Even when setting sleep to 'Never' in the power and sleep settings, the system transitions to sleep mode after a while from the display turning off

Question

On a Windows 10 Pro Modern Standby (S0) PC, even when setting sleep to "Never" in the power and sleep settings, there is an issue where the system transitions to sleep mode after a while from the display turning off.

Upon checking the logs with the "powercfg /sleepstudy" command, it was observed that the system transitions to sleep mode 0 seconds after turning off the display, and then wakes up from sleep during events like Edge updates, before returning to the display-off state, and then transitioning back to sleep mode.

To prevent the system from transitioning to sleep mode, the "System unattended sleep timeout" under sleep settings was set to 0, which resolved the issue. The logs from sleepstudy also confirm that the display-off state is maintained.

While the issue has been resolved, the reason for its resolution is not fully understood. The "System unattended sleep timeout" setting determines how long the system remains awake after automatically waking up from sleep, before returning to sleep mode. However, it is unclear why the system was transitioning to sleep mode automatically despite sleep being set to "Never".

One hypothesis is that on Modern Standby (S0) PCs, both the display-off state and sleep state are in the S0 state, which might cause the system to interpret the display-off state as sleep mode, leading to an immediate transition to sleep when the display is turned off.

It is understandable that the system wakes up from sleep during events and returns to sleep afterward if there is no operation for the set time under "System unattended sleep timeout." However, the explanation for why setting "System unattended sleep timeout" to 0 prevents the system from transitioning to sleep when the display is turned off is not clear.

If anyone familiar with the Modern Standby specifications can provide insights into why this issue was resolved, it would be greatly appreciated.

Answer 1

Hello

If may be related to the wakeup way.

"For example, if the system wakes from sleep because of a timed event or a wake on LAN (WoL) event, the sleep unattended idle timeout value will be used instead of thesleep idle timeoutvalue."

Sleep unattended idle timeout | Microsoft Learn