2020-01-07 09:49:07

by Hugues Fruchet

Subject: Re: [PATCH] media: stm32-dcmi: Use dma_request_chan() instead dma_request_slave_channel()

Hi Peter,

If not too late, could you change trace to only trig error trace when
error is not "probe defered" ? See below:

- chan = dma_request_slave_channel(&pdev->dev, "tx");
- if (!chan) {
- dev_info(&pdev->dev, "Unable to request DMA channel, defer probing\n");
- return -EPROBE_DEFER;
+ chan = dma_request_chan(&pdev->dev, "tx");
+ if (IS_ERR(chan)) {
+ if (PTR_ERR(chan) != -EPROBE_DEFER)
+ dev_err(&pdev->dev, "Unable to request DMA channel\n");
+ return PTR_ERR(chan);


Best regards,
Hugues.

On 12/18/19 11:52 AM, Hugues FRUCHET wrote:
> Thanks for patching Peter,
>
> No regression observed on my side.
>
> Acked-by: Hugues Fruchet <[email protected]>
>
> Best regards,
> Hugues.
>
> On 12/17/19 11:41 AM, Peter Ujfalusi wrote:
>> dma_request_slave_channel() is a wrapper on top of dma_request_chan()
>> eating up the error code.
>>
>> By using dma_request_chan() directly the driver can support deferred
>> probing against DMA.
>>
>> Signed-off-by: Peter Ujfalusi <[email protected]>
>> ---
>>   drivers/media/platform/stm32/stm32-dcmi.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/platform/stm32/stm32-dcmi.c
>> b/drivers/media/platform/stm32/stm32-dcmi.c
>> index 9392e3409fba..55351872b0c7 100644
>> --- a/drivers/media/platform/stm32/stm32-dcmi.c
>> +++ b/drivers/media/platform/stm32/stm32-dcmi.c
>> @@ -1910,10 +1910,10 @@ static int dcmi_probe(struct platform_device
>> *pdev)
>>           return PTR_ERR(mclk);
>>       }
>> -    chan = dma_request_slave_channel(&pdev->dev, "tx");
>> -    if (!chan) {
>> +    chan = dma_request_chan(&pdev->dev, "tx");
>> +    if (IS_ERR(chan)) {
>>           dev_info(&pdev->dev, "Unable to request DMA channel, defer
>> probing\n");
>> -        return -EPROBE_DEFER;
>> +        return PTR_ERR(chan);
>>       }
>>       spin_lock_init(&dcmi->irqlock);
>>

2020-01-07 10:39:41

by Peter Ujfalusi

Subject: Re: [PATCH] media: stm32-dcmi: Use dma_request_chan() instead dma_request_slave_channel()

Hi Hugues,

On 07/01/2020 11.46, Hugues FRUCHET wrote:
> Hi Peter,
>
> If not too late, could you change trace to only trig error trace when
> error is not "probe defered" ? See below:
>
> - chan = dma_request_slave_channel(&pdev->dev, "tx");
> - if (!chan) {
> - dev_info(&pdev->dev, "Unable to request DMA channel, defer probing\n");
> - return -EPROBE_DEFER;
> + chan = dma_request_chan(&pdev->dev, "tx");
> + if (IS_ERR(chan)) {
> + if (PTR_ERR(chan) != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "Unable to request DMA channel\n");
> + return PTR_ERR(chan);

Sure, I don't know how I missed it.

Regards,
- Péter

>
> Best regards,
> Hugues.
>
> On 12/18/19 11:52 AM, Hugues FRUCHET wrote:
>> Thanks for patching Peter,
>>
>> No regression observed on my side.
>>
>> Acked-by: Hugues Fruchet <[email protected]>
>>
>> Best regards,
>> Hugues.
>>
>> On 12/17/19 11:41 AM, Peter Ujfalusi wrote:
>>> dma_request_slave_channel() is a wrapper on top of dma_request_chan()
>>> eating up the error code.
>>>
>>> By using dma_request_chan() directly the driver can support deferred
>>> probing against DMA.
>>>
>>> Signed-off-by: Peter Ujfalusi <[email protected]>
>>> ---
>>>   drivers/media/platform/stm32/stm32-dcmi.c | 6 +++---
>>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/stm32/stm32-dcmi.c
>>> b/drivers/media/platform/stm32/stm32-dcmi.c
>>> index 9392e3409fba..55351872b0c7 100644
>>> --- a/drivers/media/platform/stm32/stm32-dcmi.c
>>> +++ b/drivers/media/platform/stm32/stm32-dcmi.c
>>> @@ -1910,10 +1910,10 @@ static int dcmi_probe(struct platform_device
>>> *pdev)
>>>           return PTR_ERR(mclk);
>>>       }
>>> -    chan = dma_request_slave_channel(&pdev->dev, "tx");
>>> -    if (!chan) {
>>> +    chan = dma_request_chan(&pdev->dev, "tx");
>>> +    if (IS_ERR(chan)) {
>>>           dev_info(&pdev->dev, "Unable to request DMA channel, defer
>>> probing\n");
>>> -        return -EPROBE_DEFER;
>>> +        return PTR_ERR(chan);
>>>       }
>>>       spin_lock_init(&dcmi->irqlock);
>> >


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

2020-01-07 11:10:56

by Hugues Fruchet

Subject: Re: [PATCH] media: stm32-dcmi: Use dma_request_chan() instead dma_request_slave_channel()

Y're welcome.

On 1/7/20 11:38 AM, Peter Ujfalusi wrote:
> Hi Hugues,
>
> On 07/01/2020 11.46, Hugues FRUCHET wrote:
>> Hi Peter,
>>
>> If not too late, could you change trace to only trig error trace when
>> error is not "probe defered" ? See below:
>>
>> - chan = dma_request_slave_channel(&pdev->dev, "tx");
>> - if (!chan) {
>> - dev_info(&pdev->dev, "Unable to request DMA channel, defer probing\n");
>> - return -EPROBE_DEFER;
>> + chan = dma_request_chan(&pdev->dev, "tx");
>> + if (IS_ERR(chan)) {
>> + if (PTR_ERR(chan) != -EPROBE_DEFER)
>> + dev_err(&pdev->dev, "Unable to request DMA channel\n");
>> + return PTR_ERR(chan);
>
> Sure, I don't know how I missed it.
>
> Regards,
> - Péter
>
>>
>> Best regards,
>> Hugues.
>>
>> On 12/18/19 11:52 AM, Hugues FRUCHET wrote:
>>> Thanks for patching Peter,
>>>
>>> No regression observed on my side.
>>>
>>> Acked-by: Hugues Fruchet <[email protected]>
>>>
>>> Best regards,
>>> Hugues.
>>>
>>> On 12/17/19 11:41 AM, Peter Ujfalusi wrote:
>>>> dma_request_slave_channel() is a wrapper on top of dma_request_chan()
>>>> eating up the error code.
>>>>
>>>> By using dma_request_chan() directly the driver can support deferred
>>>> probing against DMA.
>>>>
>>>> Signed-off-by: Peter Ujfalusi <[email protected]>
>>>> ---
>>>>   drivers/media/platform/stm32/stm32-dcmi.c | 6 +++---
>>>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/media/platform/stm32/stm32-dcmi.c
>>>> b/drivers/media/platform/stm32/stm32-dcmi.c
>>>> index 9392e3409fba..55351872b0c7 100644
>>>> --- a/drivers/media/platform/stm32/stm32-dcmi.c
>>>> +++ b/drivers/media/platform/stm32/stm32-dcmi.c
>>>> @@ -1910,10 +1910,10 @@ static int dcmi_probe(struct platform_device
>>>> *pdev)
>>>>           return PTR_ERR(mclk);
>>>>       }
>>>> -    chan = dma_request_slave_channel(&pdev->dev, "tx");
>>>> -    if (!chan) {
>>>> +    chan = dma_request_chan(&pdev->dev, "tx");
>>>> +    if (IS_ERR(chan)) {
>>>>           dev_info(&pdev->dev, "Unable to request DMA channel, defer
>>>> probing\n");
>>>> -        return -EPROBE_DEFER;
>>>> +        return PTR_ERR(chan);
>>>>       }
>>>>       spin_lock_init(&dcmi->irqlock);
>>>>
>
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>