What is Selective Suspend?
Selective Suspend is a power management feature that is implemented in USB devices. It is designed to save energy by selectively suspending the operation of certain USB devices when they are not in use. By temporarily shutting down or reducing the power consumption of these devices, the overall power consumption of the system can be reduced, contributing to longer battery life on portable devices and reduced energy consumption on desktop computers.
When a USB device is connected to a computer, it constantly exchanges information with the operating system to ensure smooth communication. However, for devices that are idle or not actively transferring data, this constant communication can be unnecessary and drain power.
Selective Suspend addresses this issue by allowing the operating system to intelligently manage the power state of USB devices. When a device enters a state of idle or low activity, the operating system sends a request to the device to enter a suspended state, in which the device stops consuming power and goes into a low-power mode.
How does Selective Suspend work?
The Selective Suspend feature is implemented by the USB hub driver and the hardware of the USB device. When the operating system determines that a USB device is idle, it sends a suspend request to the hub driver, which in turn sends a request to the device driver of the respective USB device. The device driver then puts the device in a suspended state, halting its operation and reducing its power consumption.
During this suspended state, the USB device remains connected to the USB port, but it enters a low-power mode to conserve energy. The device can quickly return to an operational state when it receives a resume request from the operating system, which happens when the user interacts with the device or when data needs to be transmitted or received.
Selective Suspend can be particularly useful for USB devices that are not required to be constantly active, such as input devices like keyboards and mice, or storage devices like external hard drives. By selectively suspending these devices when they are not in use, power consumption can be significantly reduced, leading to greater energy efficiency.
It’s important to note that not all USB devices support the Selective Suspend feature. The device manufacturer must implement the necessary functionality in the device’s firmware and drivers for it to work. Additionally, in some cases, it may be necessary to configure the power management settings in the operating system to enable or tweak the behavior of Selective Suspend for specific devices.
In conclusion, Selective Suspend is a power management feature implemented in USB devices that allows the operating system to selectively suspend the operation of idle devices, reducing power consumption and contributing to energy efficiency. By intelligently managing the power state of USB devices, Selective Suspend helps improve battery life on portable devices, reduces energy consumption on desktop computers, and overall enhances the user experience.
Reference Articles
Read also
[Google Chrome] The definitive solution for right-click translations that no longer come up.