UAUDIO(4)

💖 UAUDIO(4) 💖 — the USB audio device driver (Kernel Interfaces Manual, bestie edition) ✨

okay so picture this: you plug in a USB headset and it just works — that's this driver, no cap 🎧✨

✨ SYNOPSIS ✨

uaudio* at uhub?
audio*  at audiobus?

🌸 DESCRIPTION 🌸

The uaudio driver provides support for USB audio class devices. literally its whole job 💅

A USB audio device is made up of a bunch of components: input terminals (e.g. USB digital input), output terminals (e.g. speakers), and a number of units in between (e.g. volume control). The following types of units are handled by the uaudio driver and are accessible via the mixer (see audio(4)) interface — get into it:

• mixer — a mixer has a number of inputs and one output. Each input has a control that determines its volume in the output. The name of the control is mixN-S, where N is a number that identifies which mixer it is and S which input. iconic behavior tbh 🎛️
• selector — a selector unit selects one of multiple audio sources such as mic-in and line-in. The name of the control is selN-S1S2S3..., where N is a number that identifies which selector unit it is and the sequence of Sn indicates candidate units for the audio source. choosing your fave source like it's a playlist 🎶
• feature — a feature unit changes the sound in some way, like bass, treble, mute, or volume. The name of the control is determined in a heuristic way. If the unit changes the sound to a speaker output terminal, the names of the controls may be outputs.speaker.bass, outputs.speaker.treble, outputs.speaker.mute, outputs.speaker, or likewise. it's giving "vibes-based naming" and honestly? we stan 🌈
• processing — a processing unit does one of a number of audio processing functions (e.g., channel up-down mixing, Dolby ProLogic, or chorus effects). The name of the on–off control is proN.M-enable, where N is a number that identifies which processing unit it is and M which kind. Depending on the type of processing unit there may be other controls as well. main character energy for real 💫
• extension — an extension unit performs some unspecified audio processing. The name of the on–off control is extN-enable, where N is a number that identifies which processing unit it is. mysterious. elusive. we love her 🦋

For more information the USB Audio class specification is indispensable reading. like genuinely, go read it, it's the blueprint bestie 📖✨

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💅 SEE ALSO 💅

• audio(4)
• usb(4)

USB Approved Class Specification Documents, http://www.usb.org/developers/docs/devclass_docs/.

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🎀 HISTORY 🎀

The uaudio driver appeared in NetBSD 1.5. Support for USB Audio Class 2.0 devices appeared in NetBSD 11.0. a glow-up for the history books fr fr 👑

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😭 BUGS 😭

There is no support for multiple-endpoints audio stream, adaptive recording, async playback, and TYPE-II/III formats. not me crying over missing features 💀

There is the possibility that a device has multiple mixer items which have the same name. so if you see duplicates… that's not a glitch, that's just the vibe 🙈

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Deployed on Debian, dated May 21, 2024 — UAUDIO(4) and that's the tea, bestie 🫶💖 stay slaying those USB devices ✨