arrivals;
reaped on remove and teardown.
Client tier A (pf-client-core/pad_audio.rs): settings pad_haptics (default
on) and pad_speaker (default "pad"); tier A = wired USB DS5/Edge via SDL
connection state with an audio-sibling fallback; correlation maps the SDL
HID path to the pad's own render endpoint (Windows: ContainerId match +
4ch gate via registry; Linux: Sony sink signature); renderer decodes both
kinds into a quad interleave and plays it on the pad's endpoint (WASAPI
autoconvert / PipeWire target.object, 240-2400 frame ring floor,
dont-reconnect so an unplug never re-routes haptics to the desktop
speakers). SDL's DualSense driver sets "disable audio haptics" whenever it
drives rumble emulation, so tier-A pads suppress wire rumble and send one
cleared-enable-bits effects packet to keep the actuators live; AudioCtl
bytes fold back into the effects packet at report-minus-one offsets.
Verification: punktfunk-core 265 tests (macOS) + clippy -D warnings (mac +
Linux docker); pf-inject 85 tests (Linux docker); punktfunk-host cargo
check + clippy + 19 pad tests + 46 audio-module tests (Windows box);
pf-client-core 30 tests + clippy (Linux docker CI image) + cargo check
(Windows box); punktfunk-client-session clippy (Linux) + check (Windows);
cargo fmt --all --check clean on the final tree. NOT yet verified: any
on-glass run (host deploy + real title + physical pad), the stamp-route
split at runtime, exclusive-mode Initialize isolation, Linux-host emission
(the per-pad PipeWire sink is not in this change - Windows hosts only).
Scope excluded deliberately: tier B (Apple CoreHaptics) and tier C
(haptics->rumble derivation), pad_speaker="mix", Android leg, settings UI
surfaces (keys are serde-defaulted), GameStream-plane arrivals (audio_caps
always 0 there).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
enricobuehlerandClaude Fable 5
ed3d236ab8