Dell External OEMR XL R210II Technical Manual

Dell External OEMR XL R210II Technical Manual Manual pdf 41 page image

DellPowerEdge R210 Technical Guide 419.3.2 Power Saving BIOS Setting (OS Control)Intel processors support Demand Based Switching (DBS) which enables the processor todynamically change its operating frequency in response to workload changes. Theindustry standard implementation of this power management feature is in theOperating System (OS). The OS monitors process/thread level utilization of theprocessor and uses processor controls to change the processor’s operating frequency.For heavy workloads, the OS will run the processor at higher frequencies for additionalperformance. Lighter workloads do not need high performance, thus the OS will runthe processor at lower frequencies.9.3.3 Maximum PerformanceThe Maximum Performance Mode disables power management. In this mode, theprocessor frequency is statically set to the highest supported frequency.The power management features are implemented via two categories: fixed orgeneric. Fixed features use bits defined in the ACPI specification for specificcapabilities. The fixed feature bits give the OS complete control over the powermanagement of a device since the location of the bits is given to the OS in the FACPtable. Thus, a driver can directly access bits to control a device’s power management.Generic features have defined enable and status bits, but the functionality is not fullyvisible to the OS. Dell provides ASL code to handle the details of generic features,allowing the OS to intelligently communicate with system-specific hardware.Table 15. Summary of R210 Power Management FeaturesFeature Type Enable/Status/Ctrl bitlocationDescriptionACPI modeswitchFixed PCH The OS uses the SCI_EN bit to switch fromlegacy mode to ACPI mode.Sleep states Fixed PCH Supported states: S0(Working), S4-OS(‘Hibernation’ in W2K), and S5 (Soft-off).S1 (also called ‘standby’ or ‘suspend’) and S3are not supported.Power Button Fixed PCH In ACPI mode, OS has control of the powerbutton. In non-ACPI mode, SMI handler ownspower button events.Real-TimeClockFixed PCH The OS is able to configure the system to wakeon the RTC alarm.Power Mgmt.TimerFixed PCH 24-bit power management timer is used.Power Mgmt.Event (PME)Generic PCH Each host bus’s PME# signal is routed to aseparate general-purpose event pin in thechipset. When a device signals PME#, the systemwakes (if necessary), the OS detects the event,and a Dell defined ASL routine handles theevent. Wake-on-LAN is one example of a PME.