tb_tunnel_alloc_pci(9)

💖 NAME 💖

okay bestie, meet tb_tunnel_alloc_pci(9) from the Kernel API Manual — the function that does exactly what it says on the tin: tb_tunnel_alloc_pci will allocate a pci tunnel. no cap, she’s the tunnel-booking bestie for PCI. 🎀

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✨ SYNOPSIS ✨

the signature is giving “I know my types,” and here it is verbatim so you can copy-paste like a main character:

struct tb_tunnel * tb_tunnel_alloc_pci (struct tb *tb , struct tb_port
       *up , struct tb_port *down );

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🫶 ARGUMENTS 🫶

• tb — pointer to the domain structure. literally the domain context, bestie.
• up — PCIe upstream adapter port. the upward queen. 🌸
• down — PCIe downstream adapter port. the downward queen. 🦋

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🌸 DESCRIPTION 🌸

Allocate a PCI tunnel. The way this works is the ports have to be the right vibe: they must be of type TB_TYPE_PCIE_UP and TB_TYPE_PCIE_DOWN. that’s the requirement, iykyk. ✨

bestie, those port types are mandatory — don’t try to make fetch happen with other types. 💅

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💅 RETURN 💅

Pointer to struct tb_tunnel — or NULL on failure. so if it comes back NULL, that’s the fail-girl moment. 😭

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🌈 SEE ALSO 🌈

Kernel file ./drivers/thunderbolt/tunnel.c is the home base. and here’s the whole friend group, in order:

• tb_available_credits(9)
• tb_tunnel_event(9)
• tb_tunnel_discover_pci(9)
• tb_tunnel_reserved_pci(9)
• tb_dp_bandwidth_mode_maximum_bandwidth(9)
• tb_tunnel_discover_dp(9)
• tb_tunnel_alloc_dp(9)
• tb_tunnel_alloc_dma(9)
• tb_tunnel_match_dma(9)
• tb_tunnel_discover_usb3(9)
• tb_tunnel_alloc_usb3(9)
• tb_tunnel_is_invalid(9)
• tb_tunnel_activate(9)
• tb_tunnel_deactivate(9)
• tb_tunnel_port_on_path(9)
• tb_tunnel_maximum_bandwidth(9)
• tb_tunnel_allocated_bandwidth(9)
• tb_tunnel_alloc_bandwidth(9)
• tb_tunnel_consumed_bandwidth(9)
• tb_tunnel_release_unused_bandwidth(9)
• tb_tunnel_reclaim_available_bandwidth(9)

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signed off with a sparkle from the ./drivers/thunderbolt source/version corner, stamped October 2026, page tb_tunnel_alloc_pci(9) — mwah 💋🧚‍♀️