Re: [PATCH 2/2] net: phy: adin: implement cable-test support

From: Andrew Lunn
Date: Wed Oct 21 2020 - 10:28:08 EST


> Actually, I'd also be interested [for this PHY], to report a
> "significance impedance" detection, which is similar to the
> short-detection that is already done.

You can add that as just another element of the enum.

> At first, this report would sound like it could be interesting; but
> feel free to disagree with me.
>
> And there's also some "busy" indicator; as-in "unknown activity during
> diagnostics"; to-be-honest, I don't know what this is yet.

The link partner did not go quiet. You can only do cable tests if the
partner is not sending frames or pulses. You will find most PHYs have
some sort of error status for this. For the Marvell driver, this is
MII_VCT7_RESULTS_INVALID. In that case, the Marvell driver returns
ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC.

Andrew