nhi_mailbox_cmd(9)

💌 nhi_mailbox_cmd(9) — the kernel API manual, bestie edition 💌

okay so welcome to the nhi_mailbox_cmd(9) page, from your fave kernel API manual 🫶 this one is short and sweet, so let's get into it.

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✨ NAME ✨

nhi_mailbox_cmd — Send a command through NHI mailbox 📬

like, literally that's the whole job. it sends a command through the NHI mailbox. iconic behavior.

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✨ SYNOPSIS ✨

int nhi_mailbox_cmd (struct tb_nhi *nhi , enum nhi_mailbox_cmd cmd , u32
data );

look at that signature. so clean. so demure. 💅

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✨ ARGUMENTS ✨

• nhi — Pointer to the NHI structure 🌸 that's your NHI, she's the main character here
• cmd — Command to send 📨 the one you're yeeting off to the firmware
• data — Data to be send with the command 💖 yes bestie, the original says "send" not "sent", and we're keeping it that way, no cap

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✨ DESCRIPTION ✨

Sends mailbox command to the firmware running on NHI. 🧚 that's it. that's the vibe. you hand it a command and some data, and off it goes to the firmware living on the NHI. lowkey simple, highkey essential.

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✨ RETURN ✨

• 0 on success 🎀 slay
• negative errno otherwise 😭 not slay

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✨ SEE ALSO ✨

Kernel file ./drivers/thunderbolt/nhi.c plus the whole thunderbolt ring crew, all of them, no one left behind:

• 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_mode(9)

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fr fr go read those too, they're all in the same friend group 💜

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and that's the page!! 🦋 sign-off time: this lil manual lives in ./drivers/thunderbolt, dated October 2026, and honestly? she ate. 🌈⭐💅 periodt.