Copyright (c) 2003, 2004 Sean M. Kelly <smkelly@FreeBSD.org>
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$FreeBSD: head/share/man/man4/watchdog.4 130748 2004-06-19 21:17:07Z smkelly $
.Dd June 25, 2003 .Dt WATCHDOG 4 .Os .Sh NAME .Nm watchdog .Nd "hardware and software watchdog" .Sh SYNOPSIS .Cd "options CPU_ELAN" .Cd "options CPU_GEODE" .Cd "options SW_WATCHDOG"
p n sys/watchdog.h .Sh DESCRIPTION The .Nm facility is used for controlling hardware and software watchdogs.
p The interface is through a device named .Qq Li /dev/ .Dv _PATH_WATCHDOG which responds to a single .Xr ioctl 2 call, .Dv WDIOCPATPAT .
p The call takes a single argument which represents a timeout value specified as an integer power of two nanoseconds.
p The .Dv WD_ACTIVE flag signals that the .Nm will be kept from timing out from userland, for instance by the .Xr watchdogd 8 daemon.
p To disable the watchdogs, an argument of zero should be used.
p
The
.Xr ioctl 2
call will return success if just one of the available
.Xr watchdog 9
implementations support the request.
If the call fails, for instance if none of
.Xr watchdog 9
implementations support the timeout
length, all watchdogs are disabled and must be explicitly re-enabled.
.Sh EXAMPLES
XXX insert some descriptive text here
d -literal -offset indent u_int u = WD_ACTIVE | WD_TO_8SEC;
int fd = open("/dev/" _PATH_WATCHDOG, O_RDWR);
ioctl(fd, WDIOCPATPAT, &u);
.Ed
.Sh SEE ALSO
.Xr watchdogd 8 ,
.Xr watchdog 9
.Sh HISTORY
The
.Nm
code first appeared in
.Fx 5.1 .
.Sh AUTHORS
.An -nosplit
The
.Nm
facility was written by
.An Poul-Henning Kamp Aq phk@FreeBSD.org .
The software watchdog code
and this manual page were written by
.An Sean Kelly Aq smkelly@FreeBSD.org .
Some contributions were made by
.An Jeff Roberson Aq jeff@FreeBSD.org .