1.\" Copyright (c) 2004 Poul-Henning Kamp <phk@FreeBSD.org> 2.\" Copyright (c) 2003 Sean M. Kelly <smkelly@FreeBSD.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd June 25, 2003 29.Dt watchdog 4 30.Os 31.Sh NAME 32.Nm watchdog 33.Nd Hardware and Software watchdog 34.Sh SYNOPSIS 35.Cd options CPU_ELAN 36.Cd options CPU_GEODE 37.Cd options SW_WATCHDOG 38.Pp 39.In sys/watchdog.h 40.Bd -literal 41 42u_int u = WD_ACTIVE | WD_8SEC; 43int fd = open("/dev/" _PATH_WATCHDOG, O_RDWR); 44 45ioctl(fd, WDIOCPATPAT, &u); 46.Ed 47.Sh DESCRIPTION 48.Nm 49is a facility for controlling hardware and software watchdog facilities. 50.Pp 51The interface is through a device named "/dev/" _PATH_WATCHDOG which 52responds to a single ioctl call, WDIOCPATPAT. 53.Pp 54The ioctl call takes an argument which consists of a timeout value 55specified an integer power of two nanoseconds. 56.Pp 57In the flag WD_ACTIVE signals that the watchdog will be kept from 58timing out from userland, for instance by the 59.Xr watchdogd 8 60daemon. 61.Pp 62To disable the watchdogs, use an argument of zero. 63.Pp 64The ioctl call will return success if just one of the available 65watchdog implementations support the request. 66If the ioctl fails, for instance if no watchdog supports the timeout 67length, all watchdogs are disabled and must be explicitly reenabled. 68.Sh SEE ALSO 69.Xr sysctl 8 , 70.Xr watchdogd 8 71.Xr watchdogd 9 72.Sh HISTORY 73The 74.Nm 75code first appeared in 76.Fx 5.1 . 77.Sh AUTHORS 78.An -nosplit 79The 80.Nm watchdog 81facility were written by 82.An Poul-Henning Kamp Aq phk@FreeBSD.org . 83.Pp 84The 85.Nm SW_WATCHDOG 86code and manual page were written by 87.An Sean Kelly Aq smkelly@FreeBSD.org . 88Some contributions were made by 89.An Jeff Roberson Aq jeff@FreeBSD.org . 90