.\"-
.\" Copyright (c) 2007 Dag-Erling Coïdan Smørgrav
.\" All rights reserved.
.\"
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.\" $FreeBSD$
.\"
.Dd August 20, 2008
.Dt ICHWD 4
.Os
.Sh NAME
.Nm ichwd
.Nd device driver for the Intel ICH watchdog interrupt timer
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device ichwd"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
ichwd_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides
.Xr watchdog 4
support for the watchdog interrupt timer present on
all Intel ICH motherboard chipsets.
.Pp
The ICH WDT counts down in ticks of approximately 0.6 seconds; the
exact value depends on hardware quality and environmental factors.
Supported watchdog intervals range from 2 to 63 ticks.
.Pp
Note that on some ICH-based systems, the WDT may be present but
disabled, either in hardware or by the BIOS.
The
.Nm
driver attempts to detect this condition and will refuse to attach if
it believes the WDT is disabled.
.Sh SEE ALSO
.Xr watchdog 4 ,
.Xr watchdog 8 ,
.Xr watchdogd 8 ,
.Xr watchdog 9
.Rs
.%T Using the Intel ICH Family Watchdog Timer (WDT)
.%R Intel Application Note AP-725
.%O Document Number 292273-001
.Re
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 5.3 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Wm. Daryl Hawkins Aq dhawkins@tamu.edu
of Texas A&M University and
.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org .
This manual page was written by
.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org .