Strange timer LED behavior

["Bollinger, Seth" <Seth.Bollinger@xxxxxxxx>]

Hello All,

We use the sysfs timer trigger of the led subsystem to control our leds (turn on, turn off, and blink).  While doing this we found a strange behavior.  If the values of delay_on and delay_off are ever both zero, the led subsystem will make the decision to blink at a 500ms on and 500ms off rate.

# cd /sys/class/leds/g01
# cat delay_on
0
# cat delay_off
86400
# echo 0 > delay_off
# cat delay_on
500
# cat delay_off
500

drivers/led/led-core.c:184
    /* blink with 1 Hz as default if nothing specified */
    if (!*delay_on && !*delay_off)
        *delay_on = *delay_off = 500;

Is there a reason that the kernel would decide to blink at this default rate instead of leaving the timer disabled?

Thanks,

Seth