On Sat, 2021-02-13 at 01:09 +0000, Russell King - ARM Linux admin wrote:
> On Fri, Feb 12, 2021 at 06:26:29PM -0600, Robert Hancock wrote:
> > When 88E111 is operating in SGMII mode, auto-negotiation should be enabled
>
> 88E1111.
yup..
>
> > on the SGMII side so that the link will come up properly with PCSes which
> > normally have auto-negotiation enabled. This is normally the case when the
> > PHY defaults to SGMII mode at power-up, however if we switched it from some
> > other mode like 1000BaseX, as may happen in some SFP module situations,
> > it may not be.
>
> Do you actually have a module where this applies?
>
> I have modules that do come up in 1000base-X mode, but do switch to
> SGMII mode with AN just fine. So I'm wondering what the difference is.
I saw this with a Finisar FCLF8520P2BTL, which defaults to 1000Base-X with
host-side auto-negotiation disabled. So presumably the auto-negotiation
disabled state carries over when it is switched to SGMII mode. I previously
wrote a patch ("net: phy: marvell: add special handling of Finisar modules with
88E1111") which enabled auto-negotiation for 1000Base-X mode, but we are trying
to switch over to using SGMII with these now.
>
--
Robert Hancock
Senior Hardware Designer, Calian Advanced Technologies
www.calian.com
