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 calls flush_scheduled_work().
As flush_scheduled_work() may affect other drivers' suspend routines,
take a more contained approach which uses blocking op to make sure the
LED gets turned off.
Signed-off-by: Kai-Heng Feng <[email protected]>
---
drivers/leds/led-core.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index f1f718dbe0f8..9a5bfcd7a704 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -269,6 +269,11 @@ EXPORT_SYMBOL_GPL(led_set_brightness);
void led_set_brightness_nopm(struct led_classdev *led_cdev,
enum led_brightness value)
{
+
+ if (led_cdev->flags & LED_SUSPENDED &&
+ !__led_set_brightness_blocking(led_cdev, value))
+ return;
+
/* Use brightness_set op if available, it is guaranteed not to sleep */
if (!__led_set_brightness(led_cdev, value))
return;
--
2.17.1
Hi Kai-Heng,
Thank you for the patch.
On 7/1/20 11:35 AM, Kai-Heng Feng wrote:
> Sometimes LED won't be turned off by LED_CORE_SUSPENDRESUME flag upon
> system suspend.
Just out of curiosity - are you experiencing that on some hardware?
> 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 calls flush_scheduled_work().
>
> As flush_scheduled_work() may affect other drivers' suspend routines,
> take a more contained approach which uses blocking op to make sure the
> LED gets turned off.
>
> Signed-off-by: Kai-Heng Feng <[email protected]>
> ---
> drivers/leds/led-core.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index f1f718dbe0f8..9a5bfcd7a704 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -269,6 +269,11 @@ EXPORT_SYMBOL_GPL(led_set_brightness);
> void led_set_brightness_nopm(struct led_classdev *led_cdev,
> enum led_brightness value)
> {
> +
> + if (led_cdev->flags & LED_SUSPENDED &&
> + !__led_set_brightness_blocking(led_cdev, value))
> + return;
> +
This function is "nopm" for a reason - we do not make here any
pm management related operations.
Instead of that, please just add
flush_work(&led_cdev->set_brightness_work);
at the end of led_classdev_suspend()
in drivers/leds/led-class.c.
--
Best regards,
Jacek Anaszewski
> On Jul 2, 2020, at 05:28, Jacek Anaszewski <[email protected]> wrote:
>
> Hi Kai-Heng,
>
> Thank you for the patch.
>
> On 7/1/20 11:35 AM, Kai-Heng Feng wrote:
>> Sometimes LED won't be turned off by LED_CORE_SUSPENDRESUME flag upon
>> system suspend.
>
> Just out of curiosity - are you experiencing that on some hardware?
Yes, mute and micmute LED on laptops sometimes are still on during suspend-to-idle.
>
>> 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 calls flush_scheduled_work().
>> As flush_scheduled_work() may affect other drivers' suspend routines,
>> take a more contained approach which uses blocking op to make sure the
>> LED gets turned off.
>> Signed-off-by: Kai-Heng Feng <[email protected]>
>> ---
>> drivers/leds/led-core.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
>> index f1f718dbe0f8..9a5bfcd7a704 100644
>> --- a/drivers/leds/led-core.c
>> +++ b/drivers/leds/led-core.c
>> @@ -269,6 +269,11 @@ EXPORT_SYMBOL_GPL(led_set_brightness);
>> void led_set_brightness_nopm(struct led_classdev *led_cdev,
>> enum led_brightness value)
>> {
>> +
>> + if (led_cdev->flags & LED_SUSPENDED &&
>> + !__led_set_brightness_blocking(led_cdev, value))
>> + return;
>> +
>
> This function is "nopm" for a reason - we do not make here any
> pm management related operations.
>
> Instead of that, please just add
>
> flush_work(&led_cdev->set_brightness_work);
>
> at the end of led_classdev_suspend()
>
> in drivers/leds/led-class.c.
Right, will send v2.
Kai-Heng
>
> --
> Best regards,
> Jacek Anaszewski