---
name: "usb_claim_bandwidth"
section: "9"
platform: "linux"
package: "linux-manual-2.6.18"
version: "2.6.18.dfsg.1-26etch2"
release: "Debian 4.0 (Etch)"
platforms: ["linux"]
url: "https://new.carta.tech/usb_claim_bandwidth"
---

# usb\_claim\_bandwidth(9)

records bandwidth for a periodic transfer

## NAME

usb\_claim\_bandwidth - records bandwidth for a periodic transfer

## SYNOPSIS

**void usb\_claim\_bandwidth(struct usb\_device \*** *dev***, struct urb \*** *urb***, int** *bustime***, int** *isoc***);**

## ARGUMENTS

*dev*

source/target of request

*urb*

request (urb-\>dev == dev)

*bustime*

bandwidth consumed, in (average) microseconds per frame

*isoc*

true iff the request is isochronous

## DESCRIPTION

Bus bandwidth reservations are recorded purely for diagnostic purposes. HCDs are expected not to overcommit periodic bandwidth, and to record such reservations whenever endpoints are added to the periodic schedule.

FIXME averaging per-frame is suboptimal. Better to sum over the HCD's entire periodic schedule ... 32 frames for OHCI, 1024 for UHCI, settable for EHCI (256/512/1024 frames, default 1024) and have the bus expose how large its periodic schedule is.

## COPYRIGHT