QT2_WRITE_BUFFER_SIZE
port_priv->write_buffer = kmalloc(QT2_WRITE_BUFFER_SIZE, GFP_KERNEL);
QT2_WRITE_BUFFER_SIZE,
r = QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE;
count = min(count, QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE);