From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: RFC: Enabling ethernet drivers to return FCS in the skb? Date: Wed, 19 Nov 2003 07:33:53 -0800 Sender: netdev-bounce@oss.sgi.com Message-ID: <3FBB8D61.6010106@candelatech.com> References: <3FB94311.10004@candelatech.com> <20031119123556.A7622@sygehus.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: "'netdev@oss.sgi.com'" Return-path: To: Rask Ingemann Lambertsen In-Reply-To: <20031119123556.A7622@sygehus.dk> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Rask Ingemann Lambertsen wrote: > On Mon, Nov 17, 2003 at 01:52:17PM -0800, Ben Greear wrote: > >>Is there any interest in adding an Ethtool command to tell the driver to >>push the extra 4 bytes of CSUM into the skb? >> >>When enabling this feature, I'd also like to allow drivers to receive >>frames with bad FCS as well. > > [cut] > >>At least some hardware appears >>to support receiving bad FCS frames (e1000, evidently), but I am not sure >>how wide-spread this feature is... > > > The Intel i82586 and i82596 and can be told to receive frames with a bad FCS. > They can also be told to send a precomputed FCS rather than computing it on > the fly. The i82596 and tulip can also transfer the FCS to memory when > receiving frames. I guess all of this is also supported on the i82557/8/9. If you have a patch or example code that shows how to do this, I'd love to see it. I have code that should RX bad CSUM from the Intel folks, but I can't get it to generate bad CRC (it does framing errors instead with my attempt), so I can't test the RX code properly! I have the path from user-space to the NIC written, so just need to tweak the drivers a bit... Do you know if tulip can be told to accept bad FCS and/or if it can generate a frame with bad FCS somehow? Thanks! Ben > -- Ben Greear Candela Technologies Inc http://www.candelatech.com