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-rw-r--r--drivers/acpi/device_pm.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index c4d0a1c..3d96e4d 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -543,6 +543,7 @@ static int acpi_dev_pm_get_state(struct device *dev, struct acpi_device *adev,
unsigned long long ret;
int d_min, d_max;
bool wakeup = false;
+ bool has_sxd = false;
acpi_status status;
/*
@@ -581,6 +582,10 @@ static int acpi_dev_pm_get_state(struct device *dev, struct acpi_device *adev,
else
return -ENODATA;
}
+
+ if (status == AE_OK)
+ has_sxd = true;
+
d_min = ret;
wakeup = device_may_wakeup(dev) && adev->wakeup.flags.valid
&& adev->wakeup.sleep_state >= target_state;
@@ -599,7 +604,11 @@ static int acpi_dev_pm_get_state(struct device *dev, struct acpi_device *adev,
method[3] = 'W';
status = acpi_evaluate_integer(handle, method, NULL, &ret);
if (status == AE_NOT_FOUND) {
- if (target_state > ACPI_STATE_S0)
+ /* No _SxW. In this case, the ACPI spec says that we
+ * must not go into any power state deeper than the
+ * value returned from _SxD.
+ */
+ if (has_sxd && target_state > ACPI_STATE_S0)
d_max = d_min;
} else if (ACPI_SUCCESS(status) && ret <= ACPI_STATE_D3_COLD) {
/* Fall back to D3cold if ret is not a valid state. */
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