2020-07-02 05:47:34

by Kai-Heng Feng

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

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 <[email protected]>
---
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


2020-07-02 20:52:12

by Jacek Anaszewski

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

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 <[email protected]>
> ---
> 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 <[email protected]>

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

2020-07-12 08:15:18

by Pavel Machek

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

Hi!

> > EXPORT_SYMBOL_GPL(led_classdev_suspend);
> >
>
> Acked-by: Jacek Anaszewski <[email protected]>
>
> 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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