From patchwork Wed Jun 12 22:14:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 10993301 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C398115E6 for ; Thu, 13 Jun 2019 17:12:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ABE0722B39 for ; Thu, 13 Jun 2019 17:12:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9FFAB22F3E; Thu, 13 Jun 2019 17:12:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3AC6E22B39 for ; Thu, 13 Jun 2019 17:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729107AbfFMRME (ORCPT ); Thu, 13 Jun 2019 13:12:04 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:60540 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729076AbfFLWOG (ORCPT ); Wed, 12 Jun 2019 18:14:06 -0400 Received: from 79.184.253.190.ipv4.supernova.orange.pl (79.184.253.190) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.267) id 991125ee90f9fcfa; Thu, 13 Jun 2019 00:14:02 +0200 From: "Rafael J. Wysocki" To: Linux PCI Cc: Linux PM , Linux ACPI , LKML , Bjorn Helgaas , Mika Westerberg , Keith Busch , Kai-Heng Feng Subject: [PATCH] PCI: PM: Skip devices in D0 for suspend-to-idle Date: Thu, 13 Jun 2019 00:14:02 +0200 Message-ID: <2513600.jR9RdVMSR0@kreacher> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rafael J. Wysocki Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue") attempted to avoid a problem with devices whose drivers want them to stay in D0 over suspend-to-idle and resume, but it did not go as far as it should with that. Namely, first of all, it is questionable to change the power state of a PCI bridge with a device in D0 under it, but that is not actively prevented from happening during system-wide PM transitions, so use the skip_bus_pm flag introduced by commit d491f2b75237 for that. Second, the configuration of devices left in D0 (whatever the reason) during suspend-to-idle need not be changed and attempting to put them into D0 again by force may confuse some firmware, so explicitly avoid doing that. Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue") Reported-by: Kai-Heng Feng Signed-off-by: Rafael J. Wysocki --- Tested on Dell XPS13 9360 with no issues. --- drivers/pci/pci-driver.c | 47 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 35 insertions(+), 12 deletions(-) Index: linux-pm/drivers/pci/pci-driver.c =================================================================== --- linux-pm.orig/drivers/pci/pci-driver.c +++ linux-pm/drivers/pci/pci-driver.c @@ -524,7 +524,6 @@ static void pci_pm_default_resume_early( pci_power_up(pci_dev); pci_restore_state(pci_dev); pci_pme_restore(pci_dev); - pci_fixup_device(pci_fixup_resume_early, pci_dev); } /* @@ -842,18 +841,16 @@ static int pci_pm_suspend_noirq(struct d if (pci_dev->skip_bus_pm) { /* - * The function is running for the second time in a row without + * Either the device is a bridge with a child in D0 below it, or + * 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. + * suspend-to-idle in a spurious wakeup case. The device should + * be in D0 at this point, but if it is a bridge, it may be + * necessary to save its state. */ - 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 { + if (!pci_dev->state_saved) + pci_save_state(pci_dev); + } else if (!pci_dev->state_saved) { pci_save_state(pci_dev); if (pci_power_manageable(pci_dev)) pci_prepare_to_sleep(pci_dev); @@ -862,6 +859,22 @@ static int pci_pm_suspend_noirq(struct d dev_dbg(dev, "PCI PM: Suspend power state: %s\n", pci_power_name(pci_dev->current_state)); + if (pci_dev->current_state == PCI_D0) { + pci_dev->skip_bus_pm = true; + /* + * Changing the power state of a PCI bridge with a device in D0 + * below it is questionable, so avoid doing that by setting the + * skip_bus_pm flag for the parent bridge. + */ + if (pci_dev->bus->self) + pci_dev->bus->self->skip_bus_pm = true; + } + + if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) { + dev_dbg(dev, "PCI PM: Skipped\n"); + goto Fixup; + } + pci_pm_set_unknown_state(pci_dev); /* @@ -909,7 +922,16 @@ static int pci_pm_resume_noirq(struct de if (dev_pm_smart_suspend_and_suspended(dev)) pm_runtime_set_active(dev); - pci_pm_default_resume_early(pci_dev); + /* + * In the suspend-to-idle case, devices left in D0 during suspend will + * stay in D0, so it is not necessary to restore or update their + * configuration here and attempting to put them into D0 again may + * confuse some firmware, so avoid doing that. + */ + if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware()) + pci_pm_default_resume_early(pci_dev); + + pci_fixup_device(pci_fixup_resume_early, pci_dev); if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume_early(dev); @@ -1200,6 +1222,7 @@ static int pci_pm_restore_noirq(struct d } pci_pm_default_resume_early(pci_dev); + pci_fixup_device(pci_fixup_resume_early, pci_dev); if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume_early(dev);