tb_xdomain_downstream_port(9)

💅 tb_xdomain_downstream_port — the Kernel API Manual moment 🦋

okay so bestie, we're in the Kernel API Manual today and this little function is genuinely iconic. it's called tb_xdomain_downstream_port and it does exactly one thing but it does it flawlessly. no notes. periodt.

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✨ NAME ✨

tb_xdomain_downstream_port — literally returns the downstream facing port of the parent router 🫶

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🌸 SYNOPSIS 🌸

struct tb_port * tb_xdomain_downstream_port (struct tb_xdomain *xd );

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🎀 ARGUMENTS 🎀

• xd — the Xdomain pointer, bestie. that's it. that's the whole argument. she's low maintenance 👑

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🔥 RETURN 🔥

returns a pointer to struct tb_port — and if things go sideways? NULL. in case of failure. no cap, that's the whole vibe check 💀

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🧚 SEE ALSO 🧚

okay this list is long long, but every single one of these is a friend of ours so we're listing them all fr fr. they all live in the kernel file ./drivers/thunderbolt/tb.h:

• struct tb_nvm(9)
• enum tb_switch_tmu_mode(9)
• struct tb_switch_tmu(9)
• struct tb_switch(9)
• struct tb_bandwidth_group(9)
• struct tb_port(9)
• struct usb4_port(9)
• struct tb_retimer(9)
• struct tb_path_hop(9)
• enum tb_path_port(9)
• struct tb_path(9)
• struct tb_cm_ops(9)
• tb_upstream_port(9)
• tb_is_upstream_port(9)
• tb_port_has_remote(9)
• tb_domain_event(9)
• tb_switch_for_each_port(9)
• tb_switch_downstream_port(9)
• tb_switch_depth(9)
• tb_switch_is_icm(9)
• tb_switch_tmu_is_configured(9)
• tb_switch_tmu_is_enabled(9)
• tb_switch_clx_is_enabled(9)
• tb_port_path_direction_downstream(9)
• tb_for_each_port_on_path(9)
• tb_for_each_upstream_port_on_path(9)
• tb_path_for_each_hop(9)
• tb_downstream_route(9)
• usb4_switch_version(9)
• tb_switch_is_usb4(9)
• enum usb4_sb_target(9)
• enum usb4_margin_sw_error_counter(9)
• struct usb4_port_margining_params(9)

like… the crossover episode we all deserved 🌈

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💖 reminder bestie: if it returns NULL, that's a failure, not a personality trait. check your xd, okay? 🫶

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and that's the whole page!! tysm for reading, mwah 💋

sign-off time 🎀 — this one comes from the source dir ./drivers/thunderbolt, dated October 2026, and it's filed under tb_xdomain_downstream_port(9). slay. go touch some thunderbolt hardware. 💅✨