Serial port doesn't work on windows OS

After calling method QSerialPort.write () data isn't transfered until you will call method QSerialPort.waitForWrite(). Also signal QSerialPort.readyRead() is emited rarely than it should.

There is another problem which exists for a long time. When two sofware exchange data via virtual serial ports (created with com0com or VSPE or similar) in ten or so minutes QSerialPort instance stops data exchange but doesn't indicate it with an error message.  

It happens on all tested PCs with windows 10