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From: "Stephan Linke" <Stephan.Linke@epygi•de>
To: <joakim.tjernlund@lumentis•se>
Cc: "Linuxppc-Embedded" <linuxppc-embedded@lists•linuxppc.org>
Subject: RE: 8xx_io/enet.c
Date: Tue, 10 Dec 2002 16:02:40 +0100	[thread overview]
Message-ID: <FCEAKDJJAPHPLJFINDAJGENJCLAA.Stephan.Linke@epygi.de> (raw)
In-Reply-To: <IGEFJKJNHJDCBKALBJLLGEKOFIAA.joakim.tjernlund@lumentis.se>


Hi Joakim,

> > Since the errors are reported on packet base it is always the last
packed
> > that get's corrupted. (I think it's like this: when there are no more
> > buffers the CPM simply continues writing on the current buffer causing
this
> > problem).
>
> I think not, once the CPM has received a packet in a BD, it
> closes that BD and
> will not modify that BD until you tell the CPM its free again. Atleast
> this should be the case for the SCC, don't know if the FEC is supposed
> to do the same
>

we are using the one in the 2.4.18 kernel (hardhead). Sorry I don't actualy
know wich patch. :(

But I recall that we had this problem with fec.c while our CPU was under
heavy load. But I think it's the same situation on enet.c.
Finaly you are right. SCCE_ENET_BSY dosn't cause such problems. At the FEC
there is no BSY interrupt event. There's only BD_ENET_RX_OV signaling a
buffer overflow. Since that is an error condition the buffer has to be
discarded leading to the  condition I tried to describe.
It looks like BD_ENET_RX_OV occures in enet.c ONLY for 'oversized' frames.
On FEC it occures on missing BD's too cuasing that stupid behavior.
I didn't expect that mutch of a difference. Sorry.


Stephan


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

       reply	other threads:[~2002-12-10 15:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <IGEFJKJNHJDCBKALBJLLGEKOFIAA.joakim.tjernlund@lumentis.se>
2002-12-10 15:02 ` Stephan Linke [this message]
     [not found] <IGEFJKJNHJDCBKALBJLLMELCFIAA.joakim.tjernlund@lumentis.se>
2002-12-10 17:52 ` 8xx_io/enet.c Stephan Linke
2002-12-10 12:03 8xx_io/enet.c Kári Davíðsson
  -- strict thread matches above, loose matches on Subject: below --
2002-12-10 10:19 8xx_io/enet.c Kári Davíðsson
2002-12-10 10:46 ` 8xx_io/enet.c Joakim Tjernlund

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