[PATCH v2] leds: core: Flush scheduled work for system suspend

[PATCH v2] leds: core: Flush scheduled work for system suspend

[Kai-Heng Feng]

Sometimes LED won't be turned off by LED_CORE_SUSPENDRESUME flag upon
system suspend.

led_set_brightness_nopm() uses schedule_work() to set LED brightness.
However, there's no guarantee that the scheduled work gets executed
because no one flushes the work.

So flush the scheduled work to make sure LED gets turned off.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v2:
 - Use flush_work() instead.

 drivers/leds/led-class.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 3363a6551a70..cc3929f858b6 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -173,6 +173,7 @@ void led_classdev_suspend(struct led_classdev *led_cdev)
 {
 	led_cdev->flags |= LED_SUSPENDED;
 	led_set_brightness_nopm(led_cdev, 0);
+	flush_work(&led_cdev->set_brightness_work);
 }
 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 
-- 
2.17.1

Re: [PATCH v2] leds: core: Flush scheduled work for system suspend

[Jacek Anaszewski]

Hi Kai-Heng,

Thank you for the update.

On 7/2/20 7:45 AM, Kai-Heng Feng wrote:
> Sometimes LED won't be turned off by LED_CORE_SUSPENDRESUME flag upon
> system suspend.
> 
> led_set_brightness_nopm() uses schedule_work() to set LED brightness.
> However, there's no guarantee that the scheduled work gets executed
> because no one flushes the work.
> 
> So flush the scheduled work to make sure LED gets turned off.
> 
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> v2:
>   - Use flush_work() instead.
> 
>   drivers/leds/led-class.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 3363a6551a70..cc3929f858b6 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -173,6 +173,7 @@ void led_classdev_suspend(struct led_classdev *led_cdev)
>   {
>   	led_cdev->flags |= LED_SUSPENDED;
>   	led_set_brightness_nopm(led_cdev, 0);
> +	flush_work(&led_cdev->set_brightness_work);
>   }
>   EXPORT_SYMBOL_GPL(led_classdev_suspend);
>   
> 

Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

Pavel, this needs to go to stable as well, so let's add the tag:

Fixes: 81fe8e5b73e3 ("leds: core: Add led_set_brightness_nosleep{nopm} 
functions")

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH v2] leds: core: Flush scheduled work for system suspend

[Pavel Machek]

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Hi!

> >  EXPORT_SYMBOL_GPL(led_classdev_suspend);
> >
> 
> Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
> 
> Pavel, this needs to go to stable as well, so let's add the tag:
> 
> Fixes: 81fe8e5b73e3 ("leds: core: Add led_set_brightness_nosleep{nopm}
> functions")

Applied, and I added the tag (thanks).

Documentation says stable is for "very bad" bugs, but ... stable
maintainers ignore documenation.

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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