usb_gadget_vbus_draw(9)

💖 usb_gadget_vbus_draw(9) — the Kernel API Manual page you didn't know you needed 💖

okay so bestie, welcome to the usb_gadget_vbus_draw(9) page from the Kernel API Manual ✨ this one's short and sweet and honestly it's giving "small but mighty" energy, so let's get into it 🫶

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🌸 NAME 🌸

usb_gadget_vbus_draw — constrain controller's VBUS power usage ⚡

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🎀 SYNOPSIS 🎀

int usb_gadget_vbus_draw (struct usb_gadget *gadget , unsigned mA );

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🦋 ARGUMENTS 🦋

• gadget — the device whose VBUS usage is being described, iykyk 👑 this is the gadget in question, no cap
• mA — how much current to draw, in milliAmperes 💅 and listen, this one has a lil rule: this should be twice the value listed in the configuration descriptor bMaxPower field. twice!! fr fr, don't forget the 2x 🙈

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✨ DESCRIPTION ✨

so this call is used by gadget drivers during SET_CONFIGURATION calls, and it's basically reporting how much power the device may consume 🔥 for example, this could affect how quickly batteries are recharged — like literally, it can change your charging vibe 🍓

Returns zero on success, else negative errno 💀 (that's the whole return story, bestie — zero means slay, negative means something went sideways)

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🌈 SEE ALSO 🌈

okay this list is LONG but we don't skip, periodt. first up, the kernel file itself: ./drivers/usb/gadget/udc/core.c 🧚 and then all the friends:

• struct usb_udc(9)
• usb_ep_set_maxpacket_limit(9)
• usb_ep_enable(9)
• usb_ep_disable(9)
• usb_ep_alloc_request(9)
• usb_ep_free_request(9)
• usb_ep_queue(9)
• usb_ep_dequeue(9)
• usb_ep_set_halt(9)
• usb_ep_clear_halt(9)
• usb_ep_set_wedge(9)
• usb_ep_fifo_status(9)
• usb_ep_fifo_flush(9)
• usb_gadget_frame_number(9)
• usb_gadget_wakeup(9)
• usb_gadget_set_remote_wakeup(9)
• usb_gadget_set_selfpowered(9)
• usb_gadget_clear_selfpowered(9)
• usb_gadget_vbus_connect(9)
• usb_gadget_vbus_disconnect(9)
• usb_gadget_connect(9)
• usb_gadget_disconnect(9)
• usb_gadget_deactivate(9)
• usb_gadget_activate(9)
• usb_gadget_giveback_request(9)
• gadget_find_ep_by_name(9)
• usb_gadget_check_config(9)
• usb_udc_vbus_handler(9)
• usb_gadget_udc_reset(9)
• usb_gadget_udc_start_locked(9)
• usb_gadget_udc_stop_locked(9)
• usb_gadget_udc_set_speed(9)
• usb_gadget_enable_async_callbacks(9)
• usb_gadget_disable_async_callbacks(9)
• usb_udc_release(9)
• usb_initialize_gadget(9)
• usb_add_gadget(9)
• usb_add_gadget_udc_release(9)
• usb_get_gadget_udc_name(9)
• usb_add_gadget_udc(9)
• usb_del_gadget(9)
• usb_del_gadget_udc(9)

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that's the whole page bestie, no filler, all facts 💖 go forth and constrain that VBUS power usage responsibly 💅

and a lil sign-off 🎀 this one comes from the source ./drivers/usb/gadget/udc, dated October 2026 — iconic, we love a dated queen 👑✨