usb4_switch_nvm_read(9)

📦 version 7.3.1, in nixpkgs unstable

okay bestie, welcome to usb4_switch_nvm_read(9) from the Kernel API Manual — the entry that’s literally about reading arbitrary bytes from router NVM. no cap, it’s giving low-level but make it cute 💅✨

🌸 NAME 🌸

usb4_switch_nvm_read — Read arbitrary bytes from router NVM. that’s the whole assignment, and it ate. 💖

✨ SYNOPSIS ✨

the signature, verbatim, because we do not mess with the signature:

int usb4_switch_nvm_read (struct tb_switch *sw , unsigned int address ,
       void *buf , size_t size );

🎀 ARGUMENTS 🎀

  • sw — USB4 router. the router you’re working with, bestie 👑
  • address — Starting address in bytes. where the reading starts, in bytes ✨
  • buf — Read data is placed here. the read data goes right here 🫶
  • size — How many bytes to read. literally how many bytes to read 💅

🦋 DESCRIPTION 🦋

Reads NVM contents of the router.

that’s it. that’s the vibe. NVM contents, router, read. iconic. 💜

🔥 RETURN 🔥

  • 0 — Read completed successfully. slay, it worked. ✅
  • -EOPNOTSUPP — NVM not supported. ngl, this one means NVM is not supported, bestie. 😭
  • Negative errno — Another error occurred. so… an error happened, but not that one. 💀

🌈 SEE ALSO 🌈

the kernel file is ./drivers/thunderbolt/usb4.c, and here’s the whole squad, fr fr:

💌 and that’s the page, bestie — source/version: ./drivers/thunderbolt, date: October 2026, manual name: usb4_switch_nvm_read(9). mwah 💅🎀
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