Coming back to the issue described in this patch,
usbnet_get_link_ksettings_internal is currently only used in
cdc_ether.c and cdc_ncm.c as a callback for ethtool.
Can we assume that this part only concerns Ethernet devices
(and that, at least for now, none of the existing devices can
retrieve the duplex status through this interface)?

"ethtool" can be used with any sort of interface, if the driver
implements the op. So you should not assume it is only used for
Ethernet.

	Andrew