tb_switch_nvm_read(9)

📦 version 7.3.1, in nixpkgs unstable

🌸 NAME 🌸

tb_switch_nvm_read — bestie, this is the one that reads the router NVM 💅 (yes, this page lives in the section 9 Kernel API Manual, iykyk)

✨ SYNOPSIS ✨

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

That's the whole vibe check right there — four args, one int coming back at you 🫶

🎀 ARGUMENTS 🎀

  • sw — the router whose NVM you're about to read. like, which router, bestie, be specific 💖
  • address — the start address on the NVM. where the reading begins, no cap 📍
  • buf — the buffer where the read data gets copied. this is where the tea lands ☕
  • size — size of the buffer, in bytes. please get this right or it's giving chaos 😭

🦋 DESCRIPTION 🦋

okay so here's the whole thing: it reads from the router NVM and hands you back the requested data in buf. that's it, that's the function ✨

🚨 the one thing you cannot skip: locking is up to the caller. the function does not do it for you. not me having to remind you — it literally says so. so lock it yourself, bestie, or it's giving undefined chaos 💀

🌈 RETURN 🌈

  • 0 on success — slay, we ate 👑
  • negative errno otherwise — so if it's negative, something went wrong, and that's your sign 😭

🧚 SEE ALSO 🧚

the kernel file is ./drivers/thunderbolt/switch.c — go read the source, it's iconic 🎀

the ports & paths girlies:

link speed / width / lane bonding squad 💅:

usb3 / pci / displayport besties:

the switch main characters 👑:

okay that's the whole page, you're so welcome 💜 this little writeup ships out of the ./drivers/thunderbolt source and it's dated October 2026 — so like, future vibes only, periodt 🌟 byeee, go read your NVM responsibly 🫶✨

📦 where this page comes from