Re: [PATCH net-next RFC 0/5] net: phy: Introduce a port representation

[Oleksij Rempel]

On Tue, Jan 07, 2025 at 03:14:43PM +0000, Russell King (Oracle) wrote:
> On Tue, Jan 07, 2025 at 03:02:46PM +0100, Oleksij Rempel wrote:
> > On Tue, Jan 07, 2025 at 02:26:05PM +0100, Kory Maincent wrote:
> > > On Thu, 2 Jan 2025 18:03:52 +0100
> > > Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote:
> > The IEEE 802.3 - 2022 has following variants:
> > 14.5.2 Crossover function - only A<>B swap is supported
> > 40.4.4 Automatic MDI/MDI-X Configuration - only A<>B swap is supported?
> > 55.4.4 Automatic MDI/MDI-X configuration - 4 swap variants are supported
> > 113.4.4 Automatic MDI/MDI-X configuration - 4 swap variants are supported
> > 126.4.4 Automatic MDI/MDI-X configuration - 4 swap variants are supported
> > 
> > This was only the pair swap. How to reflect the polarity swap withing
> > the pairs?
> 
> 802.3 supports this because of the problems caused by miswired cables,
> which are typically a user thing. It's not really there to give freedom
> to designers to wire their sockets incorrectly.
> 
> Do we have any real cases where a socket has been wired incorrectly?

Yes. I tested some low cost adapter using same driver but reporting
incorrect results, depending on board. I can explain it only by
incorrect PCB design.

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