Re: [PATCH v2] leds: fix hibernation on arm when gpio-led used with CPU led trigger

From: Grygorii.Strashko@xxxxxxxxxx
Date: Wed Mar 18 2015 - 15:39:24 EST

Hi All,

On 02/24/2015 06:12 PM, Grygorii.Strashko@xxxxxxxxxx wrote:
On 02/05/2015 04:37 PM, grygorii.strashko@xxxxxxxxxx wrote:
From: Grygorii Strashko <Grygorii.Strashko@xxxxxxxxxx>

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.

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.

Signed-off-by: Grygorii Strashko <Grygorii.Strashko@xxxxxxxxxx>
This patch actually fixes commit:
73e1ab4 "leds: Convert led class driver from legacy pm ops to dev_pm_ops"

On 02/24/2015 06:12 PM, Grygorii.Strashko@xxxxxxxxxx wrote:
Changes in v2:
- fixed compile time warnings when !CONFIG_PM_SLEEP
- updated commit message


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 dbeebac..5033e0d 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -183,6 +183,7 @@ void led_classdev_resume(struct led_classdev *led_cdev)

static int led_suspend(struct device *dev)
struct led_classdev *led_cdev = dev_get_drvdata(dev);
@@ -202,11 +203,9 @@ static int led_resume(struct device *dev)

return 0;

-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.

Could you pay attention on this patch, pls? It fixes a real issue for me.

Actually, I'd like to note that it fixes regression introduced by commit
"leds: Convert led class driver from legacy pm ops to dev_pm_ops" from
Shuah Khan <> (Jun 20 2013).

Gentle reminder. Any comments on this?

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