Date:   Wed, 8 Mar 2023 11:35:40 +0000
From:   "Russell King (Oracle)" <linux@armlinux.org.uk>
To:     Daniel Golle <daniel@makrotopia.org>
Cc:     netdev@vger.kernel.org, linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Mark Lee <Mark-MC.Lee@mediatek.com>,
        John Crispin <john@phrozen.org>, Felix Fietkau <nbd@nbd.name>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Vladimir Oltean <olteanv@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        Jianhui Zhao <zhaojh329@gmail.com>,
        =?iso-8859-1?Q?Bj=F8rn?= Mork <bjorn@mork.no>,
        Frank Wunderlich <frank-w@public-files.de>,
        Alexander Couzens <lynxis@fe80.eu>
Subject: Re: [PATCH net-next v12 08/18] net: ethernet: mtk_eth_soc: fix
 1000Base-X and 2500Base-X modes
Message-ID: <ZAhzDDjZ8+gxyo3V@shell.armlinux.org.uk>
References: <cover.1678201958.git.daniel@makrotopia.org>
 <fd5c7ea79a7f84caac7d0b64b39fe5c4043edfa8.1678201958.git.daniel@makrotopia.org>
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Sender: Russell King (Oracle) <linux@armlinux.org.uk>
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On Tue, Mar 07, 2023 at 03:53:58PM +0000, Daniel Golle wrote:
> After conversion to phylink_pcs the 1000Base-X and 2500Base-X modes
> would work only after `ethtool -s eth1 autoneg off`.
> As ethtool autoneg and the ETHTOOL_LINK_MODE_Autoneg_BIT is supposed
> to control auto-negotiation on the external interface it doesn't make
> much sense to use it to control on-board SGMII auto-negotiation between
> MAC and PHY.
> Set correct values to really only enable SGMII auto-negotiation when
> actually operating in SGMII mode. For 1000Base-X and 2500Base-X mode,
> enable remote-fault detection only if in-band-status is enabled.
> This fixes using 1000Base-X and 2500Base-X SFPs on the BananaPi R3
> board and also makes it possible to use interface-mode-switching PHYs
> operating in either SGMII mode for 10M/100M/1000M or in 2500Base-X for
> 2500M mode on other boards.
> 
> Fixes: 14a44ab0330d ("net: mtk_eth_soc: partially convert to phylink_pcs")
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>

NAK.

There are PHYs out there which operate in SGMII mode but do not
exchange the SGMII 16-bit configuration word. The code implemented
here by me was explicitly to allow such a configuration to work,
which is defined as:

	SGMII *without* mode == inband

An example of this is the Broadcom 84881 PHY which can be found on
SFP modules.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!