Messages in this thread | | | Date | Mon, 18 Jul 2022 19:01:30 +0100 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH net-next v3 08/47] net: phylink: Support differing link speeds and interface speeds |
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On Mon, Jul 18, 2022 at 07:28:58PM +0200, 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.
... and passing the SGMII link speed (1G) will break a lot of stuff where the MAC/PCS may need to know the media speed to do the right number of symbol replication.
So I don't think we can get away with just saying ->speed is the link speed which will prevent drivers breaking. I don't think it's that simple. Like everything with phylink, all the drivers need to be looked at and tweaked with every damn change, which makes phylink development painfully slow.
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