Hi Martin, > I reworked the commit message because I noticed the upstream Linux kernel has > a > difference with the Raspberry Pi fork of the kernel regarding the algorithm > used to determine the MAC address of the smsc95xx.
So looking at this on an original 3B because that's what I had booted for other testing. > There is no smsc95xx.macaddr in the upstream kernel, and using the upstream > kernel is actually the real use case for the patch. In most cases in device tree this is dealt with aliases [1] to ethernet0, 1 etc. In the U-Boot env I have two env set, ethaddr and usbethaddr both to the same MAC address with b8:27:eb prefix which is assigned to RPi foundation [2]. When I boot Linux I get that MAC address on the interface as expected. > I'm now wondering whether some users are using the module parameter > smsc95xx.macaddr of the Raspberry Pi fork of the kernel to try to change the > MAC, and put one which is not the factory default? I would have thought that the recent RPi kernels would also fall back to the upstream variation too if their fork option wasn't available. > Does this use case exists? If this is the case, the current algorithm in the > forked kernel would mean that, the FDT-provided MAC would have priority over > anything set in the module parameter. > This is already the case anyway when people give to the forked kernel the > firmware-provided FDT (smsc95xx.macaddr is ignored). So this patch aligns > behaviors. > But we should be aware that applying this patch would change the behavior in > the following situation (all conditions need to be true): > - Forked kernel is used > - Fresh FDT (not firmware one) is provided to the kernel > - Custom (not factory) MAC was set in smsc95xx.macaddr parameter Can we take a step back, I'm still unsure what you're trying to resolve here. For me with the upstream U-Boot and the upstream kernel I get the vendor MAC address as I would expect. It should work on any kernel/DT combo as long as the ether ethernet alias is present in the DT. Peter [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/broadcom/bcm283x-rpi-smsc9514.dtsi#n3 [2] https://maclookup.app/search/result?mac=b8:27:eb:
