[RFC][PATCH 3/3] ACPI / PM: Avoid resuming devices in ACPI PM domain during system suspend

Rafael J. Wysocki
2014-05-13T01:10:52Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Rework the ACPI PM domain's PM callbacks to avoid resuming devices
during system suspend (in order to modify their wakeup settings etc.)
if that isn't necessary.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/acpi/device_pm.c | 43 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 36 insertions(+), 7 deletions(-)

Index: linux-pm/include/acpi/acpi_bus.h
===================================================================
--- linux-pm.orig/include/acpi/acpi_bus.h
+++ linux-pm/include/acpi/acpi_bus.h
@@ -261,7 +261,8 @@ struct acpi_device_power_flags {
u32 inrush_current:1; /* Serialize Dx->D0 */
u32 power_removed:1; /* Optimize Dx->D0 */
u32 ignore_parent:1; /* Power is independent of parent power state */
- u32 reserved:27;
+ u32 dsw_present:1; /* _DSW present? */
+ u32 reserved:26;
};

struct acpi_device_power_state {
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -1551,9 +1551,13 @@ static void acpi_bus_get_power_flags(str
*/
if (acpi_has_method(device->handle, "_PSC"))
device->power.flags.explicit_get = 1;
+
if (acpi_has_method(device->handle, "_IRC"))
device->power.flags.inrush_current = 1;

+ if (acpi_has_method(device->handle, "_DSW"))
+ device->power.flags.dsw_present = 1;
+
/*
* Enumerate supported power management states
*/
Index: linux-pm/drivers/acpi/device_pm.c
===================================================================
--- linux-pm.orig/drivers/acpi/device_pm.c
+++ linux-pm/drivers/acpi/device_pm.c
@@ -900,18 +900,46 @@ EXPORT_SYMBOL_GPL(acpi_dev_resume_early)
*/
int acpi_subsys_prepare(struct device *dev)
{
- /*
- * Devices having power.ignore_children set may still be necessary for
- * suspending their children in the next phase of device suspend.
- */
- if (dev->power.ignore_children)
- pm_runtime_resume(dev);
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+ u32 sys_target;
+ int ret, state;
+
+ ret = pm_generic_prepare(dev);
+ if (ret < 0)
+ return ret;
+
+ if (!adev || !pm_runtime_suspended(dev)
+ || device_may_wakeup(dev) != !!adev->wakeup.prepare_count)
+ return 0;
+
+ sys_target = acpi_target_system_state();
+ if (sys_target == ACPI_STATE_S0)
+ return 1;
+
+ if (adev->power.flags.dsw_present)
+ return 0;

- return pm_generic_prepare(dev);
+ ret = acpi_dev_pm_get_state(dev, adev, sys_target, NULL, &state);
+ return !ret && state == adev->power.state;
}
EXPORT_SYMBOL_GPL(acpi_subsys_prepare);

/**
+ * acpi_subsys_complete - Finalize device's resume during system resume.
+ * @dev: Device to handle.
+ */
+void acpi_subsys_complete(struct device *dev)
+{
+ /*
+ * If the device had been runtime-suspended before the system went into
+ * the sleep state it is going out of and it has never been resumed till
+ * now, resume it in case the firmware powered it up.
+ */
+ if (dev->power.direct_complete)
+ pm_request_resume(dev);
+}
+
+/**
* acpi_subsys_suspend - Run the device driver's suspend callback.
* @dev: Device to handle.
*
@@ -979,6 +1007,7 @@ static struct dev_pm_domain acpi_general
#endif
#ifdef CONFIG_PM_SLEEP
.prepare = acpi_subsys_prepare,
+ .complete = acpi_subsys_complete,
.suspend = acpi_subsys_suspend,
.suspend_late = acpi_subsys_suspend_late,
.resume_early = acpi_subsys_resume_early,