Re: racing ndo_open()/phylink*connect() with phy_probe()

Andrew Lunn
2024-05-01T15:23:22Z

> > It seems unlikely, but one possibility is:
> >
> > static int stmmac_xgmac2_mdio_read_c22(struct mii_bus *bus, int phyaddr,
> > int phyreg)
> > {
> > struct net_device *ndev = bus->priv;
> > struct stmmac_priv *priv;
> > u32 addr;
> >
> > priv = netdev_priv(ndev);
> >
> > /* Until ver 2.20 XGMAC does not support C22 addr >= 4 */
> > if (priv->synopsys_id < DWXGMAC_CORE_2_20 &&
> > phyaddr > MII_XGMAC_MAX_C22ADDR)
> > return -ENODEV;
> >
> > Maybe if the interface is down, priv->synopsys_id has not been set
> > yet? Your devices are at address 8 and 10, so if priv->synopsys_id
> > where 0, this would give you the ENODEV.
>
> Yes, I did look at that, but didn't read the DT snippet to realise
> that the addresses would be trapped by that. So, looking at where
> priv->synopsys_id is set... is in stmmac_hwif_init(), which is
> called from stmmac_hw_init(), which in turn is called from
> stmmac_dvr_probe(). This is the only path that leads here.
>
> This all happens before the MDIO bus is registered, so the value of
> priv->synopsys_id should be set by the time the MDIO bus is registered.
>
> So I'm unconvinced...

Me too. I just wanted to give an example of why it is important to
track down the source of the ENODEV.

Andrew