From: Rask Ingemann Lambertsen <rask@sygehus.dk>
To: Linux netdev mailing list <netdev@oss.sgi.com>
Subject: Re: RFC: Enabling ethernet drivers to return FCS in the skb?
Date: Mon, 24 Nov 2003 01:05:05 +0100 [thread overview]
Message-ID: <20031124010501.C1657@sygehus.dk> (raw)
In-Reply-To: <3FC077B1.1050807@candelatech.com>; from greearb@candelatech.com on Sun, Nov 23, 2003 at 01:02:41AM -0800
On Sun, Nov 23, 2003 at 01:02:41AM -0800, Ben Greear wrote:
[Intel i82557/8/9 Ethernet chips]
Saving bad frames to memory is controlled by CB_CFIG_SAVE_BAD_FRAMES in byte
6. Saving the FCS to memory is controlled by CB_CFIG_CRC_IN_MEM in byte 18.
See drivers/net/e100/e100_config.h.
> It's less clear what happens when you turn off the FCS generation. One part of
> the document mentions it gets it from RAM, which I assume means it uses the last
> part of the DMA'd packet???
Yes. The last four octets from the skb will be interpreted as an FCS by
whichever board receives that frame.
> Another explanation of the transmit state machine does
> not mention that you can disable FCS generation... I'm going to print this out
> and read it again in detail...
There is a bit in the command word of a TX command which disables FCS
generation. I can't find that bit defined in drivers/net/e100/e100.h, so
you'll have to find it in the docs.
--
Regards,
Rask Ingemann Lambertsen
prev parent reply other threads:[~2003-11-24 0:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-17 21:52 RFC: Enabling ethernet drivers to return FCS in the skb? Ben Greear
2003-11-19 11:35 ` Rask Ingemann Lambertsen
2003-11-19 13:20 ` Maciej W. Rozycki
2003-11-19 15:33 ` Ben Greear
2003-11-20 16:34 ` Rask Ingemann Lambertsen
2003-11-23 9:02 ` Ben Greear
2003-11-24 0:05 ` Rask Ingemann Lambertsen [this message]
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