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Subject: Re: [PATCH] net/dsa: remove unused macros to tame gcc warning
From:   Joe Perches <joe@perches.com>
To:     Alex Shi <alex.shi@linux.alibaba.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>
Cc:     Vivien Didelot <vivien.didelot@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Sat, 07 Nov 2020 09:39:42 -0800
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On Sat, 2020-11-07 at 20:54 +0800, Alex Shi wrote:
> 在 2020/11/7 上午12:39, Florian Fainelli 写道:
> > > It is good to remember that there are multiple readers of source
> > > files. There is the compiler which generates code from it, and there
> > > is the human trying to understand what is going on, what the hardware
> > > can do, how we could maybe extend the code in the future to make use
> > > of bits are currently don't, etc.
> > > 
> > > The compiler has no use of these macros, at the moment. But i as a
> > > human do. It is valuable documentation, given that there is no open
> > > datasheet for this hardware.
> > > 
> > > I would say these warnings are bogus, and the code should be left
> > > alone.
> > Agreed, these definitions are intended to document what the hardware
> > does. These warnings are getting too far.
> 
> Thanks for all comments! I agree these info are much meaningful.
> Is there other way to tame the gcc warning? like put them into a .h file
> or covered by comments?

Does _any_ version of gcc have this warning on by default?

I still think my proposal of moving the warning from W=2 to W=3
quite reasonable.

Another possibility is to turn the warning off altogether.