CC2640R2F: No Write response with Android O

Hi Holly,

It looks like you're in the middle of streaming of voice at this time.

Sometimes it can be difficult to get the response enqueued while performing high throughput applications using the stack.

Is the customer's application processing blePending when receiving GATT messages? See a relevant code snippet from simple_peripheral.c::SimpleBLEPeripheral_processGATTMsg

  if (pMsg->hdr.status == blePending)
  {
    // No HCI buffer was available. Let's try to retransmit the response
    // on the next connection event.
    if (HCI_EXT_ConnEventNoticeCmd(pMsg->connHandle, selfEntity,
                                   SBP_HCI_CONN_EVT_END_EVT) == SUCCESS)
    {
      // First free any pending response
      SimpleBLEPeripheral_freeAttRsp(FAILURE);

      // Hold on to the response message for retransmission
      pAttRsp = pMsg;

      // Don't free the response message yet
      return (FALSE);
    }
  }

In summary, sometimes the GATT server cannot enqueue the message to be sent by the lower stack layers and in this case the stack will send a GATT message to the application where the application will have to store any messages with status blePending for further response in the stack.

If a blePending message is received, the application should stop streaming voice and attempt to resend the packet (you can copy the simple_peripheral application for reference. Once the message is sent successfully, the voice stream can be resumed. Synchronous ATT traffic should always be prioritized if possible over notifications.