1.\"- 2.\" Copyright (c) 2007 Dag-Erling Smørgrav 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 AUTHOR 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 AUTHOR 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.Dd August 20, 2008 27.Dt ICHWD 4 28.Os 29.Sh NAME 30.Nm ichwd 31.Nd device driver for the Intel ICH watchdog interrupt timer 32.Sh SYNOPSIS 33To compile this driver into the kernel, 34place the following line in your 35kernel configuration file: 36.Bd -ragged -offset indent 37.Cd "device ichwd" 38.Ed 39.Pp 40Alternatively, to load the driver as a 41module at boot time, place the following line in 42.Xr loader.conf 5 : 43.Bd -literal -offset indent 44ichwd_load="YES" 45.Ed 46.Sh DESCRIPTION 47The 48.Nm 49driver provides 50.Xr watchdog 4 51support for the watchdog interrupt timer present on 52all Intel ICH motherboard chipsets. 53.Pp 54The ICH WDT counts down in ticks of approximately 0.6 seconds; the 55exact value depends on hardware quality and environmental factors. 56Supported watchdog intervals range from 2 to 63 ticks. 57.Pp 58Note that on some ICH-based systems, the WDT may be present but 59disabled, either in hardware or by the BIOS. 60The 61.Nm 62driver attempts to detect this condition and will refuse to attach if 63it believes the WDT is disabled. 64.Sh SEE ALSO 65.Xr watchdog 4 , 66.Xr watchdog 8 , 67.Xr watchdogd 8 , 68.Xr watchdog 9 69.Rs 70.%T Using the Intel ICH Family Watchdog Timer (WDT) 71.%R Intel Application Note AP-725 72.%O Document Number 292273-001 73.Re 74.Sh HISTORY 75The 76.Nm 77driver first appeared in 78.Fx 5.3 . 79.Sh AUTHORS 80.An -nosplit 81The 82.Nm 83driver was written by 84.An Wm. Daryl Hawkins Aq Mt dhawkins@tamu.edu 85of Texas A&M University and 86.An Dag-Erling Sm\(/orgrav Aq Mt des@FreeBSD.org . 87This manual page was written by 88.An Dag-Erling Sm\(/orgrav Aq Mt des@FreeBSD.org . 89