Intel® Server System Server System "Emerald Ridge ... - CTL

錯 誤 ! 尚 未 定 義 樣 式 。 EPSFunctional Specification• During runtime, if BIOS needs to return bus ownership to the BMC, it must first try to dothis using the IPMI OEM command method. Only if the BMC doesn’t respond to the IPMIOEM command, then BIOS must reset the associated semaphore bit to indicate that theBMC now owns the bus.• During runtime, if BIOS needs to return bus ownership to the BMC, it must first try to dothis using the IPMI OEM command method. Only if the BMC doesn’t respond to the IPMIOEM command, then BIOS must reset the associated semaphore bit to indicate that theBMC now owns the bus.• The BMC FW checks that it is owner of the bus prior to initiating any transaction on thebus by inspecting the state of the associated mailbox semaphore bit.3.23.1 Sequence of Operations during Memory Hot PlugThe BIOS/BMC interactions are as follows:• BIOS owns all the bus segments until completion of POST. After POST completes, theBMC becomes the default owner.• When a memory hot-plug or memory on-line operation is initiated, BIOS must requestaccess of the applicable SMBus segment from the BMC using the Acquire SystemResource OEM IPMI command. If the BMC is in the middle of a SMBus transaction, itmust respond to the BIOS with an appropriate response code and halt any furthertransactions on that bus. After waiting to allow the BMC to finish its transaction for250ms, BIOS must retry its request for bus ownership. It is recommended that BIOSshould attempt a minimum of 2 retries. .If the BMC doesn’t relinquish the bus or is notresponding to the command request after BIOS has completed its retry attempts thenBIOS may assume ownership of the bus segment by forcibly clearing the semaphore bitin order to complete the hot-plug operation.• Once BIOS has gained ownership of the bus segment, BMC will no longer poll on thatbus until it regains ownership.• Once BIOS has completed the memory operation, BIOS sends new DIMM populationmapping data to the BMC.• BIOS must relinquish ownership to the BMC by resending the command after it hascompleted all bus accesses required for the operation. Note that if BIOS hangs anddoesn’t return the semaphore, the BMC will eventually detect an SMI timeout and resetthe system.• Once BMC has regained ownership of the SMBus segment and there are no pendingBIOS requests for access to the segment, then BMC begins polling temperature sensorsthat are present on that bus.When BIOS has ownership of a bus segment, then the BMC can no longer poll the DIMMtemperature sensors on that bus. The associated IPMI aggregate sensors, the DIMM ThermalMargin and Memory Buffer Thermal Margin sensors, will then enter and remain in the “readingRevision 1.1Intel ® Confidential 39