Modern Standby Wake Sources
A PC supporting the Modern Standby power model must wake from standby in response to specific events, even in a low-power idle state.
This topic details the wake sources that must wake the processor and explains which events should turn the screen on or keep it off. System integrators should use this information to ensure their hardware, firmware, and software can configure wake sources appropriately.
Overview of Modern Standby User Experience
The Modern Standby experience is designed to mimic a cellular phone. When users finish using their phones, they press the power button, and the phone enters sleep mode. It remains asleep until the user presses the power button again or receives a call, email, or message.
Similarly, a PC in Modern Standby appears off—the screen is blank, there are no visible LEDs, and no acoustic noise. However, it remains on and connected to the Internet, using any available network connection (Wi-Fi, mobile broadband, or Ethernet). The Modern Standby PC also has long battery life in its screen-off state, similar to a cell phone.
Achieving the Modern Standby experience requires all devices and software in the PC to participate in system power management. Long standby battery life is achieved by allowing all devices and the core silicon or System on a Chip (SoC) to enter a low-power idle state. The networking subsystem stays connected to wake the system for incoming emails or VoIP calls. The real-time nature of Modern Standby is enabled by platform devices waking the SoC for the correct events at the correct times.
All wake sources in a Modern Standby PC must wake the SoC from its deepest idle state. Some wake sources should generate a wake signal that turns on the display. The difference between waking the SoC and turning on the display is crucial for the Modern Standby experience. The following rules govern platform wake behavior:
- Wake source operation and scenarios are consistent across all Modern Standby PCs, regardless of processor architecture (x86, x64 or Arm).
- Wake source operation may differ based on whether the system is on AC or DC power. Differences are noted in the tables below.
- Some wake sources are hardware-dependent, e.g., wake on fingerprint or optical disc drive ejection. Modern Standby systems should support all wake scenarios for which they have the necessary hardware.
Note
Starting in Windows 11, version 24H2, a new power-saving measure was introduced to Modern Standby to prevent unexpected battery drain. If excessive battery drain is detected, most wake sources will be disabled. In this state, the device can be woken from Modern Standby by pressing the power button or opening the lid.
The remainder of this topic describes the different types of wake sources, including whether they can turn on a device's display, whether they are enabled by default, and any differences in operation based on AC or DC power.
Most systems enable Adaptive Connected Standby by default.
Types of Wake Sources
Always-on timer
The core silicon or SoC chip in a Modern Standby platform has one or more timers that are always powered on that so that Windows can schedule future work and place the SoC into a deep idle state. During standby, the always-on timer reliably wakes the SoC as programmed by the OS.
Buttons and Lid
The system power button is a common user-initiated wake source in a Modern Standby platform. All Modern Standby PCs must ensure the power button can always send a wake interrupt to the SoC. To deliver an instant-on experience, the power button must wake the SoC from the deepest idle state without delay. Another common wake source on clamshell devices is opening the lid, which wakes the SoC. The Windows button can also wake the SoC.
Communications Devices
Wi-Fi, Ethernet, and mobile broadband (MBB) devices provide continuous connectivity in Modern Standby. They enable wake sources like Universal Windows Platform (UWP) application notifications and syncing, as well as Bluetooth notifications and syncing.
When Disconnected Standby, certain applications in above will not have connectivity in standby states. However, this does not apply to specific system processes, which can remain active (e.g., DHCP) and use the network during Disconnected Standby.
When using a DC power source, the networking stacks may initiate disconnection from networks. This includes L2 disconnect for Ethernet, disconnection of Wi-Fi and Bluetooth, and turning off the MBB radio to save power consumption.
Input Devices
Using HIDI2C for input peripherals is recommended for better power efficiency, but not required. USB can be used to connect input devices like TouchPads, touch digitizers, or pen digitizers. A precision TouchPad should be capable of waking the system from deep idle, regardless of connection type (USB, I2C, or SPI). Pen digitizers must not wake the system from deep idle.
In addition to chassis buttons, a Modern Standby PC might have other input devices integrated into or attached to the system. User input through these devices must always wake the SoC from the deepest idle state and turn on the display, unless the lid is closed and input suppression is engaged.
Starting in Windows 11, touch screens may also wake the system from deep idle or S3, though it is not required. OEMs, ODMs, and system implementers should consider the additional battery drain of a wake-capable touch screen in standby mode.
Voice Input
On systems with a hardware keyword spotter (HW-KWS), voice input of a specific keyword can wake the SoC from the deepest idle state and turn on the display. Systems with Multiple Voice Assistants (MVA) support and an MVA-capable driver can wake the SoC and turn on the display with additional voice assistant commands.
Insertion or Removal of a Connector or Device
Inserting or removing certain connectors or devices can wake the SoC from the deepest idle state and turn on the display.
Windows Update
Windows Update can always wake the SoC from the deepest idle state to scan for updates. It can also wake the SoC to download and install updates and restart a device, depending on the power source.
Universal Windows Platform (UWP) Applications
UWP applications can wake the SoC from the deepest idle state to sync and display notifications, depending on the power source, notification priority levels, and app-specific user configurations.
Remote Access
Remote Desktop and File Sharing can wake the SoC from the deepest idle state, depending on the target device's power source and network connection. Remote Desktop can turn on the display on the target system.
Audio
Audio from internal or Bluetooth speakers can wake the SoC, allowing audio to continue playing even when the screen is off.
Environmental Context Changes
The Modern Standby PC must respond in real-time to changes in environmental conditions, such as thermal events and power source changes.
Wakes SoC and can turn on display
Buttons and Lid
| Device | Turns on Display (AC Power) | Turns on Display (DC Power) | Remarks |
|---|---|---|---|
| Power Button | Yes | Yes | The Windows power manager activates the display when the power button is pressed. |
| Windows Button | Yes (if wake-enabled) | Yes (if wake-enabled) | The Windows power manager activates the display when the Windows button is pressed. The button is considered user input. |
| Lid Switch (mechanical or sensor-based) | Yes | Yes | Various types of lid switches (mechanical or sensor-based) are treated similarly by Windows. These switches can turn off the display when a tablet is docked or covered. Opening the lid or cover, or adjusting the display, will turn on the display. The Windows power manager handles this automatically. |
Input Devices
| Device | Turns on Display (AC Power) | Turns on Display (DC Power) | Remarks |
|---|---|---|---|
| Integrated Keyboard (HIDI2C) | Yes | Yes (See Note) | The display turns on with keyboard input. All keys, except volume buttons, must generate a wake interrupt. Consumer control keys must also generate a wake interrupt. Note: In convertible tablets, the keyboard should not wake the SoC if not visible. |
| External USB Keyboard | Yes | Yes (See Note) | Multiple key presses might be needed to generate a resume event. Note: Keyboard wake may be disabled on DC power to save battery. |
| External Bluetooth Keyboard | Yes | Yes (See Note) | Note: Keyboard wake may be disabled on DC power to save battery. |
| Integrated Precision TouchPad (I2C, USB, or SPI) | Yes | Yes (See Note) | Finger movement or button activation on the TouchPad should cause a wake event. Note: TouchPad wake is optional. In convertible tablets, the TouchPad should not wake the SoC if not visible. |
| External USB Mouse | Yes | Yes (See Note) | Pressing any button should generate a resume event. Multiple button presses might be needed. Note: Mouse wake may be disabled on DC power to save battery. |
| External Bluetooth Mouse | Yes | Yes (See Note) | Pressing any button will generate a resume event. Movement wake is optional. Note: Mouse wake may be disabled on DC power to save battery. |
| Fingerprint Reader | Yes | Yes (See Note) | Note: Fingerprint reader wake may be disabled on DC power to save battery. |
| Touch Screen | Yes | Yes (See Note) | Note: Starting in Windows 11, touch screens can wake the system from deep idle or S3. This is optional and may increase battery drain. |
Note
The display will not turn on DC power on a clamshell form factor system if the lid is closed and input suppression is engaged.
Voice Input
| Event | Turns on Display (AC Power) | Turns on Display (DC Power) | Remarks |
|---|---|---|---|
| Voice Input (Multiple Voice Assistants) | Yes, if Wake on Voice-capable and enabled by user. | Yes, if Wake on Voice-capable, with hardware keyword spotter and MVA-capable driver. If only software keyword spotter, Wake on Voice is off by default on DC power. | Wake on Voice may be disabled on DC power to save battery. |
Note
Beginning with Windows 11, version 24H2, Voice Input will no longer be supported to wake the device from Sleep.
Connector or Device Insertion/Removal
| Device | Turns on Display (AC Power) | Turns on Display (DC Power) | Remarks |
|---|---|---|---|
| Dock Attachment/Removal | Varies | Varies | Depends on the devices in the dock and their state. Dock attachment should be treated as individual device attachment. Detection of new devices in the dock should wake the SoC. |
Windows Update
| Event | Turns on the display - AC power | Turns on the display - DC power | Remarks |
|---|---|---|---|
| Restart | Yes | No. Restart for Windows Update is disabled on DC power. |
Universal Windows Platform (UWP) Applications
| Event | Turns on the display - AC power | Turns on the display - DC power | Remarks |
|---|---|---|---|
| Skype: incoming calls and IMs | No longer supported starting with version v8.61 | No longer supported starting with version v8.61 | |
| 3rd party VoIP calls and IMs | Depends on the type of notification. | Depends on whether the app is exempt, the notification priority level, and the type of notification. | See Note. |
| Bluetooth device notification | Depends on the type of notification. | No | See Note. |
| Bluetooth authentication: proximity | Depends on the type of notification. | No | See Note. |
| Location services (Geofencing APIs trigger push notification) | No | No | See Note. |
| Location services (Geofencing APIs trigger push notification) | No | No | See Note. |
| Other UWP apps: push notifications | Depends on the type of notification. | Depends on whether the app is exempt, the notification priority level, and the type of notification. | See Note. |
Note
If the device is connected to AC power, the notifications of all priorities (high, medium, or low priority) deliver for the UWP apps. If the device is on DC (battery) power, the notifications of all priorities deliver only for the exempt UWP apps. Different types of notifications have different levels of priority, depending on the specific app. For example, the Inbox Mail app considers a notification of incoming mail as low priority. If the notifications are being delivered during Modern Standby, only toast notifications will turn on the display. For more information about UWP app notifications, see WNS Notification Priorities.
To set an app as exempt, right-click Start, and then select Settings>System>Battery. You can see the apps that consume high battery usage. If you want to exempt an app, select the app. If Let Windows decide is turned on, select Always to allow the app to run in the background. To allow notifications from the app, select Settings>System>Notifications & actions, and then turn on the app in Get notifications from these senders.
To configure location services, go to Settings>Privacy>Location. Location services, including apps using Geovisits and Geofencing APIs, are not functional during Modern Standby.
Remote Access
| Event | Turns on the display - AC power | Turns on the display - DC power | Remarks |
|---|---|---|---|
| Remote Desktop | Yes | Yes, if the target system has an Ethernet connection. |
Environmental context changes
| Event | Turns on the display - AC power | Turns on the display - DC power | Remarks |
|---|---|---|---|
| Connecting a power source | Yes (on AC attach) | No (on AC detach) | The Windows power manager will turn on the display when the battery subsystem has indicated AC power has been connected. The GPIO interrupt for power source changes must cause the ACPI _PSR method under the power supply device to be executed. The power subsystem must wake the SoC any time the power source changes, including when the system is attached or removed from a dock that has a battery or AC power source. After AC power is connected, the display will remain on for five seconds, unless there is input to the system during this five-second window. |
Wakes SoC but cannot turn on display
| Device | Remarks |
|---|---|
| Always-on timer | Each SoC has a different mechanism for programming the always-on timer. |
| Device | Remarks |
|---|---|
| SD card insertion/removal (SDIO controller-attached) | |
| SD card insertion/removal (USB-attached) | The SD controller selected must be capable of detecting card insertion and removal while in the USB suspend state drawing less than 1 milliwatt average. |
| Headphone or microphone insertion/removal | Attaching a headphone or microphone to the system provides an interrupt to enable the audio stack to correctly route audio. |
| eSATA insertion/removal |
| Device | Remarks |
|---|---|
| Wi-Fi radio | The Wi-Fi wake source is not required for Disconnected Standby systems. |
| Mobile broadband (MBB) radio | |
| Bluetooth radio | Windows and its drivers are responsible for detecting the type of associated Bluetooth device. If a keyboard, mouse, or other user-input device is responsible for causing the Bluetooth radio to wake the SoC, the display will turn on. Other Bluetooth devices such as portable audio headphones will not cause the display to turn on. |
| Wired LAN (USB-attached, Modern Standby-capable) | Wired LAN devices in Modern Standby platforms or their supported docks must support pattern-match offloads in order to be Modern Standby-capable. Wired LAN devices connected over USB may undergo a Device-S4 transition during Modern Standby and lose wake capability. |
Note
Windows can turn on the display when an incoming critical alert or activity is detected over the network. Examples include high priority notifications from lock-screen applications and VoIP calls.
Windows Update
| Event | Enabled by default - AC power | Enabled by default - DC power | Remarks |
|---|---|---|---|
| Scan | Yes | Yes | |
| Download | Yes | Yes, but only limited to interactive download. All non-interactive downloads are paused. No new downloads will be initiated. | |
| Install | Yes | No. In-progress installs get paused. Does not kick off new install. |
Remote Access
| Event | Enabled by default - AC power | Enabled by default - DC power | Remarks |
|---|---|---|---|
| File Sharing | Yes | No | Please refer to File sharing over a network in Windows 10 for more information. |
Universal Windows Platform (UWP) Applications
| Event | Enabled by default - AC power | Enabled by default - DC power | Remarks |
|---|---|---|---|
| Background download of content | Yes | No, unless the app is exempt. | See Note. |
| Inbox Mail app: mail sync notifications | Yes | No, unless the app is exempt. | See Note. |
| Inbox People app: contact sync notifications | Yes | No, unless the app is exempt. | See Note. |
| Inbox Calendar app: calendar sync notifications | Yes | No, unless the app is exempt. | See Note. |
| Sync with Bluetooth devices | Yes | No | |
| App operations that require network (via SocketActivityTrigger) | Yes | Yes | |
| OneNote and VoiceRecorder: background audio recording | Yes | Yes |
Note
If the device is connected to AC power, the notifications of all priorities (high, medium, or low priority) deliver for the UWP apps. If the device is on DC (battery) power, the notifications of all priorities deliver only for the exempt UWP apps. Different types of notifications have different levels of priority, depending on the specific app. For example, the Inbox Mail app considers a notification of incoming mail as low priority. If the notifications are being delivered during Modern Standby, only toast notifications will turn on the display. For more information about UWP app notifications, see WNS Notification Priorities.
To set an app as exempt, right-click Start, and then select Settings>System>Battery. You can see the apps that consume high battery usage. If you want to exempt an app, select the app. If Let Windows decide is turned on, select Always to allow the app to run in the background. To allow notifications from the app, select Settings>System>Notifications & actions, and then turn on the app in Get notifications from these senders.
Audio
| Event | Standby Entry Method | Enabled by default - AC power | Enabled by default - DC power | Remarks |
|---|---|---|---|---|
| Audio local and streaming playback (internal speakers) during screen off | Idle to Standby | Yes | Yes | |
| Audio local and streaming playback (internal speakers) during screen off | Explicit entry to Standby (Power button press, closing the lid or through Start menu) | No | No | |
| Audio local and streaming playback (Bluetooth speakers) during screen off | Idle to Standby | Yes | Yes | Low Power Audio is not currently supported for Bluetooth speakers, so audio will play during Modern Standby but not be low power. |
| Audio local and streaming playback (Bluetooth speakers) during screen off | Explicit entry to Standby (Power button press, closing the lid or through Start menu) | No | No | Low Power Audio is not currently supported for Bluetooth speakers, so audio will play during Modern Standby but not be low power. |
Environmental Context Changes
| Event | Remarks |
|---|---|
| Thermal event | All temperature sensors must wake the SoC from the deepest power state to indicate temperature change. ACPI firmware should monitor thermal zone temperature changes continuously during standby and when the SoC is in the deepest idle state. The ACPI firmware should report to the Windows thermal manager when the temperature rises above the trip points. |
| Battery charge completion | |
| Battery threshold change | The battery subsystem must wake the SoC from its deepest idle state anytime the remaining capacity goes below the value specified by Windows in the _BTP control method. The battery subsystem must wake the SoC from its deepest idle state anytime the remaining capacity goes below the value specified by DesignCapacityOfLow in the_BIX control method. Windows will hibernate (x86) or shut down (Arm) the system when the remaining capacity falls below DesignCapacityOfLow. |
| Unplugging from a power source | The GPIO interrupt for power source changes must cause the ACPI _PSR method under the power supply device to be executed. The power subsystem must wake the SoC any time the power source changes, including when the system is attached or removed from a dock that has a battery or AC power source. |