On 01/09/2017 07:16 PM, Grygorii Strashko wrote:
>
>
> On 01/09/2017 11:03 AM, Alexandre Bailon wrote:
>> Sometime, a transfer may not be queued due to a race between runtime pm
>> and cppi41_dma_issue_pending().
>> Sometime, cppi41_runtime_resume() may be interrupted right before to
>> update device PM state to RESUMED.
>> When it happens, if a new dma transfer is issued, because the device is not
>> in active state, the descriptor will be added to the pendding list.
>> But because the descriptors in the pendding list are only queued to cppi41
>> on runtime resume, the descriptor will not be queued.
>> On runtime suspend, the list is not empty, which is causing a warning.
>> Queue the descriptor if the device is active or resuming.
>>
>> Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
>> ---
>> drivers/dma/cppi41.c | 18 +++++++++++++++++-
>> 1 file changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
>> index d5ba43a..025fee4 100644
>> --- a/drivers/dma/cppi41.c
>> +++ b/drivers/dma/cppi41.c
>> @@ -471,6 +471,8 @@ static void cppi41_dma_issue_pending(struct dma_chan *chan)
>> {
>> struct cppi41_channel *c = to_cpp41_chan(chan);
>> struct cppi41_dd *cdd = c->cdd;
>> + unsigned long flags;
>> + bool active;
>> int error;
>>
>> error = pm_runtime_get(cdd->ddev.dev);
>> @@ -482,7 +484,21 @@ static void cppi41_dma_issue_pending(struct dma_chan *chan)
>> return;
>> }
>>
>> - if (likely(pm_runtime_active(cdd->ddev.dev)))
>> + active = pm_runtime_active(cdd->ddev.dev);
>> + if (!active) {
>
> just curious, what does prevent from using pm_runtime_get_sync() here and in
> cppi41_dma_issue_pending()?
This function is called from atomic or interrupt context.
>
>> + /*
>> + * Runtime resume may be interrupted before runtime_status
>> + * has been updated. Test if device has resumed.
>> + */
>> + if (error == -EINPROGRESS) {
>> + spin_lock_irqsave(&cdd->lock, flags);
>> + if (list_empty(&cdd->pending))
>> + active = true;
>> + spin_unlock_irqrestore(&cdd->lock, flags);
>> + }
>> + }
>> +
>> + if (likely(active))
>> push_desc_queue(c);
>> else
>> pending_desc(c);
>>
>
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