Manually test suspend/resume on Workbench

This guide provides instructions on how to manually test suspend and resume on a device running a suitable Workbench image.

Perform manual suspend and resume

With serial

  1. Connect to the device via USB.

  2. Take an Application Activity lease via ffx power's helper component:

    ffx power system-activity application-activity start

  3. Drop the session wake lease:

    ffx session drop-power-lease

  4. Disconnect USB to eliminate the persistent wake lease caused by the USB or charger connection.

  5. Using serial, drop the Application Activity lease and reacquire it after a delay:

    powerutil system-activity application-activity restart --wait-time 5s

    This will allow the system to suspend as long as no other wake leases are active.

  6. Wait until serial logs show evidence of system suspension. Logs are not necessarily flushed prior to suspension, so you may see them abruptly stop.

  7. Reconnect USB or take another suitable action (touch, button press, etc.) to resume the device. If --wait-time has elapsed, the helper component will reacquire an Application Activity lease and prevent further suspension on its own.

Without serial

  1. Connect to the device via USB.

  2. Take an Application Activity lease via ffx power's helper component:

    ffx power system-activity application-activity start

  3. Drop the session wake lease:

    ffx session drop-power-lease

  4. Drop the Application Activity lease and reacquire it after a delay:

    ffx power system-activity application-activity restart --wait-time 5s

  5. Disconnect USB to eliminate the persistent wake lease caused by the USB or charger connection.

  6. Wait for several seconds. Without a serial connection, you will not be able to confirm whether suspension has occurred until you replug the device.

  7. Reconnect USB.

  8. Use ffx log to look for evidence of suspension. There isn't a canonical message to indicate this, but at time of writing, the kernel message INFO: Suspending non-boot CPUs... is a good indicator.

Troubleshooting

Check wake leases

Any active wake leases prevent the system from suspending. To check active wake leases:

Serial

inspect show bootstrap/system-activity-governor:root/wake_leases

USB

ffx inspect show bootstrap/system-activity-governor:root/wake_leases

Increase delay before wake lease reacquisition

To give the system longer to suspend, increase the delay using the --wait-time option:

powerutil system-activity application-activity restart --wait-time 10s