ACPI / PM: Ignore wakeup setting if the ACPI companion can't wake up

commit 78579b7c7eb45f0e7ec5e9437087ed21749f9a9c upstream.

As reported by Dmitry, on some Chromebooks there are devices with
corresponding ACPI objects and with unusual system wakeup
configuration.  Namely, they technically are wakeup-capable, but the
wakeup is handled via a platform-specific out-of-band mechanism and
the ACPI PM layer has no information on the wakeup capability.  As
a result, device_may_wakeup(dev) called from acpi_dev_suspend_late()
returns 'true' for those devices, but the wakeup.flags.valid flag is
unset for the corresponding ACPI device objects, so acpi_device_wakeup()
reproducibly fails for them causing acpi_dev_suspend_late() to return
an error code.  The entire system suspend is then aborted and the
machines in question cannot suspend at all.

Address the problem by ignoring the device_may_wakeup(dev) return
value in acpi_dev_suspend_late() if the ACPI companion of the device
being handled has wakeup.flags.valid unset (in which case it is clear
that the wakeup is supposed to be handled by other means).

This fixes a regression introduced by commit a76e9bd89ae7 (i2c:
attach/detach I2C client device to the ACPI power domain) as the
affected systems could suspend and resume successfully before that
commit.

Fixes: a76e9bd89ae7 (i2c: attach/detach I2C client device to the ACPI power domain)
Reported-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 5e9cbd664286e621d1bd512e0e0e031129e9be50..7462ad1675c0f273114ef7cfc677f78c85c2bb4e 100644 (file)
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -877,7 +877,7 @@ int acpi_dev_suspend_late(struct device *dev)
                return 0;
 
        target_state = acpi_target_system_state();
-       wakeup = device_may_wakeup(dev);
+       wakeup = device_may_wakeup(dev) && acpi_device_can_wakeup(adev);
        error = acpi_device_wakeup(adev, target_state, wakeup);
        if (wakeup && error)
                return error;