Correction to the "Ethernet problem"

[Leon Pollak]

On Tuesday, 5 בFebruary 2008, Ian Caddy wrote:
> Hi Leon,
>
> Look like we are getting closer now... ;-)
I am sure that there are no undecidable problems in the world...:)


> > Well, the switch theory is clear.
> > But isn't the first arp request enough for the switch to learn that RTEMS
> > box has that MAC address? Actually, even the first arp "box to itself"
> > should teach it were is it, no?
> > Besides, IMHO, this can not explain the loss of INCOMING packet after two
> > outgoing were sent and I saw them in my PC via the same switch.
>
>  From your debugging it looks like it is something to do with the PHY
> interaction with the particular switch.
Hmm... May be... Why do you think so?


> Are you using an external PHY?  
Not sure what do you mean... The PHY is external to the MPC8247 CPU, but it is 
on-board...:)


> If so, do you have the part number? 
DP83849ID from National.


> Does you firmware initialise the PHY at all or do you expect it to come
> up in the correct state?
The PHY does auto-negotiation. The spec says that this may take 2-3s after 
reset. I give it about 14-16s as minimum and it is still not enough!?


> Is there an interrupt line from the PHY?  If so, do you service this
> interrupt line?
No, there is not, AFAIK.


> It is possible that something is happening with the PHY on the
> completion of the negotiation or reception of the first packet, and it
> may want to tell the MAC about it.  I am just clutching at straws here
> though... ;-)
Yes, I understand.
I read again through the spec and did not find anything suspicious. But I am 
already  old enough to know, that I read not what it written, but what I 
expect(want) to read...:)


> regards,
> Ian Caddy
Thanks for your willing to help.

-- 
Leon