On Mon, Jan 04, 2021 at 06:31:05PM +0100, Andrew Lunn wrote: > > The basic rules here should be, if the MDIO bus is registered, it is > > usable. There are things like PHY statistics, HWMON temperature > > sensors, etc, DSA switches, all which have a life cycle separate to > > the interface being up. > > [Goes and looks at the code] > > Yes, this is runtime PM which is broken. > > sh_mdio_init() needs to wrap the mdp->mii_bus->read and > mdp->mii_bus->write calls with calls to > > pm_runtime_get_sync(&mdp->pdev->dev); > > and > > pm_runtime_put_sync(&mdp->pdev->dev); > Agree. Thanks for actually looking into it.. I'm not really well versed in runtime PM. > The KSZ8041RNLI supports statistics, which ethtool --phy-stats can > read, and these will also going to cause problems. > Not really, this driver connects to the PHY on .ndo_open(), thus any try to actually dump the PHY statistics before an ifconfig up would get an -EOPNOTSUPP since the dev->phydev is not yet populated. This is exactly why I do not understand why some drivers insist on calling of_phy_connect() and its variants on .ndo_open() and not while probing the device - you can access the debug stats only if the interface was started.
