Hi AceLan,
I wish we can detect if the MAC passthrough is enabled, so that we
know if we need to poll for the MAC address.
Unfortunately, like you I am not aware of any way for the driver to know
whether MAC passthrough via FW is enabled. Because of this we have been
exploring a simpler way to support this feature via ACPI objects (which are
set by the BIOS when MAC passthrough is enabled and are easy for the driver
to query). I know some vendors have already implemented it, and I am
currently drafting a patch to send.
Any good news about this patch?
The patch is here:
https://lists.osuosl.org/pipermail/intel-wired-lan/Week-of-Mon-20260706/055944.html
I tested it on my setup with MAC passthrough enabled in the BIOS, with
good results; no community feedback yet. I encourage you to try it.
Lenovo and Dell laptops should have the capability.
The mechanism I have in mind does not require BIOS support - the I225/I226
FW already supports the required interrupt, AFAIK - it merely needs to be
enabled in the igc driver. With that said, there still remains the question
of how to notify the network stack above us that the MAC address has changed
post-probe - and whether it is even supported.
Looking at it again, this may not be as big of a deal as I feared. If we
can call eth_hw_addr_set at any point in time to change the address,
then we should be able to do this in a response to a FW interrupt. I can
try to draft a patch for that, in parallel to collecting feedback on the
ACPI approach. These are two different means to the same end, and some
solutions may implement one but not the other.
--Dima
