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 C484AC4332F for ; Thu, 7 Apr 2022 17:51:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346626AbiDGRxR (ORCPT ); Thu, 7 Apr 2022 13:53:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346630AbiDGRxP (ORCPT ); Thu, 7 Apr 2022 13:53:15 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B29B722EB35; Thu, 7 Apr 2022 10:51:11 -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 ams.source.kernel.org (Postfix) with ESMTPS id 6C510B82901; Thu, 7 Apr 2022 17:51:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05E26C385A0; Thu, 7 Apr 2022 17:51:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649353869; bh=cmP0BZ3fNUvcP7KxHKtR0yiNgwGpwH3espXWf6j0OxA=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=Ib2H7AYJZPo72aQsw1/OYImofH7OAeCmw1QztjPZCt5O7vxkDFE3uXOi5E3ORoV/K GHIbKSEdMghvbX/hZBM7JZxdjReU0uda2rUmEpwYxyRgZNtv7daLjG0NvC53UhnWSO lOr+jHVCnKOJR19X1z+r2NAlMzRtN6UzKqfxz+4AHbnWalXuJHl8a3CvsmJf65gXHc TrLgEGJD3Vgwv7EvremvCWzqboi9Tod94Y4FAGtJ+ICkXc7fNGUr0nEfJWkiW+ADSk Nz9CghzPAtZZ0CpoFIfYZEeKMvooc/1zoVfFxKkP64oNi7RFkuEYDDXui6ZlspGzxs K9/WHcmwdmfLQ== Date: Thu, 7 Apr 2022 12:51:07 -0500 From: Bjorn Helgaas To: "Rafael J. Wysocki" Cc: Linux ACPI , LKML , Linux PM , Linux PCI , Mika Westerberg Subject: Re: [PATCH v1 3/3] PCI: ACPI: PM: Power up devices in D3cold before scanning them Message-ID: <20220407175107.GA252647@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5729439.MhkbZ0Pkbq@kreacher> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Mon, Apr 04, 2022 at 05:25:04PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > The initial configuration of ACPI power resources on some systems > implies that some PCI devices on them are initially in D3cold. > > In some cases, especially for PCIe Root Ports, this is a "logical" > D3cold, meaning that the configuration space of the device is > accessible, but some of its functionality may be missing, but it > very well may be real D3cold, in which case the device will not > be accessible at all. However, the PCI bus type driver will need > to access its configuration space in order to enumerate it. > > To prevent possible device enumeration failures that may ensue as > a result of ACPI power resources being initially in the "off" > state, power up all children of the host bridge ACPI device object > that hold valid _ADR objects (which indicates that they will be > enumerated by the PCI bus type driver) and do that to all children > of the ACPI device objects corresponding to PCI bridges (including > PCIe ports). > > Signed-off-by: Rafael J. Wysocki Acked-by: Bjorn Helgaas > --- > drivers/acpi/pci_root.c | 2 ++ > drivers/pci/pci-acpi.c | 3 +++ > 2 files changed, 5 insertions(+) > > Index: linux-pm/drivers/acpi/pci_root.c > =================================================================== > --- linux-pm.orig/drivers/acpi/pci_root.c > +++ linux-pm/drivers/acpi/pci_root.c > @@ -927,6 +927,8 @@ struct pci_bus *acpi_pci_root_create(str > host_bridge->preserve_config = 1; > ACPI_FREE(obj); > > + acpi_dev_power_up_children_with_adr(device); > + > pci_scan_child_bus(bus); > pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info, > info); > Index: linux-pm/drivers/pci/pci-acpi.c > =================================================================== > --- linux-pm.orig/drivers/pci/pci-acpi.c > +++ linux-pm/drivers/pci/pci-acpi.c > @@ -1374,6 +1374,9 @@ void pci_acpi_setup(struct device *dev, > > acpi_pci_wakeup(pci_dev, false); > acpi_device_power_add_dependent(adev, dev); > + > + if (pci_is_bridge(pci_dev)) > + acpi_dev_power_up_children_with_adr(adev); > } > > void pci_acpi_cleanup(struct device *dev, struct acpi_device *adev) > > >