I have two I210-AT network controllers on the same board.
No.1 has an attached flash and runs fine.
No.2 is in flashless mode and has been initially programmed with "eeupdate64e /nic=2 /invmupdate /file=I210_Invm_Copper_NoAPM_v0.6.txt".
Both run under Linux with driver igb version 5.3.2 (latest version from intel).
When No.2 is connected to a Gigabit-switch, the driver reports:
"igb 0000:03:00.0 eth1: igb: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX" and it runs fine.
When No.2 is connected to a 100Mbit-switch, the driver reports (as expected):
"igb 0000:03:00.0 eth1: igb: eth1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: RX/TX", however the performance is
very bad. I have a packet loss of about 95%
Interface No.1 connected to the same switch has no problems at all.
What could be the reason for this strange behaviour? What is more sensitive for 100Base-T than for 1000Base-T?
Phy-circuits (transformer and connector) are equal on both interfaces.
Any help is appreciated.