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=-10.1 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,USER_AGENT_GIT 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 A4B69C33CAF for ; Thu, 16 Jan 2020 17:08:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78D4820663 for ; Thu, 16 Jan 2020 17:08:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194532; bh=qGCvbFL5fX//JsOK2d4ucXPkoRsm4vNcS0c4doK2kGQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XYDyLj2SMbBIW8fc/fgmcztncyTA0TOAisScW9K/mULywTIV9A31fVTuuqRFyd3gX nOQOLtrgHmBQxfY9lN9Kclh0d2quZPBcluZtpPpu4owBoljyZOcsdds+KiCND+k08t x7PWs6SU6M1t7fmpQIDQbAMZGYCFLEFOUSS7vgIg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389513AbgAPRIv (ORCPT ); Thu, 16 Jan 2020 12:08:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:42940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389464AbgAPRIm (ORCPT ); Thu, 16 Jan 2020 12:08:42 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 89C3B24685; Thu, 16 Jan 2020 17:08:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194521; bh=qGCvbFL5fX//JsOK2d4ucXPkoRsm4vNcS0c4doK2kGQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QKuemI4Nbw13GBzN+hv2i0EepCrU+H/koeP6WmViGvn/yirfBpzDRZ2UAQ4v+KIbg AdKURLKl8zaJMC7v2bZhdA8/t4VN+c2jy6cqU15+6CMjpkZ+4lNzD5DdcVGLwUPefY gCASUBGC/wHOr6klT548y2annMWxxoN/h4oOqkeU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Rafael J. Wysocki" , Kai-Heng Feng , Mika Westerberg , Sasha Levin , linux-pci@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 412/671] PCI: PM: Skip devices in D0 for suspend-to-idle Date: Thu, 16 Jan 2020 12:00:50 -0500 Message-Id: <20200116170509.12787-149-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116170509.12787-1-sashal@kernel.org> References: <20200116170509.12787-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Rafael J. Wysocki" [ Upstream commit 3e26c5feed2add218046ecf91bab3cfa9bf762a6 ] 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, the power state of a PCI bridge with a downstream device in D0 must be D0 (based on the PCI PM spec r1.2, sec 6, table 6-1, if the bridge is not in D0, there can be no PCI transactions on its secondary bus), but that is not actively enforced 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 is pointless, 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 Reviewed-by: Mika Westerberg Tested-by: Kai-Heng Feng Signed-off-by: Sasha Levin --- drivers/pci/pci-driver.c | 47 ++++++++++++++++++++++++++++++---------- 1 file changed, 35 insertions(+), 12 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 5c9873fcbd08..e69af9b8361d 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -526,7 +526,6 @@ static void pci_pm_default_resume_early(struct pci_dev *pci_dev) pci_power_up(pci_dev); pci_restore_state(pci_dev); pci_pme_restore(pci_dev); - pci_fixup_device(pci_fixup_resume_early, pci_dev); } /* @@ -833,18 +832,16 @@ static int pci_pm_suspend_noirq(struct device *dev) 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); @@ -853,6 +850,22 @@ static int pci_pm_suspend_noirq(struct device *dev) 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; + /* + * Per PCI PM r1.2, table 6-1, a bridge must be in D0 if any + * downstream device is in D0, so avoid changing the power state + * of the parent bridge by setting the skip_bus_pm flag for it. + */ + 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); /* @@ -900,7 +913,16 @@ static int pci_pm_resume_noirq(struct device *dev) 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); @@ -1201,6 +1223,7 @@ static int pci_pm_restore_noirq(struct device *dev) } 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); -- 2.20.1