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Subject[PATCH 1/2] ACPI: PM: Avoid evaluating _PS3 on transitions from D3hot to D3cold
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If the power state of a device with ACPI PM is changed from D3hot to
D3cold, it merely is a matter of dropping references to additional
power resources (specifically, those in the list returned by _PR3),
and the _PS3 method should not be invoked for the device then (as
it has already been evaluated during the previous transition to
D3hot).

Fixes: 20dacb71ad28 (ACPI / PM: Rework device power management to follow ACPI 6)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/acpi/device_pm.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/acpi/device_pm.c
===================================================================
--- linux-pm.orig/drivers/acpi/device_pm.c
+++ linux-pm/drivers/acpi/device_pm.c
@@ -215,9 +215,15 @@ int acpi_device_set_power(struct acpi_de
return -ENODEV;
}

- result = acpi_dev_pm_explicit_set(device, state);
- if (result)
- goto end;
+ /*
+ * If the device goes from D3hot to D3cold, _PS3 has been
+ * evaluated for it already, so skip it in that case.
+ */
+ if (device->power.state < ACPI_STATE_D3_HOT) {
+ result = acpi_dev_pm_explicit_set(device, state);
+ if (result)
+ goto end;
+ }

if (device->power.flags.power_resources)
result = acpi_power_transition(device, target_state);


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