介紹apmbios接口ppt53-文庫吧資料
2025-02-25 06:56本頁面
【正文】 System returns quickly to the APM Enable State. ? Interrupts must still be processed normally. 2/27/2023 12 APM Suspend ? The system enter the APM Suspend State after a relatively long period of inactivity. ? System takes a relative long time to return to the APM Enable State. ? System is not working and in a low power state with maximum power savings ? Most power managed device are not powered ? The CPU clock is stopped and the CPU core is in its minimum power state. 2/27/2023 13 Off State ? In this State the system is not working. ? The power supply is off. ? Operational parameters are not saved. ? System resets and initializes when the transitioning to the Full On State. 2/27/2023 14 Device Control ? Device Control Overview ? Device On Mode ? Device Power Managed Mode ? Device Power Low Mode ? Device Off Mode 2/27/2023 15 Device Control Overview ? Devices may be powermanaged either by the system BIOS or by the OS. ? Using the “ Disable Device Power Management” function, the OS may tell the BIOS to stop power managing a particular device. ? The device control has four modes: Device On, Device Power Managed, Device Low Power, and Device Off. 2/27/2023 16 ? Device On Mode: In this mode device is fully powered and able to perform work, all device features are available. Device On Mode 2/27/2023 17 Device Power Managed Mode ? Device Power Managed: In this mode Device is working, but some features may not be operational, or may be functioning at reduced performance levels. 2/27/2023 18 ? Device Low Power: in this mode device is not working. Power is maintained and devices may have variable numbers of low power sub modes. Device Low Power 2/27/2023 19 Device Off Mode ? Device Off: in this mode device is not working. Device is powered off. 2/27/2023 20 CPU Core Control ? CPU Core Control Overview ? CPU Core Control Modes 2/27/2023 21 CPU Core Control Overview ? The CPU core is typically the last device to power off and the first device to power on. ? The CPU core includes the CPU clock, cache, system bus, and system timers. ? The CPU core is controlled through APM BIOS. APM Driver may notify the APM BIOS about CPU usage but the APM BIOS determines the action to take. 2/27/2023 22 ? The CPU core is required to perform system power state changes. ? Slow Clock: Reduced speed operation, reduced power consumption, reduced performance level, interrupts restore to Full On Mode, restoration to Full On appears instantaneous. ? Stop: Only a hardware interrupt starts the clock, restoration to Full On appears instantaneous. CPU Core Control Modes 2/27/2023 23 System Power
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