From: "H. Peter Anvin" <hpa@zytor.com>
To: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>,
x86@kernel.org,
Jonas Fonseca <jonas.fonseca@savoirfairelinux.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [v2 3/4] platform: (TS-5500) add LED support
Date: Tue, 30 Aug 2011 15:04:00 -0700 [thread overview]
Message-ID: <4E5D5E50.2080809@zytor.com> (raw)
In-Reply-To: <20110830175644.2ff5d086@v0nbox>
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
next prev parent reply other threads:[~2011-08-30 22:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-26 23:40 [v2 0/4] Support for the TS-5500 platform Vivien Didelot
2011-08-26 23:40 ` [v2 1/4] platform: (TS-5500) add base support Vivien Didelot
2011-08-26 23:40 ` [v2 2/4] platform: (TS-5500) add GPIO support Vivien Didelot
2011-08-29 22:11 ` Mark Brown
2011-08-30 5:36 ` H. Peter Anvin
2011-08-30 11:00 ` Mark Brown
2011-08-30 14:49 ` Vivien Didelot
2011-08-30 15:12 ` Mark Brown
2011-10-12 16:41 ` Linus Walleij
2011-10-13 3:31 ` Grant Likely
2011-08-30 18:39 ` Vivien Didelot
2011-08-30 18:41 ` Mark Brown
2011-08-30 18:43 ` H. Peter Anvin
2011-08-30 21:12 ` Vivien Didelot
2011-10-12 15:35 ` Ingo Molnar
2011-10-14 6:14 ` Ingo Molnar
2011-10-15 14:29 ` Vivien Didelot
2011-08-26 23:40 ` [v2 3/4] platform: (TS-5500) add LED support Vivien Didelot
2011-08-29 22:16 ` Mark Brown
2011-08-30 5:37 ` H. Peter Anvin
2011-08-30 21:14 ` Vivien Didelot
2011-08-30 21:15 ` Mark Brown
2011-08-30 21:17 ` H. Peter Anvin
2011-08-30 21:56 ` Vivien Didelot
2011-08-30 22:04 ` H. Peter Anvin [this message]
2011-08-31 20:01 ` Vivien Didelot
2011-10-12 15:34 ` Ingo Molnar
2011-10-15 14:42 ` Vivien Didelot
2011-10-15 14:56 ` Ingo Molnar
2011-11-16 5:41 ` Ingo Molnar
2011-11-16 12:50 ` Mark Brown
2011-10-26 15:41 ` Ingo Molnar
2011-11-17 15:27 ` Vivien Didelot
2011-08-26 23:40 ` [v2 4/4] platform: (TS-5500) add ADC support Vivien Didelot
2011-08-29 22:13 ` Mark Brown
2011-09-12 7:28 ` [v2 0/4] Support for the TS-5500 platform Pavel Machek
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