tb_switch_next_cap(9)

💅 tb_switch_next_cap — the kernel API manual, but make it cute

okay so bestie, welcome to tb_switch_next_cap from the Kernel API Manual. this one is a tiny little function that walks a linked list of capabilities on a Thunderbolt switch, and honestly? she's short but she delivers. let's get into it ✨

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✨ NAME ✨

tb_switch_next_cap — return the next capability in the linked list 🦋

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🌸 SYNOPSIS 🌸

int tb_switch_next_cap (struct tb_switch *sw , unsigned int offset );

that's it. that's the whole signature. two arguments, one int coming back at you. no cap. 💅

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🎀 ARGUMENTS 🎀

• sw — the switch we're finding the capability for. this is your main character right here 👑
• offset — the previous capability offset, and listen: pass 0 for the start. like, literally 0. that's your "beginning of the list" vibe 🌈

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🧚 DESCRIPTION 🧚

so what she does is find the dword offset of the next capability in the port config space capability list. yep — the next one in the chain, the linked-list energy is real 🔥

and here's the cute part: when you pass 0 in the offset parameter, the first entry will be returned, if it exists. so 0 is basically the "take me to the top of the list" button 🫶

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⭐ RETURN ⭐

• Double word offset of the first or next capability — on success 💖
• 0 — if no next capability is found. she looked, bestie, and there was nothing there 😭
• Negative errno — another error occurred. not the vibe, but she's telling you anyway 💀

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🦋 SEE ALSO 🦋

• kernel file ./drivers/thunderbolt/cap.c
• tb_port_next_cap(9)
• tb_port_find_cap(9)
• tb_switch_find_cap(9)
• tb_switch_find_vse_cap(9)

all her besties, all in the same friend group, all worth a read 📚✨

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okay that's the whole page, no gatekeeping 💜 this icon lives in ./drivers/thunderbolt, she's dated October 2026, and the header/footer energy is pure Kernel API Manual + tb_switch_next_cap(9). go forth and walk that capability list, periodt 💅🎀