Re: [PATCH V5 net-next 05/11] net: hibmcge: Implement some .ndo functions

[Jijie Shao]

on 2024/8/29 22:59, Andrew Lunn wrote:
> On Thu, Aug 29, 2024 at 07:43:39AM -0700, Jakub Kicinski wrote:
> > On Thu, 29 Aug 2024 10:40:07 +0800 Jijie Shao wrote:
> > > on 2024/8/29 9:39, Jakub Kicinski wrote:
> > > > On Tue, 27 Aug 2024 21:14:49 +0800 Jijie Shao wrote:
> > > > > +static int hbg_net_open(struct net_device *dev)
> > > > > +{
> > > > > +	struct hbg_priv *priv = netdev_priv(dev);
> > > > > +
> > > > > +	if (test_and_set_bit(HBG_NIC_STATE_OPEN, &priv->state))
> > > > > +		return 0;
> > > > > +
> > > > > +	netif_carrier_off(dev);
> > > > Why clear the carrier during open? You should probably clear it once on
> > > > the probe path and then on stop.
> > > In net_open(), the GMAC is not ready to receive or transmit packets.
> > > Therefore, netif_carrier_off() is called.
> > >
> > > Packets can be received or transmitted only after the PHY is linked.
> > > Therefore, netif_carrier_on() should be called in adjust_link.
> > But why are you calling _off() during .ndo_open() ?
> > Surely the link is also off before ndo_open is called?
> I wounder what driver they copied?
>
> The general trend is .probe() calls netif_carrier_off(). After than,
> phylib/phylink is in control of the carrier and the MAC driver does
> not touch it. in fact, when using phylink, if you try to change the
> carrier, you will get SHOUTED at from Russell.
>
> 	Andrew

Read the PHY driver code:
netif_carrier_on() or netif_carrier_off()
has been called in phy_link_change() based on the link status.
Therefore, the driver does not need to process it.

static void phy_link_change(struct phy_device *phydev, bool up)
{
	struct net_device *netdev = phydev->attached_dev;

	if (up)
		netif_carrier_on(netdev);
	else
		netif_carrier_off(netdev);
	phydev->adjust_link(netdev);
	if (phydev->mii_ts && phydev->mii_ts->link_state)
		phydev->mii_ts->link_state(phydev->mii_ts, phydev);
}

Thank you. I'll delete it in v6.
	Jijie Shao