Part 2 of the discussion... A similar issue applies to PHY_INTERFACE_MODE_USXGMII, but is reversed. USXGMII supports 10M, 100M, 1G, 2.5G, 5G and 10G. Phylink allows all of these because that's what the appropriate standard says. dwxgmac2 initialises config register settings for speeds from 10M up to 10G. However, the PHY_INTERFACE_MODE_USXGMII switch() block in stmmac_mac_link_up() only handles 2.5G, 5G and 10G. Shouldn't it handle the other speed cases - it looks like the MAC does support them. The initialisation done by dwxgmac2_setup() does setup control register masks for everything from 10M to 10G, so on the face of it, it looks like a mistake in stmmac_mac_link_up(). If it's something outside of the MAC that doesn't support these speeds when operating as USXGMII, then that needs to be handled. The other weird thing is that when using PHY_INTERFACE_MODE_USXGMII with XPCS, XPCS supports 1G, 2.5G and 10G ethtool link modes, but not 5G. So combining the implementation in stmmac_mac_link_up(), that means only 2.5G and 10G can actually be functional. Is that a fair assessment of the USXGMII situation with stmmac? Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
