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 35A2FC3ABC0 for ; Wed, 7 May 2025 09:14:59 +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=iWiWVg5s2LaiWyVZ3HqLb66u+VgHxdzMz0QC9VUL/60=; b=aHDfF0N11aDjrNCt0dK1R7cCWo 8mirQV/P/3Gmz1dnHcf9/pah2LXDNnv5CX3vTorujg8Sl7X4oiXrA3MNFcwKUGgbHrOWEtkYcgDjX J51+LvgNLT2GiVy1A7DpP3Oxo3596oql7EzkF7jsc+mHXSlFa4gdZszCumenxX6AMyroeuYTTpbSj Ji7A3CX8j2i3c0YgaO47ViuCWAOPFl9ChcyWgBBDogvWQRokt8Lr61ZZ6WOGN51R0U8M++QHlXa88 WYqGOeK7WE78Jk4M//F1GcnuCd3r4Be9/cus1d0BOabC7PpZCNOoOJDYMvkZVEuxvIJGj3Nhp265C Sa1Xxq2A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uCara-0000000Et9p-3vZw; Wed, 07 May 2025 09:14:50 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uCZM2-0000000EYuw-2CTB; Wed, 07 May 2025 07:38:11 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 57B9D4A670; Wed, 7 May 2025 07:38:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB7A2C4CEE7; Wed, 7 May 2025 07:38:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746603489; bh=u+94YTkIK1yodzp++T2HMB+oePCPOpIrqtliTXH6QBg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jyVJurjeBVyWd0G4t6kNsd8et1PSYUrBGqs3MV3TTtICVDqAPr1gZrx094VjLWDPk S1RHk810ExOMe3Plnpi/9lAoeGTwFcSOqjzcfHXAJmJ7VvllQ4kRLt6V5lDIhirnCG ayPbPG5iFPwEFPD/0sbOGcniB0tkc3uJURu1rXFsnN0jYdEooMQHvgIdL/BPdNCJzS zUCCV72YUsIzuaSVGk1+1RGJ2M85dEfzB/HVz72Hm0RC4pYgQtYszjDkqRI9TL5usf qYo0Gdh/ulmD9cwhOOIvH1+8pwt6FhazSFU6pwVosm3T1ltDep5tY6IRvhxDDiaP1I W5upt/sdhcU9g== Date: Wed, 7 May 2025 09:38:03 +0200 From: Niklas Cassel To: Hans Zhang <18255117159@163.com> Cc: lpieralisi@kernel.org, kw@linux.com, bhelgaas@google.com, heiko@sntech.de, manivannan.sadhasivam@linaro.org, yue.wang@amlogic.com, pali@kernel.org, neil.armstrong@linaro.org, robh@kernel.org, jingoohan1@gmail.com, khilman@baylibre.com, jbrunet@baylibre.com, martin.blumenstingl@googlemail.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v3 1/3] PCI: Configure root port MPS during host probing Message-ID: References: <20250506173439.292460-1-18255117159@163.com> <20250506173439.292460-2-18255117159@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250506173439.292460-2-18255117159@163.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250507_003810_579839_E9B836AB X-CRM114-Status: UNSURE ( 9.80 ) 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 On Wed, May 07, 2025 at 01:34:37AM +0800, Hans Zhang wrote: (snip) > static void pci_configure_mps(struct pci_dev *dev) > { > struct pci_dev *bridge = pci_upstream_bridge(dev); > @@ -2178,6 +2209,10 @@ static void pci_configure_mps(struct pci_dev *dev) > return; > } We should probably add a comment explaining why we are doing this here. Perhaps something like: /* * Unless MPS strategy is PCIE_BUS_TUNE_OFF (don't touch MPS at all), * start off by setting root ports' MPS to MPSS. Depending on the MPS * strategy, and the MPSS of the devices below the root port, the MPS * of the root port might get overriden later. */ > + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && > + pcie_bus_config != PCIE_BUS_TUNE_OFF) > + pcie_write_mps(dev, 128 << dev->pcie_mpss); > + > if (!bridge || !pci_is_pcie(bridge)) > return; > Kind regards, Niklas