Lack of functioning link and activity LEDs on devices without an EEPROM
is expected (not a bug). Quoting the EVB-LAN7850 User's Guide:
When configured with the default internal register settings, the
Ethernet Link status LEDs are not enabled. To enable Ethernet Link
status LEDs, enable the EEPROM.
This is an artifact of the different ways in which the evaluation board
can be used. End-user USB-Ethernet adapters using the Microchip LAN78XX
or LAN7515 controllers should use an EEPROM or have OTP configuration,
if their product configuration does not match the boot default register
configuration.
Sponsored by: The FreeBSD Foundation
Differences between LAN7800 and LAN7850 from the driver's perspective:
* The LAN7800 muxes EEPROM signals with LEDs, so LED mode needs to be
disabled when reading/writing EEPROM. The EEPROM is not muxed on the
LAN7850.
* The Linux driver enables automatic duplex and speed detection when
there is no EEPROM, for the LAN7800 only. With this FreeBSD driver
LAN7850-based adapters without a configuration EEPROM fail to link
(with or without the automatic duplex and speed detection code), so
I have just followed the example of the Linux driver for now.
Sponsored by: The FreeBSD Foundation
Sponsored by: Microchip (hardware)
