The Linux client's pad-audio renderer matched a PipeWire sink by name signature
alone and streamed a positioned FL/FR/RL/RR quad at it. The voice coils ARE
channels 3 and 4 of the pad's USB sound card, and a DualSense almost never
presents four channels by default: PipeWire's ACP picks a stereo profile, and a
modern alsa-ucm-conf splits the card into a mono Speaker and a stereo Headphones
sink instead. Every one of those opens perfectly and then position-remixes our
quad into the speaker pair, so the coils are never excited — nothing is felt, and
nothing looks wrong. The Windows half of the same module has required a 4-channel
endpoint since it was written; only Linux never did, and it was compile-verified
only (the on-glass leg was Android -> Linux host, which renders over raw USB and
never touches a graph).
Correlation now walks nodes AND devices, and picks a four-channel node that
belongs to a DualSense CARD:
- Identity comes from the USB ids (base 16, either 0x spelling) with the old name
signature as the fallback, and it may sit on either the node or its card — a
split card's public sinks publish neither.
- `device.id` is required, which is also what keeps a Punktfunk HOST's own minted
pad sink out: it carries the full DualSense identity on purpose, and rendering
into it would loop the plane back at the host.
- Unpositioned (AUX) quads are preferred, then positioned ones, then the hidden
four-channel parent a split sink names in `api.alsa.split.name` — GE-Proton's
own preferred haptic leg.
- With no four-channel node anywhere, the card's profile is moved to Pro Audio for
the session and restored when it ends (never saved; `PUNKTFUNK_PAD_AUDIO_PROFILE=0`
opts out; a sandboxed client that is refused the write gets told to do it by hand).
The stream itself now sets `stream.dont-remix` and AUX0..AUX3 rather than
FL/FR/RL/RR, so channel k reaches channel k whatever the node advertises — the
same shape the host-side sink mints and GE forces on its own haptic streams.
Also here:
- `punktfunk-session --pad-audio-test` prints every DualSense object in the graph,
the node it chose, and drives a tone into the coils. It separates "the plane
never arrived" from "it arrived and the graph folded it away" with no host, no
game and no pairing — the diagnostic whose absence made this a field report.
- The GTK client grows Controller haptics / Controller speaker rows; they were
reachable from Android and the settings file only. Not profileable (which pad is
in your hands is a fact about this device), and a stored "mix" survives the
round trip.
- The tier-A activation packet no longer swallows its error: where SDL does not own
the pad's HID link (Linux's own hid-playstation has it), that is worth saying,
because that driver asserts the same audio-haptics disable bit on every rumble.
- Docs: the client half of controller-audio, the two settings rows, and
PUNKTFUNK_PAD_AUDIO_PROFILE. The "speaker is opt-in" line was only true of
Android; desktop has shipped it on.
Gates (Ubuntu 26.04 rust-ci container, linux/amd64): clippy --all-targets -D
warnings over pf-client-core, pf-presenter, punktfunk-client-session and
punktfunk-client-linux; plain build; 204 tests green including 5 new ones for the
matcher, the identity parse and the profile chooser; cargo fmt --check. The graph
walk was smoke-tested against a live PipeWire daemon on home-bazzite-1 (2 sinks,
2 cards enumerated, matching --list-audio; correct "no DualSense" verdict with no
pad attached). NOT yet exercised against a real DualSense — that is the on-glass
step this leaves open.
enricobuehler
d227db06e8