v4l2_subdev...active_state(9)

📦 version 7.3.1, in nixpkgs unstable

💅 v4l2_subdev_get_unlocked_active_state(9) — like, the whole glow-up

okay so bestie, welcome to the Kernel API Manual ✨ pull up a chair, grab a strawberry 🍓, and let's talk about the single most specific little function in the v4l2 subdev cinematic universe. it's giving "tiny helper, huge main character energy" and honestly? we're obsessed.

🎀 NAME

v4l2_subdev_get_unlocked_active_state — this one checks that the active subdev state is unlocked, and then hands it right back to you. yes, it's a vibe check and a delivery service 🫶

✨ SYNOPSIS

struct v4l2_subdev_state * v4l2_subdev_get_unlocked_active_state (struct
v4l2_subdev *sd );

🦋 ARGUMENTS

  • sd — the subdevice, bestie. that's it. that's the whole argument. one (1) subdevice, as the universe intended 💜

🌸 DESCRIPTION

so here's the tea 🔥 — this function returns the active state for the subdevice. and if the subdev just… doesn't support active state? you get NULL. no drama, no crash, just a polite little NULL and everyone moves on.

but if the state is not NULL, then it calls lockdep_assert_not_held to issue a warning if the state is locked. yes ma'am, it's checking your work — if you were supposed to come in here without the lock and you didn't, you're gonna hear about it 😭

and when do you even use this? the manpage says it best: use it e.g. when getting the active state for the sole purpose of passing it forward, without accessing the state fields. literally just holding its hand and walking it to the next function. no snooping in its fields, no reading its diary 🙈 that's the whole point.

ngl bestie, this is a "don't touch, just pass it along" kind of function. respect the boundaries and you'll slay 💅

👑 SEE ALSO

the friend group is massive, and we're listing every single one of them, no cap. also shoutout to the kernel file ./include/media/v4l2-subdev.h ⭐

and that's the whole page, bestie 🧚 no notes, ate and left no crumbs. this lil cutie lives in ./include/media and the version on the label says October 2026 — so like, mark your calendars, screenshot for the group chat, and go read your state fields somewhere else 💖💅🌈

📦 where this page comes from