From c733b77475707cc3980542c86ee0ad5c841d544c Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Wed, 26 Dec 2012 10:39:23 -0700 Subject: [PATCH] PCI/PM: Do not suspend port if any subordinate device needs PME polling Ulrich reported that his USB3 cardreader does not work reliably when connected to the USB3 port. It turns out that USB3 controller failed to awaken when plugging in the USB3 cardreader. Further experiments found that the USB3 host controller can only be awakened via polling, not via PME interrupt. But if the PCIe port to which the USB3 host controller is connected is suspended, we cannot poll the controller because its config space is not accessible when the PCIe port is in a low power state. To solve the issue, the PCIe port will not be suspended if any subordinate device needs PME polling. [bhelgaas: use bool consistently rather than mixing int/bool] Reference: http://lkml.kernel.org/r/50841CCC.9030809@uli-eckhardt.de Reported-by: Ulrich Eckhardt Tested-by: Sarah Sharp Signed-off-by: Huang Ying Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki CC: stable@vger.kernel.org # v3.6+ --- drivers/pci/pcie/portdrv_pci.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index d4824cb78b49..08c243ab034e 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -134,10 +134,28 @@ static int pcie_port_runtime_resume(struct device *dev) return 0; } +static int pci_dev_pme_poll(struct pci_dev *pdev, void *data) +{ + bool *pme_poll = data; + + if (pdev->pme_poll) + *pme_poll = true; + return 0; +} + static int pcie_port_runtime_idle(struct device *dev) { + struct pci_dev *pdev = to_pci_dev(dev); + bool pme_poll = false; + + /* + * If any subordinate device needs pme poll, we should keep + * the port in D0, because we need port in D0 to poll it. + */ + pci_walk_bus(pdev->subordinate, pci_dev_pme_poll, &pme_poll); /* Delay for a short while to prevent too frequent suspend/resume */ - pm_schedule_suspend(dev, 10); + if (!pme_poll) + pm_schedule_suspend(dev, 10); return -EBUSY; } #else -- 2.39.5