From patchwork Wed Oct 19 14:07:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 9384113 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 CC26960CDC for ; Wed, 19 Oct 2016 14:24:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BF0882979F for ; Wed, 19 Oct 2016 14:24:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B3AB729A46; Wed, 19 Oct 2016 14:24:37 +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=ham 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 E5C2F29A2F for ; Wed, 19 Oct 2016 14:24:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941563AbcJSOYb (ORCPT ); Wed, 19 Oct 2016 10:24:31 -0400 Received: from mailout2.hostsharing.net ([83.223.90.233]:41143 "EHLO mailout2.hostsharing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941509AbcJSOY3 (ORCPT ); Wed, 19 Oct 2016 10:24:29 -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 mailout2.hostsharing.net (Postfix) with ESMTPS id C13D010189A89; Wed, 19 Oct 2016 16:08:47 +0200 (CEST) Received: from localhost (3-38-90-81.adsl.cmo.de [81.90.38.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 2AB2E60C01D8; Wed, 19 Oct 2016 16:08:46 +0200 (CEST) X-Mailbox-Line: From a2073dcdc8287e1a7755ca7c2a48f4124888f143 Mon Sep 17 00:00:00 2001 Message-Id: In-Reply-To: References: From: Lukas Wunner Date: Wed, 19 Oct 2016 16:07:13 +0200 Subject: [PATCH 4/9] PCI: Activate runtime PM on a PCIe port only if it can suspend To: linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Bjorn Helgaas Cc: Mika Westerberg , "Rafael J. Wysocki" , Andreas Noever , Keith Busch 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 Currently pcie_portdrv_probe() activates runtime PM on a PCIe port even if it will never actually suspend because the BIOS is too old or the "pcie_port_pm=off" option was specified on the kernel command line. A few CPU cycles can be saved by not activating runtime PM at all in these cases, because rpm_idle() and rpm_suspend() will bail out right at the beginning when calling rpm_check_suspend_allowed(), instead of carrying out various locking and assignments, invoking rpm_callback(), getting back -EBUSY and rolling everything back. The conditions checked in pci_bridge_d3_possible() are all static, they never change during uptime of the system, hence it's safe to call this to determine if runtime PM should be activated. No functional change intended. Cc: Mika Westerberg Cc: Rafael J. Wysocki Signed-off-by: Lukas Wunner --- drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 1 + drivers/pci/pcie/portdrv_pci.c | 5 +++-- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index bc60f2c..854d185 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2226,7 +2226,7 @@ void pci_config_pm_runtime_put(struct pci_dev *pdev) * This function checks if it is possible to move the bridge to D3. * Currently we only allow D3 for recent enough PCIe ports. */ -static bool pci_bridge_d3_possible(struct pci_dev *bridge) +bool pci_bridge_d3_possible(struct pci_dev *bridge) { unsigned int year; diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 27048bb..ffffef3 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -85,6 +85,7 @@ void pci_pm_init(struct pci_dev *dev); void pci_ea_init(struct pci_dev *dev); void pci_allocate_cap_save_buffers(struct pci_dev *dev); void pci_free_cap_save_buffers(struct pci_dev *dev); +bool pci_bridge_d3_possible(struct pci_dev *dev); void pci_bridge_d3_update(struct pci_dev *dev); static inline void pci_wakeup_event(struct pci_dev *dev) diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 79327cc..1ae712c 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -19,6 +19,7 @@ #include #include +#include "../pci.h" #include "portdrv.h" #include "aer/aerdrv.h" @@ -157,7 +158,7 @@ static int pcie_portdrv_probe(struct pci_dev *dev, * subordinate devices). We can't be sure for native PCIe hotplug * either so prevent that as well. */ - if (!dev->is_hotplug_bridge) { + if (pci_bridge_d3_possible(dev) && !dev->is_hotplug_bridge) { /* * Keep the port resumed 100ms to make sure things like * config space accesses from userspace (lspci) will not @@ -175,7 +176,7 @@ static int pcie_portdrv_probe(struct pci_dev *dev, static void pcie_portdrv_remove(struct pci_dev *dev) { - if (!dev->is_hotplug_bridge) { + if (pci_bridge_d3_possible(dev) && !dev->is_hotplug_bridge) { pm_runtime_forbid(&dev->dev); pm_runtime_get_noresume(&dev->dev); pm_runtime_dont_use_autosuspend(&dev->dev);