freebsd man page for wbwd

WBWD(4) 						   BSD Kernel Interfaces Manual 						   WBWD(4)

NAME
     wbwd -- device driver for watchdog timer found on Winbond Super I/O chips

SYNOPSIS
     To compile this driver into the kernel, place the following line in your kernel configuration file:

	   device wbwd

     Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):

	   wbwd_load="YES"

DESCRIPTION
     The wbwd driver provides watchdog(4) support for the watchdog interrupt timer present on at least the following Winbond Super I/O chips:

     o	 83627HF/F/HG/G Rev. G
     o	 83627HF/F/HG/G Rev. J
     o	 83627HF/F/HG/G Rev. UD-A
     o	 83627DHG IC ver. 5

SYSCTL VARIABLES
     The wbwd driver provides the following options as sysctl(8) variables.

     dev.wbwd.0.timeout_override
	     This variable allows to program the timer to a value independent on the one provided by the watchdog(4) framework while still relying
	     on the regular updates from e.g.  watchdogd(8).  This is particularly useful if your system provides multiple watchdogs and you want
	     them to fire in a special sequence to trigger an NMI after a shorter period than the reset timeout for example.  The value set must
	     not be lower than the sleep time of watchdogd(8).	A value of 0 disables this feature and the timeout value provided by watchdog(4)
	     will be used.

     dev.wbwd.0.debug_verbose
	     If set this sysctl will tell the driver to log its current state before and after the timer reset on each invocation from watchdog(9)
	     to the kernel message buffer for debugging.

     dev.wbwd.0.debug
	     This read-only value gives the state of some registers on last update.

     The wbwd driver also provides further sysctl options that are hidden by default.  See the source code for more information.

SEE ALSO
     watchdog(4), device.hints(5), watchdog(8), watchdogd(8), watchdog(9)

HISTORY
     The wbwd driver first appeared in FreeBSD 10.0.

AUTHORS
     This manual page was written by Bjoern A. Zeeb <bz@FreeBSD.org>.

BSD
								 December 28, 2012							       BSD