From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751847AbeEEUfp (ORCPT ); Sat, 5 May 2018 16:35:45 -0400 Received: from mail-pg0-f51.google.com ([74.125.83.51]:39969 "EHLO mail-pg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751230AbeEEUfm (ORCPT ); Sat, 5 May 2018 16:35:42 -0400 X-Google-Smtp-Source: AB8JxZrMyMXbiFn78MtZ4I0MF+6hjaCNJGxGJRPDBjpa+ILAmQM44ZmgQlikr35R3osIr2Q71JiGmA== Date: Sat, 05 May 2018 13:35:34 -0700 In-Reply-To: <20180504152103.18152-1-antoine.tenart@bootlin.com> References: <20180504152103.18152-1-antoine.tenart@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Autocrypt: addr=f.fainelli@gmail.com; keydata=mQGiBEjPuBIRBACW9MxSJU9fvEOCTn RNqG/13rAGsj+vJqontvoDSNxRgmafP8d3nesnqPyRxGlkaOSDuu09rxuW+69Y2f1TzjFuGpBk4y sWOR85O2Nx8AJ6fYGCoeTbovrNlGT1M9obSFGQX3IzRnWoqlfudjTO5TKoqkbOgpYqIo5n1QbEjC CwCwCg3DOH/4ug2AUUlcIT9/l3pGvoRJ0EAICDzi3l7pmC5IWn2n1mvP5247urtHFs/uusE827DD j3K8Upn2vYiOFMBhGsxAk6YKV6IP0dZdWX6fqkJJlu9cSDvWtO1hXeHIfQIE/xcqvlRH783KrihL csmnBqOiS6rJDO2x1eAgC8meAXSAgsrBhcgGl2Rl5gh/jkeA5ykwbxA/9u1eEuL70Qzt5APJmqVX R+kWvrqdBVPoUNy/tQ8mYcnzJJ63ng3tHhnwHXZOu8hL4nqwlYHRa9eeglXYhBqja4ZvIvCEqSmE ukfivk+DlIgVoOAJbhqIWgvr3SIEuR6ayY3f5j0f2ejUMYlYYnKdiHXFlF9uXm1ELrb0YX4GMHz7 QnRmxvcmlhbiBGYWluZWxsaSA8Zi5mYWluZWxsaUBnbWFpbC5jb20+iGYEExECACYCGyMGCwkIBw MCBBUCCAMEFgIDAQIeAQIXgAUCVF/S8QUJHlwd3wAKCRBhV5kVtWN2DvCVAJ4u4/bPF4P3jxb4qE Y8I2gS6hG0gACffNWlqJ2T4wSSn+3o7CCZNd7SLSC5BA0ESM+4EhAQAL/o09boR9D3Vk1Tt7+gpY r3WQ6hgYVON905q2ndEoA2J0dQxJNRw3snabHDDzQBAcqOvdi7YidfBVdKi0wxHhSuRBfuOppupd Xkb7zxuPQuSveCLqqZWRQ+Cc2QgF7SBqgznbe6Ngout5qXY5Dcagk9LqFNGhJQzUGHAsIshap1f0 B1PoUyUNeEInV98D8Xd/edM3mhO9nRpUXRK9Bvt4iEZUXGuVtZLT52nK6Wv2EZ1TiTOiqZlf1P+v xYLBx9eKmabPdm3yjalhY8yr1S1vL0gSA/C6W1o/TowdieF1rWN/MYHlkpyj9cRpc281gAO0AP3V 1G00YzBEdYyi0gaJbCEQnq8Vz1vDXFxHzyhgGz7umBsVKmYwZgA8DrrB0MoaP35wuGR3RJcaG30A nJpEDkBYHznI2apxdcuTPOHZyEilIRrBGzDwGtAhldzlBoBwE3Z3MY31TOpACu1ZpNOMysZ6xiE3 5pWkwc0KYm4hJA5GFfmWSN6DniimW3pmdDIiw4Ifcx8b3mFrROBbDIW13E51j9RjbO/nAaK9ndZ5 LRO1B/8Fwat7bLzmsCiEXOJY7NNpIEpkoNoEUfCcZwmLrU+eOTPzaF6drw6ayewEi5yzPg3TAT6F V3oBsNg3xlwU0gPK3v6gYPX5w9+ovPZ1/qqNfOrbsEFRuiSVsZQ5s3AAMFD/9XjlnnVDh9GX/r/6 hjmr4U9tEsM+VQXaVXqZuHKaSmojOLUCP/YVQo7IiYaNssCS4FCPe4yrL4FJJfJAsbeyDykMN7wA nBcOkbZ9BPJPNCbqU6dowLOiy8AuTYQ48mvIyQ4Ijnb6GTrtxIUDQeOBNuQC/gyyx3nbL/lVlHbx r4tb6YkhkO6shjXhQh7nQb33FjGO4PWU11Nr9i/qoV8QCo12MQEo244RRA6VMud06y/E449rWZFS TwGqb0FS0seTcYNvxt8PB2izX+HZA8SL54j479ubxhfuoTu5nXdtFYFj5Lj5x34LKPx7MpgAmj0H 7SDhpFWF2FzcC1bjiW9mjWHaKaX23Awt97AqQZXegbfkJwX2Y53ufq8Np3e1542lh3/mpiGSilCs aTahEGrHK+lIusl6mzJoil+u3k01ofvJMK0ZdzGUZ/aPMZ16LofjFA+MNxWrZFrkYmiGdv+LG45z SlZyIvzSiG2lKykuVag+IijCIom78P9jRtB1q1Q5lwZp2TLAJlz92DmFwBg1hyFzwDADjZ2nrDxK UiybXIgZp9aU2d++ptEGCVJOfEW4qpWCCLPbOT7XBr+g/4H3qWbs3j/cDDq7LuVYIe+wchy/iXEJ aQVeTCy5arMQorqTFWlEOgRA8OP47L9knl9i4xuR0euV6DChDrguup2aJVU4hPBBgRAgAPAhsMBQ JUX9LxBQkeXB3fAAoJEGFXmRW1Y3YOj4UAn3nrFLPZekMeqX5aD/aq/dsbXSfyAKC45Go0YyxVHG uUuzv+GKZ6nsysJw== Subject: Re: [PATCH net-next] net: phy: sfp: handle cases where neither BR,min nor BR,max is given To: Antoine Tenart , davem@davemloft.net, linux@armlinux.org.uk CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, maxime.chevallier@bootlin.com, gregory.clement@bootlin.com, miquel.raynal@bootlin.com, nadavh@marvell.com, stefanc@marvell.com, ymarkman@marvell.com, mw@semihalf.com From: Florian Fainelli Message-ID: <53A4DFE3-C335-49B2-89C5-061A96C6D99D@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id w45KaBbd003246 On May 4, 2018 8:21:03 AM PDT, Antoine Tenart wrote: >When computing the bitrate using values read from an SFP module EEPROM, >we use the nominal BR plus BR,min and BR,max to determine the >boundaries. But in some cases BR,min and BR,max aren't provided, which >led the SFP code to end up having the nominal value for both the >minimum >and maximum bitrate values. When using a passive cable, the nominal >value should be used as the maximum one, and there is no minimum one >so we should use 0. > >Signed-off-by: Antoine Tenart >--- > >Hi Russell, > >I'm not completely sure about this patch as this case is not really >specified in the specification. But the issue is there, and I've >discuss >this with others. It seemed logical (at least to us :)) to use the >BR,nominal values as br_max and 0 as br_min when using a passive cable >which only provides BR,nominal as this would be the highest rate at >which the cable could work. And because it's passive, there should be >no >issues using it at a lower rate. > >I've tested this with one passive cable which only reports its >BR,nominal (which was 10300) while it could be used when using >1000baseX >or 2500baseX modes. Which SFP modules (vendor and model) exposed this out of curiosity? Russell and I already saw the Cotsworks modules having so e issues with checksums, so building a table of quirks would help. Thanks! -- Florian