Re: [PATCH v2 net-next 3/3] net: phy: aquantia: add support for aqr115c

From: Russell King (Oracle)
Date: Thu Jun 27 2024 - 08:10:09 EST


On Thu, Jun 27, 2024 at 01:30:17PM +0200, Bartosz Golaszewski wrote:
> +static int aqr115c_config_init(struct phy_device *phydev)
> +{
> + /* Check that the PHY interface type is compatible */
> + if (phydev->interface != PHY_INTERFACE_MODE_SGMII &&
> + phydev->interface != PHY_INTERFACE_MODE_2500BASEX)
> + return -ENODEV;
> +
> + phy_set_max_speed(phydev, SPEED_2500);

Please can you explain why this is necessary? Does the PHY report that
it incorrectly supports faster speeds than 2500base-X ?

If phylib is incorrectly detecting the PHYs features, then this should
be corrected via the .get_features method, not in the .config_init
method.

(The same should be true of the other Aquantia PHYs.)

Note that phy_set_max_speed() is documented as:

* The PHY might be more capable than the MAC. For example a Fast Ethernet
* is connected to a 1G PHY. This function allows the MAC to indicate its
* maximum speed, and so limit what the PHY will advertise.

Aquantia seems to be the only PHY driver that calls this function.

Thanks.

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!