WBWD(4)                FreeBSD Kernel Interfaces Manual                WBWD(4)

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

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

           device superio
           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 Super I/O chips:
     •   Winbond 83627HF/F/HG/G
     •   Winbond 83627S
     •   Winbond 83697HF
     •   Winbond 83697UG
     •   Winbond 83637HF
     •   Winbond 83627THF
     •   Winbond 83687THF
     •   Winbond 83627EHF
     •   Winbond 83627DHG
     •   Winbond 83627UHG
     •   Winbond 83667HG
     •   Winbond 83627DHG-P
     •   Winbond 83667HG-B
     •   Nuvoton NCT6775
     •   Nuvoton NCT6776
     •   Nuvoton NCT6102
     •   Nuvoton NCT6779
     •   Nuvoton NCT6791
     •   Nuvoton NCT6792

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
     superio(4), 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>.

FreeBSD 13.1-RELEASE-p6        October 16, 2019        FreeBSD 13.1-RELEASE-p6