1.\" Copyright (c) 2004 Poul-Henning Kamp <phk@FreeBSD.org> 2.\" Copyright (c) 2003, 2004 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/" 52.Dv _PATH_WATCHDOG 53which 54responds to a single ioctl call, 55.Dv WDIOCPATPAT . 56.Pp 57The ioctl call takes an argument which consists of a timeout value 58specified as an integer power of two nanoseconds. 59.Pp 60The 61.Dv WD_ACTIVE 62flag signals that the watchdog will be kept from 63timing out from userland, for instance by the 64.Xr watchdogd 8 65daemon. 66.Pp 67To disable the watchdogs, use an argument of zero. 68.Pp 69The ioctl call will return success if just one of the available 70watchdog implementations support the request. 71If the ioctl fails, for instance if no watchdog supports the timeout 72length, all watchdogs are disabled and must be explicitly reenabled. 73.Sh SEE ALSO 74.Xr watchdogd 8 , 75.Xr watchdog 9 76.Sh HISTORY 77The 78.Nm 79code first appeared in 80.Fx 5.1 . 81.Sh AUTHORS 82.An -nosplit 83The 84.Nm watchdog 85facility were written by 86.An Poul-Henning Kamp Aq phk@FreeBSD.org . 87.Pp 88The 89.Nm SW_WATCHDOG 90code and manual page were written by 91.An Sean Kelly Aq smkelly@FreeBSD.org . 92Some contributions were made by 93.An Jeff Roberson Aq jeff@FreeBSD.org . 94