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Commit 6cd937c4 authored by Robert Wu's avatar Robert Wu
Browse files

USB MIDI: Use Thread.interrupt() to close threads 

We start input threads before setting mIsOpen.
This means that sometimes, input threads immediately exit
due to a race condition.

The fix here is to remove the use of mIsOpen and use a new
mechanism with Thread.interrupt() and Thread.interrupted()
to mark a thread to be closed.

Bug: 223316278
Test: MidiScope/MidiKeyboard
Test: CTS Verifier Bluetooth Tests
Change-Id: I7c221504ae8a8814c1aa5598552494c80c202eb2
parent 96ad5cca

services/usb/java/com/android/server/usb/UsbDirectMidiDevice.java

+48 −12
Original line number Diff line number Diff line
@@ -80,9 +80,13 @@ public final class UsbDirectMidiDevice implements Closeable { 
    // of cycles and not being permanently stuck.

    private static final int BULK_TRANSFER_TIMEOUT_MILLISECONDS = 10;



    // Arbitrary number for timeout when closing a thread

    private static final int THREAD_JOIN_TIMEOUT_MILLISECONDS = 50;



    private ArrayList<UsbDeviceConnection> mUsbDeviceConnections;

    private ArrayList<ArrayList<UsbEndpoint>> mInputUsbEndpoints;

    private ArrayList<ArrayList<UsbEndpoint>> mOutputUsbEndpoints;

    private ArrayList<Thread> mThreads;



    private UsbMidiBlockParser mMidiBlockParser = new UsbMidiBlockParser();

    private int mDefaultMidiProtocol = MidiDeviceInfo.PROTOCOL_UMP_MIDI_1_0_UP_TO_64_BITS;
@@ -273,9 +277,10 @@ public final class UsbDirectMidiDevice implements Closeable { 
        // to USB MIDI for each USB output.

        mUsbMidiPacketConverter = new UsbMidiPacketConverter(mNumOutputs);



        mUsbDeviceConnections = new ArrayList<UsbDeviceConnection>(mUsbInterfaces.size());

        mInputUsbEndpoints = new ArrayList<ArrayList<UsbEndpoint>>(mUsbInterfaces.size());

        mOutputUsbEndpoints = new ArrayList<ArrayList<UsbEndpoint>>(mUsbInterfaces.size());

        mUsbDeviceConnections = new ArrayList<UsbDeviceConnection>();

        mInputUsbEndpoints = new ArrayList<ArrayList<UsbEndpoint>>();

        mOutputUsbEndpoints = new ArrayList<ArrayList<UsbEndpoint>>();

        mThreads = new ArrayList<Thread>();



        for (int interfaceIndex = 0; interfaceIndex < mUsbInterfaces.size(); interfaceIndex++) {

            ArrayList<UsbEndpoint> inputEndpoints = new ArrayList<UsbEndpoint>();
@@ -327,7 +332,7 @@ public final class UsbDirectMidiDevice implements Closeable { 
                        mInputUsbEndpoints.get(connectionIndex).get(endpointIndex);

                final int portFinal = portNumber;



                new Thread("UsbDirectMidiDevice input thread " + portFinal) {

                Thread newThread = new Thread("UsbDirectMidiDevice input thread " + portFinal) {

                    @Override

                    public void run() {

                        final UsbRequest request = new UsbRequest();
@@ -335,9 +340,12 @@ public final class UsbDirectMidiDevice implements Closeable { 
                            request.initialize(connectionFinal, endpointFinal);

                            byte[] inputBuffer = new byte[endpointFinal.getMaxPacketSize()];

                            while (true) {

                                if (Thread.currentThread().interrupted()) {

                                    Log.w(TAG, "input thread interrupted");

                                    break;

                                }

                                // Record time of event immediately after waking.

                                long timestamp = System.nanoTime();

                                if (!mIsOpen) break;

                                final ByteBuffer byteBuffer = ByteBuffer.wrap(inputBuffer);

                                if (!request.queue(byteBuffer)) {

                                    Log.w(TAG, "Cannot queue request");
@@ -382,8 +390,9 @@ public final class UsbDirectMidiDevice implements Closeable { 
                        }

                        Log.d(TAG, "input thread exit");

                    }

                }.start();



                };

                newThread.start();

                mThreads.add(newThread);

                portNumber++;

            }

        }
@@ -402,18 +411,23 @@ public final class UsbDirectMidiDevice implements Closeable { 
                final int portFinal = portNumber;

                final MidiEventScheduler eventSchedulerFinal = mEventSchedulers[portFinal];



                new Thread("UsbDirectMidiDevice output thread " + portFinal) {

                Thread newThread = new Thread("UsbDirectMidiDevice output thread " + portFinal) {

                    @Override

                    public void run() {

                        while (true) {

                            if (Thread.currentThread().interrupted()) {

                                Log.w(TAG, "output thread interrupted");

                                break;

                            }

                            MidiEvent event;

                            try {

                                event = (MidiEvent) eventSchedulerFinal.waitNextEvent();

                            } catch (InterruptedException e) {

                                // try again

                                continue;

                                Log.w(TAG, "event scheduler interrupted");

                                break;

                            }

                            if (event == null) {

                                Log.w(TAG, "event is null");

                                break;

                            }
@@ -446,8 +460,9 @@ public final class UsbDirectMidiDevice implements Closeable { 
                        }

                        Log.d(TAG, "output thread exit");

                    }

                }.start();



                };

                newThread.start();

                mThreads.add(newThread);

                portNumber++;

            }

        }
@@ -523,6 +538,27 @@ public final class UsbDirectMidiDevice implements Closeable { 


    private void closeLocked() {

        Log.d(TAG, "closeLocked()");



        // Send an interrupt signal to threads.

        for (Thread thread : mThreads) {

            if (thread != null) {

                thread.interrupt();

            }

        }



        // Wait for threads to actually stop.

        for (Thread thread : mThreads) {

            if (thread != null) {

                try {

                    thread.join(THREAD_JOIN_TIMEOUT_MILLISECONDS);

                } catch (InterruptedException e) {

                    Log.w(TAG, "thread join interrupted");

                    break;

                }

            }

        }

        mThreads = null;



        for (int i = 0; i < mEventSchedulers.length; i++) {

            mMidiInputPortReceivers[i].setReceiver(null);

            mEventSchedulers[i].close();