AFAIK Holger(?) wrote something about that a few days ago: The driver
should not drop packets on his own if this is not supported in the hardware.
Anyway since Augusto mentioned, that the FlexcopII (not IIb or III; I
didn't know that) has _only_ the 6 hw filters it could be worth to have
a low level emulation at least in this case.
So, if skystar2.c can push more packets than asked for, the question
becomes "is it better to software filter or let them go?" (from the
speed point of view).
one of the first checks in the swfilter code will discard them. If you
implement a second check in the hardware driver code this means that
every packet gets checked twice which is probably more expensive.