From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D3DC7CA1013 for ; Thu, 18 Sep 2025 15:05:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id: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-Owner; bh=gT7EyJhqaGT1c/vVbat3yyZR0Yh/jcDyJmsQcPvAhhs=; b=IjTyXZxv2QpCLUtP/a3XPsoB6b BhT9tSXEbUaVPAPRvBD4bqnN39t1KOzCDvjMun5+TfkWWPGg/uEhVZ9e3SOYFdZ6yOza7xvdugB8e je2231vkFE7+ZU9jNoOa7juH/vUggrnMoReZRXJmiTeXMouYr9+L346fEw3OWMZoyMg4kjP0KEZdv QaFRhUIGGmqRrEDVxh3os8IHNCDEuQP3PKhobOCPaIW0fqHZKpB+zBvpToFRH/k4h52bVTErInVoC vSQ2WffG7U019YirEhqewY90H9LTuoaFSC04jl7xx1odz3VQ67e3x9PFexWdjKCAX91Fhw4hwSEF5 p0azBTuA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzGC4-00000000GW0-3rOA; Thu, 18 Sep 2025 15:05:08 +0000 Received: from vps0.lunn.ch ([156.67.10.101]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzGC2-00000000GUv-44rU for linux-arm-kernel@lists.infradead.org; Thu, 18 Sep 2025 15:05:08 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=gT7EyJhqaGT1c/vVbat3yyZR0Yh/jcDyJmsQcPvAhhs=; b=2Mg6dsQRTBgEVP1SD38awP1HMR VvKK0efTP0JUtG5xvhbIVACkueM+2moVFWtAlmpRQfbaX166ZQBeUMz63JIUb4QIolAa6aTlcBmdP E50ZUVM0uxw1NFBK57Eg0qCdzKXOiyM4dwi4vS3tzX+voRwq5MUK3j+7fA8h8V9Vy8QA=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1uzGBr-008q5n-Ct; Thu, 18 Sep 2025 17:04:55 +0200 Date: Thu, 18 Sep 2025 17:04:55 +0200 From: Andrew Lunn To: David Jander Cc: Jonas Rebmann , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Liam Girdwood , Mark Brown , Shengjiu Wang , Shawn Guo , Sascha Hauer , Fabio Estevam , Pengutronix Kernel Team , Vladimir Oltean , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Lucas Stach , Oleksij Rempel Subject: Re: [PATCH v2 3/3] arm64: dts: add Protonic PRT8ML board Message-ID: <7f1d9289-4102-4db9-a2bb-ff270e8871b7@lunn.ch> References: <20250918-imx8mp-prt8ml-v2-0-3d84b4fe53de@pengutronix.de> <20250918-imx8mp-prt8ml-v2-3-3d84b4fe53de@pengutronix.de> <20250918165156.10e55b85@erd003.prtnl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250918165156.10e55b85@erd003.prtnl> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250918_080507_011260_FA42BBB9 X-CRM114-Status: UNSURE ( 9.55 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > Yes, unfortunately the SJA1105Q does not support PAUSE frames, and the i.MX8MP > FEC isn't able to sustain 1000Mbps (only about 400ish) due to insufficient > internal bus bandwidth. It will generate PAUSE frames, but the SJA1105Q > ignores these, leading to packet loss, which is obviously worse than > restricting this link to 100Mbps. Ironically both chips are from the same > manufacturer, yet are incompatible in this regard. Thanks for the explanation. Maybe add a comment that the bandwidth is limited due to the lack of flow control resulting in packet loss in the FEC. Anything which looks odd deserves a comment, otherwise somebody will question it.... Andrew