[3.16.y-ckt stable] Patch "leds / PM: fix hibernation on arm when gpio-led used with CPU led trigger" has been added to staging queue

[Luis Henriques]

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

    leds / PM: fix hibernation on arm when gpio-led used with CPU led trigger

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt15.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 5578a0cd41bf4fb252fa41b80cccf944d19e5459 Mon Sep 17 00:00:00 2001
From: Grygorii Strashko <Grygorii.Strashko at linaro.org>
Date: Fri, 24 Apr 2015 14:57:10 +0300
Subject: leds / PM: fix hibernation on arm when gpio-led used with CPU led
 trigger

commit 084609bf727981c7a2e6e69aefe0052c9d793300 upstream.

Setting a dev_pm_ops suspend/resume pair of callbacks but not a set of
hibernation callbacks means those pm functions will not be
called upon hibernation - that leads to system crash on ARM during
freezing if gpio-led is used in combination with CPU led trigger.
It may happen after freeze_noirq stage (GPIO is suspended)
and before syscore_suspend stage (CPU led trigger is suspended)
- usually when disable_nonboot_cpus() is called.

Log:
  PM: noirq freeze of devices complete after 1.425 msecs
  Disabling non-boot CPUs ...
    ^ system may crash or stuck here with message (TI AM572x)

  WARNING: CPU: 0 PID: 3100 at drivers/bus/omap_l3_noc.c:148 l3_interrupt_handler+0x22c/0x370()
  44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4_PER1_P3 (Idle): Data Access in Supervisor mode during Functional access

  CPU1: shutdown
    ^ or here

Fix this by using SIMPLE_DEV_PM_OPS, which appropriately
assigns the suspend and hibernation callbacks and move
led_suspend/led_resume under CONFIG_PM_SLEEP to avoid
build warnings.

Fixes: 73e1ab41a80d (leds: Convert led class driver from legacy pm ops to dev_pm_ops)
Signed-off-by: Grygorii Strashko <Grygorii.Strashko at linaro.org>
Acked-by: Jacek Anaszewski <j.anaszewski at samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/leds/led-class.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index f37d63cf726b..825545cdfb10 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -178,6 +178,7 @@ void led_classdev_resume(struct led_classdev *led_cdev)
 }
 EXPORT_SYMBOL_GPL(led_classdev_resume);

+#ifdef CONFIG_PM_SLEEP
 static int led_suspend(struct device *dev)
 {
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
@@ -197,11 +198,9 @@ static int led_resume(struct device *dev)

 	return 0;
 }
+#endif

-static const struct dev_pm_ops leds_class_dev_pm_ops = {
-	.suspend        = led_suspend,
-	.resume         = led_resume,
-};
+static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);

 /**
  * led_classdev_register - register a new object of led_classdev class.