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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38D29C433DF for ; Wed, 13 May 2020 19:23:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE1B02065C for ; Wed, 13 May 2020 19:23:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390540AbgEMTXl (ORCPT ); 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: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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.