register_root_hub(9)

✨ register_root_hub(9) ✨

okay so bestie, welcome to the Kernel API Manual page for register_root_hub(9) 💅 this one is all about the root hub registration moment, and it's giving “USB subsystem official paperwork” in the best way 🦋

🎀 NAME 🎀

register_root_hub — called by usb_add_hcd() to register a root hub 💖

🫶 SYNOPSIS 🫶

int register_root_hub (struct usb_hcd *hcd );

🌸 ARGUMENTS 🌸

• hcd — host controller for this root hub. that's the main-character struct this whole function is working with 🦋

💫 DESCRIPTION 💫

so this function registers the root hub with the USB subsystem. literally its whole job 💅 it sets up the device properly in the device tree, and then calls usb_new_device to register the usb device. it also assigns the root hub's USB address, and that address is always 1 👑 like no cap, always one.

🔥 RETURN 🔥

• 0 if successful ✨
• a negative error code otherwise 😭 so nonzero means it did not go off, check the error

🌈 SEE ALSO 🌈

first up, the kernel file: ./drivers/usb/core/hcd.c 📁

and these other pages are in the group chat too, iykyk:

• ascii2desc(9)
• rh_string(9)
• usb_bus_init(9)
• usb_register_bus(9)
• usb_deregister_bus(9)
• usb_calc_bus_time(9)
• usb_hcd_link_urb_to_ep(9)
• usb_hcd_check_unlink_urb(9)
• usb_hcd_unlink_urb_from_ep(9)
• usb_hcd_giveback_urb(9)
• usb_hcd_alloc_bandwidth(9)
• usb_hcd_reset_endpoint(9)
• usb_alloc_streams(9)
• usb_free_streams(9)
• usb_hcd_resume_root_hub(9)
• usb_bus_start_enum(9)
• usb_hcd_irq(9)
• usb_hc_died(9)
• usb_create_shared_hcd(9)
• usb_create_hcd(9)
• usb_stop_hcd(9)
• usb_add_hcd(9)
• usb_remove_hcd(9)

okay that's the page bestie 🫶 it comes from source/version ./drivers/usb/core, dated October 2026, and the footer title is register_root_hub(9) — periodt 💅✨