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

On Mon, May 10, 2021 at 11:06:56AM +0200, Oleksij Rempel wrote:

On Wed, May 05, 2021 at 02:47:19PM +0200, Andrew Lunn wrote:

quoted

On Wed, May 05, 2021 at 11:20:24AM +0200, Oleksij Rempel wrote:

quoted

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.

Yes, patch "net: phy: micrel: add patch for erratas on port1" provides
a flag to return -ENOTSUPP on this port.

Is it acceptable way? Should I squash this patches?

This is O.K. Maybe add a comment that later patches in the series with
handle the errata?

       Andrew