ACPI Power Management Program

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ACPI Power Management Program [Copy link]

ACPI is the abbreviation of Advanced Configuration and Power Interface, which means "Advanced Configuration and Power Interface". It is a power management standard jointly developed by Intel, Microsoft and Toshiba. Under ACPI power management mode, it can support five sleep states S1, S2, S3, S4 and S5 according to the different states of CPU, memory, L2 cache, main control chip, hard disk and other devices when suspended. ? S0--Normal, that is, normal working state, all devices are fully turned on, and the power consumption generally exceeds 80W; S1--CPU stops working, also known as POS (Power on Suspend). At this time, except for shutting down the CPU through the CPU clock controller, other components are still working normally. The power consumption at this time is generally below 30W; (Some CPU cooling software uses this working principle) S2--CPU is turned off. At this time, the CPU is in a stopped state, the bus clock is also turned off, but the rest of the devices are still running; S3--All components except the memory stop working (standby), that is, STR (Suspend to RAM: suspend to memory), and the power consumption at this time does not exceed 10W; S4--Memory information is written to the hard disk (hibernation), all components stop working, also known as STD (Suspend to Disk), at this time the system main power is turned off, but the hard disk is still powered and can be awakened; S5--Shutdown, all devices are turned off (including power), and the power consumption is 0. Comparison between ACPI and APM APM1.0 & 1.1: BIOS performs power management; APM1.2: The operating system defines the power management time, which is executed by the BIOS; ACPI: BIOS collects hardware information and defines the power management plan, which is executed by the operating system. APM is a software solution, so it is related to the operating system, while ACPI is an industrial standard that includes software and hardware specifications.

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