From: gregory.clement@free-electrons•com (Gregory CLEMENT)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] cpuidle: mvebu: Fix the CPU PM notifier usage
Date: Tue, 03 Mar 2015 11:34:35 +0100 [thread overview]
Message-ID: <54F58E3B.9040302@free-electrons.com> (raw)
In-Reply-To: <54F58D2F.2010907@linaro.org>
Hi Rafael,
On 03/03/2015 11:30, Daniel Lezcano wrote:
> On 02/27/2015 10:39 AM, Gregory CLEMENT wrote:
>> Hi Rafael,
>>
>> On 26/02/2015 22:55, Rafael J. Wysocki wrote:
>>> On Thursday, February 26, 2015 06:20:48 PM Gregory CLEMENT wrote:
>>>> As stated in kernel/cpu_pm.c, "Platform is responsible for ensuring
>>>> that cpu_pm_enter is not called twice on the same CPU before
>>>> cpu_pm_exit is called.". In the current code in case of failure when
>>>> calling mvebu_v7_cpu_suspend, the function cpu_pm_exit() is never
>>>> called whereas cpu_pm_enter() was called just before.
>>>>
>>>> This patch moves the cpu_pm_exit() in order to balance the
>>>> cpu_pm_enter() calls.
>>>>
>>>> Reported-by: Fulvio Benini <fbf@libero•it>
>>>> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons•com>
>>>
>>> Should that go to "stable" too? Which "stable" series it should go to if so?
>>
>> Yes as it fixes a potential issue, you're right it should go
>> to "stable". The bug was here since the introduction of the driver
>> in 3.16.
>
> Hi Gregory,
>
> actually the 'stable' rules state clearly:
>
> "- It must fix a real bug that bothers people (not a, "This could be a
> problem..." type thing)."
>
> You say "it fixes a potential issue", so no bug has been raise yet, right ?
Indeed nobody claimed yet having a bug related to this issue.
Gregory
>
>>>> ---
>>>> drivers/cpuidle/cpuidle-mvebu-v7.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/cpuidle/cpuidle-mvebu-v7.c b/drivers/cpuidle/cpuidle-mvebu-v7.c
>>>> index 38e68618513a..cefa07438ae1 100644
>>>> --- a/drivers/cpuidle/cpuidle-mvebu-v7.c
>>>> +++ b/drivers/cpuidle/cpuidle-mvebu-v7.c
>>>> @@ -37,11 +37,11 @@ static int mvebu_v7_enter_idle(struct cpuidle_device *dev,
>>>> deepidle = true;
>>>>
>>>> ret = mvebu_v7_cpu_suspend(deepidle);
>>>> + cpu_pm_exit();
>>>> +
>>>> if (ret)
>>>> return ret;
>>>>
>>>> - cpu_pm_exit();
>>>> -
>>>> return index;
>>>> }
>>>>
>>>>
>>>
>>
>>
>
>
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
next prev parent reply other threads:[~2015-03-03 10:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-26 17:20 [PATCH] cpuidle: mvebu: Fix the CPU PM notifier usage Gregory CLEMENT
2015-02-26 21:55 ` Rafael J. Wysocki
2015-02-27 9:39 ` Gregory CLEMENT
2015-03-03 10:30 ` Daniel Lezcano
2015-03-03 10:34 ` Gregory CLEMENT [this message]
2015-03-03 10:52 ` Fulvio
2015-03-03 11:12 ` Daniel Lezcano
2015-03-03 12:51 ` Gregory CLEMENT
2015-03-03 13:00 ` Daniel Lezcano
2015-03-03 14:58 ` Fulvio
2015-03-03 15:20 ` Daniel Lezcano
2015-03-04 14:53 ` Rafael J. Wysocki
2015-03-04 14:34 ` Daniel Lezcano
2015-02-27 16:50 ` Daniel Lezcano
2015-02-27 22:18 ` Rafael J. Wysocki
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