On 03/20/2017 06:43 PM, Florian Fainelli wrote: > On 03/20/2017 10:29 AM, Niklas Cassel wrote: >> From: Niklas Cassel <niklas.cas...@axis.com> >> >> It is usually possible to do >> ethtool -s autoneg on >> so that you trigger an autoneg before calling >> ip link set dev eth0 up > This is completely driver specific and there is no guarantee for this to > work universally across all device drivers because when your interface > is brought down, the most sensible thing to expect in return is that > your PHY is powered down (unless your interface participates in > Wake-on-LAN). > >> However, stmmac returns -EBUSY if !netif_running. >> The only reason for this appears to be that stmmac_init_phy >> is called from stmmac_open instead of from stmmac_dvr_probe. >> >> Move stmmac_init_phy to stmmac_dvr_probe so that ethool >> works as soon as register_netdev has been called. >> stmmac_check_ether_addr was also moved to probe, >> so that the ordering doesn't change. > Are you sure this is a good idea? There are many drivers that moved the > PHY probe into ndo_open() for mainly two things: > > - phy_connect() starts the PHY state machine and starting the state > machine without a network device running is kind of wasting cycles > > - if the interface is probed, but not used, you are keeping the Ethernet > link running without being able to service packets, which is at best a > waste of power
Hello Florian Thank you for your input. I can see the point in keeping phy_connect in ndo_open. What I dislike is the -EBUSY from stmmac_ethtool_get_link_ksettings, since this will create warnings in user space by our favorite monolith. (Please don't flame me, I dislike it as much as you guys.) [ WARNING ] systemd-udevd[236]: link_config: could not get ethtool features for eth0 [ WARNING ] systemd-udevd[236]: Could not set offload features of eth0: Device or resource busy However, it is kind of sad that drivers are so inconsistent of what goes in probe and what goes in ndo_open...which is tied together with the whole mess of when certain ethtool commands work or do not work. Do you know of a good way to avoid the -EBUSY in stmmac_ethtool_get_link_ksettings, but still keep phy_connect in ndo_open? The current code checks netif_running(), which checks __LINK_STATE_START, which gets set by __dev_open(). stmmac_ethtool_get_link_ksettings also returns -ENODEV if ndev->phydev == NULL.
