[3.13.y-ckt stable] Patch "ACPI / PM: Ignore wakeup setting if the ACPI companion can't wake up" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

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

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d367a4c321a03eb2827e5211200830c69ffe3032 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki at intel.com>
Date: Wed, 19 Nov 2014 01:44:11 +0100
Subject: 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 at chromium.org>
Reviewed-by: Dmitry Torokhov <dtor at chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/acpi/device_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index b3480cf..5b39ae5 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -857,7 +857,7 @@ 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_sleep_wake(adev, target_state, wakeup);
 	if (wakeup && error)
 		return error;
--
1.9.1