tb_switch_pcie_l1_enable(9)

📦 version 7.3.1, in nixpkgs unstable

💅 tb_switch_pcie_l1_enable(9) — a Kernel API Manual moment

Okay bestie, so this is from the Kernel API Manual, section 9 (that's the kernel-functions girlies 🎀), and today's main character is tb_switch_pcie_l1_enable — yes the whole name, we don't abbreviate 💖

✨ NAME ✨

tb_switch_pcie_l1_enable — literally just enabling the PCIe link to vibe its way into the L1 state 🦋

✨ SYNOPSIS ✨

int tb_switch_pcie_l1_enable (struct tb_switch *sw );

✨ ARGUMENTS ✨

  • sw — the router you're telling to enable PCIe L1, no cap 🌸

✨ DESCRIPTION ✨

So here's the tea ☕: for a Titan Ridge switch to enter CLx state, its PCIe bridges shall enable entry to the PCIe L1 state. Like, that's the whole requirement, it's giving non-negotiable 💅

And timing matters, bestie — this shall be called after the upstream PCIe tunnel was configured. Don't jump the gun 🙈

Also, due to an Intel platforms limitation, this shall be called only for the first hop switch. First hop only. That's the rule, periodt 👑

✨ RETURN ✨

0 on success, negative errno otherwise 😭 (so like, check your return value, fr fr)

✨ SEE ALSO ✨

Kernel file ./drivers/thunderbolt/switch.c — and the whole friend group 🫶:

Okay that's the page!! 💜 Sign-off time: this lil icon lives in ./drivers/thunderbolt, it's the October 2026 edition of the manual, and it's brought to you by the section-9 girlies — slay, go enable some L1 🔥👑

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