Hifive-U vs 1000baseT

Palmer Dabbelt palmer at sifive.com
Thu Oct 18 10:41:44 PDT 2018

On Thu, 18 Oct 2018 02:40:17 PDT (-0700), schwab at suse.de wrote:
> Are there any known issues with ethernet on the Hifive-U connecting to a
> 1Gb port?  I see that the port gets a link, but no traffic at all.  When
> connecting to a 100Mb port it works fine.

That's weird.  If anything I'd expect it to be the other way around, with 100Mb 
ports not working and 1Gb ports working -- it was that way for a while because 
the link type detection is a bit flaky so we just defaulted to 1Gb.

I just checked all the boards we have out on the lab bench, and assuming I 
managed to follow through the big tangles of wires correctly everything is at 
1Gb.  Some early revisions of the boards had a screwed up trace on some of the 
1Gb lines that mandated a special cable to un-reverse the pairs, but I don't 
think any of those made it out of the lab -- if you send me your serial number 
then I'll double-check.

Have you tried more than one ethernet cable?

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