[javax-usb-devel] Reading a magstripe; UsbPipe.syncSubmit never returns

[Mirza Garibovic]

Hello,

I have an MT-215 before me, the development machine runs Ubuntu
Desktop 7.04, and javax-usb is at version 1.0.1. As far as I've
understood from the technical doc[1], the device simply sends input
reports on the interrupt in pipe (and sending anything to it is
usually not necessary), and as far as I can see from usbview and from
traversing the device, there is only a single
configuration-interface-endpoint.

So away I go, find the device, force-claim the interface, open the
pipe, start a runnable (like the mouse driver example). The device LED
turns on and reacts correctly when I swipe a card, but
UsbPipe.syncSubmit never returns. I've tried various methods:
submitting an Irp, submitting a byte[], attaching a PipeListener, and
attaching a DeviceListener. I never get anything from the device.

I figure I must be doing something wrong or not reading it correctly.
What ways are there to get data from a device? I've attached some
relevant code in case anyone wants details.

Mirza

[1] page 19, <http://www.magtek.com/docs/99875205.pdf>

package pressrec;
import javax.usb.*;
import javax.usb.event.UsbDeviceDataEvent;
import javax.usb.event.UsbDeviceErrorEvent;
import javax.usb.event.UsbDeviceEvent;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

class ForceClaimUsbInterfacePolicy implements javax.usb.UsbInterfacePolicy{
	public boolean forceClaim(UsbInterface arg0) {
		return true;
	}
}

public class Application {
	public static void main(String argv[]) throws UsbNotActiveException, UsbNotClaimedException, UsbDisconnectedException, UsbException, InterruptedException, SecurityException, IOException{
		System.out.println("Looking for device..");
		List devices = findDevices(MT215.idVendor, MT215.idProduct);

		if(devices.size() == 0){
			System.out.println("Couldn't find device with matching vendor and product id!");
			return;
		}
		
		UsbDevice device = (UsbDevice) devices.get(0);
		UsbInterface iface = (UsbInterface) device.getActiveUsbConfiguration().getUsbInterfaces().get(0);

		iface.claim(new ForceClaimUsbInterfacePolicy());

		UsbPipe pipe = ((UsbEndpoint) iface.getUsbEndpoints().get(0)).getUsbPipe();
		pipe.open();
		
		MT215Runnable runner = new MT215Runnable(pipe);
		Thread t = new Thread(runner);
		
		System.out.println("Driving MT215 reader, swipe away.");
		System.out.println("Press Enter when done.");
		
		t.start();
		
		System.in.read();
		
		runner.stop();
		
		pipe.close();
		iface.release();
		
		System.out.println("Done!");
	}
	
	/*
	 * Get a List of all devices that match the specified vendor and
	 * product id.
	 * 
	 * @param vendorId  The vendor id to match.
	 * @param productId The product id to match.
	 */
	public static List findDevices(short vendorId, short productId) throws SecurityException, UsbException, UnsupportedEncodingException, UsbDisconnectedException{
		return findDevices(vendorId, productId, null);
	}

	/*
	 * Get a List of all devices that match the specified vendor and
	 * product id.  Call like findDevices(vendor, product) to start
	 * from the root hub.
	 * 
	 * @param vendorId  The vendor id to match.
	 * @param productId The product id to match.
	 * @param usbDevice The UsbDevice to start looking from.
	 */
	public static List findDevices(short vendorId, short productId, UsbDevice usbDevice) throws SecurityException, UsbException, UnsupportedEncodingException, UsbDisconnectedException
	{
		if(usbDevice == null)
			usbDevice = UsbHostManager.getUsbServices().getRootUsbHub();
		
		List list = new ArrayList();

		if (vendorId == usbDevice.getUsbDeviceDescriptor().idVendor()
				&& productId == usbDevice.getUsbDeviceDescriptor().idProduct())
			list.add(usbDevice);
		
		if (usbDevice.isUsbHub()) {
			List devices = ((UsbHub) usbDevice).getAttachedUsbDevices();
			for (int i = 0; i < devices.size(); i++)
				list.addAll(findDevices(vendorId, productId,
						(UsbDevice) devices.get(i)));
		}

		return list;
	}

}

package pressrec;

import javax.usb.*;
import javax.usb.util.*;

public class MT215Runnable implements Runnable {
	UsbPipe pipe = null;
	boolean running = true;
	
	MT215Runnable(UsbPipe pipe){
		this.pipe = pipe;
	}
	
	public void run() {
		byte[] buffer = new byte[338];
		
		UsbIrp irp = pipe.createUsbIrp( );
		irp.setData(buffer);
		
		System.out.println("Running listener..");
		while(running){
			System.out.println(">>>");
			try{
				pipe.syncSubmit(irp);
			}
			catch(UsbException uex){
				// abortAllSubmissions after-effect
			}
			
			for (int i = 0; i < irp.getActualLength(); i++)
				System.out.print(" 0x" + UsbUtil.toHexString(irp.getData()[i]));
			
			System.out.println("");
		}
	}
	
	public void stop()
	{
		running = false;
		pipe.abortAllSubmissions();
	}
}
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