From: Ben Hutchings <bhutchings@solarflare•com>
To: Matt Carlson <mcarlson@broadcom•com>
Cc: "davem@davemloft•net" <davem@davemloft•net>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
Michael Chan <mchan@broadcom•com>
Subject: Re: [PATCH] Add ethtool to mii advertisment conversion helpers
Date: Thu, 17 Nov 2011 02:45:50 +0000 [thread overview]
Message-ID: <1321497950.2885.72.camel@deadeye> (raw)
In-Reply-To: <20111117020613.GA18232@mcarlson.broadcom.com>
On Wed, 2011-11-16 at 18:06 -0800, Matt Carlson wrote:
> On Wed, Nov 16, 2011 at 05:29:42PM -0800, Ben Hutchings wrote:
> > On Wed, 2011-11-16 at 17:16 -0800, Matt Carlson wrote:
> > > On Wed, Nov 16, 2011 at 04:34:37PM -0800, Ben Hutchings wrote:
> > [...]
> > > > > +#define mii_lpa_to_ethtool_100bt(lpa) mii_adv_to_ethtool_100bt(lpa)
> > > >
> > > > Shouldn't this additionally translate LPA_LPACK into ADVERTISED_Autoneg?
> > >
> > > You mean, like this?
> > >
> > > static inline u32 mii_lpa_to_ethtool_100bt(u32 lpa)
> > > {
> > > u32 result = 0;
> > >
> > > if (lpa & LPA_LPACK)
> > > result |= ADVERTISED_Autoneg;
> > >
> > > return result | mii_adv_to_ethtool_100bt(lpa);
> > > }
> > >
> > > Yes, that looks like a better implementation.
> >
> > Think so.
> >
> > And I think the mii_adv_to_ethtool_* functions should add
> > ADVERTISED_Autoneg unconditionally. But I'm not entirely sure that's
> > right.
>
> The primary purpose of these functions is to translate the information
> between two representations. It seems wise to be careful not to add
> from it or take anything away from it. It is certainly possible to
> have a valid AN advertisement register configuration, but not have
> autoneg enabled. Keeping the ADVERTISED_Autoneg out could prevent
> misuse. Do you agree?
I'm not sure what you mean about misuse. If autoneg is not enabled then
the register contents are not used and I don't think the
mii_adv_to_ethtool functions should be called at all. But I'm not that
bothered either way.
> > > > Shouldn't there be mii_lpa_to_ethtool_1000X (or
> > > > mii_lpa_to_ethtool_lpa_x)?
> > >
> > > Yes. You're right. Should it just be a preprocessor definition that
> > > points to mii_adv_to_ethtool_1000X()?
> >
> > I think that would need to handle LPA_LPACK as well.
>
> I was wondering if that was present in 1000Base-X mode. I didn't see it
> in my passing glance at a spec.
IEEE 802.3-2005 §37.2.1.6 seems to define it similarly to the TP case.
Ben.
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
prev parent reply other threads:[~2011-11-17 2:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-15 22:00 [PATCH] Add ethtool to mii advertisment conversion helpers Matt Carlson
2011-11-16 22:36 ` David Miller
2011-11-16 22:56 ` Matt Carlson
2011-11-17 0:34 ` Ben Hutchings
2011-11-17 1:16 ` Matt Carlson
2011-11-17 1:21 ` Michael Chan
2011-11-17 1:38 ` David Miller
2011-11-17 2:29 ` Ben Hutchings
2011-11-17 1:29 ` Ben Hutchings
2011-11-17 2:06 ` Matt Carlson
2011-11-17 2:45 ` Ben Hutchings [this message]
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