Re: [v2 3/4] platform: (TS-5500) add LED support

H. Peter Anvin
2011-08-30T22:05:43Z

On 08/30/2011 02:56 PM, Vivien Didelot wrote:
>>
> I wrote the led_set function like:
>
> static void ts5500_led_set(struct led_classdev *led_cdev,
> enum led_brightness value)
> {
> struct ts5500_led *led = container_of(led_cdev,
> struct ts5500_led,
> cdev);
> mutex_lock(&led->lock);
> led->new_brightness = (value == LED_OFF) ? LED_OFF : LED_FULL;
> outb(value, led->ioaddr);
> mutex_unlock(&led->lock);
> }
>
> I guess the wrong value could be read if we get preempted just before
> the outb() call, am I wrong?
>

And what happens if we do?

P.S. Your canonicalization of the value doesn't extend to outb().

-hpa