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 F172FCA0EF7 for ; Tue, 19 Aug 2025 20:42:58 +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:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=8l89w4bHTJH83H28ZxlWSCRMM0V8+br4qkqPy5/xjd0=; b=ITSsB5LDJ5hiUDAO7r6MTOjlQf 8BnxVB8lertLqmRngaXiP/W+gm3aIhaFVdFqUd7INyF0aA/vLsMDBCzoOm7JBQQSyfMHKhBe649ZV ZKKaHaFx52hUH2gdvVuyd9CTde5+rvewkprX/zGUIluDpyOh2Fxja0UKgSqPkPG568kXNyZjdULe8 bjwEABxRKs60dQTtMpK4jW83PI9SzzZ/HheMUHpud+W17ym26CXJ5dVwbVKOf9Ia8vqn5a8f7wADr 62VXI6pxDt0LWip6H53MYhsp/Oz6NHm2sBnp/7kuJrLD4ihy9snEpDADs1+1QCOpxVPY6SITmvJHA 7O4mFs+Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uoTAT-0000000BYvV-0caa; Tue, 19 Aug 2025 20:42:53 +0000 Received: from gloria.sntech.de ([185.11.138.130]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uoRJu-0000000BKU6-0JZL; Tue, 19 Aug 2025 18:44:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sntech.de; s=gloria202408; h=Content-Type:Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Reply-To; bh=8l89w4bHTJH83H28ZxlWSCRMM0V8+br4qkqPy5/xjd0=; b=gcR8kMD9Q71A7ezSFp0EEPQhem TJqW4ftDjs3qSqnC8AZ0XXhgHZn9wkOD+bwUNPMEn9JTbWOm4DsgbMES6CmD5dWREc3BFGop2eJBH +TEB01ubMjD8uJ0/T1fiSq4Kz5l21rKXWIGHnvm7CgRquGhL6v9H3ZimHeWfL86D6drVCh++UxjGF +dln30WIYeoic3imgQ0tnzjIhzqNBvTtJzfsn0kbKxQD0VKHwsevGtMvh9gsvX/jTdh5wiYHs1bO+ g4+6KZTKeWf93whbuJErQgPevIuN1gl77doOV9YB98XI5+YjJoVzD/v5nVw9he7hC0hMegIiAgzGU pZuimlAQ==; Received: from i53875a31.versanet.de ([83.135.90.49] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1uoRJq-0004Ru-TA; Tue, 19 Aug 2025 20:44:26 +0200 From: Heiko =?UTF-8?B?U3TDvGJuZXI=?= To: Dongjin Kim , Andrew Lunn Cc: Rob Herring , Krzysztof Kozlowski , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: dts: rockchip: Change ethernet TXD timing delay value Date: Tue, 19 Aug 2025 20:44:26 +0200 Message-ID: <2821088.9PvXe5no7K@diego> In-Reply-To: <4d25c642-d457-4cb7-8bc1-587edd4f1d75@lunn.ch> References: <20250819045018.2094282-1-tobetter@gmail.com> <4d25c642-d457-4cb7-8bc1-587edd4f1d75@lunn.ch> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250819_114430_114653_0E194E8F X-CRM114-Status: GOOD ( 15.40 ) 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 Am Dienstag, 19. August 2025, 18:03:47 Mitteleurop=C3=A4ische Sommerzeit sc= hrieb Andrew Lunn: > On Tue, Aug 19, 2025 at 01:50:17PM +0900, Dongjin Kim wrote: > > Very poor network performance is observed on the ODROID-M1 Board > > (REV 1.0 20220613) when running iperf3 (under 200Mbits/sec), and > > this problem can be resolved after changing the value of TXD > > timing to 0x35 from 0x4f. >=20 > How did you decide on 0x35? just because I accidentially stumbled over that recently, Rockchip has some scanning functionality in their vendor-kernel to get possible delay values for a board. Described in a document called "Rockchip GMAC RGMII Delayline Guide" [0] and one code location is for example the armbian tree [1] At least that is one possible source of per-board delay values :-) Heiko [0] https://lo01.g77k.com/aeb/docs/en/Common/GMAC/Rockchip_Developer_Guide_= Linux_GMAC_RGMII_Delayline_EN.pdf (random internet source Google found me) [1] https://github.com/armbian/linux-rockchip/blob/rk-6.1-rkr5.1/drivers/ne= t/ethernet/stmicro/stmmac/dwmac-rk-tool.c >=20 > ~/linux/arch/arm64$ grep -hr "tx_delay =3D " | sort | uniq -c > 4 tx_delay =3D <0x10>; > 1 tx_delay =3D <0x1a>; > 1 tx_delay =3D <0x21>; > 2 tx_delay =3D <0x22>; > 4 tx_delay =3D <0x24>; > 2 tx_delay =3D <0x26>; > 14 tx_delay =3D <0x28>; > 1 tx_delay =3D <0x2a>; > 6 tx_delay =3D <0x30>; > 1 tx_delay =3D <0x3a>; > 3 tx_delay =3D <0x3c>; > 2 tx_delay =3D <0x42>; > 5 tx_delay =3D <0x43>; > 2 tx_delay =3D <0x44>; > 1 tx_delay =3D <0x46>; > 6 tx_delay =3D <0x4f>; >=20 > The numbers are all over the place, but it is clear that 0x28 is the > most popular for some reason. But since this delay values are magic, > i've no idea why. >=20 > Andrew >=20