usb_register_bus(9)

💖 usb_register_bus(9) — like, the Kernel API Manual page you actually wanna read 🎀

okay so bestie, this is usb_register_bus from the Kernel API Manual, and honestly? it's lowkey the moment your USB host controller officially becomes A Somebody. let's get into it ✨

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🌸 NAME 🌸

usb_register_bus — registers the USB host controller with the usb core

that's it. that's the whole vibe. your controller goes from "random struct in the void" to "known and loved by usbcore" 🫶

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✨ SYNOPSIS ✨

int usb_register_bus (struct usb_bus *bus );

literally one function, one argument, returns an int. no cap, that's the whole signature 💅

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🦋 ARGUMENTS 🦋

• bus — pointer to the bus to register. yes girl, hand over your struct usb_bus * and let the kernel do its thing 🎀

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💜 CONTEXT 💜

task context, might sleep.

ngl this is the important part: it runs in task context and it might sleep, so do NOT call it from somewhere sleepy-unsafe. periodt. 😭

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🌈 DESCRIPTION 🌈

So what does it actually do? Two iconic jobs:

1. Assigns a bus number — your bus gets its very own number, main character energy 👑
2. Links the controller into usbcore data structures — so that it can be seen by scanning the bus list 🔥

that's the whole glow-up: number assigned, controller linked in, now the rest of usbcore can find it by scanning the bus list. slay. ✨

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⭐ RETURN ⭐

• 0 if successful 💖
• A negative error code otherwise 💀

so like, check the return value, bestie. 0 = we ate. negative = vibe check failed 🙈

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🧚 SEE ALSO 🧚

Kernel file ./drivers/usb/core/hcd.c, plus a whole friend group of functions — all of these, in this exact order, no notes:

• ascii2desc(9)
• rh_string(9)
• usb_bus_init(9)
• usb_deregister_bus(9)
• register_root_hub(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)

iykyk 💅

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and that's the page!! 🫶 this lil beauty lives in ./drivers/usb/core, dated October 2026 — go read the source, it's giving iconic. bye bestie, mwah 💖🎀🦋