On Wed, May 27, 2020 at 03:41:22PM +0000, Amit Cohen wrote:
> Hi Andrew,
> We are planning to send a set that exposes link-down reason in ethtool.
> It seems that the ability of your set "Ethernet cable test support" can be integrated with link-down reason.
> 
> The idea is to expose reason and subreason (if there is):
> $ ethtool ethX
> ...
> Link detected: no (No cable) // No sub reason
> 
> $ ethtool ethY
> Link detected: no (Autoneg failure, No partner detected)
> 
> Currently we have reason "cable issue" and subreasons "unsupported cable" and "shorted cable".
> The mechanism of cable test can be integrated and allow us report "cable issue" reason and "shorted cable" subreason.
> 
> However, the way the kernel reports the results of the cable test (cable-test, some seconds, get-result) may be problematic with link-down reason concept.
> We can ignore this information when reporting link-down reason, or report only if testing cable have a result,
> or maybe start testing cable and meanwhile report something like "discovery in progress". But all the options are not perfect.
> 
> We would like to know your opinion about it.

I would add some more reasons:
- master slave resolution issues: both link partners are master or
  slave.
- signal quality drop. In this case driver should be extended to notify
  the system if SQI is under some configurable limit.


Regards,
Oleksij
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