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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20030C433F5 for ; Fri, 27 May 2022 23:28:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355169AbiE0X2C (ORCPT ); Fri, 27 May 2022 19:28:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235741AbiE0X2B (ORCPT ); Fri, 27 May 2022 19:28:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6F20762A5; Fri, 27 May 2022 16:28:00 -0700 (PDT) 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 4F90E61A5F; Fri, 27 May 2022 23:28:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68C6AC385A9; Fri, 27 May 2022 23:27:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653694079; bh=tsZOyDdsn/R3PNVK/DQdKGBDnPHlMZFoXEP8WTRvpiQ=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=efWgDNo+o/YTK0ZMvEGzbW/HvGG4IleYaiYe1wKIgtfQDoxJGtVPz3Dg1RP50TToS TdMSOdrg8oPkKML2qm6L9wUpIC5fG1OLAOX43VxsyDnQRlHwanQSEkTqG4jw1+K6Ho vLkFmg7IhNMjqW/qy9WGZ1W9VQMmD7IIhcekRjfjDqqPNaHkZDwpy9ks2RVAUzK2bO 51kR5Gjx3w0QxaotMrl+e5D7/D6TO6RKezcH/ATfoIwyxXTQT3KYHo8yZT8I4ba0Ny JPhPNWbOvR9AtV+OKD9R+C6nvfjXpro6G30G27JjE4mACI42tsMwSnp6o7MFHz35wz SbQ5EQlzieeEQ== Date: Fri, 27 May 2022 18:27:57 -0500 From: Bjorn Helgaas To: Jim Quinlan Cc: linux-pci , Nicolas Saenz Julienne , Bjorn Helgaas , James Dutton , Cyril Brulebois , bcm-kernel-feedback-list , Jim Quinlan , Florian Fainelli , Lorenzo Pieralisi , Rob Herring , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , open list , "Rafael J. Wysocki" , linux-pm@vger.kernel.org Subject: Re: [PATCH v1] PCI: brcmstb: Fix regression regarding missing PCIe linkup Message-ID: <20220527232757.GA515159@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220525215739.GA275957@bhelgaas> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, May 25, 2022 at 04:57:39PM -0500, Bjorn Helgaas wrote: > On Tue, May 24, 2022 at 12:54:48PM -0400, Jim Quinlan wrote: > > On Mon, May 23, 2022 at 6:10 PM Bjorn Helgaas wrote: > > > On Sat, May 21, 2022 at 02:51:42PM -0400, Jim Quinlan wrote: > > > > On Sat, May 21, > > > > 2CONFIG_INITRAMFS_SOURCE="/work3/jq921458/cpio/54-arm64-rootfs.cpio022 > > > > at 12:43 PM Bjorn Helgaas wrote: > > > > > On Wed, May 18, 2022 at 03:42:11PM -0400, Jim Quinlan wrote: > > > > > > commit 93e41f3fca3d ("PCI: brcmstb: Add control of subdevice > > > > > > voltage regulators") > > > > > > > > > > > > introduced a regression on the PCIe RPi4 Compute Module. If the > > > > > > PCIe endpoint node described in [2] was missing, no linkup would > > > > > > be attempted, and subsequent accesses would cause a panic > > > > > > because this particular PCIe HW causes a CPU abort on illegal > > > > > > accesses (instead of returning 0xffffffff). > > > > > > > > > > > > We fix this by allowing the DT endpoint subnode to be missing. > > > > > > This is important for platforms like the CM4 which have a > > > > > > standard PCIe socket and the endpoint device is unknown. > > > > But above you say it's the *endpoint* node that doesn't exist. The > > > existing code looks like it's checking for the *bridge* node > > > (bus->dev->of_node). We haven't even enumerated the devices on the > > > child bus, so we don't know about them at this point. > > > > You are absolutely correct and I must change the commit message > > to say the "root port DT node". I'm sorry; this mistake likely did not > > help you understand the fix. :-( > > Great, that will help me out! I think including the relevant DT > snippet would also make it more concrete and might conceivably be > helpful to somebody working around it on a kernel without the fix. Where are we at with this? Linus just merged my pull request, and I'd really like to get this resolved before -rc1 (expected June 5 or so), which means I'd like to ask him to pull the fix early next week. The alternative is to ask him to pull these reverts, which have actually been in -next since May 11: 4246970a3bcb ("Revert "PCI: brcmstb: Split brcm_pcie_setup() into two funcs"") f35b19f02e01 ("Revert "PCI: brcmstb: Add mechanism to turn on subdev regulators"") ae65b283d7a4 ("Revert "PCI: brcmstb: Add control of subdevice voltage regulators"") d938b26e9b14 ("Revert "PCI: brcmstb: Do not turn off WOL regulators on suspend"") Bjorn