Specifications

QSSC-S4R Technical Product Specification Processor Presence and Population Check
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24.13.4.3 Sensor Failure
Each Tcontrol SDR sub-record has a failure control value field. The value in this field is used by the BMC as that sub-
record’s fan speed contribution if the associated sensor is enabled but is marked reading/state unavailable. If the
sensor is unreadable because it is disabled, or if a failure control value of FFh is specified, then the BMC ignores the
sub-record’s fan speed contribution.
24.13.5 Thermal and Acoustic Management (Acoustic Monitoring)
This feature refers to enhanced fan management to keep the system optimally cooled while reducing the amount of
noise generated by the system fans. Aggressive acoustics standards might require a trade-off between fan speed and
system performance parameters that contribute to the cooling requirements, primarily memory bandwidth. The BIOS,
BMC, and SDRs work together to provide control over how this trade-off is determined.
This capability requires the BMC to access temperature sensors on the individual memory DIMMs. QSSC-S4R only
supports RDIMMs.
24.13.5.1 Fan Profiles
The server system supports multiple fan control profiles to support acoustic targets and ASHRAE compliance. Fan
profile will be selected based on the altitude setting. The BIOS Setup utility can be used to configure the correct altitude
setting.
Although there are up to eight profiles available, the QSSC-S4R implementation supports only five profiles. There is
one profile associated with each of four altitude settings. The four altitude settings are: 1) less than 300m, 2) between
301m and 900m, 3) between 901 and 1500m, greater than 1501m. Additionally, a default profile is defined which the
BMC applies upon system power on until BIOS changes the enabled profile after system boot. This default profile
excludes all fan control based on DIMM and Memory Buffer temperature sensors and must be configured to provide
sufficient cooling capability under this constraint. If for any reason, the BMC cannot determine which primary profile to
use, the BMC should be set to the default profile.
Table 181. Fan Profile Mapping
Type Profile Details
Default 0 Default
CLTT 1 less than 300m altitude
CLTT 2 between 301m and 900m,
CLTT 3 between 901 and 1500m
CLTT 4 greater than 1501m
The BMC provides commands that query for fan profile support and it provides a way to enable a fan profile. Enabling
a fan profile determines which TControl SDRs are used for fan management. The BMC only supports enabling a fan
profile through the command if that profile is supported on all fan domains defined for the system. It is important to
configure the SDRs so that all desired fan profiles are supported on each fan domain. If no single profile is supported
across all domains, the BMC defaults to using profile 0 and do not allow it to be changed.
At system boot, the BIOS can use the Get Fan Control Configuration command to query the BMC about which fan
profiles are supported. The BIOS uses this information to display options in the BIOS Setup utility. The BIOS indicates
the fan profile to the BMC, as dictated by the BIOS Setup Utility options for altitude, using the Set Fan Control
Configuration command.
The BMC uses this information as input to its fan control algorithm as supported by the TControl OEM SDR. The BMC
only allows enabling fan profiles that the BMC indicates are supported using the Get Fan Control Configuration
command. For example, if the Get Fan Control Configuration command indicates that only profile 1 is supported, then
using the Set Fan Control Configuration command to enable profile 2 will result in the return of an error completion
code.
The BMC requires the BIOS to send the Set Fan Control Configuration command to the BMC on every system boot.
This must be done after BIOS has completed any throttling-related chipset configuration.