Hi Andrew > Udit, > > I think it is more like you only need ACPI if you don't have a driver.
Ok, then ACPI or say firmware needs to export AML methods, which are known to OS. > If it is standard bus with standard drivers the OS code can do power > management > without any help from ACPI. In some cases there could be some config registers in IP, which could leads to power down mode, then probably power management could be done without ACPI. If we have clock and regulators doing power management, then ACPI is needed. No ? > In general ACPI exists to abstract chipsets that don't > have OS drivers, or mother board layout of power plains, GPIOs, etc. I can think of for power management, without specific driver if such Power saving is limited to internal SOC. For example, say temperature of mother board is read using some sensor connected with SOC over i2c line. And in SOC i2c interface is behind some controller. How do you see to read temperature without having a OS drivers. For power management based on temperature, we may not need a driver. Thanks, Udit _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
