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[23.128.96.18]) by mx.google.com with ESMTP id p16si410189ejx.41.2020.05.13.12.25.04; Wed, 13 May 2020 12:25:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390542AbgEMTXl (ORCPT + 99 others); Wed, 13 May 2020 15:23:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1732218AbgEMTXk (ORCPT ); Wed, 13 May 2020 15:23:40 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA0BCC061A0C; Wed, 13 May 2020 12:23:40 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 124F2127E5AC1; Wed, 13 May 2020 12:23:39 -0700 (PDT) Date: Wed, 13 May 2020 12:23:38 -0700 (PDT) Message-Id: <20200513.122338.1849377923675371554.davem@davemloft.net> To: martin.blumenstingl@googlemail.com Cc: robh+dt@kernel.org, andrew@lunn.ch, f.fainelli@gmail.com, linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org, jianxin.pan@amlogic.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 0/8] dwmac-meson8b Ethernet RX delay configuration From: David Miller In-Reply-To: <20200512211103.530674-1-martin.blumenstingl@googlemail.com> References: <20200512211103.530674-1-martin.blumenstingl@googlemail.com> X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 13 May 2020 12:23:39 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Martin Blumenstingl Date: Tue, 12 May 2020 23:10:55 +0200 > The Ethernet TX performance has been historically bad on Meson8b and > Meson8m2 SoCs because high packet loss was seen. I found out that this > was related (yet again) to the RGMII TX delay configuration. > In the process of discussing the big picture (and not just a single > patch) [0] with Andrew I discovered that the IP block behind the > dwmac-meson8b driver actually seems to support the configuration of the > RGMII RX delay (at least on the Meson8b SoC generation). > > Since I sent the first RFC I got additional documentation from Jianxin > (many thanks!). Also I have discovered some more interesting details: > - Meson8b Odroid-C1 requires an RX delay (by either the PHY or the MAC) > Based on the vendor u-boot code (not upstream) I assume that it will > be the same for all Meson8b and Meson8m2 boards > - Khadas VIM2 seems to have the RX delay built into the PCB trace > length. When I enable the RX delay on the PHY or MAC I can't get any > data through. I expect that we will have the same situation on all > GXBB, GXM, AXG, G12A, G12B and SM1 boards. Further clarification is > needed here though (since I can't visually see these lengthened > traces on the PCB). This will be done before sending patches for > these boards. ... Series applied to net-next, thanks Martin.