customers are reporting problems with some switches and different 8255x at the time AutoNeg is enabled with ethtool (ethtool -s eth1 autoneg on).
Right after issuing this command the network LED goes off and the driver reports "no link". AutoNeg may or may not be already set when this command is issued, but this doesn't matter, as it always breaks after running the command above.
This issue only happens with some switches, notably:
Cisco 2610 XM
Cisco 1400 Series
ONE 60 router
Cisco router 2600
Load Balancer F5 BigIP
We tried to reproduce it with a couple of other switches, but without success.
This all was tested with Linux kernel 18.104.22.168 + v3.5.17 (vendor driver) and 2.6.28 (unpatched), both showing the same results. The hardware showing this behaviour is at least:
Intel Corporation 8255xER/82551IT Fast Ethernet Controller (Device ID 0x1209)
Intel Corporation 82557/8/9 [Ethernet Pro 100] (Device ID 0x1229)
I've attached 'dmesg_after', which I got right after enabling AutoNeg with debugging enabled. I also noticed that MDI status went from MDI-X to MDI after trying to enable AutoNeg. Other than that I got no interesting info from ethtool.
Please let me know if you need further information.