On Thu, Nov 26, 2020 at 05:37:22PM +0200, Baruch Siach wrote: > Hi netdev list, > > I am trying to retrieve all MAC supported link modes > (ETHTOOL_LINK_MODE_*) for network interfaces with SFP port. The > 'supported' bit mask that ETHTOOL_GLINKSETTINGS provides in > link_mode_masks[] changes to match the SFP module that happens to be > plugged in. When no SFP module is plugged, the bit mask looks > meaningless. > > I understand that ETHTOOL_LINK_MODE_* bits are meant to describe PHY > level capabilities. So I would settle for a MAC level "supported rates" > list. > > Is there anything like that?
No, because there's a problem: the link modes that the MAC supports is not a particularly certain thing. When there's no module inserted, we don't know what interface mode may be in operation, and the interface mode has a big handle in determining which link modes can be supported. For example, if it's operating as 1000BASE-X or 10GBASE-R, then we're pretty limited to a single link mode if there's nothing else present. If it's in SGMII, then 10/100/1000 speeds are possible but there's no link mode to describe that - no PHY, therefore there's no copper and therefore BASE-T is meaningless. The ethtool link modes are, in reality, _media_ link modes. If there is no media or socket that defines the media, there are no link modes. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
