snd_pcm_hw_c...raint_msbits(9)

📦 version 7.3.1, in nixpkgs unstable

💖 snd_pcm_hw_constraint_msbits — the Kernel API Manual page you didn't know you needed 💖

okay so bestie, we're in the Kernel API Manual today and honestly? this one is a lil niche but it slaps once you get it. it's called snd_pcm_hw_constraint_msbits, and yes the header abbreviates it as snd_pcm_hw_c...raint_msbits(9) because apparently even the manpage needed a vibe check on character count 💀

✨ NAME ✨

snd_pcm_hw_constraint_msbits — adds a hw constraint msbits rule, that's literally the whole thing, she's a rule-adder, an icon 👑

🌸 SYNOPSIS 🌸

int snd_pcm_hw_constraint_msbits (struct snd_pcm_runtime *runtime ,
unsigned int cond , unsigned int width , unsigned int msbits );

like, four args, returns an int, very demure, very mindful 🎀

🦋 ARGUMENTS 🦋

  • runtime — the PCM runtime instance. she's the main character of this whole story, everything happens inside her 💅
  • cond — condition bits. the little flags that gate when this rule even bothers showing up ✨
  • width — sample bits width. how wide the sample format is, in bits 🍓
  • msbits — msbits width. how many of those most significant bits we're setting 🌈

🧚 DESCRIPTION 🧚

so here's the tea, bestie: this constraint will set the number of most significant bits (msbits) if a sample format with the specified width has been selected. that's it, that's the job 🫶

and there's a lil special case you gotta know: if width is set to 0, then the msbits get set for any sample format with a width larger than the specified msbits. not me loving a wildcard case 😭🔥

ngl this is one of those "small function, big consequences" situations — it's reshaping what the hardware can actually agree to. no cap.

⭐ RETURN ⭐

  • Zero if successful, or a negative error code on failure. that's the whole return section, she's brief, she's efficient, she ate 💀✨

👑 SEE ALSO 👑

like, the whole constraint family reunion, we love a see-also list that goes off 🎉

and that's the whole page, bestie — no crumbs left behind 💅

signing off from ./sound/core, dated October 2026, with the manual name snd_pcm_hw_c...raint_msbits(9) living rent-free in the header where it started 🫶✨ mwah, go read the source, ily 🎀

📦 where this page comes from