RX_URB_FAIL
set_bit(RX_URB_FAIL, &dev->flags);
clear_bit(RX_URB_FAIL, &dev->flags);
if (test_bit(RX_URB_FAIL, &dev->flags))
set_bit(RX_URB_FAIL, &dev->flags);
clear_bit(RX_URB_FAIL, &dev->flags);