leds: turn the blink_timer off before starting to blink

BugLink: http://bugs.launchpad.net/bugs/890952

commit 488bc35bf40df89d37486c1826b178a2fba36ce7 upstream.

Depending on the implementation of the hardware blinking function in
blink_set(), the led can support hardware blinking for some values of
delay_on and delay_off and fall-back to software blinking for some other
values.

Turning off the blink_timer unconditionally before starting to blink
make sure that a sequence like:

  OFF
  hardware blinking
  software blinking
  hardware blinking

does not leave the software blinking timer active.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 5c270aecedc..661b692573e 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -267,6 +267,8 @@ void led_blink_set(struct led_classdev *led_cdev,
                    unsigned long *delay_on,
                    unsigned long *delay_off)
 {
+        del_timer_sync(&led_cdev->blink_timer);
+
         if (led_cdev->blink_set &&
             !led_cdev->blink_set(led_cdev, delay_on, delay_off)) {
                 led_cdev->blink_delay_on = *delay_on;