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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=unavailable 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 42885C04AAC for ; Mon, 20 May 2019 10:40:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21EEE20863 for ; Mon, 20 May 2019 10:40:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731045AbfETKkB (ORCPT ); Mon, 20 May 2019 06:40:01 -0400 Received: from mga01.intel.com ([192.55.52.88]:54204 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728551AbfETKkB (ORCPT ); Mon, 20 May 2019 06:40:01 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 May 2019 03:40:00 -0700 X-ExtLoop1: 1 Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by fmsmga001.fm.intel.com with SMTP; 20 May 2019 03:39:58 -0700 Received: by lahna (sSMTP sendmail emulation); Mon, 20 May 2019 13:39:57 +0300 Date: Mon, 20 May 2019 13:39:57 +0300 From: Mika Westerberg To: "Rafael J. Wysocki" Cc: Linux PCI , Linux PM , Linux ACPI , LKML , Bjorn Helgaas , Keith Busch Subject: Re: [PATCH] PCI: PM: Avoid possible suspend-to-idle issue Message-ID: <20190520103957.GL2781@lahna.fi.intel.com> References: <2315917.ZGeXE6pBFC@kreacher> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2315917.ZGeXE6pBFC@kreacher> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, May 17, 2019 at 11:08:50AM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > If a PCI driver leaves the device handled by it in D0 and calls > pci_save_state() on the device in its ->suspend() or ->suspend_late() > callback, it can expect the device to stay in D0 over the whole > s2idle cycle. However, that may not be the case if there is a > spurious wakeup while the system is suspended, because in that case > pci_pm_suspend_noirq() will run again after pci_pm_resume_noirq() > which calls pci_restore_state(), via pci_pm_default_resume_early(), > so state_saved is cleared and the second iteration of > pci_pm_suspend_noirq() will invoke pci_prepare_to_sleep() which > may change the power state of the device. > > To avoid that, add a new internal flag, skip_bus_pm, that will be set > by pci_pm_suspend_noirq() when it runs for the first time during the > given system suspend-resume cycle if the state of the device has > been saved already and the device is still in D0. Setting that flag > will cause the next iterations of pci_pm_suspend_noirq() to set > state_saved for pci_pm_resume_noirq(), so that it always restores the > device state from the originally saved data, and avoid calling > pci_prepare_to_sleep() for the device. > > Fixes: 33e4f80ee69b ("ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle") > Signed-off-by: Rafael J. Wysocki Reviewed-by: Mika Westerberg