| Message ID | 20230405165028.73579-1-eajames@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RESEND] leds: Ensure hardware blinking turns off when requested | expand |
On Wed, 05 Apr 2023, Eddie James wrote: > If an LED is blinking through the hardware and the trigger is deactivated, > the driver will set the brightness to 0 to disable blinking. However, if > the LED driver doesn't support non-blocking operations, the request for > setting brightness to 0 will get queued. Then if a user requests a new > non-zero brightness before the request for 0 brightness is executed, the > LED blinking will not get disabled since the brightness will simply be > updated. > Fix this by flushing the workqueue before updating the requested > brightness. You make a convincing argument for this. > Fixes: 4d71a4a12b13 ("leds: Add support for setting brightness in a synchronous way") > Signed-off-by: Eddie James <eajames@linux.ibm.com> > --- > drivers/leds/led-class.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c > index 9255bc11f99d..78a270300d30 100644 > --- a/drivers/leds/led-class.c > +++ b/drivers/leds/led-class.c > @@ -57,6 +57,8 @@ static ssize_t brightness_store(struct device *dev, > > if (state == LED_OFF) > led_trigger_remove(led_cdev); > + /* flush out any request to disable blinking */ > + flush_work(&led_cdev->set_brightness_work); > led_set_brightness(led_cdev, state); > flush_work(&led_cdev->set_brightness_work); Just to be clear, you want to flush the work before AND after setting the brightness? In the commit message, could you make it clear why simply moving this flush won't work.
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 9255bc11f99d..78a270300d30 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -57,6 +57,8 @@ static ssize_t brightness_store(struct device *dev, if (state == LED_OFF) led_trigger_remove(led_cdev); + /* flush out any request to disable blinking */ + flush_work(&led_cdev->set_brightness_work); led_set_brightness(led_cdev, state); flush_work(&led_cdev->set_brightness_work);
If an LED is blinking through the hardware and the trigger is deactivated, the driver will set the brightness to 0 to disable blinking. However, if the LED driver doesn't support non-blocking operations, the request for setting brightness to 0 will get queued. Then if a user requests a new non-zero brightness before the request for 0 brightness is executed, the LED blinking will not get disabled since the brightness will simply be updated. Fix this by flushing the workqueue before updating the requested brightness. Fixes: 4d71a4a12b13 ("leds: Add support for setting brightness in a synchronous way") Signed-off-by: Eddie James <eajames@linux.ibm.com> --- drivers/leds/led-class.c | 2 ++ 1 file changed, 2 insertions(+)