Messages in this thread | | | Subject | Re: [PATCH net-next v3 08/47] net: phylink: Support differing link speeds and interface speeds | From | Sean Anderson <> | Date | Mon, 18 Jul 2022 13:40:45 -0400 |
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On 7/18/22 1:28 PM, Andrew Lunn wrote: >> > I am rather worried that we have drivers using ->speed today in their >> > mac_config and we're redefining what that means in this patch. >> >> Well, kind of. Previously, interface speed was defined to be link speed, >> and both were just "speed". The MAC driver doesn't really care what the >> link speed is if there is a phy, just how fast the phy interface mode >> speed is. > > I'm not sure that is true. At least for SGMII, the MAC is passed the > line side speed, which can be 10, 100, or 1G. The PHY interface mode > speed is fixed at 1G, since it is SGMII, but the MAC needs to know if > it needs to repeat symbols because the line side speed is lower than > the host side speed.
Right. In this case the phy interface speed is changing, so the MAC needs to know about it. I suppose a more precise definition would be something like
> The data rate of the media-independent interface between the MAC and > the phy, without taking into account protocol overhead or flow control, > but including encoding overhead.
as opposed to the link speed which is
> The data rate of the medium between the local device and the link > partner, without ...
--Sean
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