snd_pcm_new_internal(9)

📦 version 7.3.1, in nixpkgs unstable

💅 snd_pcm_new_internal(9) — the Kernel API Manual, bestie edition ✨

okay so picture this: you're deep in kernel-land, the snd_pcm_new_internal(9) page is open, and you just need someone to explain it like a friend. that's me. hi. 🫶

🌸 NAME 🌸

snd_pcm_new_internal — literally creates a brand new internal PCM instance. that's the whole vibe. 💖

✨ SYNOPSIS ✨

int snd_pcm_new_internal (struct snd_card *card , const char *id , int
device , int playback_count , int capture_count , struct snd_pcm **rpcm
);

no cap, that's the full signature. copy it exactly, don't @ me. 🎀

🦋 ARGUMENTS 🦋

  • card — the card instance. yes, the whole card. iconic.
  • id — the id string, aka the name tag of this PCM 🏷️
  • device — the device index, and it's zero based — plus it's shared with normal PCMs, which lowkey matters, so remember that 💀
  • playback_count — the number of substreams for playback 🔊
  • capture_count — the number of substreams for capture 🎤
  • rpcm — the pointer where the new pcm instance gets stored. that's your output, bestie, hold onto it 💅

👑 DESCRIPTION 👑

so what does it actually do? it creates a new internal PCM instance — and here's the main character detail: it has no userspace device or procfs entries. none. zero. the door is locked. 😭

who's this for? ASoC Back End PCMs use it to make a PCM that's only used internally by kernel drivers. i.e. — and this is a direct quote from the lore — it cannot be opened by userspace. fr fr. this is a kernel-only situation 🙈

the way it works is it provides existing ASoC component drivers with a substream and access to any private data. so the components get their substream, they get their private data, everyone's happy. 🌈

⚠️ big heads up: the pcm operators have to be set afterwards on the new instance, via snd_pcm_set_ops. don't forget, bestie, or your PCM is gonna be sitting there with no ops and that's giving unfinished business 💀

⭐ RETURN ⭐

Zero if it worked, or a negative error code on failure. that's it, that's the rule 🎯

🔥 SEE ALSO 🔥

like, go read them, they're all so valid 💜

and that's a wrap on snd_pcm_new_internal(9), brought to you by the fine people over at ./sound/core 💖 this edition's date stamp is October 2026 — so yes, we're being cute about kernel docs and time traveling. slay. 🧚✨🎀

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