Further fixes from Kai Morich's fork. Many thanks for your work Kai!

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/FtdiSerialDriver.java

@@ -36,6 +36,7 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import android.os.Build;
 
 /**
  * A {@link CommonUsbSerialPort} implementation for a variety of FTDI devices
@@ -152,8 +153,6 @@ public UsbDevice getDevice() {
          * Set flow control register.
          */
         private static final int SIO_SET_FLOW_CTRL_REQUEST = 2;
-        private static final int SIO_SET_FLOW_CTRL_REQUEST_TYPE = 0x40;
-        private static final int SIO_DISABLE_FLOW_CTRL = 0;
 
         /**
          * Set baud rate.
@@ -194,10 +193,11 @@ public UsbDevice getDevice() {
          * since it gives no indication of number of bytes read. Set this to
          * {@code true} on platforms where it is fixed.
          */
-        private static final boolean ENABLE_ASYNC_READS = false;
+        private final boolean mEnableAsyncReads;
 
         public FtdiSerialPort(UsbDevice device, int portNumber) {
             super(device, portNumber);
+            mEnableAsyncReads = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1);
         }
 
         @Override
@@ -296,33 +296,29 @@ public void close() throws IOException {
         public int sread(byte[] dest, int size, int timeoutMillis) throws IOException {
             final UsbEndpoint endpoint = mDevice.getInterface(0).getEndpoint(0);
 
-            if (ENABLE_ASYNC_READS) {
-                final int readAmt;
-                synchronized (mReadBufferLock) {
-                    // mReadBuffer is only used for maximum read size.
-                    readAmt = Math.min(size, mReadBuffer.length);
-                }
-
+            if (mEnableAsyncReads) {
                 final UsbRequest request = new UsbRequest();
-                request.initialize(mConnection, endpoint);
-
                 final ByteBuffer buf = ByteBuffer.wrap(dest);
-                if (!request.queue(buf, readAmt)) {
-                    throw new IOException("Error queueing request.");
-                }
+                try {
+                        request.initialize(mConnection, endpoint);
+                        if (!request.queue(buf, dest.length)) {
+                        throw new IOException("Error queueing request.");
+                    }
 
-                final UsbRequest response = mConnection.requestWait();
-                if (response == null) {
-                    throw new IOException("Null response");
+                        final UsbRequest response = mConnection.requestWait();
+                        if (response == null) {
+                            throw new IOException("Null response");
+                        }
+                } finally {
+                    request.close();
                 }
 
-                final int payloadBytesRead = buf.position() - MODEM_STATUS_HEADER_LENGTH;
-                if (payloadBytesRead > 0) {
-                    Log.d(TAG, HexDump.dumpHexString(dest, 0, Math.min(32, size)));
-                    return payloadBytesRead;
-                } else {
-                    return 0;
+                final int totalBytesRead = buf.position();
+                if (totalBytesRead < MODEM_STATUS_HEADER_LENGTH) {
+                    throw new IOException("Expected at least " + MODEM_STATUS_HEADER_LENGTH + " bytes");
                 }
+                return filterStatusBytes(dest, dest, totalBytesRead, endpoint.getMaxPacketSize());
+
             } else {
                 final int totalBytesRead;
 
@@ -452,14 +448,6 @@ public void setParameters(int baudRate, int dataBits, int stopBits, int parity)
             if (result != 0) {
                 throw new IOException("Setting parameters failed: result=" + result);
             }
-            //disable flow control, needed for FT231X
-            result = mConnection.controlTransfer(FTDI_DEVICE_OUT_REQTYPE,
-                    SIO_SET_FLOW_CTRL_REQUEST, SIO_DISABLE_FLOW_CTRL, 0 /* index */,
-                    null, 0, USB_WRITE_TIMEOUT_MILLIS);
-            if (result != 0) {
-                throw new IOException("Cannot disable flow control: result=" + result);
-            }
-
         }
 
         private long[] convertBaudrate(int baudrate) {

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbId.java

@@ -63,9 +63,6 @@
     public static final int SILABS_CP2108 = 0xea71;
     public static final int SILABS_CP2110 = 0xea80;
 
-    public static final int VENDOR_PROLIFIC = 0x067b;
-    public static final int PROLIFIC_PL2303 = 0x2303;
-
     private UsbId() {
         throw new IllegalAccessError("Non-instantiable class.");
     }

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/UsbSerialProber.java

@@ -48,7 +48,6 @@ public static UsbSerialProber getDefaultProber() {
     public static ProbeTable getDefaultProbeTable() {
         final ProbeTable probeTable = new ProbeTable();
         probeTable.addDriver(FtdiSerialDriver.class);
-        probeTable.addDriver(ProlificSerialDriver.class);
         return probeTable;
     }