sdrangel/plugins/samplesink/soapysdroutput/soapysdroutput.cpp

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2018 Edouard Griffiths, F4EXB                                   //
//                                                                               //
// This program is free software; you can redistribute it and/or modify          //
// it under the terms of the GNU General Public License as published by          //
// the Free Software Foundation as version 3 of the License, or                  //
//                                                                               //
// This program is distributed in the hope that it will be useful,               //
// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
// GNU General Public License V3 for more details.                               //
//                                                                               //
// You should have received a copy of the GNU General Public License             //
// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
///////////////////////////////////////////////////////////////////////////////////

#include <QDebug>

#include "util/simpleserializer.h"
#include "dsp/dspcommands.h"
#include "dsp/dspengine.h"
#include "device/devicesinkapi.h"
#include "device/devicesourceapi.h"
#include "soapysdr/devicesoapysdr.h"

#include "soapysdroutputthread.h"
#include "soapysdroutput.h"

MESSAGE_CLASS_DEFINITION(SoapySDROutput::MsgConfigureSoapySDROutput, Message)
MESSAGE_CLASS_DEFINITION(SoapySDROutput::MsgStartStop, Message)

SoapySDROutput::SoapySDROutput(DeviceSinkAPI *deviceAPI) :
    m_deviceAPI(deviceAPI),
    m_deviceDescription("SoapySDROutput"),
    m_running(false),
    m_thread(0)
{
    openDevice();
}

SoapySDROutput::~SoapySDROutput()
{
    if (m_running) {
        stop();
    }

    closeDevice();
}

void SoapySDROutput::destroy()
{
    delete this;
}

bool SoapySDROutput::openDevice()
{
    m_sampleSourceFifo.resize(m_settings.m_devSampleRate/(1<<(m_settings.m_log2Interp <= 4 ? m_settings.m_log2Interp : 4)));

    // look for Tx buddies and get reference to the device object
    if (m_deviceAPI->getSinkBuddies().size() > 0) // look sink sibling first
    {
        qDebug("SoapySDROutput::openDevice: look in Tx buddies");

        DeviceSinkAPI *sinkBuddy = m_deviceAPI->getSinkBuddies()[0];
        DeviceSoapySDRShared *deviceSoapySDRShared = (DeviceSoapySDRShared*) sinkBuddy->getBuddySharedPtr();

        if (deviceSoapySDRShared == 0)
        {
            qCritical("SoapySDROutput::openDevice: the sink buddy shared pointer is null");
            return false;
        }

        SoapySDR::Device *device = deviceSoapySDRShared->m_device;

        if (device == 0)
        {
            qCritical("SoapySDROutput::openDevice: cannot get device pointer from Tx buddy");
            return false;
        }

        m_deviceShared.m_device = device;
        m_deviceShared.m_deviceParams = deviceSoapySDRShared->m_deviceParams;
    }
    // look for Rx buddies and get reference to the device object
    else if (m_deviceAPI->getSourceBuddies().size() > 0) // then source
    {
        qDebug("SoapySDROutput::openDevice: look in Rx buddies");

        DeviceSourceAPI *sourceBuddy = m_deviceAPI->getSourceBuddies()[0];
        DeviceSoapySDRShared *deviceSoapySDRShared = (DeviceSoapySDRShared*) sourceBuddy->getBuddySharedPtr();

        if (deviceSoapySDRShared == 0)
        {
            qCritical("SoapySDROutput::openDevice: the source buddy shared pointer is null");
            return false;
        }

        SoapySDR::Device *device = deviceSoapySDRShared->m_device;

        if (device == 0)
        {
            qCritical("SoapySDROutput::openDevice: cannot get device pointer from Rx buddy");
            return false;
        }

        m_deviceShared.m_device = device;
        m_deviceShared.m_deviceParams = deviceSoapySDRShared->m_deviceParams;
    }
    // There are no buddies then create the first BladeRF2 device
    else
    {
        qDebug("SoapySDROutput::openDevice: open device here");
        DeviceSoapySDR& deviceSoapySDR = DeviceSoapySDR::instance();
        m_deviceShared.m_device = deviceSoapySDR.openSoapySDR(m_deviceAPI->getSampleSinkSequence());

        if (!m_deviceShared.m_device)
        {
            qCritical("SoapySDROutput::openDevice: cannot open SoapySDR device");
            return false;
        }

        m_deviceShared.m_deviceParams = new DeviceSoapySDRParams(m_deviceShared.m_device);
    }

    m_deviceShared.m_channel = m_deviceAPI->getItemIndex(); // publicly allocate channel
    m_deviceShared.m_sink = this;
    m_deviceAPI->setBuddySharedPtr(&m_deviceShared); // propagate common parameters to API
    return true;
}

void SoapySDROutput::closeDevice()
{
    if (m_deviceShared.m_device == 0) { // was never open
        return;
    }

    if (m_running) {
        stop();
    }

    if (m_thread) { // stills own the thread => transfer to a buddy
        moveThreadToBuddy();
    }

    m_deviceShared.m_channel = -1; // publicly release channel
    m_deviceShared.m_sink = 0;

    // No buddies so effectively close the device

    if ((m_deviceAPI->getSinkBuddies().size() == 0) && (m_deviceAPI->getSourceBuddies().size() == 0))
    {
        DeviceSoapySDR& deviceSoapySDR = DeviceSoapySDR::instance();
        deviceSoapySDR.closeSoapySdr(m_deviceShared.m_device);
        m_deviceShared.m_device = 0;
    }
}

void SoapySDROutput::getFrequencyRange(uint64_t& min, uint64_t& max)
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);

    if (channelSettings && (channelSettings->m_frequencySettings.size() > 0))
    {
        DeviceSoapySDRParams::FrequencySetting freqSettings = channelSettings->m_frequencySettings[0];
        SoapySDR::RangeList rangeList = freqSettings.m_ranges;

        if (rangeList.size() > 0)
        {
            SoapySDR::Range range = rangeList[0];
            min = range.minimum();
            max = range.maximum();
        }
        else
        {
            min = 0;
            max = 0;
        }
    }
    else
    {
        min = 0;
        max = 0;
    }
}

void SoapySDROutput::getGlobalGainRange(int& min, int& max)
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);

    if (channelSettings)
    {
        min = channelSettings->m_gainRange.minimum();
        max = channelSettings->m_gainRange.maximum();
    }
    else
    {
        min = 0;
        max = 0;
    }
}


const SoapySDR::RangeList& SoapySDROutput::getRateRanges()
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);
    return channelSettings->m_ratesRanges;
}

const std::vector<std::string>& SoapySDROutput::getAntennas()
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);
    return channelSettings->m_antennas;
}

const SoapySDR::RangeList& SoapySDROutput::getBandwidthRanges()
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);
    return channelSettings->m_bandwidthsRanges;
}

const std::vector<DeviceSoapySDRParams::FrequencySetting>& SoapySDROutput::getTunableElements()
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);
    return channelSettings->m_frequencySettings;
}

const std::vector<DeviceSoapySDRParams::GainSetting>& SoapySDROutput::getIndividualGainsRanges()
{
    const DeviceSoapySDRParams::ChannelSettings* channelSettings = m_deviceShared.m_deviceParams->getTxChannelSettings(m_deviceShared.m_channel);
    return channelSettings->m_gainSettings;
}

void SoapySDROutput::init()
{
    applySettings(m_settings, true);
}

SoapySDROutputThread *SoapySDROutput::findThread()
{
    if (m_thread == 0) // this does not own the thread
    {
        SoapySDROutputThread *soapySDROutputThread = 0;

        // find a buddy that has allocated the thread
        const std::vector<DeviceSinkAPI*>& sinkBuddies = m_deviceAPI->getSinkBuddies();
        std::vector<DeviceSinkAPI*>::const_iterator it = sinkBuddies.begin();

        for (; it != sinkBuddies.end(); ++it)
        {
            SoapySDROutput *buddySink = ((DeviceSoapySDRShared*) (*it)->getBuddySharedPtr())->m_sink;

            if (buddySink)
            {
                soapySDROutputThread = buddySink->getThread();

                if (soapySDROutputThread) {
                    break;
                }
            }
        }

        return soapySDROutputThread;
    }
    else
    {
        return m_thread; // own thread
    }
}

void SoapySDROutput::moveThreadToBuddy()
{
    const std::vector<DeviceSinkAPI*>& sinkBuddies = m_deviceAPI->getSinkBuddies();
    std::vector<DeviceSinkAPI*>::const_iterator it = sinkBuddies.begin();

    for (; it != sinkBuddies.end(); ++it)
    {
        SoapySDROutput *buddySink = ((DeviceSoapySDRShared*) (*it)->getBuddySharedPtr())->m_sink;

        if (buddySink)
        {
            buddySink->setThread(m_thread);
            m_thread = 0;  // zero for others
        }
    }
}

bool SoapySDROutput::start()
{
    // There is a single thread per physical device (Tx side). This thread is unique and referenced by a unique
    // buddy in the group of sink buddies associated with this physical device.
    //
    // This start method is responsible for managing the thread and channel enabling when the streaming of a Tx channel is started
    //
    // It checks the following conditions
    //   - the thread is allocated or not (by itself or one of its buddies). If it is it grabs the thread pointer.
    //   - the requested channel is the first (0) or the following
    //
    // There are two possible working modes:
    //   - Single Output (SO) with only one channel streaming. This HAS to be channel 0.
    //   - Multiple Output (MO) with two or more channels. It MUST be in this configuration if any channel other than 0
    //     is used. For example when we will run with only channel 2 streaming from the client perspective the channels 0 and 1
    //     will actually be enabled and streaming but zero samples will be sent to it.
    //
    // It manages the transition form SO where only one channel (the first or channel 0) should be running to the
    // Multiple Output (MO) if the requested channel is 1 or more. More generally it checks if the requested channel is within the current
    // channel range allocated in the thread or past it. To perform the transition it stops the thread, deletes it and creates a new one.
    // It marks the thread as needing start.
    //
    // If the requested channel is within the thread channel range (this thread being already allocated) it simply removes its FIFO reference
    // so that the samples are not taken from the FIFO anymore and leaves the thread unchanged (no stop, no delete/new)
    //
    // If there is no thread allocated it creates a new one with a number of channels that fits the requested channel. That is
    // 1 if channel 0 is requested (SO mode) and 3 if channel 2 is requested (MO mode). It marks the thread as needing start.
    //
    // Eventually it registers the FIFO in the thread. If the thread has to be started it enables the channels up to the number of channels
    // allocated in the thread and starts the thread.
    //
    // Note: this is quite similar to the BladeRF2 start handling. The main difference is that the channel allocation (enabling) process is
    // done in the thread object.


    if (!m_deviceShared.m_device)
    {
        qDebug("SoapySDROutput::start: no device object");
        return false;
    }

    int requestedChannel = m_deviceAPI->getItemIndex();
    SoapySDROutputThread *soapySDROutputThread = findThread();
    bool needsStart = false;

    if (soapySDROutputThread) // if thread is already allocated
    {
        qDebug("SoapySDROutput::start: thread is already allocated");

        int nbOriginalChannels = soapySDROutputThread->getNbChannels();

        if (requestedChannel+1 > nbOriginalChannels) // expansion by deleting and re-creating the thread
        {
            qDebug("SoapySDROutput::start: expand channels. Re-allocate thread and take ownership");

            SampleSourceFifo **fifos = new SampleSourceFifo*[nbOriginalChannels];
            unsigned int *log2Interps = new unsigned int[nbOriginalChannels];

            for (int i = 0; i < nbOriginalChannels; i++) // save original FIFO references and data
            {
                fifos[i] = soapySDROutputThread->getFifo(i);
                log2Interps[i] = soapySDROutputThread->getLog2Interpolation(i);
            }

            soapySDROutputThread->stopWork();
            delete soapySDROutputThread;
            soapySDROutputThread = new SoapySDROutputThread(m_deviceShared.m_device, requestedChannel+1);
            m_thread = soapySDROutputThread; // take ownership

            for (int i = 0; i < nbOriginalChannels; i++) // restore original FIFO references
            {
                soapySDROutputThread->setFifo(i, fifos[i]);
                soapySDROutputThread->setLog2Interpolation(i, log2Interps[i]);
            }

            // remove old thread address from buddies (reset in all buddies).  The address being held only in the owning sink.
            const std::vector<DeviceSinkAPI*>& sinkBuddies = m_deviceAPI->getSinkBuddies();
            std::vector<DeviceSinkAPI*>::const_iterator it = sinkBuddies.begin();

            for (; it != sinkBuddies.end(); ++it) {
                ((DeviceSoapySDRShared*) (*it)->getBuddySharedPtr())->m_sink->setThread(0);
            }

            needsStart = true;
        }
        else
        {
            qDebug("SoapySDROutput::start: keep buddy thread");
        }
    }
    else // first allocation
    {
        qDebug("SoapySDROutput::start: allocate thread and take ownership");
        soapySDROutputThread = new SoapySDROutputThread(m_deviceShared.m_device, requestedChannel+1);
        m_thread = soapySDROutputThread; // take ownership
        needsStart = true;
    }

    soapySDROutputThread->setFifo(requestedChannel, &m_sampleSourceFifo);
    soapySDROutputThread->setLog2Interpolation(requestedChannel, m_settings.m_log2Interp);

    if (needsStart)
    {
        qDebug("SoapySDROutput::start: (re)sart buddy thread");
        soapySDROutputThread->setSampleRate(m_settings.m_devSampleRate);
        soapySDROutputThread->startWork();
    }

    qDebug("SoapySDROutput::start: started");
    m_running = true;

    return true;
}

void SoapySDROutput::stop()
{
    // This stop method is responsible for managing the thread and channel disabling when the streaming of
    // a Tx channel is stopped
    //
    // If the thread is currently managing only one channel (SO mode). The thread can be just stopped and deleted.
    // Then the channel is closed (disabled).
    //
    // If the thread is currently managing many channels (MO mode) and we are removing the last channel. The transition
    // from MO to SO or reduction of MO size is handled by stopping the thread, deleting it and creating a new one
    // with the maximum number of channels needed if (and only if) there is still a channel active.
    //
    // If the thread is currently managing many channels (MO mode) but the channel being stopped is not the last
    // channel then the FIFO reference is simply removed from the thread so that this FIFO will not be used anymore.
    // In this case the channel is not closed (this is managed in the thread object) so that other channels can continue with the
    // same configuration. The device continues streaming on this channel but the samples are set to all zeros.

    if (!m_running) {
        return;
    }

    int requestedChannel = m_deviceAPI->getItemIndex();
    SoapySDROutputThread *soapySDROutputThread = findThread();

    if (soapySDROutputThread == 0) { // no thread allocated
        return;
    }

    int nbOriginalChannels = soapySDROutputThread->getNbChannels();

    if (nbOriginalChannels == 1) // SO mode => just stop and delete the thread
    {
        qDebug("SoapySDROutput::stop: SO mode. Just stop and delete the thread");
        soapySDROutputThread->stopWork();
        delete soapySDROutputThread;
        m_thread = 0;

        // remove old thread address from buddies (reset in all buddies)
        const std::vector<DeviceSinkAPI*>& sinkBuddies = m_deviceAPI->getSinkBuddies();
        std::vector<DeviceSinkAPI*>::const_iterator it = sinkBuddies.begin();

        for (; it != sinkBuddies.end(); ++it) {
            ((DeviceSoapySDRShared*) (*it)->getBuddySharedPtr())->m_sink->setThread(0);
        }
    }
    else if (requestedChannel == nbOriginalChannels - 1) // remove last MO channel => reduce by deleting and re-creating the thread
    {
        qDebug("SoapySDROutput::stop: MO mode. Reduce by deleting and re-creating the thread");
        soapySDROutputThread->stopWork();
        SampleSourceFifo **fifos = new SampleSourceFifo*[nbOriginalChannels-1];
        unsigned int *log2Interps = new unsigned int[nbOriginalChannels-1];
        int highestActiveChannelIndex = -1;

        for (int i = 0; i < nbOriginalChannels-1; i++) // save original FIFO references
        {
            fifos[i] = soapySDROutputThread->getFifo(i);

            if ((soapySDROutputThread->getFifo(i) != 0) && (i > highestActiveChannelIndex)) {
                highestActiveChannelIndex = i;
            }

            log2Interps[i] = soapySDROutputThread->getLog2Interpolation(i);
        }

        delete soapySDROutputThread;
        m_thread = 0;

        if (highestActiveChannelIndex >= 0)
        {
            soapySDROutputThread = new SoapySDROutputThread(m_deviceShared.m_device, highestActiveChannelIndex+1);
            m_thread = soapySDROutputThread; // take ownership

            for (int i = 0; i < nbOriginalChannels-1; i++)  // restore original FIFO references
            {
                soapySDROutputThread->setFifo(i, fifos[i]);
                soapySDROutputThread->setLog2Interpolation(i, log2Interps[i]);
            }
        }
        else
        {
            qDebug("SoapySDROutput::stop: do not re-create thread as there are no more FIFOs active");
        }

        // remove old thread address from buddies (reset in all buddies). The address being held only in the owning sink.
        const std::vector<DeviceSinkAPI*>& sinkBuddies = m_deviceAPI->getSinkBuddies();
        std::vector<DeviceSinkAPI*>::const_iterator it = sinkBuddies.begin();

        for (; it != sinkBuddies.end(); ++it) {
            ((DeviceSoapySDRShared*) (*it)->getBuddySharedPtr())->m_sink->setThread(0);
        }

        if (highestActiveChannelIndex >= 0)
        {
            qDebug("SoapySDROutput::stop: restarting the thread");
            soapySDROutputThread->startWork();
        }
    }
    else // remove channel from existing thread
    {
        qDebug("SoapySDROutput::stop: MO mode. Not changing MO configuration. Just remove FIFO reference");
        soapySDROutputThread->setFifo(requestedChannel, 0); // remove FIFO
    }

    applySettings(m_settings, true); // re-apply forcibly to set sample rate with the new number of channels

    m_running = false;
}

QByteArray SoapySDROutput::serialize() const
{
    return m_settings.serialize();
}

bool SoapySDROutput::deserialize(const QByteArray& data __attribute__((unused)))
{
    bool success = true;

    if (!m_settings.deserialize(data))
    {
        m_settings.resetToDefaults();
        success = false;
    }

    MsgConfigureSoapySDROutput* message = MsgConfigureSoapySDROutput::create(m_settings, true);
    m_inputMessageQueue.push(message);

    if (m_guiMessageQueue)
    {
        MsgConfigureSoapySDROutput* messageToGUI = MsgConfigureSoapySDROutput::create(m_settings, true);
        m_guiMessageQueue->push(messageToGUI);
    }

    return success;
}

const QString& SoapySDROutput::getDeviceDescription() const
{
    return m_deviceDescription;
}

int SoapySDROutput::getSampleRate() const
{
    int rate = m_settings.m_devSampleRate;
    return (rate / (1<<m_settings.m_log2Interp));
}

quint64 SoapySDROutput::getCenterFrequency() const
{
    return m_settings.m_centerFrequency;
}

void SoapySDROutput::setCenterFrequency(qint64 centerFrequency)
{
    SoapySDROutputSettings settings = m_settings;
    settings.m_centerFrequency = centerFrequency;

    MsgConfigureSoapySDROutput* message = MsgConfigureSoapySDROutput::create(settings, false);
    m_inputMessageQueue.push(message);

    if (m_guiMessageQueue)
    {
        MsgConfigureSoapySDROutput* messageToGUI = MsgConfigureSoapySDROutput::create(settings, false);
        m_guiMessageQueue->push(messageToGUI);
    }
}

bool SoapySDROutput::setDeviceCenterFrequency(SoapySDR::Device *dev, int requestedChannel, quint64 freq_hz, int loPpmTenths)
{
    qint64 df = ((qint64)freq_hz * loPpmTenths) / 10000000LL;
    freq_hz += df;

    try
    {
        dev->setFrequency(SOAPY_SDR_TX,
                requestedChannel,
                m_deviceShared.m_deviceParams->getTxChannelMainTunableElementName(requestedChannel),
                freq_hz);
        qDebug("SoapySDROutput::setDeviceCenterFrequency: setFrequency(%llu)", freq_hz);
        return true;
    }
    catch (const std::exception &ex)
    {
        qCritical("SoapySDROutput::applySettings: could not set frequency: %llu: %s", freq_hz, ex.what());
        return false;
    }
}

bool SoapySDROutput::handleMessage(const Message& message)
{
    if (MsgConfigureSoapySDROutput::match(message))
    {
        MsgConfigureSoapySDROutput& conf = (MsgConfigureSoapySDROutput&) message;
        qDebug() << "SoapySDROutput::handleMessage: MsgConfigureSoapySDROutput";

        if (!applySettings(conf.getSettings(), conf.getForce())) {
            qDebug("SoapySDROutput::handleMessage: MsgConfigureSoapySDROutput config error");
        }

        return true;
    }
    else if (MsgStartStop::match(message))
    {
        MsgStartStop& cmd = (MsgStartStop&) message;
        qDebug() << "SoapySDROutput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");

        if (cmd.getStartStop())
        {
            if (m_deviceAPI->initGeneration())
            {
                m_deviceAPI->startGeneration();
            }
        }
        else
        {
            m_deviceAPI->stopGeneration();
        }

        return true;
    }
    else if (DeviceSoapySDRShared::MsgReportBuddyChange::match(message))
    {
        int requestedChannel = m_deviceAPI->getItemIndex();
        //DeviceSoapySDRShared::MsgReportBuddyChange& report = (DeviceSoapySDRShared::MsgReportBuddyChange&) message;
        SoapySDROutputSettings settings = m_settings;
        //bool fromRxBuddy = report.getRxElseTx();

        double centerFrequency = m_deviceShared.m_device->getFrequency(
                SOAPY_SDR_TX,
                requestedChannel,
                m_deviceShared.m_deviceParams->getTxChannelMainTunableElementName(requestedChannel));

        settings.m_centerFrequency = round(centerFrequency/1000.0) * 1000;
        settings.m_devSampleRate = round(m_deviceShared.m_device->getSampleRate(SOAPY_SDR_TX, requestedChannel));
        settings.m_bandwidth = round(m_deviceShared.m_device->getBandwidth(SOAPY_SDR_TX, requestedChannel));

        //SoapySDROutputThread *outputThread = findThread();

        m_settings = settings;

        // propagate settings to GUI if any
        if (getMessageQueueToGUI())
        {
            MsgConfigureSoapySDROutput *reportToGUI = MsgConfigureSoapySDROutput::create(m_settings, false);
            getMessageQueueToGUI()->push(reportToGUI);
        }

        return true;
    }
    else
    {
        return false;
    }
}

bool SoapySDROutput::applySettings(const SoapySDROutputSettings& settings, bool force)
{
    bool forwardChangeOwnDSP = false;
    bool forwardChangeToBuddies  = false;

    SoapySDR::Device *dev = m_deviceShared.m_device;
    SoapySDROutputThread *outputThread = findThread();
    int requestedChannel = m_deviceAPI->getItemIndex();
    qint64 xlatedDeviceCenterFrequency = settings.m_centerFrequency;
    xlatedDeviceCenterFrequency -= settings.m_transverterMode ? settings.m_transverterDeltaFrequency : 0;
    xlatedDeviceCenterFrequency = xlatedDeviceCenterFrequency < 0 ? 0 : xlatedDeviceCenterFrequency;

    // resize FIFO
    if ((m_settings.m_devSampleRate != settings.m_devSampleRate) || (m_settings.m_log2Interp != settings.m_log2Interp) || force)
    {
        SoapySDROutputThread *soapySDROutputThread = findThread();
        SampleSourceFifo *fifo = 0;

        if (soapySDROutputThread)
        {
            fifo = soapySDROutputThread->getFifo(requestedChannel);
            soapySDROutputThread->setFifo(requestedChannel, 0);
        }

        int fifoSize;

        if (settings.m_log2Interp >= 5)
        {
            fifoSize = DeviceSoapySDRShared::m_sampleFifoMinSize32;
        }
        else
        {
            fifoSize = std::max(
                (int) ((settings.m_devSampleRate/(1<<settings.m_log2Interp)) * DeviceSoapySDRShared::m_sampleFifoLengthInSeconds),
                DeviceSoapySDRShared::m_sampleFifoMinSize);
        }

        m_sampleSourceFifo.resize(fifoSize);

        if (fifo) {
            soapySDROutputThread->setFifo(requestedChannel, &m_sampleSourceFifo);
        }
    }

    if ((m_settings.m_devSampleRate != settings.m_devSampleRate) || force)
    {
        forwardChangeOwnDSP = true;
        forwardChangeToBuddies = true;

        if (dev != 0)
        {
            try
            {
                dev->setSampleRate(SOAPY_SDR_TX, requestedChannel, settings.m_devSampleRate);
                qDebug() << "SoapySDROutput::applySettings: setSampleRate OK: " << settings.m_devSampleRate;

                if (outputThread)
                {
                    bool wasRunning = outputThread->isRunning();
                    outputThread->stopWork();
                    outputThread->setSampleRate(settings.m_devSampleRate);

                    if (wasRunning) {
                        outputThread->startWork();
                    }
                }
            }
            catch (const std::exception &ex)
            {
                qCritical("SoapySDROutput::applySettings: could not set sample rate: %d: %s",
                        settings.m_devSampleRate, ex.what());
            }
        }
    }

    if ((m_settings.m_log2Interp != settings.m_log2Interp) || force)
    {
        forwardChangeOwnDSP = true;

        if (outputThread != 0)
        {
            outputThread->setLog2Interpolation(requestedChannel, settings.m_log2Interp);
            qDebug() << "SoapySDROutput::applySettings: set decimation to " << (1<<settings.m_log2Interp);
        }
    }

    if ((m_settings.m_centerFrequency != settings.m_centerFrequency)
        || (m_settings.m_transverterMode != settings.m_transverterMode)
        || (m_settings.m_transverterDeltaFrequency != settings.m_transverterDeltaFrequency)
        || (m_settings.m_LOppmTenths != settings.m_LOppmTenths)
        || (m_settings.m_devSampleRate != settings.m_devSampleRate)
        || (m_settings.m_log2Interp != settings.m_log2Interp) || force)
    {
        forwardChangeOwnDSP = true;
        forwardChangeToBuddies = true;

        if (dev != 0) {
            setDeviceCenterFrequency(dev, requestedChannel, settings.m_centerFrequency, settings.m_LOppmTenths);
        }
    }

    if ((m_settings.m_antenna != settings.m_antenna) || force)
    {
        if (dev != 0)
        {
            try
            {
                dev->setAntenna(SOAPY_SDR_TX, requestedChannel, settings.m_antenna.toStdString());
                qDebug("SoapySDROutput::applySettings: set antenna to %s", settings.m_antenna.toStdString().c_str());
            }
            catch (const std::exception &ex)
            {
                qCritical("SoapySDROutput::applySettings: cannot set antenna to %s: %s",
                        settings.m_antenna.toStdString().c_str(), ex.what());
            }
        }
    }

    if ((m_settings.m_bandwidth != settings.m_bandwidth) || force)
    {
        forwardChangeToBuddies = true;

        if (dev != 0)
        {
            try
            {
                dev->setBandwidth(SOAPY_SDR_TX, requestedChannel, settings.m_bandwidth);
                qDebug("SoapySDROutput::applySettings: bandwidth set to %u", settings.m_bandwidth);
            }
            catch (const std::exception &ex)
            {
                qCritical("SoapySDROutput::applySettings: cannot set bandwidth to %u: %s",
                        settings.m_bandwidth, ex.what());
            }
        }
    }

    for (const auto &oname : m_settings.m_tunableElements.keys())
    {
        auto nvalue = settings.m_tunableElements.find(oname);

        if (nvalue != settings.m_tunableElements.end() && (m_settings.m_tunableElements[oname] != *nvalue))
        {
            if (dev != 0)
            {
                try
                {
                    dev->setFrequency(SOAPY_SDR_TX, requestedChannel, oname.toStdString(), *nvalue);
                    qDebug("SoapySDROutput::applySettings: tunable element %s frequency set to %lf",
                            oname.toStdString().c_str(), *nvalue);
                }
                catch (const std::exception &ex)
                {
                    qCritical("SoapySDROutput::applySettings: cannot set tunable element %s to %lf: %s",
                            oname.toStdString().c_str(), *nvalue, ex.what());
                }
            }

            m_settings.m_tunableElements[oname] = *nvalue;
        }
    }

    if ((m_settings.m_globalGain != settings.m_globalGain) || force)
    {
        if (dev != 0)
        {
            try
            {
                dev->setGain(SOAPY_SDR_TX, requestedChannel, settings.m_globalGain);
                qDebug("SoapySDROutput::applySettings: set global gain to %d", settings.m_globalGain);
            }
            catch (const std::exception &ex)
            {
                qCritical("SoapySDROutput::applySettings: cannot set global gain to %d: %s",
                        settings.m_globalGain, ex.what());
            }
        }
    }

    for (const auto &oname : m_settings.m_individualGains.keys())
    {
        auto nvalue = settings.m_individualGains.find(oname);

        if (nvalue != settings.m_individualGains.end() && (m_settings.m_individualGains[oname] != *nvalue))
        {
            if (dev != 0)
            {
                try
                {
                    dev->setGain(SOAPY_SDR_TX, requestedChannel, oname.toStdString(), *nvalue);
                    qDebug("SoapySDROutput::applySettings: individual gain %s set to %lf",
                            oname.toStdString().c_str(), *nvalue);
                }
                catch (const std::exception &ex)
                {
                    qCritical("SoapySDROutput::applySettings: cannot set individual gain %s to %lf: %s",
                            oname.toStdString().c_str(), *nvalue, ex.what());
                }
            }

            m_settings.m_individualGains[oname] = *nvalue;
        }
    }

    if (forwardChangeOwnDSP)
    {
        int sampleRate = settings.m_devSampleRate/(1<<settings.m_log2Interp);
        DSPSignalNotification *notif = new DSPSignalNotification(sampleRate, settings.m_centerFrequency);
        m_deviceAPI->getDeviceEngineInputMessageQueue()->push(notif);
    }

    if (forwardChangeToBuddies)
    {
        // send to source buddies
        const std::vector<DeviceSourceAPI*>& sourceBuddies = m_deviceAPI->getSourceBuddies();
        const std::vector<DeviceSinkAPI*>& sinkBuddies = m_deviceAPI->getSinkBuddies();

        for (const auto &itSource : sourceBuddies)
        {
            DeviceSoapySDRShared::MsgReportBuddyChange *report = DeviceSoapySDRShared::MsgReportBuddyChange::create(
                    settings.m_centerFrequency,
                    settings.m_LOppmTenths,
                    2,
                    settings.m_devSampleRate,
                    false);
            itSource->getSampleSourceInputMessageQueue()->push(report);
        }

        for (const auto &itSink : sinkBuddies)
        {
            DeviceSoapySDRShared::MsgReportBuddyChange *report = DeviceSoapySDRShared::MsgReportBuddyChange::create(
                    settings.m_centerFrequency,
                    settings.m_LOppmTenths,
                    2,
                    settings.m_devSampleRate,
                    false);
            itSink->getSampleSinkInputMessageQueue()->push(report);
        }
    }

    m_settings = settings;

    qDebug() << "SoapySDROutput::applySettings: "
            << " m_transverterMode: " << m_settings.m_transverterMode
            << " m_transverterDeltaFrequency: " << m_settings.m_transverterDeltaFrequency
            << " m_centerFrequency: " << m_settings.m_centerFrequency << " Hz"
            << " m_LOppmTenths: " << m_settings.m_LOppmTenths
            << " m_log2Interp: " << m_settings.m_log2Interp
            << " m_devSampleRate: " << m_settings.m_devSampleRate
            << " m_bandwidth: " << m_settings.m_bandwidth
            << " m_globalGain: " << m_settings.m_globalGain;

    return true;
}