| Previous | Next |
| kIOUSBTransactionTimeout | kIOUSBConfigNotFound |
kIOUSBPortWasSuspended
Power state interrupted the transaction
kIOUSBPortWasSuspended identifies a port-suspend transition as the reason an active transaction was returned. This is more specific than a generic timeout: the request was interrupted by USB power management on the path to the device. It does not by itself prove that the device detached, that its configuration was lost, or that the application may simply issue the same command again.
Suspension is a device and host-controller state transition. By the time an asynchronous callback runs, the device can have resumed, remained suspended, or changed state through removal and re-enumeration. The client must therefore revalidate the current device and interface lifecycle before deciding how to continue.
What to check
- Log the port path, device location, endpoint, pending operation, system power event, and whether the interface was still open when completion arrived.
- Check for removal, re-enumeration, or configuration changes before reusing handles and pipe references created before suspension.
- Handle the returned request as a separate completion; do not discard it merely because a resume notification is expected later.
- Use the device protocol to decide whether a resumed operation can continue, must restart, or needs a fresh discovery and open sequence.
References
- Apple: IOUSBFamily error codes
- Apple: working with USB device interfaces
- libusb Darwin backend: handling suspended USB devices
Looking for a different code? Search another status or error code.