usb4_port_hw_margin(9)

💅 usb4_port_hw_margin(9) — Kernel API Manual, bestie edition ✨

okay so welcome to the Kernel API Manual corner where the manual name is literally usb4_port_hw_margin(9), and this page is all about running hardware lane margining on a port. No cap, every detail stays. 🫶

🌸 NAME 🌸

usb4_port_hw_margin — Run hardware lane margining on port 💖

✨ SYNOPSIS ✨

int usb4_port_hw_margin (struct tb_port *port , enum usb4_sb_target
target , u8 index , const struct usb4_port_margining_params *params ,
u32 *results , size_t nresults );

🎀 ARGUMENTS 🎀

• port — USB4 port
• target — Sideband target
• index — Retimer index if target is USB4_SB_TARGET_RETIMER
• params — Parameters for USB4 hardware margining
• results — Array to hold the results
• nresults — Number of elements in the results array

💫 DESCRIPTION 💫

Runs hardware lane margining on USB4 port and returns the result in results. That is the vibe, that is the job, and honestly? Iconic. ✨

🔥 RETURN 🔥

Returns 0 on success, negative errno otherwise. So: 0 = slay, negative errno = not the slay. 💀

🦋 SEE ALSO 🦋

Kernel file ./drivers/thunderbolt/usb4.c — and then go peek at all these besties:

• usb4_switch_check_wakes(9)
• usb4_switch_setup(9)
• usb4_switch_configuration_valid(9)
• usb4_switch_read_uid(9)
• usb4_switch_drom_read(9)
• usb4_switch_lane_bonding_possible(9)
• usb4_switch_set_wake(9)
• usb4_switch_set_sleep(9)
• usb4_switch_nvm_sector_size(9)
• usb4_switch_nvm_read(9)
• usb4_switch_nvm_set_offset(9)
• usb4_switch_nvm_write(9)
• usb4_switch_nvm_authenticate(9)
• usb4_switch_nvm_authenticate_status(9)
• usb4_switch_credits_init(9)
• usb4_switch_query_dp_resource(9)
• usb4_switch_alloc_dp_resource(9)
• usb4_switch_dealloc_dp_resource(9)
• usb4_port_index(9)
• usb4_switch_map_pcie_down(9)
• usb4_switch_map_usb3_down(9)
• usb4_switch_add_ports(9)
• usb4_switch_remove_ports(9)
• usb4_port_unlock(9)
• usb4_port_hotplug_enable(9)
• usb4_port_reset(9)
• usb4_port_configure(9)
• usb4_port_unconfigure(9)
• usb4_port_configure_xdomain(9)
• usb4_port_unconfigure_xdomain(9)
• usb4_port_sb_read(9)
• usb4_port_sb_write(9)
• usb4_port_router_offline(9)
• usb4_port_router_online(9)
• usb4_port_enumerate_retimers(9)
• usb4_port_clx_supported(9)
• usb4_port_asym_supported(9)
• usb4_port_asym_set_link_width(9)
• usb4_port_asym_start(9)
• usb4_port_margining_caps(9)
• usb4_port_sw_margin(9)
• usb4_port_sw_margin_errors(9)
• usb4_port_retimer_set_inbound_sbtx(9)
• usb4_port_retimer_unset_inbound_sbtx(9)
• usb4_port_retimer_is_last(9)
• usb4_port_retimer_is_cable(9)
• usb4_port_retimer_nvm_sector_size(9)
• usb4_port_retimer_nvm_set_offset(9)
• usb4_port_retimer_nvm_write(9)
• usb4_port_retimer_nvm_authenticate(9)
• usb4_port_retimer_nvm_authenticate_status(9)
• usb4_port_retimer_nvm_read(9)
• usb4_usb3_port_max_link_rate(9)
• usb4_usb3_port_allocated_bandwidth(9)
• usb4_usb3_port_allocate_bandwidth(9)
• usb4_usb3_port_release_bandwidth(9)
• usb4_dp_port_set_cm_id(9)
• usb4_dp_port_bandwidth_mode_supported(9)
• usb4_dp_port_bandwidth_mode_enabled(9)
• usb4_dp_port_set_cm_bandwidth_mode_supported(9)
• usb4_dp_port_group_id(9)
• usb4_dp_port_set_group_id(9)
• usb4_dp_port_nrd(9)
• usb4_dp_port_set_nrd(9)
• usb4_dp_port_granularity(9)
• usb4_dp_port_set_granularity(9)
• usb4_dp_port_set_estimated_bandwidth(9)
• usb4_dp_port_allocated_bandwidth(9)
• usb4_dp_port_allocate_bandwidth(9)
• usb4_dp_port_requested_bandwidth(9)
• usb4_pci_port_set_ext_encapsulation(9)
• usb4_pci_port_ltssm_state(9)

okay bye bestie — this page lives in ./drivers/thunderbolt, dated October 2026, and answers to usb4_port_hw_margin(9) 🎀💖✨