Appendix A Watchdog Timer Application Mode 87
Note – The system controller displays a console message as a reminder that the
watchdog, from the system controller’s perspective, is disabled.
However, when you re-enter the Solaris OS, the watchdog timer is still enabled
from the Solaris Operating System’s perspective. To have both the system
controller and the Solaris OS view the same watchdog state, you must use the
watchdog application to either enable or disable the watchdog.
■ If you perform a dynamic reconfiguration (DR) operation in which a system
board containing kernel (permanent) memory is deleted, then you must disable
the watchdog timer’s application mode before the DR operation and enable it
after the DR operation. This is required because Solaris software quiesces all
system IO and disables all interrupts during a memory-delete of permanent
memory. As a result, system controller firmware and Solaris software can not
communicate during the DR operation. Note that this limitation affects neither
the dynamic addition of memory nor the deletion of a board not containing
permanent memory. In those cases, the watchdog timer’s application mode can
run concurrently with the DR implementation.
You can execute the following command to locate the system boards that contain
kernel (permanent) memory:
sc> cfgadm -lav | grep -i permanent
■ If the Solaris Operating System hangs under the following conditions, the system
controller firmware cannot detect the Solaris software hang:
■ Watchdog timer’s application mode is set.
■ Watchdog timer is not enabled.
■ No rearming is done by the user.
■ The watchdog timer provides partial boot monitoring. You can use the
application watchdog to monitor a domain reboot.
However, domain booting is not monitored for:
■ Bootup after a cold poweron.
■ Recovery of a hung or failed domain.
In the case of a recovery of a hung or failed domain, a boot failure is not detected
and no recovery attempts are made.
■ The watchdog timer’s application mode provides no monitoring for application
startup. In application mode, if the application fails to start up, the failure is not
detected and no recovery is provided.
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