Specifications

4
Changing Shelf Settings Using HPI
75
Overriding the cooling algorithm with an HPI application
ThefollowingstepsillustratehowyoucandothisusingHPI:
1. OpenanHPIsessionusingtheactiveShelfManagerIPaddressasDomainId(seeWriting
HPIapplicationsonpage 57forinformation).
2. Usingthefanresources,setallfancontrolstotheSAHPI_CTRL_MODE_MANUALmode,
keepingtheirspeedsunchanged.Thisplacestheminthesystemmanageroverridemode.
Thefanresourcescanbeidentifiedbytheassociatedentitytype,
SAPHI_ENT_COOLING_UNIT.
3. Subscribeforeventsonthesession(seetheeventssectionoftheSAFHPISpecification).
StartlisteningforeventsinblockingmodebyissuingthesaHpiEventGet()functioncall
withTimeOut=SAHPI_TIMEOUT_BLOCK(seethefunctiondescriptionintheSAFHPI
Specification).Thisenablesreceptionofeventsdynamically.
4. Whenatemperatureassertioneventofsignificantseverityisreceived,feeditintothe
externalcoolingmodule.Thecoolingmodulecanthenusethefanresource'sfancontrol
toraiseorlowerthefanspeeds.
FormoreinformationonHPIcoolingandfancontrol,seetheSAFMappingSpecification.