snd_hdac_que...upported_pcm(9)

📦 version 7.3.1, in nixpkgs unstable

✨ snd_hdac_query_supported_pcm 💖

okay so bestie, this is a page from the Kernel API Manual (yes, that kernel manual, the 9-section one) and we're talking about snd_hdac_query_supported_pcm — the little function that goes "hey codec, what audio rates and formats do you actually support??" and comes back with answers. it's giving detective energy 🔍✨

🌸 SYNOPSIS 🌸

int snd_hdac_query_supported_pcm (struct hdac_device *codec , hda_nid_t
nid , u32 *ratesp , u64 *formatsp , u32 *subformatsp , unsigned int
*bpsp );

that's the whole signature, no cap — copy it exactly, she does not accept substitutions 💅

🎀 ARGUMENTS 🎀

so there's six things you gotta hand her, and every single one matters:

  • codec — the codec object itself. like, the actual device you're interrogating. main character of this function tbh 👑
  • nid — the NID you want to query. that's the node ID, iykyk.
  • ratesp — a pointer where she'll drop the detected rate bitflags. yes, bitflags. it's a bitmask situation 🚩
  • formatsp — pointer, stores the detected formats.
  • subformatsp — pointer, stores the detected subformats — and heads up, these are specifically the subformats for the S32_LE format. very specific, very demure.
  • bpsp — pointer, stores the detected format widths. (bit depths, basically — but the page says widths, so: widths 🫶)

💜 DESCRIPTION 💜

she queries the supported PCM rates and formats. that's the whole vibe. you ask, she goes and finds out, she reports back. iconic behavior honestly 🌈

and here's the cute part — the NULL ratesp, formatsp, subformatsp or bpsp argument is ignored. don't have a place to put one of the answers? no worries bestie, just pass NULL and she'll skip it. flexible queen 🧚

return value check: she returns 0 if it all worked out. otherwise you get a negative error code — so like, if (ret < 0) and go deal with it 😭 don't just ignore the negative, fr fr.

🦋 SEE ALSO 🦋

the kernel file lives at ./sound/hda/core/device.c — that's where the source is, go look if you're curious 👀

and here's the whole friend group, every single one, do not skip anybody they'll notice:

anyway that's the page!! this one ships out of ./sound/hda/core and it's dated October 2026 — so yeah, from the future apparently, we love a time traveler 🕰️✨ go query those PCM formats bestie, you're gonna slay 💅💖

📦 where this page comes from