From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: [PATCH 10/11] PCI PM: Make pci_set_power_state() handle devices with no PM support Date: Sat, 14 Mar 2009 12:33:55 +0100 Message-ID: <200903141233.56694.rjw__695.015586870973$1237031377$gmane$org@sisk.pl> References: <200902221837.49396.rjw@sisk.pl> <200903141224.29591.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200903141224.29591.rjw@sisk.pl> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: pm list Cc: Arve@smtp1.linux-foundation.org, Jeremy Fitzhardinge , LKML , Jesse Barnes , "Eric W. Biederman" , Linux PCI , Ingo Molnar , Linus Torvalds , Thomas Gleixner List-Id: linux-pm@vger.kernel.org From: Rafael J. Wysocki There is a problem with PCI devices without any PM support (either native or through the platform) that pci_set_power_state() always returns error code for them, even if they are being put into D0. However, such devices are always in D0, so pci_set_power_state() should return success when attempting to put such a device into D0. It also should update the current_state field for these devices as appropriate. This modification is necessary so that the standard configuration registers of these devices are successfully restored by pci_restore_standard_config() during the "early" phase of resume. In addition, pci_set_power_state() should check the value of current_state before calling the platform to change the power state of the device to avoid doing that unnecessarily. Signed-off-by: Rafael J. Wysocki --- drivers/pci/pci.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) Index: linux-2.6/drivers/pci/pci.c =================================================================== --- linux-2.6.orig/drivers/pci/pci.c +++ linux-2.6/drivers/pci/pci.c @@ -439,6 +439,10 @@ static int pci_raw_set_power_state(struc u16 pmcsr; bool need_restore = false; + /* Check if we're already there */ + if (dev->current_state == state) + return 0; + if (!dev->pm_cap) return -EIO; @@ -449,10 +453,7 @@ static int pci_raw_set_power_state(struc * Can enter D0 from any state, but if we can only go deeper * to sleep if we're already in a low power state */ - if (dev->current_state == state) { - /* we're already there */ - return 0; - } else if (state != PCI_D0 && dev->current_state <= PCI_D3cold + if (state != PCI_D0 && dev->current_state <= PCI_D3cold && dev->current_state > state) { dev_err(&dev->dev, "invalid power transition " "(from state %d to %d)\n", dev->current_state, state); @@ -570,12 +571,17 @@ int pci_set_power_state(struct pci_dev * */ return 0; - if (state == PCI_D0 && platform_pci_power_manageable(dev)) { + /* Check if we're already there */ + if (dev->current_state == state) + return 0; + + if (state == PCI_D0) { /* * Allow the platform to change the state, for example via ACPI * _PR0, _PS0 and some such, but do not trust it. */ - int ret = platform_pci_set_power_state(dev, PCI_D0); + int ret = platform_pci_power_manageable(dev) ? + platform_pci_set_power_state(dev, PCI_D0) : 0; if (!ret) pci_update_current_state(dev, PCI_D0); }