dma_port_alloc(9)

💅 dma_port_alloc(9) — like, the whole lore

okay so real talk, this is a page straight out of the Kernel API Manual, and it's about finding a DMA control port on a Thunderbolt switch. strap in bestie, it's actually short and sweet 🍓

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✨ NAME ✨

dma_port_alloc — finds the DMA control port from a switch that's pointed at by a route 🎯

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🦋 SYNOPSIS 🦋

struct tb_dma_port * dma_port_alloc (struct tb_switch *sw );

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🎀 ARGUMENTS 🎀

• sw — the switch, like, from where you're finding the DMA port. that's the whole vibe. this is the thing you hand over so it knows where to look 🔍

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💖 DESCRIPTION 💖

so what this does: the function checks whether the switch's NHI port supports the DMA configuration mailbox capability — a whole vibe check on the hardware, basically — and if it does support it, it allocates and initializes the DMA port structure. slay 💅

if that capability wasn't found? you get NULL. no port for you, bestie 😭

and here's the iconic part: the DMA control port is still functional when the switch is in safe mode. yes, even in safe mode. main character energy fr fr 👑

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🌸 RETURN 🌸

struct tb_dma_port on success ✨ — NULL otherwise 💀

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🌈 SEE ALSO 🌈

• the kernel file ./drivers/thunderbolt/dma_port.c
• struct tb_dma_port(9)
• dma_port_free(9)
• dma_port_flash_read(9)
• dma_port_flash_write(9)
• dma_port_flash_update_auth(9)
• dma_port_flash_update_auth_status(9)
• dma_port_power_cycle(9)

go read those too, iykyk 🫶

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kay that's the whole page, no cap 🧚 from ./drivers/thunderbolt, dated October 2026, and it's the dma_port_alloc(9) page in the Kernel API Manual — mwah, hope that ate 💜