apple_smc_rw(9)

📦 version 7.3.1, in nixpkgs unstable

💅 apple_smc_rw(9) — the Kernel API Manual, but make it cute

okay so real talk, bestie: this page lives in the Kernel API Manual and it's called apple_smc_rw(9), which ngl sounds like a rare Pokémon but is actually a kernel function for talking to the SMC. let's get into it 🍓

✨ NAME ✨

apple_smc_rw — write and then read using the given SMC key

like, in that order. write first, read second. it's giving two-for-one. 💅

🦋 SYNOPSIS 🦋

int apple_smc_rw (struct apple_smc *smc , smc_key key , const void *wbuf
, size_t wsize , void *rbuf , size_t rsize );

yeah she's a long one, but honestly? iconic. returns an int, takes six args, no notes. ✨

🎀 ARGUMENTS 🎀

  • smc — pointer to the apple_smc struct. your main character struct fr fr, you gotta hand her over.
  • key — the smc_key that the data gets written to. this is the address, the destination, the moment. 🌈
  • wbuf — buffer to pull from: size bytes of data get written from here into the SMC. lowkey the source of truth.
  • wsize — how many bytes get written. literally a number. count 'em. 🔥
  • rbuf — buffer where the data lands: size bytes get read from the SMC into it. the comeback arc.
  • rsize — how many bytes get read. again, just a number, but she matters. 💖
bestie reminder: the original says "size bytes" for both wbuf and rbuf, and it means the corresponding wsize / rsize. don't come for me, I'm just the messenger. 🙈

⭐ RETURN ⭐

  • 0 (zero) on success — slay 💅
  • negative errno on error — not slay 😭

that's it. no in-between. binary queen.

👑 SEE ALSO 👑

kernel file ./include/linux/mfd/macsmc.h plus the whole friend group:

go read all of them, iykyk 🧚

one thing though: this is a kernel manpage, so if you're out here in userspace trying to call apple_smc_rw directly — no. this is for kernel drivers using the macsmc MFD stuff. respect the layer, bestie. 🫶

and that's the whole page!! tysm for reading to the end, you're literally the best. this one ships from the path ./include/linux/mfd and was dated October 2026 — so mark your calendars, she's from the future 🌸✨👑

📦 where this page comes from