Commit dbe9a2ed authored May 29, 2012 by Rafael J. Wysocki

ACPI / PM: Make acpi_pm_device_sleep_state() follow the specification



The comparison between the system sleep state being entered
and the lowest system sleep state the given device may wake up
from in acpi_pm_device_sleep_state() is reversed, because the
specification (ACPI 5.0) says that for wakeup to work:

"The sleeping state being entered must be less than or equal to the
 power state declared in element 1 of the _PRW object."

In other words, the state returned by _PRW is the deepest
(lowest-power) system sleep state the device is capable of waking up
the system from.

Moreover, acpi_pm_device_sleep_state() also should check if the
wakeup capability is supported through ACPI, because in principle it
may be done via native PCIe PME, for example, in which case _SxW
should not be evaluated.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

parent 38c92fff

drivers/acpi/sleep.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -773,8 +773,8 @@ int acpi_pm_device_sleep_state(struct device dev, int d_min_p)
		* can wake the system. _S0W may be valid, too.
		*/
		if (acpi_target_sleep_state == ACPI_STATE_S0 \|\|
		(device_may_wakeup(dev) &&
		adev->wakeup.sleep_state <= acpi_target_sleep_state)) {
		(device_may_wakeup(dev) && adev->wakeup.flags.valid &&
		adev->wakeup.sleep_state >= acpi_target_sleep_state)) {
		acpi_status status;

		acpi_method[3] = 'W';

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