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Inactivity Delays

By default, the power manager performs various actions when the system is inactive for a given period of time:

 Power source    Dim screen Turn screen off Suspend / sleep
 Battery 5 minutes 6 minutes 10 minutes
 AC 7 minutes 8 minutes 30 minutes

There are different ways to define "activity":
  • User activity (keyboard or touchpad events or other events that indicate a human is present, like changing the power source or connecting or disconnecting an external display)
  • Video activity (currently defined as 15 or more 333x250 or larger updates within a second in an active tab in an onscreen window)
  • Audio activity
User activity and video activity block all of the above actions from being performed. The screen will still dim and be turned off while audio is being played, but the system will not suspend. Once activity ceases, the inactivity timer starts again.

When the suspend delay is reached while no user is logged in and the system is on battery power, the system will shut down instead of suspending.

Several events can result in the above delays being lengthened (specifically, the screen-dimming delay is doubled and the other delays' distances from the dimming delay are maintained; for example, on battery, the delays are changed to 10/11/16 minutes):
  • An external monitor is connected
  • User activity occurs while the screen is dimmed or soon after it is turned off (delays are reset after the current user logs out)
If the "Require password to wake from sleep" setting is enabled, the screen will be locked ten seconds after the screen is turned off due to inactivity.

The above delays and actions can be configured by Chrome and are sent to the power manager as PowerManagementPolicy protocol buffers via D-Bus. Chrome's settings are controlled by enterprise policies and by the chrome.power extension API.

On a running system, /var/log/power_manager/powerd.LATEST should contain enough details to understand why a given action was taken. This file is accessible via chrome://system.

Further reading

src/platform/system_api/dbus/power_manager/policy.proto - definition of PowerManagementPolicy protocol buffer
src/platform2/power_manager/powerd/policy/state_controller.{h,cc} - StateController class in power manager; responsible for managing delays
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