> I wonder what the gain of that really is? Yes, I can see the advantage
> of making the class drivers more effective. But padding is only
> relevant for the ECM class, isn't it? And are there any ECM class
> devices where SG support matters?
AFAICT the requirement for avoiding ZLP is a property of the slave.
Support for scatter-gather is a property of the host.
So connect an old slave to a modern host and you may be able to use
sg to add the header or padding (and possibly have a fragmented skb).
Generating frames that would have a ZLP should just be a matter of
sending UDP frames with ever increasing lengths - although a
printf in the driver would confirm it.
However the is a report (somewhere) that it would work sometimes
and not others with certain targets.
I've got one of the ASIX USB3 devices here, but the system is running
ubuntu 12.04 - which doesn't have the sg changes. I've not looked far
enough to see if the sg changes in usbnet.c can be applied to that
kernel.
David
