Messages in this thread | | | Date | Wed, 31 Aug 2011 16:01:05 -0400 | From | Vivien Didelot <> | Subject | Re: [v2 3/4] platform: (TS-5500) add LED support |
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On Tue, 30 Aug 2011 15:04:00 -0700, "H. Peter Anvin" <hpa@zytor.com> wrote:
> 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
In fact the new_brightness field wasn't necessary in this driver, so I removed it and now the function only contains the outb() call. Thanks.
Vivien
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