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

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Date:   Tue, 14 Mar 2017 15:18:56 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     Matthias May <matthias.may@...atec.com>,
        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

On Tue, Mar 14, 2017 at 09:56:41AM -0400, Vivien Didelot wrote:
> 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.

Please go back and look what i said. I did check the error code, in
that it gets returned to the caller. I just don't check it before
printing the debug.

But as i said, lets drop this whole topic.

    Andrew