STRUCT TB_SWITCH_TMU(9)

✨ struct tb_switch_tmu — Structure holding router TMU configuration ✨

okay bestie, so this is a page from the Kernel API Manual about struct tb_switch_tmu, and it's literally the little vibe-holder for a router's TMU config 💅. Yes, TMU. Yes, routers. Yes, you're gonna slay this.

🌸 SYNOPSIS 🌸

struct tb_switch_tmu {
    int cap;
    bool has_ucap;
    enum tb_switch_tmu_mode mode;
    enum tb_switch_tmu_mode mode_request;
};

look at her. four fields. absolute main character energy 👑

🎀 Members 🎀

• cap — the offset to the TMU capability, and if it wasn't found it's just 0. like, no cap found, cap is zero, iconic wordplay fr fr 🫶
• has_ucap — the vibe check on whether this switch supports uni-directional mode. true = she can, false = she can't, no notes 💀
• mode — the TMU mode that relates to the upstream router, and it reflects the actual HW setting. for the host router? don't care, not our problem, lowkey ignore it 🙈
• mode_request — the TMU mode that's being requested to set. also related to the upstream router, and also a don't-care for the host router. so basically mode is what she's wearing and mode_request is what she wants to wear ✨

heads up bestie: mode and mode_request are both upstream-router-coded, and both say "Don't care for host router" — so if you're on the host router, do not come for them 💅

🦋 SEE ALSO 🦋

the whole friend group, in order, no one left out (i would never) 🥰

• Kernel file ./drivers/thunderbolt/tb.h
• struct tb_nvm(9)
• enum tb_switch_tmu_mode(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)
• tb_xdomain_downstream_port(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)

and that's the whole page, bestie, you ate that 🍓

sign-off time: this lil masterpiece lives in ./drivers/thunderbolt, dated October 2026, and yes the manual page title was struct tb_switch_tmu(9) the whole time — iykyk 💜