__v4l2_devic...ll_subdevs_p(9)

📦 version 7.3.1, in nixpkgs unstable

💅 __v4l2_device_call_subdevs_p 💅

okay so real talk, this is a page out of the Kernel API Manual and it's lowkey iconic once you get what it does 🫶 the name is __v4l2_device_call_subdevs_p and it's giving "my underscore prefixes are load-bearing" energy, iykyk.

✨ NAME ✨

__v4l2_device_call_subdevs_p — Calls the specified operation for all subdevs matching the condition. that's the whole vibe fr fr 💖

🦋 SYNOPSIS 🦋

__v4l2_device_call_subdevs_p (v4l2_dev , sd , cond , o , f , args... );

like yes bestie it's a macro, yes it takes a whole little gang of arguments, no we're not scared of it 💅

🎀 ARGUMENTS 🎀

  • v4l2_dev — the struct v4l2_device that owns the sub-devices you're iterating over. it's the main character here, everything belongs to it 👑
  • sd — a pointer that the macro itself fills in with all struct v4l2_subdev pointer used as an iterator by the loop. so like, don't you worry about assigning it, the macro's got you ✨
  • cond — condition to be match. if it hits, the operation goes brrr 🔥
  • o — name of the element at struct v4l2_subdev_ops that contains f. each element in there groups a set of operations functions, so think of o as picking which lil squad you're rolling with 🌈
  • f — the operation function that will be called if cond matches. the operation functions are defined in groups, according to each element at struct v4l2_subdev_ops — so o and f are besties, they go together 💜
  • args — arguments for f. pass them through, no cap 🍓

🌸 DESCRIPTION 🌸

Ignore any errors.

genuinely that's it. that's the description. it goes through everything and if something goes wrong it simply does not care 😭 not me being emotionally unbothered, that's literally the documented behaviour, periodt 💀

⭐ NOTE ⭐

subdevs cannot be added or deleted while walking the subdevs list.

read that again bestie!! 🚨 no adding, no deleting, no funny business while the loop is walking. you're on a moving sidewalk, you don't redecorate the sidewalk. that's the whole warning, respect it 🙈

🧚 SEE ALSO 🧚

Kernel file ./include/media/v4l2-device.h and honestly the whole friend group:

and that's the page!! 🥳 source is ./include/media, dated October 2026, and the header/footer vibe is __v4l2_devic...ll_subdevs_p(9) — yes the truncation is part of the aesthetic, slay 💖✨🎀 ily, go call some subdevs responsibly 🫶

📦 where this page comes from