nhi_mailbox_mode(9)

💅 hey bestie, welcome to nhi_mailbox_mode

okay so this is a page from the Kernel API Manual — the nhi_mailbox_mode(9) one — and it's honestly kind of a little icon. short, sweet, does exactly one thing. we love a focused queen. ✨

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🌸 NAME

nhi_mailbox_mode — returns the current firmware operation mode, no cap 🎀

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✨ SYNOPSIS

enum nhi_fw_mode nhi_mailbox_mode (struct tb_nhi *nhi );

like, that's it. that's the whole vibe. one function, one argument, one return type. periodt. 💅

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🦋 ARGUMENTS

• nhi — a pointer to the NHI structure. yes queen, just hand over the pointer, that's all she needs 🫶

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🔥 DESCRIPTION

okay so what does she actually do? bestie. she reads the current firmware operation mode using the NHI mailbox registers, and then she hands it right back to whoever called her. that's the whole plot. main character energy with zero unnecessary drama. literally just: read the register, return the mode. iconic. ⭐

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👑 RETURN

she returns an enum nhi_fw_mode. that's the type, that's the answer, that's the moment. 💖

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🌈 SEE ALSO

so like, if you're going down the rabbit hole (and honestly, same), here's the whole friend group:

• the kernel file ./drivers/thunderbolt/nhi.c — go read the source bestie, it's giving transparency 🧚

and then the little family of related calls:

• tb_ring_poll(9)
• tb_ring_poll_complete(9)
• tb_ring_alloc_tx(9)
• tb_ring_alloc_rx(9)
• tb_ring_start(9)
• tb_ring_flush(9)
• tb_ring_stop(9)
• tb_ring_throttling(9)
• nhi_mailbox_cmd(9)

all of them have pages too, so like... go off, read them all, iykyk 💜

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ngl, the whole thing lives under ./drivers/thunderbolt — that's the neighborhood. 🍓

okay that's the page!! this has been the Kernel API Manual experience, October 2026 edition, filed under nhi_mailbox_mode(9) — mwah, love u, bye 💋🎀🦋