Subject: [PATCH] cpuidle: mvebu: Fix the CPU PM notifier usage

From: [email-masked] (Gregory CLEMENT)
Date: Fri, 27 Feb 2015 10:39:29 +0100

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 <[email-masked]>
>> Signed-off-by: Gregory CLEMENT <[email-masked]>
> 
> 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.

Thanks,

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