From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (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 391A0274B41; Wed, 27 Aug 2025 09:14:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756286055; cv=none; b=E/Oe571pU4GxkXdK7DMu2FwCKxZpIdEGUrQJjYwgSicS46HlEZ5PzYH5rvWXLw6wLq6jRVTijemud8CXZXE4OK1gQU00HGTU3TpQD9UzW19i8QJsymktZ6Sxfh+2jx5nJQ+eMYWvnd9KH3Zno90erwLqsbhhiV/7iXmimFJIRBk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756286055; c=relaxed/simple; bh=/yIf+mskkqkfN8f2LgY5oDpq+Ffb7eNyUGB/AAvVog4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RxtIuZfZCwL/7GyZCFS7FWbnuf9V/qb7/to81Y8KAY7VoIJKrDgGAOTFpXoKkK48m5cAGhrFezzZHySo2hOEgqLq5GmgCQCSKmS2q+K9E3s3wrW5LfBSX5PB5QwyjTUwlXFNZ3CKjudy34K1EcMA8dR641qpIblv5Oerz1Ujtpg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=RcjkirYZ; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="RcjkirYZ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=8EDTmutXv6cpnKMhKY9aCrRhZQN/VIppbHjVD097H+Y=; b=RcjkirYZ4jlG0KuHggzlLh7fXY otW2retBA8Q5OAma3JuQet9AWItJwUwa9wRAod6SP3CZfKf8fGL9qAQZskXdyPD4xKJQ+3EG2eCie YXeqnSPyODYhfSbXGZu6zIb/RwLuhtCP3lEK1e2DyP/xYDTt4PjgfUuodBLQuefxwDbf76dJM/jzA MC3cm1GfSElU3HRGwp6HWlc0O8lI8PoY5Cd2if7J6Ajhj2vxZRwcf1Gsuxr9d5Fs8pt5cVWY2Xcn3 M1RoPqfSOCtexQBur+wvKH2GPDYRJAxGd8k0b2cHS7fK/2sRzfBPr9RJDBS36KEbSgrainWf4guio fw+A7mtQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:34142) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1urCEE-000000000H8-2VQc; Wed, 27 Aug 2025 10:14:02 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1urCEB-0000000024b-1cng; Wed, 27 Aug 2025 10:13:59 +0100 Date: Wed, 27 Aug 2025 10:13:59 +0100 From: "Russell King (Oracle)" To: Alexander Wilhelm Cc: Vladimir Oltean , Andrew Lunn , Heiner Kallweit , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Aquantia PHY in OCSGMII mode? Message-ID: References: <20250804160234.dp3mgvtigo3txxvc@skbuf> <20250805102056.qg3rbgr7gxjsl3jd@skbuf> <20250806145856.kyxognjnm4fnh4m6@skbuf> <20250827073120.6i4wbuimecdplpha@skbuf> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) On Wed, Aug 27, 2025 at 11:03:42AM +0200, Alexander Wilhelm wrote: > Am Wed, Aug 27, 2025 at 09:47:49AM +0100 schrieb Russell King (Oracle): > > On Wed, Aug 27, 2025 at 10:41:11AM +0200, Alexander Wilhelm wrote: > > > Set to 100M: > > > > > > fsl_dpaa_mac: [DEBUG] called > > > fsl_dpaa_mac: [DEBUG] called > > > fsl_dpaa_mac: [DEBUG] * mode: 0 > > > fsl_dpaa_mac: [DEBUG] * phy_mode(interface): 2500base-x > > > fsl_dpaa_mac: [DEBUG] * memac_if_mode: 00000002 (IF_MODE_GMII) > > > fsl_dpaa_mac: [DEBUG] * speed: 2500 > > > fsl_dpaa_mac: [DEBUG] * duplex: 1 > > > fsl_dpaa_mac: [DEBUG] * tx_pause: 1 > > > fsl_dpaa_mac: [DEBUG] * rx_pause: 1 > > > > So the PHY reported that it's using 2500base-X ("OCSGMII") for 100M, > > which means 0x31b 3 LSBs are 4. Your hardware engineer appears to be > > incorrect in his statement. > > I asked the hardware engineer again. The point is that the MAC does not set > SGMII for 100M. It still uses 2500base-x but with 10x paket repetition. No one uses symbol repetition when in 2500base-x mode. Nothing supports it. Every device datasheet I've read states clearly that symbol repetition is unsupported when operating at 2.5Gbps. Also think about what this means. If the link is operating at 2.5Gbps with a 10x symbol repetition, that means the link would be passing 250Mbps. That's not compatible with _anything_. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!