Re: [PATCH v4 net-next 5/8] net: phylink: explicitly configure in-band autoneg for on-board PHYs

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Fri, Nov 18, 2022 at 01:25:20PM +0200, Vladimir Oltean wrote:
> On Fri, Nov 18, 2022 at 10:09:35AM +0000, Russell King (Oracle) wrote:
> > On Fri, Nov 18, 2022 at 02:01:21AM +0200, Vladimir Oltean wrote:
> > > +	if (pl->config->sync_an_inband && !phy_on_sfp(phy)) {
> > 
> > Hmm, this phy_on_sfp() is new to me, and looking at the git history, I
> > really don't think this does what it claims to do. This returns the
> > status of phydev->is_on_sfp_module, which is set by this code:
> > 
> >         phydev->phy_link_change = phy_link_change;
> >         if (dev) {
> >                 phydev->attached_dev = dev;
> >                 dev->phydev = phydev;
> > 
> >                 if (phydev->sfp_bus_attached)
> >                         dev->sfp_bus = phydev->sfp_bus;
> >                 else if (dev->sfp_bus)
> >                         phydev->is_on_sfp_module = true;
> >         }
> > 
> > ... which is very wrong. "dev" here is the net_device, and a net_device
> > will have its sfp_bus member set when there is a SFP cage present,
> > which may be behind a off-SFP PHY.
> > 
> > This means that when a PHY is attached by the network driver in their
> > ndo_open, if there is a SFP bus on the interface (such as on the
> > Macchiatobin board), the above will set is_on_sfp_module true for the
> > on-board PHY even though it is not in the SFP module.
> > 
> > Essentially, commit b834489bcecc is incorrect, and needs to be fixed
> > before use is made of phy_on_sfp() outside of the broadcom driver.
> 
> IIUC, you're saying that if there is an SFP cage after an on-board PHY
> X (presumably set using phy_sfp_attach()), then PHY X will be declared
> as having phydev->is_on_sfp_module = true despite being on-board?

Having looked more deeply, I don't think it's the problem I thought it
was, so you're all good with using phy_on_sfp(). Sorry for the noise.

-- 
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