tb_tunnel_discover_dp(9)

📦 version 7.3.1, in nixpkgs unstable

✨ tb_tunnel_discover_dp(9) ✨

okay so bestie, welcome to the Kernel API Manual for tb_tunnel_discover_dp(9) — yes that's the whole title, yes it's a mouthful, no we're not changing it 💅 this is the Thunderbolt tunnel girlies' page and it's lowkey iconic.

🦋 NAME 🦋

tb_tunnel_discover_dp — the little function that goes and discovers the Display Port tunnels that already exist 👀✨ like it's not making new ones, it's just finding the ones already vibing there.

🎀 SYNOPSIS 🎀

struct tb_tunnel * tb_tunnel_discover_dp (struct tb *tb , struct tb_port
*in , bool alloc_hopid , void (*callback)(struct tb_tunnel *, void *) ,
void *callback_data );

that's the whole signature, copied exactly, do not come for me 🫶

🌸 ARGUMENTS 🌸

  • tb — pointer to the domain structure 🏠 the whole neighborhood basically.
  • in — the DP in adapter 💖 the starting point of the adventure.
  • alloc_hopid — a bool; if true, allocate HopIDs from the visited ports ✨ (HopIDs from the ports it visited, specifically — not from anywhere, don't get it twisted).
  • callback — the callback that gets called when the DP tunnel is fully activated 🔥 (or when there's an error 😭 — yes, errors count too, it still calls you back).
  • callback_data — the data that gets passed to that callback 🎁 your little gift bag of context.

💜 DESCRIPTION 💜

so here's the vibe: if the in adapter is active, this function follows the tunnel all the way to the DP out adapter — and then back 🔁🦋 like a little round trip, a there-and-back-again situation.

It returns the discovered tunnel, or NULL if there was no tunnel at all 🙈 (which, honestly, valid — sometimes the tunnel just isn't there).

And for how the callback works? See tb_tunnel_alloc_dp. that's where the callback lore lives, iykyk 👑

⭐ RETURN ⭐

Pointer to struct tb_tunnel — or NULL if no tunnel was found 💀 that's it, that's the return.

🌈 SEE ALSO 🌈

the manpage says go read these, and honestly? main character reading list 👑:

Kernel file ./drivers/thunderbolt/tunnel.c, plus:

and that's the page fr fr 🫶 this whole thing lives in ./drivers/thunderbolt and it's dated October 2026 — so yeah, future-coded manual page, we love to see it ✨🎀 bye bestie! 💖

📦 where this page comes from