On 06.01.2021 01:52, Russell King - ARM Linux admin wrote:

On Wed, Jan 06, 2021 at 01:44:03AM +0100, Heiner Kallweit wrote:

quoted

The machine type check is there to protect from (theoretical) cases
where the n2100 code (incl. the RTL8169 quirk) may be compiled in,
but the kernel is used on another machine.

That is far from a theoretical case. The ARM port has always supported
multiple machines in a single kernel. They just had to be "compatible"
in other words, the same SoC. All the platforms supported by
arch/arm/mach-iop32x can be built as a single kernel image and run on
any of those platforms.

Good to know, then we indeed need the machine check. IOW, based on
what you state we could even now have the following situation:
N2100 support is compiled in, and the kernel is used on another machine
that by chance also has Realtek RTL8169 in PCI slots 1 or 2.
Then the PCI quirk would be applied, even though the machine doesn't
have the parity issue.