---
name: "BUS_CONFIG_INTR"
section: "9"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/BUS_CONFIG_INTR"
---

# BUS\_CONFIG\_INTR(9)

configure interrupt polarity and trigger mode

## NAME

**BUS\_CONFIG\_INTR**, **bus\_config\_intr** – configure interrupt polarity and trigger mode

## SYNOPSIS

**#include \<sys/param.h\>**

**#include \<sys/bus.h\>**

*int*\

**BUS\_CONFIG\_INTR**(*device\_t bus*, *device\_t dev*, *int irq*, *enum intr\_trigger trig*, *enum intr\_polarity pol*);

*int*\

**bus\_config\_intr**(*device\_t dev*, *int irq*, *enum intr\_trigger trig*, *enum intr\_polarity pol*);

## DESCRIPTION

The **BUS\_CONFIG\_INTR**() method allows bus or device drivers to provide interrupt polarity and trigger mode to parent buses. This typically bubbles all the way up to the root bus (e.g. nexus) where the necessary actions are taken to actually program the hardware. Since the **BUS\_CONFIG\_INTR**() method takes an interrupt number, it is assumed but not necessarily required that it is called prior to [BUS\_SETUP\_INTR(9)](/BUS_SETUP_INTR/9.md).

The **bus\_config\_intr**() function is a simple wrapper around **BUS\_CONFIG\_INTR**().

The *trig* argument can be one of:

- INTR\_TRIGGER\_CONFORM

  The interrupt trigger mode is standard for the bus to which the device is attached.

- INTR\_TRIGGER\_EDGE

  The interrupt is edge triggered. This means that the interrupt is raised by the rising edge of the signal on the interrupt line. The signal typically reverts to the original state so as to cause a spike.

- INTR\_TRIGGER\_LEVEL

  The interrupt is level triggered. This means that the interrupt is raised when the signal on the interrupt line transitions and remains unchanged after that until the interrupt has been serviced, after which the signal transitions back.

The *pol* argument can be any one of:

- INTR\_POLARITY\_CONFORM

  The interrupt polarity is standard for the bus to which the device is attached.

- INTR\_POLARITY\_HIGH

  The interrupt is activated by a high voltage on the interrupt line.

- INTR\_POLARITY\_LOW

  The interrupt is activated by a low voltage on the interrupt line.

## RETURN VALUES

Zero is returned on success, otherwise an appropriate error is returned.

## SEE ALSO

[BUS\_SETUP\_INTR(9)](/BUS_SETUP_INTR/9.md), [BUS\_TEARDOWN\_INTR(9)](/BUS_TEARDOWN_INTR/9.md), [device(9)](/device/9.md), [driver(9)](/driver/9.md)

## HISTORY

The **BUS\_CONFIG\_INTR**() method first appeared in FreeBSD 5.2.

## AUTHORS

This manual page was written by Marcel Moolenaar ⟨*marcel@xcllnt.net*⟩.