Re: mv88e6240 configuration broken for B850v3

Martyn Welch
2021-12-06T19:25:03Z

On Mon, 2021-12-06 at 20:50 +0200, Vladimir Oltean wrote:
> On Mon, Dec 06, 2021 at 06:37:44PM +0000, Martyn Welch wrote:
> > On Mon, 2021-12-06 at 20:31 +0200, Vladimir Oltean wrote:
> > > On Mon, Dec 06, 2021 at 06:26:25PM +0000, Martyn Welch wrote:
> > > > On Mon, 2021-12-06 at 17:44 +0000, Martyn Welch wrote:
> > > > > On Fri, 2021-12-03 at 17:25 +0100, Andrew Lunn wrote:
> > > > > > > Hi Andrew,
> > > > > >
> > > > > > Adding Russell to Cc:
> > > > > >
> > > > > > > I'm currently in the process of updating the GE B850v3
> > > > > > > [1] to
> > > > > > > run
> > > > > > > a
> > > > > > > newer kernel than the one it's currently running.
> > > > > >
> > > > > > Which kernel exactly. We like bug reports against net-next,
> > > > > > or
> > > > > > at
> > > > > > least the last -rc.
> > > > > >
> > > > >
> > > > > I tested using v5.15-rc3 and that was also affected.
> > > > >
> > > >
> > > > I've just tested v5.16-rc4 (sorry - just realised I previously
> > > > wrote
> > > > v5.15-rc3, it was v5.16-rc3...) and that was exactly the same.
> > >
> > > Just to clarify: you're saying that you're on v5.16-rc4 and that
> > > if
> > > you
> > > revert commit 3be98b2d5fbc ("net: dsa: Down cpu/dsa ports phylink
> > > will
> > > control"), the link works again?
> > >
> >
> > Correct
> >
> > > It is a bit strange that the external ports negotiate at
> > > 10Mbps/Full,
> > > is that the link speed you intend the ports to work at?
> >
> > Yes, that's 100% intentional due to what's connected to to those
> > ports
> > and the environment it works in.
> >
> > Martyn
>
> Just out of curiosity, can you try this change? It looks like a
> simple
> case of mismatched conditions inside the mv88e6xxx driver between
> what
> is supposed to force the link down and what is supposed to force it
> up:
>
> diff --git a/net/dsa/port.c b/net/dsa/port.c
> index 20f183213cbc..d235270babf7 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -1221,7 +1221,7 @@ int dsa_port_link_register_of(struct dsa_port
> *dp)
>                 if (of_phy_is_fixed_link(dp->dn) || phy_np) {
>                         if (ds->ops->phylink_mac_link_down)
>                                 ds->ops->phylink_mac_link_down(ds,
> port,
> -                                       MLO_AN_FIXED,
> PHY_INTERFACE_MODE_NA);
> +                                       MLO_AN_PHY,
> PHY_INTERFACE_MODE_NA);
>                         return dsa_port_phylink_register(dp);
>                 }
>                 return 0;

Yes, that appears to also make it work.

Martyn