libusb20_dev_process
if (libusb20_dev_process((void *)dev) != 0) {
err = libusb20_dev_process(ppdev[i]);
while (libusb20_dev_process(pdev) == 0) {
int libusb20_dev_process(struct libusb20_device *pdev);
libusb20_dev_process(p->usb_dev);