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| author | Hans de Goede <hdegoede@redhat.com> | 2016-10-23 21:47:26 +0200 |
|---|---|---|
| committer | Jacek Anaszewski <j.anaszewski@samsung.com> | 2016-11-22 12:07:05 +0100 |
| commit | eb1610b4c273370f491c5e194e5a56e3470d81e8 (patch) | |
| tree | ae3eaaea3b20831c561e6897f936da2f1c7652b5 /drivers | |
| parent | a9c6ce57ec2f136d08141e8220a0ffaca216f7b0 (diff) | |
| download | linux-eb1610b4c273370f491c5e194e5a56e3470d81e8.tar.bz2 | |
led: core: Fix blink_brightness setting race
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@redhat.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/leds/led-core.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c index bd6bb4d44f05..ef1360445413 100644 --- a/drivers/leds/led-core.c +++ b/drivers/leds/led-core.c @@ -66,17 +66,17 @@ 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; } @@ -245,7 +245,7 @@ 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; } |