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Date:   Wed, 31 Jul 2019 03:36:36 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Tao Ren <taoren@fb.com>
Cc:     Vladimir Oltean <olteanv@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Arun Parameswaran <arun.parameswaran@broadcom.com>,
        Justin Chen <justinpopo6@gmail.com>,
        netdev <netdev@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Andrew Jeffery <andrew@aj.id.au>,
        "openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>
Subject: Re: [PATCH net-next 2/2] net: phy: broadcom: add 1000Base-X support
 for BCM54616S
Message-ID: <20190731013636.GC25700@lunn.ch>
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> The INTF_SEL pins report correct mode (RGMII-Fiber) on my machine,
> but there are 2 "sub-modes" (1000Base-X and 100Base-FX) and I
> couldn't find a proper/safe way to auto-detect which "sub-mode" is
> active. The datasheet just describes instructions to enable a
> specific mode, but it doesn't say 1000Base-X/100Base-FX mode will be
> auto-selected. And that's why I came up with the patch to specify
> 1000Base-X mode.

Fibre does not perform any sort of auto-negotiation. I assume you have
an SFP connected? When using PHYLINK, the sfp driver will get the
supported baud rate from SFP EEPROM to determine what speed could be
used. However, there is currently no mainline support for having a
chain MAC-PHY-SFP. For that you need Russells out of tree patches.

      Andrew