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

Connect to the device via USB.
Take an Application Activity lease via ffx power's helper component:
```
ffx power suspend prevent
```
Drop the session wake lease:
```
ffx session drop-power-lease
```
Disconnect USB to eliminate the persistent wake lease caused by the USB or charger connection.

Either physically unplug the USB cable, or, if the device supports cable-breaker, disconnect USB in software and schedule an automatic reconnect over serial:
```
usb-cli cable-breaker --duration 15s
```
Ensure --duration is long enough to run the next command and allow the device to suspend before USB automatically reconnects.
Using serial, drop the Application Activity lease and reacquire it after a delay:
```
powerutil suspend prevent --restart --wait-time 5s
```
This will allow the system to suspend as long as no other wake leases are active.
Wait until serial logs show evidence of system suspension. Logs are not necessarily flushed prior to suspension, so you may see them abruptly stop.
Reconnect USB (or wait for the cable-breaker --duration timer to expire and automatically 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

Connect to the device via USB.
Take an Application Activity lease via ffx power's helper component:
```
ffx power suspend prevent
```
Drop the session wake lease:
```
ffx session drop-power-lease
```
Drop the Application Activity lease (reacquiring it after a delay) and disconnect USB to eliminate the persistent wake lease caused by the USB or charger connection:
- Physical unplug: Run the following command and unplug the USB cable before --wait-time elapses:
```
ffx power suspend prevent --restart --wait-time 5s
```
- Using cable-breaker: Because ffx power suspend prevent --restart blocks until --wait-time elapses, run it in the background and immediately invoke cable-breaker with a --duration longer than --wait-time:
```
ffx power suspend prevent --restart --wait-time 5s &
ffx component explore /core/usb-policy -c "usb-cli cable-breaker --duration 15s"
```
  Note: Both ffx commands will lose their connection once cable-breaker disconnects USB (ffx component explore may hang until interrupted with Ctrl+C). This is expected; both timers continue running on the device.
Wait for several seconds. Without a serial connection, you will not be able to confirm whether suspension has occurred until USB is reconnected.
Reconnect USB (or wait for the cable-breaker --duration timer to expire and automatically reconnect USB).
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. You can also check suspend_stats via Inspect:
```
ffx inspect show bootstrap/system-activity-governor:root/suspend_stats
```

Troubleshooting

Check `cable-breaker` support

To check whether your device supports software USB disconnect via usb-cli cable-breaker, verify that /core/usb-policy exposes fuchsia.usb.policy.Configuration:

ffx component capability fuchsia.usb.policy.Configuration

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 suspend prevent --restart --wait-time 10s