Subject: Re: [RFC PATCH net-next 1/3] net: rtnetlink: Add link-down reason to RTNL messages

From: Petr Machata <[email-masked]>
Date: Mon, 18 Mar 2019 13:15:41 +0000

Andrew Lunn <[email-masked]> writes:

>> +enum rtnl_link_down_reason_major {
>> +	RTNL_LDR_OTHER,
>
> Does 'other' make any sense? Seem better to just not report anything
> at all, or add a comment that more reasons should be added at the end
> to reflect whatever the hardware or software can determine.

You still have the minor code to give you some information.

>> +	RTNL_LDR_NO_CABLE,
>> +	RTNL_LDR_UNSUPPORTED_CABLE,
>> +	RTNL_LDR_AUTONEG_FAILURE,
>> +	RTNL_LDR_NO_LINK_PARTNER,
>> +	RTNL_LDR_LINK_TRAINING_FAILURE,
>> +	RTNL_LDR_LOGICAL_MISMATCH,
>> +	RTNL_LDR_REMOTE_FAULT,
>> +	RTNL_LDR_BAD_SIGNAL_INTEGRITY,
>> +	RTNL_LDR_CALIBRATION_FAILURE,
>> +	RTNL_LDR_POWER_BUDGET_EXCEEDED,
>> +};
>
> What about SFP cage empty?, i.e. no SFP, SFP+ module in the cage?  An

No cable? Maybe the name needs to change...

> SFP can also report LOS. That does not appear to be any of the above.
> Or that the core SFP code has been unable to read the EEPROM? We have

My assumption was that cable with unreadable EEPROM is simply a bad
cable. Does the admin actually care which particular part of the cable
is at fault?

> people reporting this problem at the moment. We also have that the
> SERDES has not yet obtained sync to its peer, which you know from
> phylink_mac_change. That probably means the peer is using a different
> bit rate.

We can add this.

> I think it would be good if you handle the general case errors which
> phylib and phylink can report, as well as the proprietary cases your
> driver can report. We don't want this to be a Mellanox only API.

Sure, I'll take a look at that. I didn't need to deal with PHY so far,
so I need to figure out what's what.