You _want_ to update those registers on every packet. Otherwise the
crappy 8139 chip breaks.
The affected users noticed a clear difference when the update was in
the no-packet branch instead of the packet processing loop. Btw the
excerpt of the documentation outlined by Hirofumi san suggests that
this update makes sense.
Any objection/suggestion regarding a patch which would allow the update
in both branches ?
--
Ueimor