Hi, On init, a device's power state is set by acpi_bus_init_power, it got the information either via power_resources or via _PSC. My BIOS vendor here did this simply as follows: Device (xx) { Name (ABPS, 0) Method (_PSC, 0, NotSerialized) { Return (ABPS) } } So on init, this device's power state will be set to D0 due to ABPS is 0, but its _PS0 never get called. If later I want to evaluate its _PS0 control method, what should I do? acpi_bus_set_power will return if it found the set state is the same with the current state. Thanks, Aaron -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html