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 B36B3C369B2 for ; Thu, 17 Apr 2025 09:58:09 +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=5AupP/j6Jgef8+U7QwlcbEzPED2LNc5rkVzdOtC09ew=; b=NCp1WZFA5DBWqmo9JrCO8A9diE 2b+yQow61GpEGYz8873NoE+4ryulmFgPBnI/uignVMxX4u8wQqqmlsYyJHnZ+TN/Tmod2YuertrsH lj6I6DmfOE2nTG96kOIMq+JUrOSdbESFanlKHvLllHtAqBuugfO/wJffQcd6PnGKMor2zC+tdqNNX hH/Ss/ceYA1N/vF1KLgyZABDSY809RMbpKumdnKPJqqeEAySrRzFE0vKol+6o2IBOnjQn5ltqXgcG jPPAFXb0EtK7jevZKoABNl7gF4scznyxLC58Ryh9BojJblvPxo5gD+KbpQW7yQwZ8OhNhJeLnGOfv zFefsMrA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u5M0N-0000000CXUy-3Gt9; Thu, 17 Apr 2025 09:57:59 +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 1u5LxG-0000000CWue-2CC1; Thu, 17 Apr 2025 09:54:48 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id DB4E349D9C; Thu, 17 Apr 2025 09:54:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15D29C4CEE4; Thu, 17 Apr 2025 09:54:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744883685; bh=vAhYR0DxNYTjOSzwAc2fvxm9d0b4bcwj8L5gWZR5QS8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UcHcbGbBno1NM6VGd/kWkWEc0O9+cEg0+k7nrMTYrN1TpBGrPb3u5LPztWhYLn5bp dvJ+8Hy4Gyz1nLpiyNAYO3nzeGmMYRBZtBTVQRfFJMwCPuphKiQg7KAIEwHBbmycdU Z1DdujIfnC+zCPPj51MMTdviv8BNdzYeuqZPPydCdHj0QGRtJEptj+KUQjqWt4ZmCl JK18Dwqr9xGceHLH5jI1GjPC2PvOLtfZ7vakGOgS/opSpbp764yjIyUuUSZ5TjRjHM 1L81SKYKL0QkGQ2UUbNyyJy1Sq4cIZXhBg5FG8UwUWGFI5n57GeD9wcmUDsXO2bdHW rUP9UGK6Sl1WQ== Date: Thu, 17 Apr 2025 11:54:40 +0200 From: Niklas Cassel To: Hans Zhang <18255117159@163.com> Cc: Shawn Lin , lpieralisi@kernel.org, kw@linux.com, bhelgaas@google.com, heiko@sntech.de, manivannan.sadhasivam@linaro.org, robh@kernel.org, jingoohan1@gmail.com, thomas.richard@bootlin.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH] PCI: dw-rockchip: Configure max payload size on host init Message-ID: References: <20250416151926.140202-1-18255117159@163.com> <85643fe4-c7df-4d64-e852-60b66892470a@rock-chips.com> <52a2f6dc-1e13-4473-80f2-989379df4e95@163.com> <4c2a94b4-e483-426f-b7d8-ed98ac474c63@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4c2a94b4-e483-426f-b7d8-ed98ac474c63@163.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250417_025446_583428_8D250D4F X-CRM114-Status: GOOD ( 20.19 ) 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 Thu, Apr 17, 2025 at 05:48:04PM +0800, Hans Zhang wrote: > > > On 2025/4/17 16:39, Niklas Cassel wrote: > > On Thu, Apr 17, 2025 at 04:07:51PM +0800, Hans Zhang wrote: > > > On 2025/4/17 15:48, Niklas Cassel wrote: > > > > > > Hi Niklas and Shawn, > > > > > > Thank you very much for your discussion and reply. > > > > > > I tested it on RK3588 and our platform. By setting pci=pcie_bus_safe, the > > > maximum MPS will be automatically matched in the end. > > > > > > So is my patch no longer needed? For RK3588, does the customer have to > > > configure CONFIG_PCIE_BUS_SAFE or pci=pcie_bus_safe? > > > > > > Also, for pci-meson.c, can the meson_set_max_payload be deleted? > > > > I think the only reason why this works is because > > pcie_bus_configure_settings(), in the case of > > pcie_bus_config == PCIE_BUS_SAFE, will walk the bus and set MPS in > > the bridge to the lowest of the downstream devices: > > https://github.com/torvalds/linux/blob/v6.15-rc2/drivers/pci/probe.c#L2994-L2999 > > > > > > So Hans, if you look at lspci for the other RCs/bridges that don't > > have any downstream devices connected, do they also show DevCtl.MPS 256B > > or do they still show 128B ? > > > > Hi Niklas, > > It will show DevCtl.MPS 256B. Ok. I guess that just means that the bridge itself is included in pci_walk_bus(). Let's wait and see what people think about my proposal earlier in the thread, or if someone can think of something better. Kind regards, Niklas