Messages in this thread | | | Subject | Re: [PATCH] leds: core: Use blocking op for system suspend | From | Jacek Anaszewski <> | Date | Wed, 1 Jul 2020 23:28:29 +0200 |
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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 <kai.heng.feng@canonical.com> > --- > 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
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