From patchwork Wed Aug 31 06:15:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 9306377 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 487E7608A0 for ; Wed, 31 Aug 2016 06:16:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3AD5028B24 for ; Wed, 31 Aug 2016 06:16:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 293EE28D99; Wed, 31 Aug 2016 06:16:35 +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=-6.9 required=2.0 tests=BAYES_00,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 A458328E26 for ; Wed, 31 Aug 2016 06:16:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759005AbcHaGQa (ORCPT ); Wed, 31 Aug 2016 02:16:30 -0400 Received: from mailout1.hostsharing.net ([83.223.95.204]:37755 "EHLO mailout1.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758994AbcHaGQZ (ORCPT ); Wed, 31 Aug 2016 02:16:25 -0400 Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout1.hostsharing.net (Postfix) with ESMTPS id 88AFF101BB5F2; Wed, 31 Aug 2016 08:16:14 +0200 (CEST) Received: from localhost (4-38-90-81.adsl.cmo.de [81.90.38.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 7739E600BAF8; Wed, 31 Aug 2016 08:16:13 +0200 (CEST) X-Mailbox-Line: From 4935437e0bfbab9079db2c8b1fbac66cef7dc569 Mon Sep 17 00:00:00 2001 Message-Id: <4935437e0bfbab9079db2c8b1fbac66cef7dc569.1472554278.git.lukas@wunner.de> In-Reply-To: References: From: Lukas Wunner Date: Wed, 31 Aug 2016 08:15:18 +0200 Subject: [PATCH 3/4] PCI: Avoid unnecessary resume after direct-complete To: linux-pci@vger.kernel.org Cc: linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org, "Rafael J. Wysocki" , Peter Wu , Andreas Noever 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 Commit 58a1fbbb2ee8 ("PM / PCI / ACPI: Kick devices that might have been reset by firmware") added a runtime resume for devices that were runtime suspended when the system entered sleep. The motivation was that devices might be in a reset-power-on state after waking from system sleep, so their power state as perceived by Linux (stored in pci_dev->current_state) would no longer reflect reality. By resuming such devices, we allow them to return to a low-power state via autosuspend and also bring their current_state in sync with reality. However for devices that are *not* in a reset-power-on state, doing an unconditional resume wastes energy. A more refined approach is called for which issues a runtime resume only if the power state after direct-complete is shallower than it was before. To achieve this, update the device's current_state by querying the platform firmware and reading its PMCSR. Cc: Rafael J. Wysocki Signed-off-by: Lukas Wunner --- drivers/pci/pci-driver.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index e39a67c..fd4b9c4 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -684,8 +684,19 @@ static int pci_pm_prepare(struct device *dev) static void pci_pm_complete(struct device *dev) { - pci_dev_complete_resume(to_pci_dev(dev)); - pm_complete_with_resume_check(dev); + struct pci_dev *pci_dev = to_pci_dev(dev); + + pci_dev_complete_resume(pci_dev); + pm_generic_complete(dev); + + /* Resume device if platform firmware has put it in reset-power-on */ + if (dev->power.direct_complete && pm_resume_via_firmware()) { + pci_power_t pre_sleep_state = pci_dev->current_state; + + pci_update_current_state(pci_dev, pci_dev->current_state); + if (pci_dev->current_state < pre_sleep_state) + pm_request_resume(dev); + } } #else /* !CONFIG_PM_SLEEP */