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 v1.2.1 From db288c9c5f9db45610dab3940377625132b4af41 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 5 Jul 2012 15:20:00 -0600 Subject: PCI / PM: restore the original behavior of pci_set_power_state() Commit cc2893b6 (PCI: Ensure we re-enable devices on resume) addressed the problem with USB not being powered after resume on recent Lenovo machines, but it did that in a suboptimal way. Namely, it should have changed the relevant code paths only, which are pci_pm_resume_noirq() and pci_pm_restore_noirq() supposed to restore the device's power and standard configuration registers after system resume from suspend or hibernation. Instead, however, it modified pci_set_power_state() which is executed in several other situations too. That resulted in some undesirable effects, like attempting to change a device's power state in the same way multiple times in a row (up to as many as 4 times in a row in the snd_hda_intel driver). Fix the bug addressed by commit cc2893b6 in an alternative way, by forcibly powering up all devices in pci_pm_default_resume_early(), which is called by pci_pm_resume_noirq() and pci_pm_restore_noirq() to restore the device's power and standard configuration registers, and modifying pci_pm_runtime_resume() to avoid the forcible power-up if not necessary. Then, revert the changes made by commit cc2893b6 to make the confusion introduced by it go away. Acked-by: Matthew Garrett Signed-off-by: Rafael J. Wysocki Signed-off-by: Bjorn Helgaas --- drivers/pci/pci-driver.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'drivers/pci/pci-driver.c') diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index ca2e4c79a588..1dd1d9dfa173 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -459,16 +459,17 @@ static int pci_restore_standard_config(struct pci_dev *pci_dev) return 0; } +#endif + +#ifdef CONFIG_PM_SLEEP + static void pci_pm_default_resume_early(struct pci_dev *pci_dev) { - pci_restore_standard_config(pci_dev); + pci_power_up(pci_dev); + pci_restore_state(pci_dev); pci_fixup_device(pci_fixup_resume_early, pci_dev); } -#endif - -#ifdef CONFIG_PM_SLEEP - /* * Default "suspend" method for devices that have no driver provided suspend, * or not even a driver at all (second part). @@ -1054,7 +1055,8 @@ static int pci_pm_runtime_resume(struct device *dev) if (!pm || !pm->runtime_resume) return -ENOSYS; - pci_pm_default_resume_early(pci_dev); + pci_restore_standard_config(pci_dev); + pci_fixup_device(pci_fixup_resume_early, pci_dev); __pci_enable_wake(pci_dev, PCI_D0, true, false); pci_fixup_device(pci_fixup_resume, pci_dev); -- cgit v1.2.1