From 448bd857d48e69b33ef323739dc6d8ca20d4cda7 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Sat, 23 Jun 2012 10:23:51 +0800 Subject: PCI/PM: add PCIe runtime D3cold support This patch adds runtime D3cold support and corresponding ACPI platform support. This patch only enables runtime D3cold support; it does not enable D3cold support during system suspend/hibernate. D3cold is the deepest power saving state for a PCIe device, where its main power is removed. While it is in D3cold, you can't access the device at all, not even its configuration space (which is still accessible in D3hot). Therefore the PCI PM registers can not be used to transition into/out of the D3cold state; that must be done by platform logic such as ACPI _PR3. To support wakeup from D3cold, a system may provide auxiliary power, which allows a device to request wakeup using a Beacon or the sideband WAKE# signal. WAKE# is usually connected to platform logic such as ACPI GPE. This is quite different from other power saving states, where devices request wakeup via a PME message on the PCIe link. Some devices, such as those in plug-in slots, have no direct platform logic. For example, there is usually no ACPI _PR3 for them. D3cold support for these devices can be done via the PCIe Downstream Port leading to the device. When the PCIe port is powered on/off, the device is powered on/off too. Wakeup events from the device will be notified to the corresponding PCIe port. For more information about PCIe D3cold and corresponding ACPI support, please refer to: - PCI Express Base Specification Revision 2.0 - Advanced Configuration and Power Interface Specification Revision 5.0 [bhelgaas: changelog] Reviewed-by: Rafael J. Wysocki Originally-by: Zheng Yan Signed-off-by: Huang Ying Signed-off-by: Bjorn Helgaas --- drivers/pci/pci-driver.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/pci/pci-driver.c') diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index bf0cee629b60..ca2e4c79a588 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -1019,10 +1019,13 @@ static int pci_pm_runtime_suspend(struct device *dev) if (!pm || !pm->runtime_suspend) return -ENOSYS; + pci_dev->no_d3cold = false; error = pm->runtime_suspend(dev); suspend_report_result(pm->runtime_suspend, error); if (error) return error; + if (!pci_dev->d3cold_allowed) + pci_dev->no_d3cold = true; pci_fixup_device(pci_fixup_suspend, pci_dev); @@ -1044,6 +1047,7 @@ static int pci_pm_runtime_suspend(struct device *dev) static int pci_pm_runtime_resume(struct device *dev) { + int rc; struct pci_dev *pci_dev = to_pci_dev(dev); const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; @@ -1054,7 +1058,11 @@ static int pci_pm_runtime_resume(struct device *dev) __pci_enable_wake(pci_dev, PCI_D0, true, false); pci_fixup_device(pci_fixup_resume, pci_dev); - return pm->runtime_resume(dev); + rc = pm->runtime_resume(dev); + + pci_dev->runtime_d3cold = false; + + return rc; } static int pci_pm_runtime_idle(struct device *dev) -- cgit v1.2.3