From: Rafael J. Wysocki <rafael.j.wyso...@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.wyso...@intel.com>
---
 drivers/acpi/device_pm.c |   31 ++++++++++++++++++++++++++++---
 drivers/acpi/scan.c      |    4 ++++
 include/acpi/acpi_bus.h  |    3 ++-
 3 files changed, 34 insertions(+), 4 deletions(-)

Index: linux-pm/drivers/acpi/device_pm.c
===================================================================
--- linux-pm.orig/drivers/acpi/device_pm.c
+++ linux-pm/drivers/acpi/device_pm.c
@@ -907,6 +907,7 @@ int acpi_subsys_prepare(struct device *d
        if (dev->power.ignore_children)
                pm_runtime_resume(dev);
 
+       pm_set_leave_runtime_suspended(dev, true);
        return pm_generic_prepare(dev);
 }
 EXPORT_SYMBOL_GPL(acpi_subsys_prepare);
@@ -914,13 +915,37 @@ EXPORT_SYMBOL_GPL(acpi_subsys_prepare);
 /**
  * acpi_subsys_suspend - Run the device driver's suspend callback.
  * @dev: Device to handle.
- *
- * Follow PCI and resume devices suspended at run time before running their
- * system suspend callbacks.
  */
 int acpi_subsys_suspend(struct device *dev)
 {
+       struct acpi_device *adev = ACPI_COMPANION(dev);
+       u32 sys_target;
+
+       if (!adev || !pm_runtime_enabled_and_suspended(dev)) {
+               pm_set_leave_runtime_suspended(dev, false);
+               goto out;
+       }
+       if (!pm_leave_runtime_suspended(dev)
+           || device_may_wakeup(dev) != !!adev->wakeup.prepare_count)
+               goto resume;
+
+       sys_target = acpi_target_system_state();
+       if (sys_target != ACPI_STATE_S0) {
+               int ret, state;
+
+               if (adev->power.flags.dsw_present)
+                       goto resume;
+
+               ret = acpi_dev_pm_get_state(dev, adev, sys_target, NULL, 
&state);
+               if (ret || state != adev->power.state)
+                       goto resume;
+       }
+       return 0;
+
+ resume:
        pm_runtime_resume(dev);
+
+ out:
        return pm_generic_suspend(dev);
 }
 
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
         */

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