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From: "Hans Feldt" <Hans.Feldt@uab.ericsson.se>
To: <joakim.tjernlund@lumentis.se>
Cc: <linuxppc-embedded@lists.linuxppc.org>, <scop@digitel.com.br>,
	<thomas@corelatus.com>
Subject: Re: [PATCH] arch/ppc/8xx_io/enet.c, version 2
Date: Wed, 13 Nov 2002 20:30:41 +0100	[thread overview]
Message-ID: <001c01c28b4b$28665b80$4f158a86@default> (raw)
In-Reply-To: IGEFJKJNHJDCBKALBJLLAEPLFHAA.joakim.tjernlund@lumentis.se


----- Original Message -----
From: Joakim Tjernlund <joakim.tjernlund@lumentis.se>

> You may be right, perhaps one must invalidate the whole buffer before giving it
> to the CPM/DMA. Suppose you reuse a buffer which has been modified before it
> was freed and the dcache must write back data to free up space and the buffer,
> which now is owned by the CPM, get written to.

I beleive this could happen. Since IP does not perform checksumming
but relies on the link (don't know this really) in that matter, I guess
the application could get wrong data...

> I have not seen any corrupted packets and you are the first to report
> any problems.

Did you run any data integrity tests?

> What modifications have you done?

I haven't used your driver patch. I used the __idea__ of delaying the
invalidate to the point where you know how much has been received. This was
in an RTOS ATM driver for a 405. An integrity test showed that some few
packets was wrong. Data was changed by means of cache lines.

> What CPU?
> Post the driver please.

Irrelevant, non-linux

Cheers,
Hans


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

  reply	other threads:[~2002-11-13 19:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-24 14:23 [PATCH] arch/ppc/8xx_io/enet.c, version 2 Joakim Tjernlund
2002-10-24 14:59 ` Tom Rini
2002-10-24 15:46   ` Joakim Tjernlund
2002-11-01 11:01     ` Joakim Tjernlund
2003-01-28 11:54     ` [PATCH] arch/ppc/8xx_io/enet.c, version 3 Joakim Tjernlund
2003-02-03 10:21       ` Joakim Tjernlund
2003-02-03 12:28         ` Pantelis Antoniou
2002-10-28 15:17 ` [PATCH] arch/ppc/8xx_io/enet.c, version 2 Stephan Linke
2002-10-28 17:24   ` Joakim Tjernlund
2002-11-13 13:50 ` Hans Feldt
2002-11-13 16:35   ` Joakim Tjernlund
2002-11-13 19:30     ` Hans Feldt [this message]
2002-11-13 21:19       ` Joakim Tjernlund
2002-11-13 22:12         ` Dan Malek
2002-11-13 22:54           ` Joakim Tjernlund
2002-11-15 11:52           ` Hans Feldt

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