Re: [RFC PATCH v1 8/9] net: phy: micrel: ksz886x/ksz8081: add cabletest support

[Andrew Lunn]

On Wed, May 05, 2021 at 11:20:24AM +0200, Oleksij Rempel wrote:
> This patch support for cable test for the ksz886x switches and the
> ksz8081 PHY.
> 
> The patch was tested on a KSZ8873RLL switch with following results:
> 
> - port 1:
>   - cannot detect any distance
>   - provides inverted values
>     (Errata: DS80000830A: "LinkMD does not work on Port 1",
>      http://ww1.microchip.com/downloads/en/DeviceDoc/KSZ8873-Errata-DS80000830A.pdf)
>     - Reports "short" on open or ok.
>     - Reports "ok" on short.

Quite broken. Distance is optional, simply don't report it.  Status is
harder. Reporting ETHTOOL_A_CABLE_RESULT_CODE_OK should really mean
the cable is O.K. If you cannot tell open from O.K, i would return
ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC.

More later.

	Andrew