vb2_poll(9)

📦 version 7.3.1, in nixpkgs unstable

💅 vb2_poll(9) — like, the poll operation but make it kernel

okay so bestie, welcome to the vb2_poll(9) page from the Kernel API Manual ✨ this is the videobuf2 girly who handles the poll userspace operation, and she is lowkey carrying the whole file-descriptor-readiness moment. let's get into it 🎀

✨ NAME ✨

vb2_poll — implements poll userspace operation 🦋

🌸 SYNOPSIS 🌸

__poll_t vb2_poll (struct vb2_queue *q , struct file *file , poll_table
*wait );

💖 ARGUMENTS 💖

  • q — pointer to struct vb2_queue with the videobuf2 queue. that's your queue bestie 🫶
  • file — the file argument that got passed to the poll file operation handler
  • wait — the wait argument that got passed to the poll file operation handler

👑 DESCRIPTION 👑

so this function implements the poll file operation handler for a driver. iconic behaviour, no cap 💅

For CAPTURE queues: if a buffer is ready to be dequeued, the userspace gets informed that the file descriptor of a video device is available for reading. periodt.

For OUTPUT queues: if a buffer is ready to be dequeued, that file descriptor gets reported as available for writing. slay.

If the driver uses struct v4l2_fh, then vb2_poll will also check for any pending events — not me forgetting to mention that, i would never 🙈

the return values from this function are intended to be directly returned from the poll handler in the driver. like, don't remix them, just hand them straight back fr fr 🔥

🌈 SEE ALSO 🌈

Kernel file ./include/media/videobuf2-v4l2.h — go read it, iykyk ⭐

and that's the whole vibe check 💜 this page lives at ./include/media, dated October 2026 — mwah, go poll something iconic bestie 🧚🍓

📦 where this page comes from