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Date: Sun, 18 Jan 2015 01:57:05 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PCI <linux-pci@...r.kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux PM list <linux-pm@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Alan Stern <stern@...land.harvard.edu>,
Aaron Lu <aaron.lu@...el.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: [RFC][PATCH][v2] PCI / PM: Avoid resuming PCI devices during system suspend
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Commit f25c0ae2b4c4 (ACPI / PM: Avoid resuming devices in ACPI PM
domain during system suspend) modified the ACPI PM domain's system
suspend callbacks to allow devices attached to it to be left in the
runtime-suspended state during system suspend so as to optimize
the suspend process.
This was based on the general mechanism introduced by commit
aae4518b3124 (PM / sleep: Mechanism to avoid resuming runtime-suspended
devices unnecessarily).
Extend that approach to PCI devices by modifying the PCI bus type's
->prepare callback to return 1 for devices that are runtime-suspended
when it is being executed and that are in a suitable power state and
need not be resumed going forward.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
drivers/pci/pci-acpi.c | 17 +++++++++++++++++
drivers/pci/pci-driver.c | 11 ++++++-----
drivers/pci/pci.c | 26 ++++++++++++++++++++++++++
drivers/pci/pci.h | 6 ++++++
4 files changed, 55 insertions(+), 5 deletions(-)
Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -521,6 +521,11 @@ static inline int platform_pci_run_wake(
pci_platform_pm->run_wake(dev, enable) : -ENODEV;
}
+static inline bool platform_pci_need_resume(struct pci_dev *dev)
+{
+ return pci_platform_pm ? pci_platform_pm->need_resume(dev) : false;
+}
+
/**
* pci_raw_set_power_state - Use PCI PM registers to set the power state of
* given PCI device
@@ -1999,6 +2004,27 @@ bool pci_dev_run_wake(struct pci_dev *de
}
EXPORT_SYMBOL_GPL(pci_dev_run_wake);
+/**
+ * pci_dev_keep_suspended - Check if the device can stay in the suspended state.
+ * @pci_dev: Device to check.
+ *
+ * Return 'true' if the device is runtime-suspended, it doesn't have to be
+ * reconfigured due to wakeup settings difference between system and runtime
+ * suspend and the current power state of it is suitable for the upcoming
+ * (system) transition.
+ */
+bool pci_dev_keep_suspended(struct pci_dev *pci_dev)
+{
+ struct device *dev = &pci_dev->dev;
+
+ if (!pm_runtime_suspended(dev)
+ || (device_can_wakeup(dev) && !device_may_wakeup(dev))
+ || platform_pci_need_resume(pci_dev))
+ return false;
+
+ return pci_target_state(dev) == dev->current_state;
+}
+
void pci_config_pm_runtime_get(struct pci_dev *pdev)
{
struct device *dev = &pdev->dev;
Index: linux-pm/drivers/pci/pci.h
===================================================================
--- linux-pm.orig/drivers/pci/pci.h
+++ linux-pm/drivers/pci/pci.h
@@ -50,6 +50,10 @@ int pci_probe_reset_function(struct pci_
* for given device (the device's wake-up capability has to be
* enabled by @sleep_wake for this feature to work)
*
+ * @need_resume: returns 'true' if the given device (which is currently
+ * suspended) needs to be resumed to be configured for system
+ * wakeup.
+ *
* If given platform is generally capable of power managing PCI devices, all of
* these callbacks are mandatory.
*/
@@ -59,6 +63,7 @@ struct pci_platform_pm_ops {
pci_power_t (*choose_state)(struct pci_dev *dev);
int (*sleep_wake)(struct pci_dev *dev, bool enable);
int (*run_wake)(struct pci_dev *dev, bool enable);
+ bool (*need_resume)(struct pci_dev *dev);
};
int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
@@ -67,6 +72,7 @@ void pci_power_up(struct pci_dev *dev);
void pci_disable_enabled_device(struct pci_dev *dev);
int pci_finish_runtime_suspend(struct pci_dev *dev);
int __pci_pme_wakeup(struct pci_dev *dev, void *ign);
+bool pci_dev_keep_suspended(struct pci_dev *dev);
void pci_config_pm_runtime_get(struct pci_dev *dev);
void pci_config_pm_runtime_put(struct pci_dev *dev);
void pci_pm_init(struct pci_dev *dev);
Index: linux-pm/drivers/pci/pci-acpi.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-acpi.c
+++ linux-pm/drivers/pci/pci-acpi.c
@@ -501,12 +501,29 @@ static int acpi_pci_run_wake(struct pci_
return 0;
}
+static bool acpi_pci_need_resume(struct pci_dev *dev)
+{
+ struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
+
+ if (!adev || !acpi_device_power_manageable(adev))
+ return false;
+
+ if (device_may_wakeup(&dev->dev) != !!adev->wakeup.prepare_count)
+ return true;
+
+ if (acpi_target_system_state() == ACPI_STATE_S0)
+ return false;
+
+ return !!adev->power.flags.dsw_present;
+}
+
static struct pci_platform_pm_ops acpi_pci_platform_pm = {
.is_manageable = acpi_pci_power_manageable,
.set_state = acpi_pci_set_power_state,
.choose_state = acpi_pci_choose_state,
.sleep_wake = acpi_pci_sleep_wake,
.run_wake = acpi_pci_run_wake,
+ .need_resume = acpi_pci_need_resume,
};
void acpi_pci_add_bus(struct pci_bus *bus)
Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -653,7 +653,6 @@ static bool pci_has_legacy_pm_support(st
static int pci_pm_prepare(struct device *dev)
{
struct device_driver *drv = dev->driver;
- int error = 0;
/*
* Devices having power.ignore_children set may still be necessary for
@@ -662,10 +661,12 @@ static int pci_pm_prepare(struct device
if (dev->power.ignore_children)
pm_runtime_resume(dev);
- if (drv && drv->pm && drv->pm->prepare)
- error = drv->pm->prepare(dev);
-
- return error;
+ if (drv && drv->pm && drv->pm->prepare) {
+ int error = drv->pm->prepare(dev);
+ if (error)
+ return error;
+ }
+ return pci_dev_keep_suspended(to_pci_dev(dev));
}
--
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