On Sat, Nov 27, 1999 at 02:59:56AM +0900, SUNAGAWA Keiki wrote:
> Hi,
> 
> I wrote driver for Focus' NuBus Ethernet card with SMC91C92.
> It kinda works so far.  I can telnet or ftp to/from my Mac
> IIci with this card.  The problem is that the driver don't
> handle fragmented packet properly.  What am I missing here?
> 
> The diffs to -current source is at:
> 
> http://www05.u-page.so-net.ne.jp/ba2/kei_sun/NetBSD/hack/if_sm.diff
> 
> To describe the problem, 192.168.0.4 is NFS server and
> 192.168.0.10 is target Mac IIci which is NFS client. it
> mounts server's /a to local /a.
> 
> Running 'find /a &', tcpdump shows the diagnosis below.
> 
> Any comments/suggestions are welcome.

I didn't look at the sources but I remeber a similar behavior with old 8 bit
isa cards: They couldn't cope with the load and always dropped the last
(or before) fragment of the 8k NFS reply. This gave this kind of behavior.

Are you sure the mac doesn't drop packets ? There should be a flag
in a register of the SMC91C92 which tells if an overflow occured ...
To confirm this theory you could try a bulk TCP transfer and see if there
are retransmissions. You could also decrease the NFS read/write sizes
to 2K (1K will work for sure, there will be no fragments :)

--
Manuel Bouyer <bouyer@antioche.eu.org>
--