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Date: Tue, 02 Jan 2024 13:55:33 +0100
From: Eric Woudstra <ericwouds@gmail.com>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
CC: Alexander Couzens <lynxis@fe80.eu>, Daniel Golle <daniel@makrotopia.org>,
 Andrew Lunn <andrew@lunn.ch>, Heiner Kallweit <hkallweit1@gmail.com>,
 "David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>,
 Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
 Matthias Brugger <matthias.bgg@gmail.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
 Frank Wunderlich <frank-w@public-files.de>, netdev@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 linux-mediatek@lists.infradead.org
Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_RFC_net-next=5D_net=3A_pcs=3A_pcs-mtk-lyn?= =?US-ASCII?Q?xi_fix_mtk=5Fpcs=5Flynxi=5Fget=5Fstate=28=29_for_2500base-x?=
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>Please describe your setup more fully=2E What is the link partner on this
>2500base-X link?

I use a BananaPi R3, with the oem-sfp2=2E5g-t module=2E It has the SFP qui=
rk that disables autoneg=2E I was trying Marek's rtl8221b patchset, but fou=
nd that even with unmodified code,  original net-next unmodified, I could g=
et link up, but no traffic is going through=2E

On the other side is a=2Erock5b with rtl8125b=2E

Only after applying this patch, it works and eth1 reports link up with 2=
=2E5Gbps instead of unknown speed=2E

If you need more debugging info, I can supply it at a later time=2E


On January 2, 2024 1:10:01 PM GMT+01:00, "Russell King (Oracle)" <linux@ar=
mlinux=2Eorg=2Euk> wrote:
>On Tue, Jan 02, 2024 at 08:44:08AM +0100, Eric Woudstra wrote:
>> From: Daniel Golle <daniel@makrotopia=2Eorg>
>>=20
>> Need to fix mtk_pcs_lynxi_get_state() in order for the pcs to function
>> correctly when the interface is set to 2500base-x, even when
>> PHYLINK_PCS_NEG_INBAND_DISABLED is set=2E
>
>Please describe your setup more fully=2E What is the link partner on this
>2500base-X link?
>
>In PHYLINK_PCS_NEG_INBAND_DISABLED mode, this means that phylink is
>operating in inband mode, but Autoneg is clear in the advertisement
>mask, meaning Autoneg is disabled and we are using a "fixed" setting=2E
>state->speed and state->duplex should already be initialised=2E
>
>> When the pcs is set to 2500base-x, the register values are not compatib=
le
>> with phylink_mii_c22_pcs_decode_state()=2E It results in parameters suc=
h as
>> speed unknown and such=2E Then the mac/pcs are setup incorrectly and do=
 not
>> function=2E
>
>Since Autoneg is clear, phylink_mii_c22_pcs_decode_state() won't
>change state->speed and state->duplex, which should already be
>correctly set=2E
>