tb_switch_fi...y_link_depth(9)

🦋 tb_switch_find_by_link_depth(9) — bestie's guide to finding a switch ✨

okay so this is a page from the Kernel API Manual (Linux kernel docs, we love her 💅) and it's all about tb_switch_find_by_link_depth, which is literally the little function that goes "hey, which Thunderbolt switch lives at this link and this depth?" 🎀

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✨ NAME ✨

tb_switch_find_by_link_depth — find a switch by link and depth 🫶

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🌸 SYNOPSIS 🌸

struct tb_switch * tb_switch_find_by_link_depth (struct tb *tb , u8 link
, u8 depth );

that's it. three args. slay.

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💖 ARGUMENTS 💖

• tb — the domain the switch belongs to 👑 (like, the whole Thunderbolt neighbourhood)
• link — the link number the switch is connected on 🔗
• depth — how deep the switch sits in that link, i.e. its depth in the hierarchy 🪜

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🧚 DESCRIPTION 🧚

so here's the tea: the switch you get back has its reference count increased 😭 which means the caller legit has to call tb_switch_put when they're done with the switch. no cap, don't forget or you'll be leaking refs and that's not the vibe. 🚩

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⭐ RETURN ⭐

a pointer to struct tb_switch 💫 — or NULL if it's not found 🙈 (sorry bestie, no switch at that link/depth combo).

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🔥 SEE ALSO 🔥

the kernel file ./drivers/thunderbolt/switch.c and honestly the whole friend group 💀:

• tb_switch_nvm_read(9)
• tb_port_state(9)
• tb_wait_for_port(9)
• tb_port_add_nfc_credits(9)
• tb_port_clear_counter(9)
• tb_port_unlock(9)
• tb_port_enable(9)
• tb_port_disable(9)
• tb_port_reset(9)
• tb_port_alloc_in_hopid(9)
• tb_port_alloc_out_hopid(9)
• tb_port_release_in_hopid(9)
• tb_port_release_out_hopid(9)
• tb_next_port_on_path(9)
• tb_port_get_link_speed(9)
• tb_port_get_link_generation(9)
• tb_port_get_link_width(9)
• tb_port_width_supported(9)
• tb_port_set_link_width(9)
• tb_port_set_lane_bonding(9)
• tb_port_lane_bonding_enable(9)
• tb_port_lane_bonding_disable(9)
• tb_port_wait_for_link_width(9)
• tb_port_update_credits(9)
• tb_port_is_enabled(9)
• tb_usb3_port_is_enabled(9)
• tb_usb3_port_enable(9)
• tb_pci_port_is_enabled(9)
• tb_pci_port_enable(9)
• tb_dp_port_hpd_is_active(9)
• tb_dp_port_hpd_clear(9)
• tb_dp_port_set_hops(9)
• tb_dp_port_is_enabled(9)
• tb_dp_port_enable(9)
• tb_switch_reset(9)
• tb_switch_wait_for_bit(9)
• tb_switch_alloc(9)
• tb_switch_alloc_safe_mode(9)
• tb_switch_configure(9)
• tb_switch_configuration_valid(9)
• tb_switch_lane_bonding_enable(9)
• tb_switch_lane_bonding_disable(9)
• tb_switch_set_link_width(9)
• tb_switch_configure_link(9)
• tb_switch_unconfigure_link(9)
• tb_switch_add(9)
• tb_switch_remove(9)
• tb_sw_set_unplugged(9)
• tb_switch_resume(9)
• tb_switch_suspend(9)
• tb_switch_query_dp_resource(9)
• tb_switch_alloc_dp_resource(9)
• tb_switch_dealloc_dp_resource(9)
• tb_switch_find_by_uuid(9)
• tb_switch_find_by_route(9)
• tb_switch_find_port(9)
• tb_switch_pcie_l1_enable(9)
• tb_switch_xhci_connect(9)
• tb_switch_xhci_disconnect(9)

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💀 reminder bestie: refcount goes up, tb_switch_put goes in your cleanup path. that's the whole assignment.

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okay that's the page!! this one's from the source ./drivers/thunderbolt, dated October 2026, and the header/name up top was tb_switch_fi...y_link_depth(9) — yes it's truncated like that, she's mysterious 💜 mwah, go read the kernel file, ily 🫶🎀✨