On May 4, 2018 8:21:03 AM PDT, Antoine Tenart <antoine.ten...@bootlin.com> 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 <antoine.ten...@bootlin.com> >--- > >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
