On Fri, Jul 17, 2020 at 12:50:07PM +0000, Martin Rowe wrote: > On Fri, 17 Jul 2020 at 09:22, Russell King - ARM Linux admin > <li...@armlinux.org.uk> wrote: > > The key file is /sys/kernel/debug/mv88e6xxx.0/regs - please send the > > contents of that file. > > $ cat regs.broken > GLOBAL GLOBAL2 SERDES 0 1 2 3 4 5 > 0: c800 0 ffff 9e07 9e4f 100f 100f 9e4f 170b > 1: 0 803e ffff 3 3 3 3 3 201f ^^^^ This is where the problem is.
> 1: 0 803e ffff 3 3 3 3 3 203f ^^^^ In the broken case, the link is forced down, in the working case, the link is forced up. What seems to be happening is: dsa_port_link_register_of() gets called, and we do this: phy_np = of_parse_phandle(dp->dn, "phy-handle", 0); if (of_phy_is_fixed_link(dp->dn) || phy_np) { if (ds->ops->phylink_mac_link_down) ds->ops->phylink_mac_link_down(ds, port, MLO_AN_FIXED, PHY_INTERFACE_MODE_NA); return dsa_port_phylink_register(dp); which forces the link down, and for some reason the link never comes back up. One of the issues here is of_phy_is_fixed_link() - it is dangerous. The function name leads you astray - it suggests that if it returns true, then you have a fixed link, but it also returns true of you have managed!="auto" in DT, so it's actually fixed-or-inband-link. Andrew, any thoughts? I think it's looking more and more like we need my phylink hack to grab the "defaults" for the port on phylink_start() to allow DSA to work sanely with phylink, so that phylink can have the complete information about the CPU port at all times. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!