Intel S2600KPFR Product Specifications page 133

Technical Product Specification
The sleep and boost states have fixed (but configurable through OEM SDRs) fan

speeds associated with them.
The nominal state has a variable speed determined by the fan domain policy. An OEM

SDR record is used to configure the fan domain policy.
The fan domain state is controlled by several factors. They are listed below in order of
precedence, high to low:
Boost

o Associated fan is in a critical state or missing. The SDR describes which fan domains
are boosted in response to a fan failure or removal in each domain. If a fan is
removed when the system is in 'Fans-off' mode it will not be detected and there
will not be any fan boost till system comes out of 'Fans-off' mode.
o Any associated temperature sensor is in a critical state. The SDR describes which
temperature-threshold violations cause fan boost for each fan domain.
o The BMC is in firmware update mode, or the operational firmware is corrupted.
o If any of the above conditions apply, the fans are set to a fixed boost state speed.
Nominal

o A fan domain's nominal fan speed can be configured as static (fixed value) or
controlled by the state of one or more associated temperature sensors.
o See section 9.3.14.3 for more details.
9.3.14.1 Fan Redundancy Detection
The BMC supports redundant fan monitoring and implements a fan redundancy sensor. A fan
redundancy sensor generates events when its associated set of fans transits between
redundant and non-redundant states, as determined by the number and health of the fans.
The definition of fan redundancy is configuration dependent. The BMC allows redundancy to
be configured on a per fan redundancy sensor basis through OEM SDR records.
A fan failure or removal of hot-swap fans up to the number of redundant fans specified in the
SDR in a fan configuration is a non-critical failure and is reflected in the front panel status. A
fan failure or removal that exceeds the number of redundant fans is a non-fatal, insufficient-
resources condition and is reflected in the front panel status as a non-fatal error.
Redundancy is checked only when the system is in the DC-on state. Fan redundancy changes
that occur when the system is DC-off or when AC is removed will not be logged until the
system is turned on.
9.3.14.2 Fan Domains
System fan speeds are controlled through pulse width modulation (PWM) signals, which are
driven separately for each domain by integrated PWM hardware. Fan speed is changed by
adjusting the duty cycle, which is the percentage of time the signal is driven high in each pulse.
Revision 1.37
Platform Management
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