Artesyn ATCA-9305 User's Manual (May 2014) - Manual (Page 153)

System Management
ATCA-9305 User’s Manual (10009109-07) 153
SMS ‘OS Watchdog’ Time-out
This indicates that the timer was being used by System Management Software (SMS). During
run-time, SMS starts the timer, then periodically resets it to keep it from expiring. This periodic
action serves as a ‘heartbeat’ that indicates that the OS (or at least the SMS task) is still
functioning. If SMS hangs, the timer expires and the IPMC generates a system reset. When SMS
enables the timer, it should make sure the ‘SMS’ bit is set to indicate that the timer is being used
in its ‘OS Watchdog’ role.
OEM
This indicates that the timer was being used for an OEM-specific function.
7.9.2.1 Using the Timer Use Field and Expiration Flags
The software that sets the Timer Use field is responsible for managing the associated Timer Use
Expiration flag. For example, if System Management Software (SMS) sets the timer use to
“SMS/OS Watchdog,” then that same SMS is responsible for acting on and clearing the
associated Timer Use Expiration flag.
In addition, software should only interpret or manage the expiration flags for watchdog timer
uses that it set. For example, the monitor should not report watchdog timer expirations or clear
the expiration flags for non-monitor uses of the timer. This is to allow the software that did set
the Timer Use to see that a matching expiration occurred.
7.9.3 Watchdog Timer Event Logging
By default, the IPMC will automatically log the corresponding sensor-specific watchdog sensor
event when a timer expiration occurs. A “don’t log” bit is provided to temporarily disable the
automatic logging. The “don’t log” bit is automatically cleared (logging re-enabled) whenever
a timer expiration occurs.
7.9.3.1 Monitor Support for Watchdog Timer
If a system “Warm Reset” occurs, the watchdog timer may still be running while the monitor
executes POST. Therefore, the monitor should take steps to stop or restart the watchdog timer
early in POST. Otherwise, the timer may expire later during POST or after the OS has booted.