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 9CA68C61DA4 for ; Thu, 9 Mar 2023 17:39:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version: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:References: List-Owner; bh=dS664FhdnGuT8xi7+E3F1T3vHYjeHwgeTzN9/U4yct8=; b=PbTeF5C5uHu1hW rfspuUqrVfmo79/TqzDwdT1PUtk3He6Y/N02puP4hU9lPP5IPXL5si635OIT8B07aTEcPeNkLwL1F SKVGnWqjDz/HmLqUzdgUFXdCGyk+WwfBmsydZUFWYOhdTrJIp9LWPy3sUtuT9A5V2OOht1865cgRC w6gGmsoNinI+L+hERqkbTW9ltfIxqh8vP6uKFJBHx0BJ3+dTnwxYjIkZWkXkWUI3GUVQt2mw3gaS+ lBlXktfI14t3DXLhfqKHZ9ZuyzsGqIHuMSKDjohgXe6gu3V29DOrtpwtcc7vIfI+pqAN3ZlVjOLyL kxsBDI5K6OuZAUD1tvLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1paKDy-00BSKQ-Lv; Thu, 09 Mar 2023 17:38:42 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1paKDv-00BSJX-N9 for linux-arm-kernel@lists.infradead.org; Thu, 09 Mar 2023 17:38:41 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8927A61CB0; Thu, 9 Mar 2023 17:38:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A326BC433EF; Thu, 9 Mar 2023 17:38:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678383518; bh=iajjPMk40xiWGEaEZlqlsOqiEOpuHw6FDCZfmoz0Cv8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=pDuWk9tubZCqcPaxKqF6b8uZ97kOMw/Lj7YS0Mz468atWYwDN+pVQ21mFE7UyRH7q 0xMwnZjji/6LfjYtrMqLMiIEKt4iuyOkXZMBEChyzSzCU3FTxgKUPOHY4vGXUJML/P 0zxalYawcdsV9Bn+ekkIVTjJQ7Ih8jZxNPso87vm3sTnCivcQAoL+NUXRAd1hGbOSa 4k80nczkm8imqt0nP0BK6sLV9wTMx99xcGi/EwsjoAUp+4I0X8AYQ0aeC8mdGfKSU4 4E4xOpQ/ppbwIw6FY/gUyMzyB3jGOG9vxMJ5t85CDqNARtS5yEs3Q4M3VbEa8Gggtf 5hiJrJKwdV/HA== Date: Thu, 9 Mar 2023 11:38:36 -0600 From: Bjorn Helgaas To: Shawn Guo Cc: Catalin Marinas , Will Deacon , Bjorn Helgaas , Maximilian Luz , Lorenzo Pieralisi , Bjorn Andersson , linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: PCI: Add quirk for platforms running Windows Message-ID: <20230309173836.GA1148798@bhelgaas> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230309025212.GB18319@T480> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230309_093839_870863_89375387 X-CRM114-Status: GOOD ( 31.01 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Mar 09, 2023 at 10:52:13AM +0800, Shawn Guo wrote: > + linux-arm-msm and MSM maintainer Bjorn > > On Wed, Mar 08, 2023 at 12:53:10PM -0600, Bjorn Helgaas wrote: > > On Mon, Feb 27, 2023 at 10:12:21AM +0800, Shawn Guo wrote: > > > Commit 8fd4391ee717 ("arm64: PCI: Exclude ACPI "consumer" resources from > > > host bridge windows") introduced a check to remove host bridge register > > > resources for all arm64 platforms, with the assumption that the PNP0A03 > > > _CRS resources would always be host bridge registers and never as windows > > > on arm64. > > > > > > The assumption stands true until Qualcomm Snapdragon Windows laptops > > > emerge. These laptops describe host bridge windows in PNP0A03 _CRS > > > resources instead. For example, the Microsoft Surface Pro X has host > > > bridges defined as > > > > > > Name (_HID, EisaId ("PNP0A08") /* PCI Express Bus */) // _HID: Hardware ID > > > Name (_CID, EisaId ("PNP0A03") /* PCI Bus */) // _CID: Compatible ID > > > > > > Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings > > > { > > > Name (RBUF, ResourceTemplate () > > > { > > > Memory32Fixed (ReadWrite, > > > 0x60200000, // Address Base > > > 0x01DF0000, // Address Length > > > ) > > > WordBusNumber (ResourceProducer, MinFixed, MaxFixed, PosDecode, > > > 0x0000, // Granularity > > > 0x0000, // Range Minimum > > > 0x0001, // Range Maximum > > > 0x0000, // Translation Offset > > > 0x0002, // Length > > > ,, ) > > > }) > > > Return (RBUF) /* \_SB_.PCI0._CRS.RBUF */ > > > } > > > > > > The Memory32Fixed holds a host bridge window, but it's not properly > > > defined as a "producer" resource. Consequently the resource gets > > > removed by kernel, and the BAR allocation fails later on: > > > > > > [ 0.150731] pci 0002:00:00.0: BAR 14: no space for [mem size 0x00100000] > > > [ 0.150744] pci 0002:00:00.0: BAR 14: failed to assign [mem size 0x00100000] > > > [ 0.150758] pci 0002:01:00.0: BAR 0: no space for [mem size 0x00004000 64bit] > > > [ 0.150769] pci 0002:01:00.0: BAR 0: failed to assign [mem size 0x00004000 64bit] > > > > > > This eventually prevents the PCIe NVME drive from being accessible. > > > > > > Add a quirk for these platforms to avoid the resource being removed. > > > > > > Signed-off-by: Shawn Guo > > > --- > > > We are running into the issue on more devices than just Surface Pro X > > > now, so trying to sort it out with a quirk as suggested by Lorenzo [1]. > > > > One thing I don't like about this application of quirks is that the > > list of affected platforms is likely to grow, which is an ongoing > > burden for users and developers. > > It's a very reasonable concern. I really hope that Qualcomm will start > thinking about Linux support on these machines in the future not too far > away, so that the list will not grow too long. > > > Can we have a conversation with Qualcomm about how they *intend* this > > to work? Linux is probably doing something wrong (interpreting > > something differently than Windows does), and if we could fix that, we > > have a better chance of future platforms working without quirks. > > Today Qualcomm only ships and cares about Windows on these machines, but > I believe it will change sooner or later. I don't maintain arch/arm64/kernel/pci.c, but my opinion is that we should not pursue quirks like this until we've tried really hard to figure out a generic approach. Bjorn _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel