All 3 of led_timer_func, led_set_brightness and led_set_software_blink
set blink_brightness. If led_timer_func or led_set_software_blink race
with led_set_brightness they may end up overwriting the new
blink_brightness. The new atomic work_flags does not protect against
this as it just protects the flags and not blink_brightness.
This commit introduces a new new_blink_brightness value which gets
set by led_set_brightness and read by led_timer_func on LED on, fixing
this.
Dealing with the new brightness at LED on time, makes the new
brightness apply sooner, which also fixes a led_set_brightness which
happens while a oneshot blink which ends in LED on is running not
getting applied.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/leds/led-core.c | 14 +++++++-------
include/linux/leds.h | 1 +
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 17a0964..d474f97 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -81,17 +81,17 @@ static void led_timer_function(unsigned long data)
brightness = led_get_brightness(led_cdev);
if (!brightness) {
/* Time to switch the LED on. */
- brightness = led_cdev->blink_brightness;
+ if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
+ &led_cdev->work_flags))
+ brightness = led_cdev->new_blink_brightness;
+ else
+ brightness = led_cdev->blink_brightness;
delay = led_cdev->blink_delay_on;
} else {
/* Store the current brightness value to be able
* to restore it when the delay_off period is over.
- * Do it only if there is no pending blink brightness
- * change, to avoid overwriting the new value.
*/
- if (!test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
- &led_cdev->work_flags))
- led_cdev->blink_brightness = brightness;
+ led_cdev->blink_brightness = brightness;
brightness = LED_OFF;
delay = led_cdev->blink_delay_off;
}
@@ -260,7 +260,7 @@ void led_set_brightness(struct led_classdev *led_cdev,
} else {
set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
&led_cdev->work_flags);
- led_cdev->blink_brightness = brightness;
+ led_cdev->new_blink_brightness = brightness;
}
return;
}
diff --git a/include/linux/leds.h b/include/linux/leds.h
index cff9df7..6669404 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -87,6 +87,7 @@ struct led_classdev {
unsigned long blink_delay_on, blink_delay_off;
struct timer_list blink_timer;
int blink_brightness;
+ int new_blink_brightness;
void (*flash_resume)(struct led_classdev *led_cdev);
struct work_struct set_brightness_work;
--
2.9.3
--
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