usb4_port_retimer_nvm_write(9)

📦 version 7.3.1, in nixpkgs unstable

💅 usb4_port_retimer_nvm_write(9) — kernel API manual, bestie edition

okay so real talk, this is a page from the Kernel API Manual, section 9 (that's the kernel-functions girly pop section 💫), and it's about writing bytes into a retimer's NVM. yes, that NVM. the flash-y one. slay.

🎀 NAME 🎀

usb4_port_retimer_nvm_write — write to retimer NVM

like, the whole vibe of this function is "put data in the retimer's non-volatile memory." that's it. that's the tweet. 💖

✨ SYNOPSIS ✨

int usb4_port_retimer_nvm_write (struct tb_port *port , u8 index ,
unsigned int address , const void *buf , size_t size );

look at her. four args, returns an int. iconic behavior honestly.

🦋 ARGUMENTS 🦋

  • port — the USB4 port. your main character. the port we're doing all this for 💅
  • index — retimer index. which retimer bestie we talking about, pick a number
  • address — byte address where to start the write. where the pen goes down on the paper 🖊️
  • buf — data to write. the payload. the goods 📦
  • size — size in bytes, how much to write. no cap, this many bytes exactly

🔥 DESCRIPTION 🔥

Writes size bytes from buf to the retimer NVM. literally just yeets your buffer into the retimer's non-volatile memory, size bytes of it, starting from address.

and the reason you'd ever do this? NVM upgrade. that's the use case. that's the moment. firmware glow-up szn ✨🧚

💜 RETURN 💜

  • 0 — if the data was written successfully. we love a clean zero, she ate 🫶
  • -ENODEV — if there is no retimer at index. nobody home. empty seat. 😭
  • Negative errno — in case of an error. any negative errno, it's giving "something went wrong" energy 💀

🌈 SEE ALSO 🌈

kernel file ./drivers/thunderbolt/usb4.c — and a truly enormous friend group, in order, no skips:

that's the whole group chat. every single one. iykyk 💖

lowkey reminder: this is a kernel-internal function page, so it's all "here's what the function does" — not "type this into your shell." no userland command here, bestie, just API lore 🧚‍♀️

🌸 that's the page!! source: ./drivers/thunderbolt, dated October 2026, and the manual id on the tin is literally usb4_port_retimer_nvm_write(9) — go off, section 9 👑 periodt ✨💅🫶

📦 where this page comes from