I'm having trouble with ethernet cards and cable length.
This is what I have when I connect an old 100Mbps NIC to a Gbps swith port with a short RJ-45 cable (all works fine):
# ethtool eth4
Settings for eth4:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
Advertised pause frame use: Symmetric
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes: 10baseT/Half 10baseT/Full
Link partner advertised pause frame use: No
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Supports Wake-on: g
Current message level: 0x00000001 (1)
Link detected: yes
# ethtool --driver eth4
However, when using a slightly longer cable (5-10m) the link speed is not successfully negotiated, and the switch port's LED does not light up.
[ 105.301478] eth4: setting half-duplex.
[ 105.301736] IPv6: ADDRCONF(NETDEV_UP): eth4: link is not ready
ICMPv4 does not work.
I tried the same cable and the same NIC with another Linux distro, and the result was a successful 100Mbps full-duplex link.
Unfortunately, I did not check if this other distro was using the same 3c59x driver.
In the meantime, does anyone have any ideas? It's the first time I encounter such a problem (it usually happens with 100+m cables, but not with such a short one -- and I tried two of them just to be sure).
Received on Thu Jun 06 2019 - 13:50:19 UTC