PulseAudio: make plugin more robust.

Handle more thoroughly error cases, such as when the PulseAudio daemon
does not respond or terminates while QAudioInput/QAudioOutput is
active, in which cases it used to crash or hang.

We now correctly emit the error signal and change the state when errors
occur.

Task-number: QTBUG-29742
Change-Id: I173d35aece60d96e578785e1522cf78b24dcb8b8
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

6 files changed, 347 insertions, 253 deletions

diff --git a/src/plugins/pulseaudio/qaudioinput_pulse.cpp b/src/plugins/pulseaudio/qaudioinput_pulse.cpp
index 83075beda..89dc08612 100644
--- a/src/plugins/pulseaudio/qaudioinput_pulse.cpp
+++ b/src/plugins/pulseaudio/qaudioinput_pulse.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Toolkit.
@@ -54,10 +54,6 @@ QT_BEGIN_NAMESPACE
 
 const int PeriodTimeMs = 50;
 
-// Map from void* (for userdata) to QPulseAudioInput instance
-// protected by pulse mainloop lock
-QMap<void *, QPulseAudioInput*> QPulseAudioInput::s_inputsMap;
-
 static void inputStreamReadCallback(pa_stream *stream, size_t length, void *userdata)
 {
     Q_UNUSED(userdata);
@@ -136,8 +132,8 @@ void QPulseAudioInput::sourceInfoCallback(pa_context *context, const pa_source_i
     Q_UNUSED(eol);
 
     Q_ASSERT(userdata);
-    QPulseAudioInput *that = QPulseAudioInput::s_inputsMap.value(userdata);
-    if (that && i) {
+    if (i) {
+        QPulseAudioInput *that = reinterpret_cast<QPulseAudioInput*>(userdata);
         that->m_volume = pa_sw_volume_to_linear(pa_cvolume_avg(&i->volume));
     }
 }
@@ -149,12 +145,11 @@ void QPulseAudioInput::inputVolumeCallback(pa_context *context, int success, voi
     if (!success)
         qWarning() << "QAudioInput: failed to set input volume";
 
-    QPulseAudioInput *that = QPulseAudioInput::s_inputsMap.value(userdata);
+    QPulseAudioInput *that = reinterpret_cast<QPulseAudioInput*>(userdata);
 
     // Regardless of success or failure, we update the volume property
-    if (that && that->m_stream) {
+    if (that->m_stream)
         pa_context_get_source_info_by_index(context, pa_stream_get_device_index(that->m_stream), sourceInfoCallback, userdata);
-    }
 }
 
 QPulseAudioInput::QPulseAudioInput(const QByteArray &device)
@@ -175,31 +170,39 @@ QPulseAudioInput::QPulseAudioInput(const QByteArray &device)
 {
     m_timer = new QTimer(this);
     connect(m_timer, SIGNAL(timeout()), SLOT(userFeed()));
-
-    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
-    s_inputsMap.insert(this, this);
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
 }
 
 QPulseAudioInput::~QPulseAudioInput()
 {
-    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
-    s_inputsMap.remove(this);
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
-
     close();
     disconnect(m_timer, SIGNAL(timeout()));
     QCoreApplication::processEvents();
     delete m_timer;
 }
 
+void QPulseAudioInput::setError(QAudio::Error error)
+{
+    if (m_errorState == error)
+        return;
+
+    m_errorState = error;
+    emit errorChanged(error);
+}
+
 QAudio::Error QPulseAudioInput::error() const
 {
     return m_errorState;
 }
 
+void QPulseAudioInput::setState(QAudio::State state)
+{
+    if (m_deviceState == state)
+        return;
+
+    m_deviceState = state;
+    emit stateChanged(state);
+}
+
 QAudio::State QPulseAudioInput::state() const
 {
     return m_deviceState;
@@ -218,41 +221,45 @@ QAudioFormat QPulseAudioInput::format() const
 
 void QPulseAudioInput::start(QIODevice *device)
 {
-    if (m_deviceState != QAudio::StoppedState)
-        close();
+    setState(QAudio::StoppedState);
+    setError(QAudio::NoError);
 
-    if (!m_pullMode && m_audioSource)
+    if (!m_pullMode && m_audioSource) {
         delete m_audioSource;
+        m_audioSource = 0;
+    }
 
-    m_pullMode = true;
-    m_audioSource = device;
-
-    m_deviceState = QAudio::ActiveState;
+    close();
 
     if (!open())
         return;
 
-    emit stateChanged(m_deviceState);
+    m_pullMode = true;
+    m_audioSource = device;
+
+    setState(QAudio::ActiveState);
 }
 
 QIODevice *QPulseAudioInput::start()
 {
-    if (m_deviceState != QAudio::StoppedState)
-        close();
+    setState(QAudio::StoppedState);
+    setError(QAudio::NoError);
 
-    if (!m_pullMode && m_audioSource)
+    if (!m_pullMode && m_audioSource) {
         delete m_audioSource;
+        m_audioSource = 0;
+    }
+
+    close();
+
+    if (!open())
+        return Q_NULLPTR;
 
     m_pullMode = false;
     m_audioSource = new InputPrivate(this);
     m_audioSource->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
 
-    m_deviceState = QAudio::IdleState;
-
-    if (!open())
-        return 0;
-
-    emit stateChanged(m_deviceState);
+    setState(QAudio::IdleState);
 
     return m_audioSource;
 }
@@ -262,56 +269,57 @@ void QPulseAudioInput::stop()
     if (m_deviceState == QAudio::StoppedState)
         return;
 
-    m_errorState = QAudio::NoError;
-    m_deviceState = QAudio::StoppedState;
-
     close();
-    emit stateChanged(m_deviceState);
+
+    setError(QAudio::NoError);
+    setState(QAudio::StoppedState);
 }
 
 bool QPulseAudioInput::open()
 {
     if (m_opened)
-        return false;
+        return true;
 
-#ifdef DEBUG_PULSE
-//    QTime now(QTime::currentTime());
-//    qDebug()<<now.second()<<"s "<<now.msec()<<"ms :open()";
-#endif
-    m_clockStamp.restart();
-    m_timeStamp.restart();
-    m_elapsedTimeOffset = 0;
+    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
 
-    if (m_streamName.isNull())
-        m_streamName = QString(QLatin1String("QtmPulseStream-%1-%2")).arg(::getpid()).arg(quintptr(this)).toUtf8();
+    if (!pulseEngine->context() || pa_context_get_state(pulseEngine->context()) != PA_CONTEXT_READY) {
+        setError(QAudio::FatalError);
+        setState(QAudio::StoppedState);
+        return false;
+    }
 
     pa_sample_spec spec = QPulseAudioInternal::audioFormatToSampleSpec(m_format);
 
     if (!pa_sample_spec_valid(&spec)) {
-        m_errorState = QAudio::OpenError;
-        m_deviceState = QAudio::StoppedState;
-        emit stateChanged(m_deviceState);
+        setError(QAudio::OpenError);
+        setState(QAudio::StoppedState);
         return false;
     }
 
     m_spec = spec;
 
 #ifdef DEBUG_PULSE
+//    QTime now(QTime::currentTime());
+//    qDebug()<<now.second()<<"s "<<now.msec()<<"ms :open()";
+#endif
+
+    if (m_streamName.isNull())
+        m_streamName = QString(QLatin1String("QtmPulseStream-%1-%2")).arg(::getpid()).arg(quintptr(this)).toUtf8();
+
+#ifdef DEBUG_PULSE
         qDebug() << "Format: " << QPulseAudioInternal::sampleFormatToQString(spec.format);
         qDebug() << "Rate: " << spec.rate;
         qDebug() << "Channels: " << spec.channels;
         qDebug() << "Frame size: " << pa_frame_size(&spec);
 #endif
 
-    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
+    pulseEngine->lock();
     pa_channel_map channel_map;
 
     pa_channel_map_init_extend(&channel_map, spec.channels, PA_CHANNEL_MAP_DEFAULT);
 
-    if (!pa_channel_map_compatible(&channel_map, &spec)) {
+    if (!pa_channel_map_compatible(&channel_map, &spec))
         qWarning() << "Channel map doesn't match sample specification!";
-    }
 
     m_stream = pa_stream_new(pulseEngine->context(), m_streamName.constData(), &spec, &channel_map);
 
@@ -338,13 +346,16 @@ bool QPulseAudioInput::open()
 
     if (pa_stream_connect_record(m_stream, m_device.data(), &buffer_attr, (pa_stream_flags_t)flags) < 0) {
         qWarning() << "pa_stream_connect_record() failed!";
-        m_errorState = QAudio::FatalError;
+        pa_stream_unref(m_stream);
+        m_stream = 0;
+        pulseEngine->unlock();
+        setError(QAudio::OpenError);
+        setState(QAudio::StoppedState);
         return false;
     }
 
-    while (pa_stream_get_state(m_stream) != PA_STREAM_READY) {
+    while (pa_stream_get_state(m_stream) != PA_STREAM_READY)
         pa_threaded_mainloop_wait(pulseEngine->mainloop());
-    }
 
     const pa_buffer_attr *actualBufferAttr = pa_stream_get_buffer_attr(m_stream);
     m_periodSize = actualBufferAttr->fragsize;
@@ -354,12 +365,16 @@ bool QPulseAudioInput::open()
 
     setPulseVolume();
 
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+    pulseEngine->unlock();
+
+    connect(pulseEngine, &QPulseAudioEngine::contextFailed, this, &QPulseAudioInput::onPulseContextFailed);
 
     m_opened = true;
     m_timer->start(m_periodTime);
-    m_errorState = QAudio::NoError;
 
+    m_clockStamp.restart();
+    m_timeStamp.restart();
+    m_elapsedTimeOffset = 0;
     m_totalTimeValue = 0;
 
     return true;
@@ -367,21 +382,30 @@ bool QPulseAudioInput::open()
 
 void QPulseAudioInput::close()
 {
+    if (!m_opened)
+        return;
+
     m_timer->stop();
 
+    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
+
     if (m_stream) {
-        QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
 
+        pa_stream_set_state_callback(m_stream, 0, 0);
         pa_stream_set_read_callback(m_stream, 0, 0);
+        pa_stream_set_underflow_callback(m_stream, 0, 0);
+        pa_stream_set_overflow_callback(m_stream, 0, 0);
 
         pa_stream_disconnect(m_stream);
         pa_stream_unref(m_stream);
         m_stream = 0;
 
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
     }
 
+    disconnect(pulseEngine, &QPulseAudioEngine::contextFailed, this, &QPulseAudioInput::onPulseContextFailed);
+
     if (!m_pullMode && m_audioSource) {
         delete m_audioSource;
         m_audioSource = 0;
@@ -393,6 +417,7 @@ void QPulseAudioInput::close()
 void QPulseAudioInput::setPulseVolume()
 {
     QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
+    Q_ASSERT(pulseEngine->context() != 0);
 
     pa_cvolume cvolume;
 
@@ -434,11 +459,8 @@ qint64 QPulseAudioInput::read(char *data, qint64 len)
 {
     m_bytesAvailable = checkBytesReady();
 
-    if (m_deviceState != QAudio::ActiveState) {
-        m_errorState = QAudio::NoError;
-        m_deviceState = QAudio::ActiveState;
-        emit stateChanged(m_deviceState);
-    }
+    setError(QAudio::NoError);
+    setState(QAudio::ActiveState);
 
     int readBytes = 0;
 
@@ -463,7 +485,8 @@ qint64 QPulseAudioInput::read(char *data, qint64 len)
 #endif
 
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
+
         const void *audioBuffer;
 
         // Second and third parameters (audioBuffer and length) to pa_stream_peek are output parameters,
@@ -471,7 +494,7 @@ qint64 QPulseAudioInput::read(char *data, qint64 len)
         // and the length is set to the length of this data.
         if (pa_stream_peek(m_stream, &audioBuffer, &readLength) < 0) {
             qWarning() << QString("pa_stream_peek() failed: %1").arg(pa_strerror(pa_context_errno(pa_stream_get_context(m_stream))));
-            pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+            pulseEngine->unlock();
             return 0;
         }
 
@@ -480,11 +503,10 @@ qint64 QPulseAudioInput::read(char *data, qint64 len)
             actualLength = m_audioSource->write(static_cast<const char *>(audioBuffer), readLength);
 
             if (actualLength < qint64(readLength)) {
-                pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+                pulseEngine->unlock();
 
-                m_errorState = QAudio::UnderrunError;
-                m_deviceState = QAudio::IdleState;
-                emit stateChanged(m_deviceState);
+                setError(QAudio::UnderrunError);
+                setState(QAudio::IdleState);
 
                 return actualLength;
             }
@@ -509,7 +531,7 @@ qint64 QPulseAudioInput::read(char *data, qint64 len)
         readBytes += actualLength;
 
         pa_stream_drop(m_stream);
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
 
         if (!m_pullMode && readBytes >= len)
             break;
@@ -534,22 +556,18 @@ void QPulseAudioInput::resume()
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
         pa_operation *operation;
 
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
 
         operation = pa_stream_cork(m_stream, 0, inputStreamSuccessCallback, 0);
-
-        while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
-            pa_threaded_mainloop_wait(pulseEngine->mainloop());
-
+        pulseEngine->wait(operation);
         pa_operation_unref(operation);
 
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
 
         m_timer->start(m_periodTime);
 
-        m_deviceState = QAudio::ActiveState;
-
-        emit stateChanged(m_deviceState);
+        setState(QAudio::ActiveState);
+        setError(QAudio::NoError);
     }
 }
 
@@ -557,23 +575,23 @@ void QPulseAudioInput::setVolume(qreal vol)
 {
     if (vol >= 0.0 && vol <= 1.0) {
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
         if (!qFuzzyCompare(m_volume, vol)) {
             m_volume = vol;
             if (m_opened) {
                 setPulseVolume();
             }
         }
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
     }
 }
 
 qreal QPulseAudioInput::volume() const
 {
     QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
+    pulseEngine->lock();
     qreal vol = m_volume;
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+    pulseEngine->unlock();
     return vol;
 }
 
@@ -614,23 +632,21 @@ qint64 QPulseAudioInput::processedUSecs() const
 void QPulseAudioInput::suspend()
 {
     if (m_deviceState == QAudio::ActiveState) {
+        setError(QAudio::NoError);
+        setState(QAudio::SuspendedState);
+
         m_timer->stop();
-        m_deviceState = QAudio::SuspendedState;
-        emit stateChanged(m_deviceState);
 
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
         pa_operation *operation;
 
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
 
         operation = pa_stream_cork(m_stream, 1, inputStreamSuccessCallback, 0);
-
-        while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
-            pa_threaded_mainloop_wait(pulseEngine->mainloop());
-
+        pulseEngine->wait(operation);
         pa_operation_unref(operation);
 
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
     }
 }
 
@@ -685,6 +701,14 @@ void QPulseAudioInput::reset()
     m_bytesAvailable = 0;
 }
 
+void QPulseAudioInput::onPulseContextFailed()
+{
+    close();
+
+    setError(QAudio::FatalError);
+    setState(QAudio::StoppedState);
+}
+
 InputPrivate::InputPrivate(QPulseAudioInput *audio)
 {
     m_audioDevice = qobject_cast<QPulseAudioInput*>(audio);
diff --git a/src/plugins/pulseaudio/qaudioinput_pulse.h b/src/plugins/pulseaudio/qaudioinput_pulse.h
index bb72628f8..e2c46c8e6 100644
--- a/src/plugins/pulseaudio/qaudioinput_pulse.h
+++ b/src/plugins/pulseaudio/qaudioinput_pulse.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Toolkit.
@@ -112,8 +112,12 @@ public:
 private slots:
     void userFeed();
     bool deviceReady();
+    void onPulseContextFailed();
 
 private:
+    void setState(QAudio::State state);
+    void setError(QAudio::Error error);
+
     int checkBytesReady();
     bool open();
     void close();
diff --git a/src/plugins/pulseaudio/qaudiooutput_pulse.cpp b/src/plugins/pulseaudio/qaudiooutput_pulse.cpp
index 2b482ba40..64a080663 100644
--- a/src/plugins/pulseaudio/qaudiooutput_pulse.cpp
+++ b/src/plugins/pulseaudio/qaudiooutput_pulse.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Toolkit.
@@ -170,11 +170,29 @@ QPulseAudioOutput::~QPulseAudioOutput()
     QCoreApplication::processEvents();
 }
 
+void QPulseAudioOutput::setError(QAudio::Error error)
+{
+    if (m_errorState == error)
+        return;
+
+    m_errorState = error;
+    emit errorChanged(error);
+}
+
 QAudio::Error QPulseAudioOutput::error() const
 {
     return m_errorState;
 }
 
+void QPulseAudioOutput::setState(QAudio::State state)
+{
+    if (m_deviceState == state)
+        return;
+
+    m_deviceState = state;
+    emit stateChanged(state);
+}
+
 QAudio::State QPulseAudioOutput::state() const
 {
     return m_deviceState;
@@ -183,19 +201,15 @@ QAudio::State QPulseAudioOutput::state() const
 void QPulseAudioOutput::streamUnderflowCallback()
 {
     if (m_deviceState != QAudio::IdleState && !m_resuming) {
-        m_errorState = QAudio::UnderrunError;
-        emit errorChanged(m_errorState);
-        m_deviceState = QAudio::IdleState;
-        emit stateChanged(m_deviceState);
+        setError(QAudio::UnderrunError);
+        setState(QAudio::IdleState);
     }
 }
 
 void QPulseAudioOutput::start(QIODevice *device)
 {
-    if (m_deviceState != QAudio::StoppedState)
-        m_deviceState = QAudio::StoppedState;
-
-    m_errorState = QAudio::NoError;
+    setState(QAudio::StoppedState);
+    setError(QAudio::NoError);
 
     // Handle change of mode
     if (m_audioSource && !m_pullMode) {
@@ -205,22 +219,19 @@ void QPulseAudioOutput::start(QIODevice *device)
 
     close();
 
+    if (!open())
+        return;
+
     m_pullMode = true;
     m_audioSource = device;
 
-    m_deviceState = QAudio::ActiveState;
-
-    open();
-
-    emit stateChanged(m_deviceState);
+    setState(QAudio::ActiveState);
 }
 
 QIODevice *QPulseAudioOutput::start()
 {
-    if (m_deviceState != QAudio::StoppedState)
-        m_deviceState = QAudio::StoppedState;
-
-    m_errorState = QAudio::NoError;
+    setState(QAudio::StoppedState);
+    setError(QAudio::NoError);
 
     // Handle change of mode
     if (m_audioSource && !m_pullMode) {
@@ -230,15 +241,14 @@ QIODevice *QPulseAudioOutput::start()
 
     close();
 
+    if (!open())
+        return Q_NULLPTR;
+
     m_audioSource = new OutputPrivate(this);
     m_audioSource->open(QIODevice::WriteOnly|QIODevice::Unbuffered);
     m_pullMode = false;
 
-    m_deviceState = QAudio::IdleState;
-
-    open();
-
-    emit stateChanged(m_deviceState);
+    setState(QAudio::IdleState);
 
     return m_audioSource;
 }
@@ -246,33 +256,38 @@ QIODevice *QPulseAudioOutput::start()
 bool QPulseAudioOutput::open()
 {
     if (m_opened)
+        return true;
+
+    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
+
+    if (!pulseEngine->context() || pa_context_get_state(pulseEngine->context()) != PA_CONTEXT_READY) {
+        setError(QAudio::FatalError);
+        setState(QAudio::StoppedState);
         return false;
+    }
 
     pa_sample_spec spec = QPulseAudioInternal::audioFormatToSampleSpec(m_format);
 
     if (!pa_sample_spec_valid(&spec)) {
-        m_errorState = QAudio::OpenError;
-        m_deviceState = QAudio::StoppedState;
+        setError(QAudio::OpenError);
+        setState(QAudio::StoppedState);
         return false;
     }
 
     m_spec = spec;
     m_totalTimeValue = 0;
-    m_elapsedTimeOffset = 0;
-    m_timeStamp.restart();
 
     if (m_streamName.isNull())
         m_streamName = QString(QLatin1String("QtmPulseStream-%1-%2")).arg(::getpid()).arg(quintptr(this)).toUtf8();
 
 #ifdef DEBUG_PULSE
-        qDebug() << "Format: " << QPulseAudioInternal::sampleFormatToQString(spec.format);
-        qDebug() << "Rate: " << spec.rate;
-        qDebug() << "Channels: " << spec.channels;
-        qDebug() << "Frame size: " << pa_frame_size(&spec);
+    qDebug() << "Format: " << QPulseAudioInternal::sampleFormatToQString(spec.format);
+    qDebug() << "Rate: " << spec.rate;
+    qDebug() << "Channels: " << spec.channels;
+    qDebug() << "Frame size: " << pa_frame_size(&spec);
 #endif
 
-    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
+    pulseEngine->lock();
 
     qint64 bytesPerSecond = m_format.sampleRate() * m_format.channelCount() * m_format.sampleSize() / 8;
 
@@ -280,7 +295,7 @@ bool QPulseAudioOutput::open()
     if (!m_category.isNull())
         pa_proplist_sets(propList, PA_PROP_MEDIA_ROLE, m_category.toLatin1().constData());
 
-    m_stream = pa_stream_new_with_proplist(pulseEngine->context(), m_streamName.constData(), &spec, 0, propList);
+    m_stream = pa_stream_new_with_proplist(pulseEngine->context(), m_streamName.constData(), &m_spec, 0, propList);
     pa_proplist_free(propList);
 
     pa_stream_set_state_callback(m_stream, outputStreamStateCallback, this);
@@ -312,15 +327,20 @@ bool QPulseAudioOutput::open()
 
     if (pa_stream_connect_playback(m_stream, m_device.data(), (m_bufferSize > 0) ? &requestedBuffer : NULL, (pa_stream_flags_t)0, &m_chVolume, NULL) < 0) {
         qWarning() << "pa_stream_connect_playback() failed!";
+        pa_stream_unref(m_stream);
+        m_stream = 0;
+        pulseEngine->unlock();
+        setError(QAudio::OpenError);
+        setState(QAudio::StoppedState);
         return false;
     }
 
-    while (pa_stream_get_state(m_stream) != PA_STREAM_READY) {
+    while (pa_stream_get_state(m_stream) != PA_STREAM_READY)
         pa_threaded_mainloop_wait(pulseEngine->mainloop());
-    }
+
     const pa_buffer_attr *buffer = pa_stream_get_buffer_attr(m_stream);
     m_periodTime = (m_category == LOW_LATENCY_CATEGORY_NAME) ? LowLatencyPeriodTimeMs : PeriodTimeMs;
-    m_periodSize = pa_usec_to_bytes(m_periodTime*1000, &spec);
+    m_periodSize = pa_usec_to_bytes(m_periodTime*1000, &m_spec);
     m_bufferSize = buffer->tlength;
     m_maxBufferSize = buffer->maxlength;
     m_audioBuffer = new char[m_maxBufferSize];
@@ -333,9 +353,12 @@ bool QPulseAudioOutput::open()
     qDebug() << "\tFragment size: " << buffer->fragsize;
 #endif
 
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+    pulseEngine->unlock();
+
+    connect(pulseEngine, &QPulseAudioEngine::contextFailed, this, &QPulseAudioOutput::onPulseContextFailed);
 
     m_opened = true;
+
     m_tickTimer->start(m_periodTime);
 
     m_elapsedTimeOffset = 0;
@@ -347,28 +370,35 @@ bool QPulseAudioOutput::open()
 
 void QPulseAudioOutput::close()
 {
+    if (!m_opened)
+        return;
+
     m_tickTimer->stop();
 
+    QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
+
     if (m_stream) {
-        QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
 
-        pa_stream_set_write_callback(m_stream, NULL, NULL);
+        pa_stream_set_state_callback(m_stream, 0, 0);
+        pa_stream_set_write_callback(m_stream, 0, 0);
+        pa_stream_set_underflow_callback(m_stream, 0, 0);
+        pa_stream_set_overflow_callback(m_stream, 0, 0);
+        pa_stream_set_latency_update_callback(m_stream, 0, 0);
 
         pa_operation *o = pa_stream_drain(m_stream, outputStreamDrainComplete, NULL);
-        if (!o) {
-            qWarning() << QString("pa_stream_drain(): %1").arg(pa_strerror(pa_context_errno(pa_stream_get_context(m_stream))));
-        } else {
+        if (o)
             pa_operation_unref(o);
-        }
 
         pa_stream_disconnect(m_stream);
         pa_stream_unref(m_stream);
         m_stream = NULL;
 
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
     }
 
+    disconnect(pulseEngine, &QPulseAudioEngine::contextFailed, this, &QPulseAudioOutput::onPulseContextFailed);
+
     if (!m_pullMode && m_audioSource) {
         delete m_audioSource;
         m_audioSource = 0;
@@ -430,17 +460,14 @@ qint64 QPulseAudioOutput::write(const char *data, qint64 len)
 {
     QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
 
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
+    pulseEngine->lock();
     len = qMin(len, static_cast<qint64>(pa_stream_writable_size(m_stream)));
     pa_stream_write(m_stream, data, len, 0, 0, PA_SEEK_RELATIVE);
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+    pulseEngine->unlock();
     m_totalTimeValue += len;
 
-    m_errorState = QAudio::NoError;
-    if (m_deviceState != QAudio::ActiveState) {
-        m_deviceState = QAudio::ActiveState;
-        emit stateChanged(m_deviceState);
-    }
+    setError(QAudio::NoError);
+    setState(QAudio::ActiveState);
 
     return len;
 }
@@ -450,10 +477,10 @@ void QPulseAudioOutput::stop()
     if (m_deviceState == QAudio::StoppedState)
         return;
 
-    m_errorState = QAudio::NoError;
-    m_deviceState = QAudio::StoppedState;
     close();
-    emit stateChanged(m_deviceState);
+
+    setError(QAudio::NoError);
+    setState(QAudio::StoppedState);
 }
 
 int QPulseAudioOutput::bytesFree() const
@@ -462,9 +489,9 @@ int QPulseAudioOutput::bytesFree() const
         return 0;
 
     QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-    pa_threaded_mainloop_lock(pulseEngine->mainloop());
+    pulseEngine->lock();
     int writableSize = pa_stream_writable_size(m_stream);
-    pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+    pulseEngine->unlock();
     return writableSize;
 }
 
@@ -509,30 +536,22 @@ void QPulseAudioOutput::resume()
 
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
 
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
 
         pa_operation *operation = pa_stream_cork(m_stream, 0, outputStreamSuccessCallback, NULL);
-
-        while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
-            pa_threaded_mainloop_wait(pulseEngine->mainloop());
-
+        pulseEngine->wait(operation);
         pa_operation_unref(operation);
 
         operation = pa_stream_trigger(m_stream, outputStreamSuccessCallback, NULL);
-
-        while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
-            pa_threaded_mainloop_wait(pulseEngine->mainloop());
-
+        pulseEngine->wait(operation);
         pa_operation_unref(operation);
 
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
 
-        m_deviceState = QAudio::ActiveState;
-
-        m_errorState = QAudio::NoError;
         m_tickTimer->start(m_periodTime);
 
-        emit stateChanged(m_deviceState);
+        setState(QAudio::ActiveState);
+        setError(QAudio::NoError);
     }
 }
 
@@ -549,24 +568,21 @@ QAudioFormat QPulseAudioOutput::format() const
 void QPulseAudioOutput::suspend()
 {
     if (m_deviceState == QAudio::ActiveState || m_deviceState == QAudio::IdleState) {
+        setError(QAudio::NoError);
+        setState(QAudio::SuspendedState);
+
         m_tickTimer->stop();
-        m_deviceState = QAudio::SuspendedState;
-        m_errorState = QAudio::NoError;
-        emit stateChanged(m_deviceState);
 
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
         pa_operation *operation;
 
-        pa_threaded_mainloop_lock(pulseEngine->mainloop());
+        pulseEngine->lock();
 
         operation = pa_stream_cork(m_stream, 1, outputStreamSuccessCallback, NULL);
-
-        while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
-            pa_threaded_mainloop_wait(pulseEngine->mainloop());
-
+        pulseEngine->wait(operation);
         pa_operation_unref(operation);
 
-        pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+        pulseEngine->unlock();
     }
 }
 
@@ -601,8 +617,8 @@ qint64 OutputPrivate::writeData(const char *data, qint64 len)
     int retry = 0;
     qint64 written = 0;
 
-    if ((m_audioDevice->m_deviceState == QAudio::ActiveState)
-            ||(m_audioDevice->m_deviceState == QAudio::IdleState)) {
+    if ((m_audioDevice->m_deviceState == QAudio::ActiveState
+         || m_audioDevice->m_deviceState == QAudio::IdleState)) {
          while(written < len) {
             int chunk = m_audioDevice->write(data+written, (len-written));
             if (chunk <= 0)
@@ -623,7 +639,7 @@ void QPulseAudioOutput::setVolume(qreal vol)
             m_volume = vol;
             if (m_opened) {
                 QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
-                pa_threaded_mainloop_lock(pulseEngine->mainloop());
+                pulseEngine->lock();
                 pa_volume_t paVolume;
                 if (qFuzzyCompare(vol, 0.0)) {
                     pa_cvolume_mute(&m_chVolume, m_spec.channels);
@@ -641,7 +657,7 @@ void QPulseAudioOutput::setVolume(qreal vol)
                     qWarning()<<"QAudioOutput: Failed to set volume";
                 else
                     pa_operation_unref(op);
-                pa_threaded_mainloop_unlock(pulseEngine->mainloop());
+                pulseEngine->unlock();
             }
         }
     }
@@ -664,6 +680,14 @@ QString QPulseAudioOutput::category() const
     return m_category;
 }
 
+void QPulseAudioOutput::onPulseContextFailed()
+{
+    close();
+
+    setError(QAudio::FatalError);
+    setState(QAudio::StoppedState);
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qaudiooutput_pulse.cpp"
diff --git a/src/plugins/pulseaudio/qaudiooutput_pulse.h b/src/plugins/pulseaudio/qaudiooutput_pulse.h
index 5954b8975..fea151ba2 100644
--- a/src/plugins/pulseaudio/qaudiooutput_pulse.h
+++ b/src/plugins/pulseaudio/qaudiooutput_pulse.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Toolkit.
@@ -105,12 +105,16 @@ public:
     void streamUnderflowCallback();
 
 private:
+    void setState(QAudio::State state);
+    void setError(QAudio::Error error);
+
     bool open();
     void close();
     qint64 write(const char *data, qint64 len);
 
 private Q_SLOTS:
     void userFeed();
+    void onPulseContextFailed();
 
 private:
     QByteArray m_device;
diff --git a/src/plugins/pulseaudio/qpulseaudioengine.cpp b/src/plugins/pulseaudio/qpulseaudioengine.cpp
index b7a3e66b7..05c8be89e 100644
--- a/src/plugins/pulseaudio/qpulseaudioengine.cpp
+++ b/src/plugins/pulseaudio/qpulseaudioengine.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Toolkit.
@@ -170,15 +170,17 @@ static void contextStateCallbackInit(pa_context *context, void *userdata)
     pa_threaded_mainloop_signal(pulseEngine->mainloop(), 0);
 }
 
-static void contextStateCallback(pa_context *context, void *userdata)
+static void contextStateCallback(pa_context *c, void *userdata)
 {
-    Q_UNUSED(userdata);
-    Q_UNUSED(context);
+    QPulseAudioEngine *self = reinterpret_cast<QPulseAudioEngine*>(userdata);
+    pa_context_state_t state = pa_context_get_state(c);
 
 #ifdef DEBUG_PULSE
-    pa_context_state_t state = pa_context_get_state(context);
     qDebug() << QPulseAudioInternal::stateToQString(state);
 #endif
+
+    if (state == PA_CONTEXT_FAILED)
+        QMetaObject::invokeMethod(self, "onContextFailed", Qt::QueuedConnection);
 }
 
 Q_GLOBAL_STATIC(QPulseAudioEngine, pulseEngine);
@@ -187,40 +189,59 @@ QPulseAudioEngine::QPulseAudioEngine(QObject *parent)
     : QObject(parent)
     , m_mainLoopApi(0)
     , m_context(0)
+    , m_prepared(false)
+{
+    prepare();
+}
+
+QPulseAudioEngine::~QPulseAudioEngine()
+{
+    if (m_prepared)
+        release();
+}
 
+void QPulseAudioEngine::prepare()
 {
     bool keepGoing = true;
     bool ok = true;
 
     m_mainLoop = pa_threaded_mainloop_new();
     if (m_mainLoop == 0) {
-        qWarning("Unable to create pulseaudio mainloop");
+        qWarning("PulseAudioService: unable to create pulseaudio mainloop");
         return;
     }
 
     if (pa_threaded_mainloop_start(m_mainLoop) != 0) {
-        qWarning("Unable to start pulseaudio mainloop");
+        qWarning("PulseAudioService: unable to start pulseaudio mainloop");
         pa_threaded_mainloop_free(m_mainLoop);
+        m_mainLoop = 0;
         return;
     }
 
     m_mainLoopApi = pa_threaded_mainloop_get_api(m_mainLoop);
 
-    pa_threaded_mainloop_lock(m_mainLoop);
+    lock();
 
-    m_context = pa_context_new(m_mainLoopApi, QString(QLatin1String("QtmPulseContext:%1")).arg(::getpid()).toLatin1().constData());
-    pa_context_set_state_callback(m_context, contextStateCallbackInit, this);
+    m_context = pa_context_new(m_mainLoopApi, QString(QLatin1String("QtPulseAudio:%1")).arg(::getpid()).toLatin1().constData());
 
-    if (!m_context) {
-        qWarning("Unable to create new pulseaudio context");
+    if (m_context == 0) {
+        qWarning("PulseAudioService: Unable to create new pulseaudio context");
+        pa_threaded_mainloop_unlock(m_mainLoop);
         pa_threaded_mainloop_free(m_mainLoop);
+        m_mainLoop = 0;
+        onContextFailed();
         return;
     }
 
-    if (pa_context_connect(m_context, NULL, (pa_context_flags_t)0, NULL) < 0) {
-        qWarning("Unable to create a connection to the pulseaudio context");
+    pa_context_set_state_callback(m_context, contextStateCallbackInit, this);
+
+    if (pa_context_connect(m_context, 0, (pa_context_flags_t)0, 0) < 0) {
+        qWarning("PulseAudioService: pa_context_connect() failed");
         pa_context_unref(m_context);
+        pa_threaded_mainloop_unlock(m_mainLoop);
         pa_threaded_mainloop_free(m_mainLoop);
+        m_mainLoop = 0;
+        m_context = 0;
         return;
     }
 
@@ -241,47 +262,49 @@ QPulseAudioEngine::QPulseAudioEngine(QObject *parent)
                 break;
 
             case PA_CONTEXT_TERMINATED:
-                qCritical("Context terminated.");
+                qCritical("PulseAudioService: Context terminated.");
                 keepGoing = false;
                 ok = false;
                 break;
 
             case PA_CONTEXT_FAILED:
             default:
-                qCritical() << QString("Connection failure: %1").arg(pa_strerror(pa_context_errno(m_context)));
+                qCritical() << QString("PulseAudioService: Connection failure: %1").arg(pa_strerror(pa_context_errno(m_context)));
                 keepGoing = false;
                 ok = false;
         }
 
-        if (keepGoing) {
+        if (keepGoing)
             pa_threaded_mainloop_wait(m_mainLoop);
-        }
     }
 
     if (ok) {
         pa_context_set_state_callback(m_context, contextStateCallback, this);
     } else {
-        if (m_context) {
-            pa_context_unref(m_context);
-            m_context = 0;
-        }
+        pa_context_unref(m_context);
+        m_context = 0;
     }
 
-    pa_threaded_mainloop_unlock(m_mainLoop);
+    unlock();
 
     if (ok) {
-        serverInfo();
-        sinks();
-        sources();
+        updateDevices();
+        m_prepared = true;
+    } else {
+        pa_threaded_mainloop_free(m_mainLoop);
+        m_mainLoop = 0;
+        onContextFailed();
     }
 }
 
-QPulseAudioEngine::~QPulseAudioEngine()
+void QPulseAudioEngine::release()
 {
+    if (!m_prepared)
+        return;
+
     if (m_context) {
-        pa_threaded_mainloop_lock(m_mainLoop);
         pa_context_disconnect(m_context);
-        pa_threaded_mainloop_unlock(m_mainLoop);
+        pa_context_unref(m_context);
         m_context = 0;
     }
 
@@ -290,62 +313,52 @@ QPulseAudioEngine::~QPulseAudioEngine()
         pa_threaded_mainloop_free(m_mainLoop);
         m_mainLoop = 0;
     }
+
+    m_prepared = false;
 }
 
-void QPulseAudioEngine::serverInfo()
+void QPulseAudioEngine::updateDevices()
 {
-    pa_operation *operation;
-
-    pa_threaded_mainloop_lock(m_mainLoop);
-
-    operation = pa_context_get_server_info(m_context, serverInfoCallback, this);
+    lock();
 
+    // Get default input and output devices
+    pa_operation *operation = pa_context_get_server_info(m_context, serverInfoCallback, this);
     while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
         pa_threaded_mainloop_wait(m_mainLoop);
-
     pa_operation_unref(operation);
 
-    pa_threaded_mainloop_unlock(m_mainLoop);
-}
-
-void QPulseAudioEngine::sinks()
-{
-    pa_operation *operation;
-
-    pa_threaded_mainloop_lock(m_mainLoop);
-
+    // Get output devices
     operation = pa_context_get_sink_info_list(m_context, sinkInfoCallback, this);
-
     while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
         pa_threaded_mainloop_wait(m_mainLoop);
+    pa_operation_unref(operation);
 
+    // Get input devices
+    operation = pa_context_get_source_info_list(m_context, sourceInfoCallback, this);
+    while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
+        pa_threaded_mainloop_wait(m_mainLoop);
     pa_operation_unref(operation);
 
-    pa_threaded_mainloop_unlock(m_mainLoop);
+    unlock();
 
-    // Swap the default sink to index 0
+    // Swap the default output to index 0
     m_sinks.removeOne(m_defaultSink);
     m_sinks.prepend(m_defaultSink);
+
+    // Swap the default input to index 0
+    m_sources.removeOne(m_defaultSource);
+    m_sources.prepend(m_defaultSource);
 }
 
-void QPulseAudioEngine::sources()
+void QPulseAudioEngine::onContextFailed()
 {
-    pa_operation *operation;
-
-    pa_threaded_mainloop_lock(m_mainLoop);
-
-    operation = pa_context_get_source_info_list(m_context, sourceInfoCallback, this);
+    // Give a chance to the connected slots to still use the Pulse main loop before releasing it.
+    emit contextFailed();
 
-    while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
-        pa_threaded_mainloop_wait(m_mainLoop);
-
-    pa_operation_unref(operation);
+    release();
 
-    pa_threaded_mainloop_unlock(m_mainLoop);
-
-    // Swap the default source to index 0
-    m_sources.removeOne(m_defaultSource);
-    m_sources.prepend(m_defaultSource);
+    // Try to reconnect later
+    QTimer::singleShot(3000, this, SLOT(prepare()));
 }
 
 QPulseAudioEngine *QPulseAudioEngine::instance()
diff --git a/src/plugins/pulseaudio/qpulseaudioengine.h b/src/plugins/pulseaudio/qpulseaudioengine.h
index 1c6c2aaf4..04591d035 100644
--- a/src/plugins/pulseaudio/qpulseaudioengine.h
+++ b/src/plugins/pulseaudio/qpulseaudioengine.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the Qt Toolkit.
@@ -74,12 +74,36 @@ public:
     pa_threaded_mainloop *mainloop() { return m_mainLoop; }
     pa_context *context() { return m_context; }
 
+    inline void lock()
+    {
+        if (m_mainLoop)
+            pa_threaded_mainloop_lock(m_mainLoop);
+    }
+
+    inline void unlock()
+    {
+        if (m_mainLoop)
+            pa_threaded_mainloop_unlock(m_mainLoop);
+    }
+
+    inline void wait(pa_operation *op)
+    {
+        while (m_mainLoop && pa_operation_get_state(op) == PA_OPERATION_RUNNING)
+            pa_threaded_mainloop_wait(m_mainLoop);
+    }
+
     QList<QByteArray> availableDevices(QAudio::Mode mode) const;
 
+Q_SIGNALS:
+    void contextFailed();
+
+private Q_SLOTS:
+    void prepare();
+    void onContextFailed();
+
 private:
-    void serverInfo();
-    void sinks();
-    void sources();
+    void updateDevices();
+    void release();
 
 public:
     QList<QByteArray> m_sinks;
@@ -93,6 +117,7 @@ private:
     pa_mainloop_api *m_mainLoopApi;
     pa_threaded_mainloop *m_mainLoop;
     pa_context *m_context;
+    bool m_prepared;
  };
 
 QT_END_NAMESPACE