usb4_port_retimer_is_last(9)

okay bestie, welcome to the usb4_port_retimer_is_last(9) page — yes, that's the title, and yes, it's from the Kernel API Manual. we're checking whether a retimer is the last on-board retimer. lowkey niche, highkey useful. 💅

🌸 NAME 🌸

usb4_port_retimer_is_last — is the retimer last on-board retimer? literally the whole vibe: find out if the retimer at your index is the final one in the chain.

✨ SYNOPSIS ✨

int usb4_port_retimer_is_last (struct tb_port *port , u8 index );

that's the signature, bestie — don't touch the commas. 🫶

🎀 ARGUMENTS 🎀

• port — the USB4 port. main character energy.
• index — the retimer index. like, which retimer are we checking?

🦋 RETURN 🦋

• 1 — retimer at index is the last one (connected directly to the Type-C port). slay, it's the final girl. 👑
• 0 — retimer at index is not the last one. not the finale, bestie.
• -ENODEV — retimer is not present. 😭 she's not here.
• Negative errno — other failure occurred. 💀 something else went wrong.

🔥 SEE ALSO 🔥

the kernel file is ./drivers/thunderbolt/usb4.c, and here's the whole group chat of related functions:

• 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(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_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)

mwah 💋 this page comes from ./drivers/thunderbolt, dated October 2026, in the Kernel API Manual — go check those retimers, bestie. 🫶