• Registered: 2015-03-20
  • Posts: 14

Topic: Ethernet tweaks

Hi,

I'm trying to figure out why the FEC ethernet is flaky on OpenBSD. http://www.kosagi.com/w/index.php?title … _every_day lists some tweaks that were needed to make the it work properly, but I can't see any sign they were integrated to the kernel. Did they get merged, or were they fixed in hardware?

-d

  • Registered: 2015-03-20
  • Posts: 14

Re: Ethernet tweaks

nevermind - found it. The skew values are poked in via the FDT. Copying them into a hacked-up version of FreeBSD's micphy.c driver (since OpenBSD doesn't yet have FDT support) to poke them into the phy gives me stable net.

  • xobs
  • Administrator
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  • Registered: 2014-05-25
  • Posts: 442

Re: Ethernet tweaks

Yes, there's an obscure reference in the RGMII spec that says you're supposed to route the clock lines 10cm longer than the data lines.  Nobody does that, which is why those registers exist.

Interestingly, the Sabre i.MX6 reference board uses the same PHY, routes the signals the same, and requires the same PHY fix.