Hi, Jack, On Jul 22, 2014, at 1:46 PM, Jack Hickish wrote:
> Judging by the switch diagnostics, everything is making it through the > switch and only being dropped at the ROACH RX end. I'm digging through > the switch manual at the moment, but haven't found anything too > promising looking so far. > It would seem that some of the SFP ports on the ROACH are noticeably > worse than others -- the long cable pretty consistently causes > problems everywhere, but if I use only the worst ports with the short > cable, they get much better, but far from perfect. You could try going from ROACH2 to switch to 10 GbE NIC is a PC. If that works fine (I suspect it will), then the problem would indeed seem to tbe on the ROACH2 RX side. > I've twiddled the SFP+ RX parameters on the roach, but to no avail > (though I think these only affect the short link between the FPGA and > the vitesse tranceiver anyway, I can't see any control ports between > the FPGA and the vitesse in system.mhs) Oh, yeah, the pre-emph and other parameters that can be changed in the 10 GbE yellow block are only for the MGT drivers in the ROACH2 FPGA that talk to the Vitesse PHY. I think there is an MDIO interface to the SFP+ PHY that might provide a path for tweaking things in the SFP+ PHY itself. This MDIO interface used to be unreliable, but I think it has been fixed (though I haven't tried it since then). Dave
