Re: [BUG] mv88e6xxx: tx regression in v5.3

[Marek Behun <marek.behun@nic.cz>]

On Thu, 12 Dec 2019 20:31:29 +0100
Andrew Lunn <andrew@lunn.ch> wrote:

> > diff --git a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
> > index bd881497b872..8f61cae9d3b0 100644
> > --- a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
> > +++ b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
> > @@ -408,6 +408,11 @@ port@5 {
> >  				reg = <5>;
> >  				label = "cpu";
> >  				ethernet = <&cp1_eth2>;
> > +
> > +				fixed-link {
> > +					speed = <2500>;
> > +					full-duplex;
> > +				};
> >  			};
> >  		};  
> 
> The DSA driver is expected to configure the CPU port at its maximum
> speed. You should only add a fixed link if you need to slow it down.
> I expect 2500 is the maximum speed of this port.
> 
>   Andrew

Baruch, if the cpu port is in 2500 base-x, remove the fixed-link and do
this:

port@5 {
	reg = <5>;
	label = "cpu";
	ethernet = <&cp1_eth2>;
	phy-mode = "2500base-x";
	managed = "in-band-status";
};

Andrew, if the dsa driver is expected to do that, the code certainly
does not do so. For example in mv88e6xxx_port_set_cmode you have:
 /* Default to a slow mode, so freeing up SERDES interfaces for
  * other ports which might use them for SFPs.
  */
 if (mode == PHY_INTERFACE_MODE_NA)
         mode = PHY_INTERFACE_MODE_1000BASEX;

Marek