Re: [PATCH v2 2/2] dmaengine: cppi41: Ignore EINPROGRESS for PM runtime in interrupt handler

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On 01/09/2017 12:39 PM, Tony Lindgren wrote:
> * Alexandre Bailon <abailon@xxxxxxxxxxxx> [170109 09:04]:
>> We can occasionally get -EINPROGRESS for pm_runtime_get.
>> This is happening when an interrupt is fired before PM runtime had time
>> to update the PM state to RESUMED.
>> In that case, don't print any error.
> 
> Hmm if the cppi41 interrupt fires, the device has resumed :)
> 
> I think we should have a cppi41.c specific flag that we can set
> at the end of cppi41_resume() instead of list_empty() or
> pm_runtime_active().
> 
> Regars,
> 
> Tony
> 
> 
>> Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
>> ---
>>  drivers/dma/cppi41.c | 5 ++---
>>  1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
>> index 025fee4..2306020 100644
>> --- a/drivers/dma/cppi41.c
>> +++ b/drivers/dma/cppi41.c
>> @@ -320,7 +320,7 @@ static irqreturn_t cppi41_irq(int irq, void *data)
>>  			int error;
>>  
>>  			error = pm_runtime_get(cdd->ddev.dev);
>> -			if (error < 0)
>> +			if ((error != -EINPROGRESS) && error < 0)
>>  				dev_err(cdd->ddev.dev, "%s pm runtime get: %i\n",
>>  					__func__, error);

Another question of curiosity :) -EINPROGRESS and pm_runtime_get() in general doesn't
guarantee that device is powered on and accessible immediately after this call, but
few lines below there are code which try to access registers 
	desc = cppi41_pop_desc(cdd, q_num);
Is it ok?

>>  
>> @@ -492,8 +492,7 @@ static void cppi41_dma_issue_pending(struct dma_chan *chan)
>>  		 */
>>  		if (error == -EINPROGRESS) {
>>  			spin_lock_irqsave(&cdd->lock, flags);
>> -			if (list_empty(&cdd->pending))
>> -				active = true;
>> +			active = !!list_empty(&cdd->pending);
>>  			spin_unlock_irqrestore(&cdd->lock, flags);
>>  		}
>>  	}
>> -- 
>> 2.10.2

> 

-- 
regards,
-grygorii
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