[vortex] MTU setting controls ?

[Andrew Morton]

Matti Aarnio wrote:
> 
> Hi,
> 
>   I need the card to support frames of larger than normal size,
> and ways to do it seem to be simple at least in case one has 3c905B
> (or latter) card.  One way to do it is to supply global 'mtu'
> value of e.g. 1504, and let the existing code to handle the thing.
> 

I'd suggest simply failing the MTU change if the device is open.
That way, vortex_up() will take care of lots of initialisation.
Does that work OK?  If you do:

	ifconfig eth0 down
	ifconfig eth0 mtu 2000
	ifconfig eth0 up

The 905C has a 256-slot multicast filter.  3com forgot to document
the hashing algorithm, but there is an implementation in their
3c90x.c.

I'd be interested in Donald's opinion on the overall idea.

What's your timing on this?  I have a small amount of stuff which
needs to go into 2.4.0 for the 3c905CX.  Then as soon as 2.4.1
hits the streets Alexey has a patch which adds scatter-gather
for the fragmented SKBs which are part of the zerocopy-sendfile
changes.

I guess we could include this work in that changeset.