Messages in this thread | | | Date | Tue, 30 Aug 2011 15:04:00 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [v2 3/4] platform: (TS-5500) add LED support |
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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
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