Retry up to USB_RETRY_MAX times to clear a halt condition before failing.

usbutils.c

@@ -2310,6 +2310,9 @@ usb_bulk_transfer(struct libusb_device_handle *dev_handle, int intinfo,
 				usb_cmdname(cmd), *transferred, err, errn);
 
 	if (err == LIBUSB_ERROR_PIPE || err == LIBUSB_TRANSFER_STALL) {
+		int retries = 0;
+
+		do {
 			cgpu->usbinfo.last_pipe = time(NULL);
 			cgpu->usbinfo.pipe_count++;
 			applog(LOG_INFO, "%s%i: libusb pipe error, trying to clear",
@@ -2320,6 +2323,7 @@ usb_bulk_transfer(struct libusb_device_handle *dev_handle, int intinfo,
 
 			if (err)
 				cgpu->usbinfo.clear_fail_count++;
+		} while (err && ++retries < USB_RETRY_MAX);
 	}
 	if ((endpoint & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_IN)
 		memcpy(data, buf, length);