NAME

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

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 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

     Driver may be forced to attach to unknown chips by adding to /boot/device.hints:
     hint.wbwd.0.at="isa"

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>.