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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72E93C433DF for ; Wed, 24 Jun 2020 18:55:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C45E20702 for ; Wed, 24 Jun 2020 18:55:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406066AbgFXSzE (ORCPT ); Wed, 24 Jun 2020 14:55:04 -0400 Received: from mga04.intel.com ([192.55.52.120]:45383 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406019AbgFXSzE (ORCPT ); Wed, 24 Jun 2020 14:55:04 -0400 IronPort-SDR: 5vFrg2Gpi18PUvIhmJYwDyTr0Iju2BNTStiPq+VJ5UXvrH37HmJecX4B/O3+8pVZ36q+Vn/mne kmChtDpUMeLg== X-IronPort-AV: E=McAfee;i="6000,8403,9662"; a="142080699" X-IronPort-AV: E=Sophos;i="5.75,276,1589266800"; d="scan'208";a="142080699" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2020 11:55:04 -0700 IronPort-SDR: aANov6vjSZGZtORqh4D03erAF1CDI6QmLcOFKgsk2+UG6alKTWdnmcBssRFT9bmvXPZYPwMFTs UiQr4ybHUO5A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,276,1589266800"; d="scan'208";a="385254827" Received: from linux.intel.com ([10.54.29.200]) by fmsmga001.fm.intel.com with ESMTP; 24 Jun 2020 11:55:04 -0700 Received: from debox1-desk1.jf.intel.com (debox1-desk1.jf.intel.com [10.7.201.137]) by linux.intel.com (Postfix) with ESMTP id D77E65804D6; Wed, 24 Jun 2020 11:55:03 -0700 (PDT) Message-ID: <12d36fdcdbcf438dd3aac7769e8366afd9d5aa1a.camel@linux.intel.com> Subject: Re: [PATCH V2 0/2] nvme: Add support for ACPI StorageD3Enable property From: "David E. Box" Reply-To: david.e.box@linux.intel.com To: shyjumon.n@intel.com, rjw@rjwysocki.net, lenb@kernel.org, bhelgaas@google.com, dan.j.williams@intel.com, kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org Date: Wed, 24 Jun 2020 11:55:03 -0700 In-Reply-To: <20200612204820.20111-1-david.e.box@linux.intel.com> References: <20200428003214.3764-1-david.e.box@linux.intel.com> <20200612204820.20111-1-david.e.box@linux.intel.com> Organization: David E. Box Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.3 (3.34.3-1.fc31) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Friendly reminder. Thanks. David On Fri, 2020-06-12 at 13:48 -0700, David E. Box wrote: > This patch set implements a solution for a BIOS hack used on some > currently > shipping Intel systems to address issues with power management policy > decisions concerning PCIe NVMe drives. Some newer Intel platforms, > like > some Comet Lake systems, require that PCIe devices use D3 when doing > suspend-to-idle in order to allow the platform to realize maximum > power > savings. This is particularly needed to support ATX power supply > shutdown > on desktop systems. In order to ensure this happens for root ports > with > storage devices, Microsoft apparently created this ACPI _DSD property > as a > way to override their driver policy. To my knowledge this property > has not > been discussed with the NVME specification body. > > Though the solution is not ideal, it addresses a problem that also > affects > Linux since the NVMe driver's default policy of using NVMe APST > during > suspend-to-idle would lead to higher power consumption for these > platforms. > > Patch 1 provides a symbol in the PCI/ACPI layer to read the property. > Patch 2 uses the symbol in the NVMe driver to select D3 as a quirk if > set. > > Changes from V2: > - Export the pci_acpi_storage_d3 function for use by drivers as > needed instead of modifying the pci header. > - Add missing put on acpi device handle. > - Add 'noacpi' module parameter to allow undoing this change. > - Add info message that this is a platform quirk. > > David E. Box (2): > PCI: Add ACPI StorageD3Enable _DSD support > drivers/nvme: Add support for ACPI StorageD3Enable property > > drivers/acpi/property.c | 3 +++ > drivers/nvme/host/pci.c | 14 ++++++++++ > drivers/pci/pci-acpi.c | 59 > +++++++++++++++++++++++++++++++++++++++++ > include/linux/pci.h | 2 ++ > 4 files changed, 78 insertions(+) >