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 D8776EC1EB3 for ; Thu, 5 Feb 2026 13:28:28 +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-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hWKzf6vrUReo+tp1QBwyrmEp+vwwk6NvvtFGXbT83gY=; b=ky2sgOozyvJo3obMuYyyIecZAc 3rZm1hyMEQDboPY3/swe5cFjognZbQ/EsQlhBSwphKy6GWVbQwVO5nqILFuQt9aYAP6BdPx7M/Upl BOqITjCpgRFjsMm6h94GCNAMn30zsrKtROdvj0u+eRJc1+vdD+KjB9NMW2Tw+ghV4b4iGpcODjQRA V6cSVXXyYalbihn216vsic9v5Vq2wA0JLWz1yU3gIEGRVGWoEohnK8wopdc5LHqAumnSDA4AA7AiN ux4LyCFhJnUmSR8HQCgSelmWQVjEb7vqyinIuZKKVe42KzWgi89cI+FMwFgR+e5In6i2WI3VIxpbp wXyc6JrA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnzPC-00000009ws2-1Hhn; Thu, 05 Feb 2026 13:28:22 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnzPB-00000009wrm-05kh; Thu, 05 Feb 2026 13:28:21 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 71CBE60010; Thu, 5 Feb 2026 13:28:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10184C4CEF7; Thu, 5 Feb 2026 13:28:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770298100; bh=RVwIHojJPFtR1L6mECLDirnCU93wad5+Ug+yqXZvlGY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hCy9lXRU7VwFbtpEzZC8tJW3BxP0Y+kkOtXRSjO0Y/EbAqe2ZZTbmD3BTi+LY6IvV 3VDoNHBAthurR5saMIBgCknSgSKPY2kGtXATsfjShk+vrtTpIeuOCp/3+PRWt4h+7V NfsIGMCSL9N8FHQWjGcnLmRfl9x363lCi8STV4b2xUCDb+V5S7N4RZFBFOyHW5eVAh p+nrJ0Y1mgPjQ2mbhzLmSLjkiqokuvr17PC7JJzYeMGiQeTE4nPNaH4ako1HCiqwT/ 303Cny++W7VOs+ai2NNL3LA5Vh9EvxCBWwE1HqldlEbOWmjNfjQjG11uvFZZKfRlIm Z5WIAf475MuMg== Date: Thu, 5 Feb 2026 14:28:13 +0100 From: Niklas Cassel To: Hans Zhang <18255117159@163.com> Cc: Ricardo Pardini , lpieralisi@kernel.org, kwilczynski@kernel.org, bhelgaas@google.com, helgaas@kernel.org, heiko@sntech.de, mani@kernel.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 v7 0/2] PCI: Configure Root Port MPS during host probing Message-ID: References: <20251127170908.14850-1-18255117159@163.com> <1ff0d069-14f0-439a-afca-4ecc1b569834@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1ff0d069-14f0-439a-afca-4ecc1b569834@163.com> 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 Sun, Jan 18, 2026 at 09:26:45PM +0800, Hans Zhang wrote: > On 2025/12/31 10:58, Ricardo Pardini wrote: > > On 27/11/2025 18:09, Hans Zhang wrote: > > > Current PCIe initialization exhibits a key optimization gap: Root Ports > > > may operate with non-optimal Maximum Payload Size (MPS) settings. While > > > downstream device configuration is handled during bus enumeration, Root > > > Port MPS values inherited from firmware or hardware defaults often fail > > > to utilize the full capabilities supported by controller hardware. This > > > results in suboptimal data transfer efficiency throughout the PCIe > > > hierarchy. > > > > > > This patch series addresses this by: > > > > > > 1. Core PCI enhancement (Patch 1): > > > - Proactively configures Root Port MPS during host controller probing > > > - Sets initial MPS to hardware maximum (128 << dev->pcie_mpss) > > > - Conditional on PCIe bus tuning being enabled (PCIE_BUS_TUNE_OFF unset) > > >    and not in PCIE_BUS_PEER2PEER mode (which requires default 128 bytes) > > > - Maintains backward compatibility via PCIE_BUS_TUNE_OFF check > > > - Preserves standard MPS negotiation during downstream enumeration > > > > > > 2. Driver cleanup (Patch 2): > > > - Removes redundant MPS configuration from Meson PCIe controller driver > > > - Functionality is now centralized in PCI core > > > - Simplifies driver maintenance long-term > > > > > > --- > > > Changes in v7: > > > - Exclude PCIE_BUS_PEER2PEER mode from Root Port MPS configuration > > > - Remove redundant check for upstream bridge (Root Ports don't have one) > > > - Improve commit message and code comments as per Bjorn. > > Hi Hans, > > > > I've tested on an Odroid-HC4 with a SATA SSD (via an ASM1061) by > > applying your v7 on v6.19-rc3 + Bjorn's 20251103221930.1831376-1- > > helgaas@kernel.org ("PCI: meson: Remove meson_pcie_link_up() timeout, > > message, speed check" which is required to get the meson PCIe to work at > > all since 6.18). With that setup I get: > > > > # hdparm --direct -t /dev/sda > >  Timing O_DIRECT disk reads: 832 MB in  3.00 seconds = 277.33 MB/sec > > > > I've an identical machine, with a similar disk (even slightly faster, on > > paper), running plain 6.12.y and there I get: > > > > # hdparm --direct -t /dev/sda > >  Timing O_DIRECT disk reads: 764 MB in  3.00 seconds = 254.26 MB/sec > > > > I repeated those a few times, not very scientific, I know; but anyway: > > > > Tested-by: Ricardo Pardini # on Odroid-HC4 > > > > I've also feedback from another user running with this series with > > success on a different meson PCIe machine, will ask them to TB as well; > > they had reported a significant drop in performance since v6.18 without > > this. > Hi, > > Thank you very much for your test. Let's wait for Bjorn's reply. Probably too late for the 6.20 / 7.0 merge window... But.. it would be nice with some kind of feedback from Bjorn. Is there any chance that this gets applied for 6.21/7.1 or is there any fundamental objection against this series? Kind regards, Niklas