usb_interrupt_msg(9)

📦 version 7.3.1, in nixpkgs unstable

💅 usb_interrupt_msg — Kernel API Manual, section 9

okay so bestie, welcome to usb_interrupt_msg(9) — the one where you build an interrupt urb, yeet it off into the world, and then just stand there waiting for it to come back. 💖

✨ NAME ✨

usb_interrupt_msg — builds an interrupt urb, sends it off and waits for completion 🎀

🦋 SYNOPSIS 🦋

int usb_interrupt_msg (struct usb_device *usb_dev , unsigned int pipe ,
void *data , int len , int *actual_length , int timeout );

🌸 ARGUMENTS 🌸

  • usb_dev — pointer to the usb device to send the message to 💫
  • pipe — the endpoint "pipe" you're sending the message to, iykyk
  • data — pointer to the data to send
  • len — length in bytes of the data to send
  • actual_length — pointer to a location to put the actual length transferred in bytes (yes, actual — it's giving receipts)
  • timeout — time in msecs to wait for the message to complete before timing out ⏰

🧚 CONTEXT 🧚

task context, might sleep. 😴 like, it will nap, and that's legal here.

👑 DESCRIPTION 👑

This function sends a simple interrupt message to a specified endpoint and waits for the message to complete, or timeout. simple as that, no cap.

🚨 do NOT use this function from within an interrupt context. literally do not.

If you need an asynchronous message, or need to send a message from within interrupt context, use usb_submit_urb ✨. If a thread in your driver uses this call, make sure your disconnect method can wait for it to complete — and here's the shady part: since you don't have a handle on the URB used, you can't cancel the request. 💀 no take-backs, no refunds.

🔥 RETURN 🔥

If successful, 0. Otherwise a negative error number. The number of actual bytes transferred will be stored in the actual_length parameter. 📬

🌈 SEE ALSO 🌈

Kernel file ./drivers/usb/core/message.c — and the whole friend group:

and that's the whole page, bestie 🫶 this lil icon lives in ./drivers/usb/core, dated October 2026, and it's manual usb_interrupt_msg(9). go forth and interrupt (responsibly, in task context only) 💜✨

📦 where this page comes from