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Date: Sun, 7 Jan 2024 16:10:50 +0000
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Josua Mayer <josua@solid-run.com>
Cc: 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>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: sfp: add fixup for tplink 2.5gbase-t rj45 modules
Message-ID: <ZZrNChuIw0X9fr6Z@shell.armlinux.org.uk>
References: <20240106-tplink-25gbaset-sfp-fixup-v1-1-8d26696bd2f4@solid-run.com>
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In-Reply-To: <20240106-tplink-25gbaset-sfp-fixup-v1-1-8d26696bd2f4@solid-run.com>
Sender: Russell King (Oracle) <linux@armlinux.org.uk>

On Sat, Jan 06, 2024 at 05:29:56PM +0100, Josua Mayer wrote:
> TP-Link TL-SM410U modules are single-rate 2.5GBase-T RJ45 SFP modules.
> The EEPROM data is lying about connector and extended cc,
> reporting 25Gbps fiber.
> 
> Add fixup for these specific modules forcing RJ45 @ 2.5Gbase-T.
> 
> For reference original eeprom data dump from ethtool:
> 
> Identifier                : 0x03 (SFP)
> Extended identifier       : 0x04 (GBIC/SFP defined by 2-wire interface ID)
> Connector                 : 0x07 (LC)
> Transceiver codes         : 0x00 0x00 0x00 0x00 0x00 0x00 0x40 0x00 0x00
> Transceiver type          : FC: Twisted Pair (TP)
> Encoding                  : 0x01 (8B/10B)
> BR, Nominal               : 3100MBd

This isn't 25Gbps - it's 2.5Gbps!

So what actually happens with this module without the quirk? We should
end up marking it for use as a 2500base-X fibre module which should
result in it working.

(Please include in the commit message how it works or not without the
patch.)

Also, patches to netdev need to have "net" (for -rc) or "net-next"
(for the next merge window) in the "[PATCH ...]" n the subject line.

Thanks.
-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!