AW: [PATCH net-next v5 2/8] net: mdio: realtek-rtl9300: Add polling documentation

["Markus Stockhausen" <markus.stockhausen@gmx.de>]

> Von: Andrew Lunn <andrew@lunn.ch> 
> Gesendet: Donnerstag, 23. Juli 2026 16:18
> An: Markus Stockhausen <markus.stockhausen@gmx.de>
> Betreff: Re: [PATCH net-next v5 2/8] net: mdio: realtek-rtl9300: Add
polling documentation
> ..
> Just to be sure. You have a broken cable, so could trigger downshift?

I usually tape pin 8 for these kind of tests.
RTL838x switch side gives (port 8 aka LAN1):

MAC link status:
root@OpenWrt:~# devmem 0x1b00a190
0x00010000

So Port 8 = 100 Mbit
see https://svanheule.net/realtek/maple/register/mac_link_spd_sts

MAC force mode for port 8:
root@OpenWrt:~# devmem 0x1b00a124
0x00D71EEC

So port 8: NWAY_EN=1 SPD_SEL=3 (aka 1000Mbit)
See https://svanheule.net/realtek/maple/register/mac_force_mode_ctrl

PHY view
root@OpenWrt:~# ethtool lan1
Settings for lan1:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: No
        Link partner advertised auto-negotiation: Yes
        Link partner advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 8
        Transceiver: external
        Auto-negotiation: on
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes

Nanopi R5S on other side gives:

root@nanopi:~# ethtool eth2
Settings for eth2:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: Symmetric Receive-only
        Link partner advertised auto-negotiation: Yes
        Link partner advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: Unknown
        Supports Wake-on: pumbg
        Wake-on: d
        Link detected: yes