USB-specific:
+-EBUSY The URB is already active.
+
-ENODEV specified USB-device or bus doesn't exist
-ENOENT specified interface or endpoint does not exist or
d) ISO: number_of_packets is < 0
e) various other cases
--EAGAIN a) specified ISO start frame too early
- b) (using ISO-ASAP) too much scheduled for the future
- wait some time and try again.
+-EXDEV ISO: URB_ISO_ASAP wasn't specified and all the frames
+ the URB would be scheduled in have already expired.
-EFBIG Host controller driver can't schedule that many ISO frames.