IOUSBHostPipe - Unable to enqueue… | Apple Developer Forums

IOUSBHostPipe - Unable to enqueue IO

Hi. I'm hitting an error when attempting to enqueue IO on a IOUSBHostPipe.

The error info is:
code=268435459, description=<Unable to enqueue IO.>

I'm not sure what that error means or how to address it.

I'm trying to communicate through a USB Bluetooth dongle. I've done the following:

Instantiated a device using IOUSBHostDevice with a service specifying the USB Dongle.
I've set the configuration (there's only one) as the active configuration.
I've claimed all four interfaces for the active configuration.
I've cycled through the endpoints for each interface and used copyPipeWithAddress:error: to copy the pipe.
I've stored those pipes in a dictionary keyed by the endpoint address.

I'm hitting the error when attempting to read from the pipe as such:

Code Block [pipe enqueueIORequestWithData:data completionTimeout:0.0 error:&error completionHandler:^(IOReturn status, NSUInteger bytesTransferred) {
    NSLog(@"<submit_bulk_transfer> Read completed, status=%d, bytes transfered=%lu", status, bytesTransferred);
   }]

Code Block
[pipe enqueueIORequestWithData:data completionTimeout:0.0 error:&error completionHandler:^(IOReturn status, NSUInteger bytesTransferred) {
NSLog(@"<submit_bulk_transfer> Read completed, status=%d, bytes transfered=%lu", status, bytesTransferred);
}]

Any guidance on how to address this issue? Thanks.