usb4_port_sw_margin(9)

💅 usb4_port_sw_margin(9) — the Kernel API Manual glow-up 🎀

okay bestie, so this is a page straight out of the Kernel API Manual and it's literally about running software lane margining on a USB4 port. yes it's as niche as it sounds and yes it's iconic ✨

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💖 NAME 💖

usb4_port_sw_margin — run software lane margining on a port, no cap 🦋

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🌸 SYNOPSIS 🌸

int usb4_port_sw_margin (struct tb_port *port , enum usb4_sb_target
target , u8 index , const struct usb4_port_margining_params *params ,
u32 *results );

like... look at that signature. she's giving main character energy 👑

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🫶 ARGUMENTS 🫶

• port — the USB4 port we're doing all this on 💜
• target — which sideband target we're aiming at
• index — the retimer index, but only if target is USB4_SB_TARGET_RETIMER (iykyk)
• params — the parameters for USB4 software margining, i.e. the whole vibe of the operation ✨
• results — a data word where the operation completion data lands 🎀

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⭐ DESCRIPTION ⭐

So basically this runs software lane margining on a USB4 port. that's the whole thing. slay.

and then — this part matters, don't skip it — you read back the error counters by calling usb4_port_sw_margin_errors. fr fr, that's the follow-up move, not optional garnish 🌈

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🔥 RETURN 🔥

0 on success, and a negative errno otherwise 😭 (we love a clean contract)

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👑 SEE ALSO 👑

the kernel file lives at ./drivers/thunderbolt/usb4.c and here is the entire squad, every single one of them, no skips 💀💖

• 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_hw_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)

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ngl that's a whole group chat worth of cross-references and every one of them made the list 💅

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and that's the page babes 🍓 — sourced from ./drivers/thunderbolt, dated October 2026, and honestly usb4_port_sw_margin(9) ate and left no crumbs. periodt. 💜✨