usb_composite_probe(9)

💖 usb_composite_probe(9): register a composite driver 💖

Okay bestie, this is usb_composite_probe(9) from the Kernel API Manual, and it's literally the “make it official” moment for composite drivers. No cap. 🫶

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🌸 NAME 🌸

usb_composite_probe — register a composite driver

✨ SYNOPSIS ✨

int usb_composite_probe (struct usb_composite_driver *driver );

🎀 ARGUMENTS 🎀

• driver — the driver to register. That's the whole assignment, bestie. 💅

🦋 CONTEXT 🦋

Single threaded during gadget setup. So yeah, no parallel chaos energy in this phase — it's giving focused, one-thing-at-a-time setup. ✨

💜 DESCRIPTION 💜

This function is how you register drivers using the composite driver framework. Iconic, necessary, we love her.

The return value is zero, or a negative errno value. Those values normally come from the driver's bind method, which does all the work of setting up the driver to match the hardware. So the bind method is the main character here — she does the heavy lifting. 👑

On successful return, the gadget is ready to respond to requests from the host — unless one of its components invokes usb_gadget_disconnect while it was binding. That would usually be done in order to wait for some userspace participation. Yup, sometimes the gadget has to pause and let userspace pull up. 😭

⚠️ tiny but important vibe check: “successful return” means the gadget is ready to respond to host requests unless a component called usb_gadget_disconnect during binding. Don't forget that exception, bestie.

🔥 SEE ALSO 🔥

• Kernel file ./drivers/usb/gadget/composite.c
• struct usb_os_string(9)
• function_descriptors(9)
• next_desc(9)
• config_ep_by_speed_and_alt(9)
• config_ep_by_speed(9)
• usb_add_function(9)
• usb_function_deactivate(9)
• usb_function_activate(9)
• usb_interface_id(9)
• usb_func_wakeup(9)
• bos_desc(9)
• usb_add_config(9)
• usb_string_id(9)
• usb_string_ids_tab(9)
• usb_gstrings_attach(9)
• usb_string_ids_n(9)
• usb_composite_unregister(9)
• usb_composite_setup_continue(9)

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Big sparkly sign-off from the source/version ./drivers/usb/gadget, dated October 2026, for usb_composite_probe(9) — periodt. 💖✨🎀