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@xxxxxxxxxxxxx>
---
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
