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Date: Fri, 10 Jul 2015 14:20:17 +0300
From: Stas Sergeev <stsp@list.ru>
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To: Sebastien Rannou <mxs@sbrk.org>
CC: Florian Fainelli <f.fainelli@gmail.com>,
        Linux kernel <linux-kernel@vger.kernel.org>,
        Arnaud Ebalard <arno@natisbad.org>,
        Stas Sergeev <stsp@users.sourceforge.net>,
        Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Kumar Gala <galak@codeaurora.org>,
        Grant Likely <grant.likely@linaro.org>, devicetree@vger.kernel.org,
        netdev <netdev@vger.kernel.org>,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Subject: Re: [PATCH 1/2] of_mdio: add new DT property 'link' for fixed-link
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10.07.2015 11:46, Sebastien Rannou пишет:
> On Fri, 10 Jul 2015, Stas Sergeev wrote:
> 
>> 10.07.2015 00:15, Florian Fainelli пишет:
>>> Then, if the in-band status indication is not reliable (which really
>>> should be completely understood),
>> Agree!
>> But this is not something I can help with.
>> Sebastien Rannou reports the problem, please ask him whatever
>> you see fits to get a better understanding of a problem.
>> The fact that his HW does not generate the inband status, is
>> _my own guess_.
> 
> Yes, I confirm that my HW does not generate an in-band status. AFAIK, it's
> a PHY that aggregates 4xSGMIIs to 1xQSGMII ; the MAC side of the PHY (with
> inband status) is connected to the switch through QSGMII, and in this context
> we are on the media side of the PHY.
Hmm, interesting.
So if I parse the above correctly, you have something like 88E1340S set
up into a mode when SGMII is used as media interface and QSGMII as system
interface (terms are from datasheet page 5), then you connect the media
interface to armada-xp and system interface to the switch.

I wonder if it is the right thing to do.
AFAIK you could as well set up armada-xp into QSGMII mode and connect
that to switch. The driver would then disable the use of inband status
and everything would be fine.
Either way, your use-case proves that only DT can decide the use of an
inband status.