---
name: "wdatwd"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/wdatwd"
---

# wdatwd(4)

device driver for the ACPI WDAT based watchdog interrupt timer

## NAME

**wdatwd** – device driver for the ACPI WDAT based watchdog interrupt timer

## SYNOPSIS

**device** **wdatwd**

In [loader.conf(5)](/loader.conf/5.md): **wdatwd\_load="YES"**

## DESCRIPTION

The **wdatwd** driver provides [watchdog(4)](/watchdog/4.md) support for the watchdog interrupt timer in ACPI WDAT (Watchdog Action Table).

Since WDAT itself is an abstraction for the real hardware such as ICH WDT, it must be noted that only one driver can be used at a time, either the real hardware specific driver or this driver.

## SYSCTL VARIABLES

The following read-only [sysctl(8)](/sysctl/8.md) variables are available:

- *dev.wdatwd.%d.running*

  The status of the watchdog timer. 0 if not running, or 1 if running.

- *dev.wdatwd.%d.timeout*

  The current value of the watchdog timeout in millisecond. This can be 0 on some systems, and the zero value means that the default timeout is used.

- *dev.wdatwd.%d.timeout\_configurable*

  Whether the timeout is configurable or not. It is 0 if configurable or any positive value if not.

- *dev.wdatwd.%d.timeout\_default*

  The default value of the watchdog timeout in millisecond if any.

## SEE ALSO

[ichwd(4)](/ichwd/4.md), [watchdog(4)](/watchdog/4.md), [watchdog(8)](/watchdog/8.md), [watchdogd(8)](/watchdogd/8.md), [watchdog(9)](/watchdog/9.md) Microsoft Corporation, *Hardware Watchdog Timers Design Specification*, Requirements for Hardware Watchdog Timers Supported by Microsoft(R) Windows Vista(R) and Microsoft Windows Server(R) 2008 Operating Systems, 2006, https://msdn.microsoft.com/en-us/windows/hardware/gg463320.aspx.

## AUTHORS

The **wdatwd** driver was written by Tetsuya Uemura ⟨*t\_uemura@macome.co.jp*⟩ of MACOME, Corporation.