comedi_dio_update_state(9)

📦 version 7.3.1, in nixpkgs unstable

💅 comedi_dio_update_state(9) — from the Kernel API Manual, bestie ✨

okay so real talk, this one's a kernel function and it lives in the comedi directory, and honestly? it's lowkey iconic. it's giving "small helper, big responsibility." let's get into it 🫶

✨ NAME ✨

comedi_dio_update_state — updates the internal state of DIO subdevices 💅

like, it literally just keeps track of stuff for you. no cap.

🌸 SYNOPSIS 🌸

unsigned int comedi_dio_update_state (struct comedi_subdevice *s ,
unsigned int *data );

two args, one unsigned int coming back at you. that's the whole vibe check 💖

🎀 ARGUMENTS 🎀

  • s — your COMEDI subdevice. the main character here, fr fr. 👑
  • data — the channel mask and bits to update. it's giving "instructions in an array," and honestly? we love that for us. 🦋

💜 DESCRIPTION 💜

okay so here's the tea ☕ — this function updates s->state, which is the field holding the internal state of the outputs for DIO or DO subdevices (up to 32 channels, so like, don't get too excited 🥲).

the array does the talking:

  • data[0] contains a bit-mask of the channels to be updated. that's the "who" 🕵️
  • data[1] contains a bit-mask of those channels to be set to '1'. that's the "what" ⭐

and then — and this is the part nobody wants to hear — the caller is responsible for updating the outputs in hardware according to s->state. not me, not the function, you. 😭 as a minimum, the channels in the returned bit-mask need to be updated.

⚠️ like seriously bestie, the function does NOT touch your hardware. it updates the bookkeeping and hands you a mask. what you do with it is your business, but you gotta do it.

it returns a mask with non-existent channels removed. so if you asked about channels that don't even exist? gone. filtered. ghosted only in the gentlest, most correct way 🙈✨

🌈 SEE ALSO 🌈

Kernel file ./drivers/comedi/drivers.c, plus the whole friend group 🫶:

that's the whole page, no notes. 💖

and finally, the cute sign-off you asked for: this little gem comes from the source path ./drivers/comedi, dated October 2026 — so yeah, future-coded and thriving. slay, periodt. 🌸🎀💅

📦 where this page comes from