Copyright (c) 2003 Sean M. Kelly <smkelly@FreeBSD.org>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
$FreeBSD: head/share/man/man4/watchdog.4 126383 2004-02-28 20:56:35Z phk $
.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 d -literal u_int u = WD_ACTIVE | WD_8SEC; int fd = open("/dev/" _PATH_WATCHDOG, O_RDWR); ioctl(fd, WDIOCPATPAT, &u); .Ed .Sh DESCRIPTION .Nm is a facility for controlling hardware and software watchdog facilities.
p The interface is through a device named "/dev/" _PATH_WATCHDOG which responds to a single ioctl call, WDIOCPATPAT.
p The ioctl call takes an argument which consists of a timeout value specified an integer power of two nanoseconds.
p In the flag WD_ACTIVE signals that the watchdog will be kept from timing out from userland, for instance by the .Xr watchdogd 8 daemon.
p To disable the watchdogs, use an argument of zero.
p The ioctl call will return success if just one of the available watchdog implementations support the request. If the ioctl fails, for instance if no watchdog supports the timeout length, all watchdogs are disabled and must be explicitly reenabled. .Sh SEE ALSO .Xr sysctl 8 , .Xr watchdogd 8 .Xr watchdogd 9 .Sh HISTORY The .Nm code first appeared in .Fx 5.1 . .Sh AUTHORS .An -nosplit The .Nm watchdog facility were written by .An Poul-Henning Kamp Aq phk@FreeBSD.org .
p The .Nm SW_WATCHDOG code and manual page were written by .An Sean Kelly Aq smkelly@FreeBSD.org . Some contributions were made by .An Jeff Roberson Aq jeff@FreeBSD.org .