# # Copyright (c) 2014-2015 Wind River Systems, Inc. # Copyright (c) 2016 Intel Corporation # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # menuconfig SYS_POWER_MANAGEMENT bool prompt "Power management" default n help This option enables the board to implement extra power management policies whenever the kernel becomes idle. The kernel informs the power management subsystem of the number of ticks until the next kernel timer is due to expire. if SYS_POWER_MANAGEMENT config SYS_POWER_LOW_POWER_STATE bool prompt "Low power state" default n depends on SYS_POWER_LOW_POWER_STATE_SUPPORTED help This option enables the kernel to interface with a power manager application. This permits the system to enter a custom CPU low power state when the kernel becomes idle. The low power state could be any of the CPU low power states supported by the processor. Generally the one saving most power. config SYS_POWER_DEEP_SLEEP bool prompt "Deep sleep state" default n depends on SYS_POWER_DEEP_SLEEP_SUPPORTED help This option enables the kernel to interface with a power manager application. This permits the system to enter a Deep sleep state supported by the SOC where the system clock is turned off while RAM is retained. This state would be entered when the kernel becomes idle for extended periods and would have a high wake latency. Resume would be from the reset vector same as cold boot. The interface allows restoration of states that were saved at the time of suspend. config DEVICE_POWER_MANAGEMENT bool prompt "Device power management" default n help This option enables the device power management interface. The interface consists of hook functions implemented by device drivers that get called by the power manager application when the system is going to suspend state or resuming from suspend state. This allows device drivers to do any necessary power management operations like turning off device clocks and peripherals. The device drivers may also save and restore states in these hook functions. config TICKLESS_IDLE bool prompt "Tickless idle" default y if TICKLESS_IDLE_SUPPORTED help This option suppresses periodic system clock interrupts whenever the kernel becomes idle. This permits the system to remain in a power saving state for extended periods without having to wake up to service each tick as it occurs. config TICKLESS_IDLE_THRESH int prompt "Tickless idle threshold" default 3 depends on TICKLESS_IDLE help This option enables clock interrupt suppression when the kernel idles for only a short period of time. It specifies the minimum number of ticks that must occur before the next kernel timer expires in order for suppression to happen. endif