QLowEnergyController disconnectFromDevice not working

[Slingy]

Hi All,
I am implementing a Qt app on Windows 10 to communicate with an embedded system over BLE (peripheral device), using the Qt Bluetooth Low Energy API. My app is central role. I am using Qt 5.15.2 MinGW 64-bit. I can successfully discover my embedded peripheral device, connect to it, discover services and details (characteristics and properties) and can send and receive data to/from the device successfully via its characteristics. The only problem is it seems that disconnecting from the peripheral device via the QLowEnergyController::disconnectFromDevice() API does not work. I enable notifications for the peripheral device's Tx characteristic to be notified when data is received. Before attempting to disconnect from the device, I disable the notifications (and wait for its notification via QLowEnergyService::descriptorWritten). The peripheral device has a debug port and I can see the notification being disabled successfully. However, calling disconnectFromDevice() after that does not seem to have any effect. In this state I cannot connect to the device again. However, if I close the App, the connection to the device is broken (I can see this via the device debug port) and then I can make a new connection to the device when running the App again. Below are some code snippets. I would greatly appreciate it if someone can shed some light on this problem and maybe suggest on how to fix it. Thank you very much in advance. Regards.

    // Service details had been discovered.
    connect( periphService, &QLowEnergyService::characteristicChanged,
                this, &btDevice::charateristicChanged );
    
    connect( periphService, &QLowEnergyService::descriptorWritten,
                    this, &btDevice::descriptorWritten );

    // Enable notifications for Tx characteristic
    if ( ch.isValid() )
    {
        // Valid Tx characteristic
        QLowEnergyDescriptor desc =
            ch.descriptor( QBluetoothUuid::ClientCharacteristicConfiguration );

        if ( desc.isValid() )
        {
            if ( ch.properties() & QLowEnergyCharacteristic::Notify )
            {
                // Enable notifications
                periphService->writeDescriptor( desc, QByteArray::fromHex( "0100" ) );
            }
        }
    }

//...
// Data transferred between app (central) and peripheral. About to disconnect...
//..

    // Public method to disconnect after data transfer done.
    void btDevice::disconnectFromDevice()
    {
        if ( leController->state() != QLowEnergyController::UnconnectedState )
        {
            // Disable notifications. The actual disconnect is done when the 
            // descriptorWritten slot is invoked.
            periphService->writeDescriptor( desc, QByteArray::fromHex( "0000" ) );
        }
    }
    
    void btDevice::descriptorWritten( const QLowEnergyDescriptor & desc, const QByteArray & value )
    {
        if ( desc == descTxCharacteristic )
        {
            QString valueStr = QString( value.toHex() );
            if ( valueStr == "0000" )
            {
                // Notifications disabled. On the peripheral device
                // debug port I can see this was successful. Now disconnect.
                // This disconnect does not seem to have any effect on the
                // peripheral device. 
                leController->disconnectFromDevice();
                
                QString stateStr = QVariant::fromValue( leController->state() ).toString();
                qDebug() << "LE Controller State:" << stateStr;
                
                // The debug output from the above 2 lines show:
                // LE Controller State: "UnconnectedState"
            }
        }
    }

[schoppem]

@Slingy Hello Slingy, i am experiencing exact same behaviour. i know that the qt bluetooth api is not entirely compatible with mingw in qt 5.14. but switching to msvc compiler is not an option for me. Did you get any further on this?