In the case when the no_direct_complete flag is set for the ACPI device, we
can under some conditions during system sleep, avoid runtime resuming the
device in acpi_subsys_suspend|freeze(). This means we can decrease the time
needed for the device to enter its system sleep state, but also that we can
avoid to waste power.
More precisely, calling acpi_dev_needs_resume() from the
acpi_subsys_suspend|freeze() in cases when the no_direct_complete flag has
been set for the device, tells us if a runtime resume of the device is
needed. Thus it may allow us to avoid it.
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
Changes in v2:
- Clarified changelog.
- Improved comments is code.
- Rebased.
- Improved change to avoid open-coding.
---
drivers/acpi/device_pm.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index b595968..5dd23de 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -1117,11 +1117,19 @@ EXPORT_SYMBOL_GPL(acpi_subsys_complete);
* @dev: Device to handle.
*
* Follow PCI and resume devices suspended at run time before running their
- * system suspend callbacks.
+ * system suspend callbacks. However, try to avoid it when no_direct_complete
+ * is set.
*/
int acpi_subsys_suspend(struct device *dev)
{
- pm_runtime_resume(dev);
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+
+ if (!adev)
+ return 0;
+
+ if (!adev->power.no_direct_complete || acpi_dev_needs_resume(dev, adev))
+ pm_runtime_resume(dev);
+
return pm_generic_suspend(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_suspend);
@@ -1178,13 +1186,20 @@ EXPORT_SYMBOL_GPL(acpi_subsys_resume_early);
*/
int acpi_subsys_freeze(struct device *dev)
{
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+
+ if (!adev)
+ return 0;
+
/*
* This used to be done in acpi_subsys_prepare() for all devices and
* some drivers may depend on it, so do it here. Ideally, however,
* runtime-suspended devices should not be touched during freeze/thaw
- * transitions.
+ * transitions. In case the no_direct_complete is set, try to avoid it.
*/
- pm_runtime_resume(dev);
+ if (!adev->power.no_direct_complete || acpi_dev_needs_resume(dev, adev))
+ pm_runtime_resume(dev);
+
return pm_generic_freeze(dev);
}
EXPORT_SYMBOL_GPL(acpi_subsys_freeze);
--
2.7.4
--
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