javax.usb - syncSubmit causes a delay sometimes

Question

I'm developing a java app which uses javax.usb library, It's working perfectly but sometimes when I push it hard,It starts to return late from function syncSubmit .around 2 seconds instead of 10 ms.

What can be the reason? I tried re initialize the javax usb library but It didn't change anything.

Thanks..

    private int BootloaderGetStatus(UsbDevice device) {
    try {
        byte[] data_6 = new byte[6];
        byte bmRequestType = (byte) ((BMREQUEST_DEVICE_TO_HOST << 7) | (BMREQUEST_CLASS << 5)
                | (BMREQUEST_TO_INTERFACE << 0)); // device to host
        byte bRequest = (byte) DFU_REQ_GETSTATUS;
        short wValue = 0;
        short wIndex = 0;
        UsbControlIrp controlIrp = device.createUsbControlIrp(bmRequestType, bRequest, wValue, wIndex);
        
        controlIrp.setData(data_6);
        device.syncSubmit(controlIrp);
        return controlIrp.getActualLength();
    } catch (Exception e) {
        log.error(e);
        return -1;
    }
}

Library-Version

  <dependency>
    <groupId>org.usb4java</groupId>
    <artifactId>usb4java</artifactId>
    <version>1.3.0</version>
  </dependency>
   <dependency>
    <groupId>org.usb4java</groupId>
    <artifactId>usb4java-javax</artifactId>
    <version>1.3.0</version>
  </dependency>

Answer 1

I solved the problem, do NOT poll connected USB devices, use Listener methods like attached or detached USB devices. Then the library starts to work well!