From b3c32c4f9565f93407921c0d8a4458042eb8998e Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Thu, 25 Oct 2012 09:36:03 +0800 Subject: PCI/PM: Fix proc config reg access for D3cold and bridge suspending In https://bugzilla.kernel.org/show_bug.cgi?id=48981 Peter reported that /proc/bus/pci/??/??.? does not work for 3.6. This is because the device configuration space registers are not accessible if the corresponding parent bridge is suspended or the device is put into D3cold state. This is the same as /sys/bus/pci/devices/0000:??:??.?/config access issue. So the function used to solve sysfs issue is used to solve this issue. This patch moves pci_config_pm_runtime_get()/_put() from pci/pci-sysfs.c to pci/pci.c and makes them extern so they can be used by both the sysfs and proc paths. [bhelgaas: changelog, references, reporters] Reference: https://bugzilla.kernel.org/show_bug.cgi?id=48981 Reference: https://bugzilla.kernel.org/show_bug.cgi?id=49031 Reported-by: Forrest Loomis Reported-by: Peter Reported-by: Micael Dias Signed-off-by: Huang Ying Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki CC: stable@vger.kernel.org # v3.6+ --- drivers/pci/pci.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'drivers/pci/pci.c') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 54858838f09..aabf64798bd 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1858,6 +1858,38 @@ bool pci_dev_run_wake(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_dev_run_wake); +void pci_config_pm_runtime_get(struct pci_dev *pdev) +{ + struct device *dev = &pdev->dev; + struct device *parent = dev->parent; + + if (parent) + pm_runtime_get_sync(parent); + pm_runtime_get_noresume(dev); + /* + * pdev->current_state is set to PCI_D3cold during suspending, + * so wait until suspending completes + */ + pm_runtime_barrier(dev); + /* + * Only need to resume devices in D3cold, because config + * registers are still accessible for devices suspended but + * not in D3cold. + */ + if (pdev->current_state == PCI_D3cold) + pm_runtime_resume(dev); +} + +void pci_config_pm_runtime_put(struct pci_dev *pdev) +{ + struct device *dev = &pdev->dev; + struct device *parent = dev->parent; + + pm_runtime_put(dev); + if (parent) + pm_runtime_put_sync(parent); +} + /** * pci_pm_init - Initialize PM functions of given PCI device * @dev: PCI device to handle. -- cgit v1.2.3