3

Under power management is a feature for "Selective Suspend" in which Windows will suspend devices as it sees fit to save power.

Is there a way to manually set a device to be suspended, rather than wait on selective suspend?

I'm trying to test the design of a USB device to handle waking up appropriately after it's been suspended.

0

2 Answers 2

2

There is no function under Windows USB framework to suspend USB devices at will. This function was deemed to be unnecessary from Microsoft designer's point of view.

However, for testing purposes, there is a tool from USB-IF to perform SUSPEND (and wake-up) and many more isolated functions on USB ports, mostly to invoke various test patterns for electrical characterization. It is called xHSETT. Unfortunately, this function is implemented as a special USB test driver that replaces the standard stack and has no standard application functionality.

There is also a little nuisance with this driver that when something gets wrong and ports end up in some unexpected state, the test driver will fail to unload, and the system may stuck in this test mode without basic USB functionality. So you will have no control over the system with keyboard or mouse even after system reboot. To keep the system functional, it is advised either to use a test system with PS/2 port, or have an extra plug-in PCIe-USB card.

0

If no app or service is using your device, usually windows sends it to suspend mode. I'm working on a HID USB device and when I close its app, windows sends my device to suspend mode after a few seconds.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.