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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 D5562C43613 for ; Wed, 19 Jun 2019 21:01:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE2F521537 for ; Wed, 19 Jun 2019 21:01:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560978087; bh=2+w/sDc7TOGcJqUGNqoLVM4ANfIB5qdNfkMoJOUEWRQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=tsMln3Bm9QNTUYgcm8Pa68IE2fth2bYr4LjEj6x9dFXrulB1p+BicUIwxRfs5oX5E M/bBItOhrGNPQFECmAepHyxqf353MuJeF2RUDlV6NC58Onin6k3go9e/NAVOP34jXb xstbud4LfY1ZbyBmpr7oQCLDQ9Y8FYqkMqydEdOI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726246AbfFSVB1 (ORCPT ); Wed, 19 Jun 2019 17:01:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:58186 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726175AbfFSVB1 (ORCPT ); Wed, 19 Jun 2019 17:01:27 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5944A215EA; Wed, 19 Jun 2019 21:01:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560978085; bh=2+w/sDc7TOGcJqUGNqoLVM4ANfIB5qdNfkMoJOUEWRQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nswNsuVILZTLvHSmd9m/WJSBlUuD27RumWInokuIMM+7tLdj0pQm6bmm4k5RFJDG3 5jXPCOZmZXFWqZ1VCTYWySLjtcyokLtjSFi00xL5IGf341Mw5/N3r5YYqO7FCu9qlf mbWcMVhqQdhJ3Q+ju0pDqysLhQ5xAwMnWLtCgqKA= Date: Wed, 19 Jun 2019 17:01:24 -0400 From: Sasha Levin To: "Rafael J. Wysocki" Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Keith Busch , Mika Westerberg , linux-pci@vger.kernel.org Subject: Re: [PATCH AUTOSEL 4.14 15/31] PCI: PM: Avoid possible suspend-to-idle issue Message-ID: <20190619210124.GF2226@sasha-vm> References: <20190608114646.9415-1-sashal@kernel.org> <20190608114646.9415-15-sashal@kernel.org> <7003865c-8689-78f2-d441-f2a223fb3122@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <7003865c-8689-78f2-d441-f2a223fb3122@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Jun 11, 2019 at 05:25:48PM +0200, Rafael J. Wysocki wrote: >On 6/8/2019 1:46 PM, Sasha Levin wrote: >>From: "Rafael J. Wysocki" >> >>[ Upstream commit d491f2b75237ef37d8867830ab7fad8d9659e853 ] >> >>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: Keith Busch >>Reviewed-by: Mika Westerberg >>Signed-off-by: Sasha Levin >>--- >> drivers/pci/pci-driver.c | 17 ++++++++++++++++- >> include/linux/pci.h | 1 + >> 2 files changed, 17 insertions(+), 1 deletion(-) >> >>diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c >>index ea69b4dbab66..f5d66335fe53 100644 >>--- a/drivers/pci/pci-driver.c >>+++ b/drivers/pci/pci-driver.c >>@@ -726,6 +726,8 @@ static int pci_pm_suspend(struct device *dev) >> struct pci_dev *pci_dev = to_pci_dev(dev); >> const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; >>+ pci_dev->skip_bus_pm = false; >>+ >> if (pci_has_legacy_pm_support(pci_dev)) >> return pci_legacy_suspend(dev, PMSG_SUSPEND); >>@@ -799,7 +801,20 @@ static int pci_pm_suspend_noirq(struct device *dev) >> } >> } >>- if (!pci_dev->state_saved) { >>+ if (pci_dev->skip_bus_pm) { >>+ /* >>+ * The function is running for the second time in a row without >>+ * going through full resume, which is possible only during >>+ * suspend-to-idle in a spurious wakeup case. Moreover, the >>+ * device was originally left in D0, so its power state should >>+ * not be changed here and the device register values saved >>+ * originally should be restored on resume again. >>+ */ >>+ pci_dev->state_saved = true; >>+ } else if (pci_dev->state_saved) { >>+ if (pci_dev->current_state == PCI_D0) >>+ pci_dev->skip_bus_pm = true; >>+ } else { >> pci_save_state(pci_dev); >> if (pci_power_manageable(pci_dev)) >> pci_prepare_to_sleep(pci_dev); >>diff --git a/include/linux/pci.h b/include/linux/pci.h >>index 59f4d10568c6..430f3c335446 100644 >>--- a/include/linux/pci.h >>+++ b/include/linux/pci.h >>@@ -346,6 +346,7 @@ struct pci_dev { >> D3cold, not set for devices >> powered on/off by the >> corresponding bridge */ >>+ unsigned int skip_bus_pm:1; /* Internal: Skip bus-level PM */ >> unsigned int ignore_hotplug:1; /* Ignore hotplug events */ >> unsigned int hotplug_user_indicators:1; /* SlotCtl indicators >> controlled exclusively by > >This has been reported to be problematic, I wouldn't recommend taking >it for -stable at this point. I've dropped it, thank you. -- Thanks, Sasha