netdev - Re: [PATCH net-next] net: dsa: mv88e6xxx: debug ATU Age Time

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Date:   Tue, 14 Mar 2017 09:56:41 -0400
From:   Vivien Didelot <vivien.didelot@...oirfairelinux.com>
To:     Andrew Lunn <andrew@...n.ch>,
        Matthias May <matthias.may@...atec.com>
Cc:     Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...oirfairelinux.com,
        "David S. Miller" <davem@...emloft.net>,
        Jason Cobham <jcobham@...stertangent.com>
Subject: Re: [PATCH net-next] net: dsa: mv88e6xxx: debug ATU Age Time

Hi Andrew,

Andrew Lunn <andrew@...n.ch> writes:

>> The never ever seeing R/W failure on MDIO bus is not exactly accurate.
>> We had with art (atheros calibration tool) the problem that interrupts
>> were being disabled which lead to MDIO operations running into
>> timout/failing.
>
> Yes, i've seen similar with power management bugs for the MDIO
> driver. But you get a cascade of failures, lots of warnings and error
> prints, it is clear something bad has happened, and the switch is in
> an inconsistent state. So having one more debug print which is also
> inconsistent does no really harm.
>
> Anyway, this whole conversation has taken more effort than just making
> this simple change to remove a few lines of code. So lets drop it and
> move on.

I don't understand nor agree with the fact that sometimes it's OK to not
check for errors, based on one developer assumptions. Not checking
return code is wrong and very likely error-prone.

If you really want to stand for that point, please send a patch series
which turns mv88e6xxx_read() and mv88e6xxx_write() into void functions.
I'd be glad to review and discuss this further. That would indeed make
*all* the driver code simpler.

Thanks,

        Vivien