From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-175.mta1.migadu.com (out-175.mta1.migadu.com [95.215.58.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB17614F9C4 for ; Tue, 25 Feb 2025 18:42:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740508947; cv=none; b=cWkp0FXPD4ZF4xVDeUflZinUW8WfCB8ZLer9D8Djd/+7kHVN5Gv9wB9MELCNvDzasvOqfL1foR7yzJc8E0bg2BDlvh5/dwC6pEoD3B4QdQdoXiZLwlra5Q0fZkOOLF6BIApfLYHp1AUruG4l5+VQQv8RIXAxcMSIT5ZTrBNDqUE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740508947; c=relaxed/simple; bh=GiLzflQqnYT63CKA1QIohp0eMWR5pxFRNdl+pFZXxr0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=O7sCtSumPB4HetZN3k3SKkNNpTl7NCvqQ5gu0m+iHgbYr7R+QuyXqHfpcDu3/LUbqLiXF2Xu86lCpfnhnDLFnOiaPOQC89Q5FgzlheqJBPJlsZ53dv2B/G2s5TLfKdjNSerZTLjTjG2BNOo7Rvqr2rckdyQ3MkqGQNu26f8ZQas= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=StJD/FFz; arc=none smtp.client-ip=95.215.58.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="StJD/FFz" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1740508932; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=poK85tAG9kc5+agyzOdb9jltGXyCsuZa9R+6oO7Rx7U=; b=StJD/FFzkuVleq2d0UK1wOXi4UY6DIy8AC91U6gelNR9Z0rFdfrHnLcZgKr78PSvMTpDdy BRj27YNyy1Uj6Alu+GcDomRZvOctukjcypF38iok6QeKpWdhXvGMMTCc/JeYL9CqSrNmvX ymXe24OwQ6yZic0H6cKguDqJL+FVGpg= Date: Tue, 25 Feb 2025 13:41:57 -0500 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next v2 1/2] net: phy: sfp: Add support for SMBus module access To: "Russell King (Oracle)" , Maxime Chevallier Cc: davem@davemloft.net, Andrew Lunn , Jakub Kicinski , Eric Dumazet , Paolo Abeni , Heiner Kallweit , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, Florian Fainelli , =?UTF-8?Q?K=C3=B6ry_Maincent?= , Simon Horman , Romain Gantois , Antoine Tenart , =?UTF-8?Q?Marek_Beh=C3=BAn?= , =?UTF-8?Q?Bj=C3=B8rn_Mork?= References: <20250225112043.419189-1-maxime.chevallier@bootlin.com> <20250225112043.419189-2-maxime.chevallier@bootlin.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2/25/25 13:04, Russell King (Oracle) wrote: > On Tue, Feb 25, 2025 at 12:20:39PM +0100, Maxime Chevallier wrote: >> The SFP module's eeprom and internals are accessible through an i2c bus. >> However, all the i2c transfers that are performed are SMBus-style >> transfers for read and write operations. > > Note that there are SFPs that fail if you access them by byte - the > 3FE46541AA locks the bus if you byte access the emulated EEPROM at > 0x50, address 0x51. This is documented in sfp_sm_mod_probe(). > > So there's a very real reason for adding the warning - this module > will not work! > I had a look at sfp_sm_mod_probe, and from what I can tell the SFP that I was having issues with should have been fixed by commit 426c6cbc409c ("net: sfp: add workaround for Realtek RTL8672 and RTL9601C chips"). I re-tested without this series applied, and the SFP still worked. So I guess I don't have an SFP module with the issue this series is trying to address after all. --Sean