[libcamera-devel] [PATCH] cam: Fail capture if to few Requests asked for

[Kieran Bingham]

Hi Niklas,

Also s/to/too/ in $SUBJECT

On 08/02/2021 10:14, Jacopo Mondi wrote:
> Hi Niklas,
> 
> On Mon, Feb 08, 2021 at 10:44:16AM +0100, Niklas Söderlund wrote:
>> Running cam with the --capture=N option only queues N Requests to the
>> camera. If N is less then the number of requests needed by the camera to
>> operate cam may deadlock waiting for the camera to complete requests
>> while the camera waits for the application to give it more buffers.
>>
>> Fix this by adding a check in cam to no attempt a capture session if to
>> few requests are requested.

and here s/to/too/

>>
>> Reported-by: Sebastian Fricke <sebastian.fricke at posteo.net>
>> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
>> ---
>>  src/cam/capture.cpp | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
>> index 7b55fc6770225e2a..18aa97c7cdb55dcc 100644
>> --- a/src/cam/capture.cpp
>> +++ b/src/cam/capture.cpp
>> @@ -90,6 +90,13 @@ int Capture::capture(FrameBufferAllocator *allocator)
>>  		nbuffers = std::min(nbuffers, allocated);
>>  	}
>>
>> +	if (captureLimit_ && captureLimit_ < nbuffers) {
>> +		std::cerr << "Camera requiers at least " << nbuffers
> 
> s/requiers/requires
> 
>> +			  << " reqests to function, " << captureLimit_
> 
> s/reqests/requests
> 
>> +			  << " requested" << std::endl;
> 
> I would make it shorter
>                         << "Camera requires " << nbuffers << " requests, "
>                         << "but only " << captureLimit_ << " have been provided";
> 
> Which is not that shorter :/
> 
> Up to you
> 
> Spelling fixes apart
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Should we increase the capture lmit to the minimum? Or do you want to
make sure cam fails if too few are requested?

Either way,

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>


> 
> Thanks
>   j
> 
>> +		return -EINVAL;
>> +	}
>> +
>>  	/*
>>  	 * TODO: make cam tool smarter to support still capture by for
>>  	 * example pushing a button. For now run all streams all the time.
>> --
>> 2.30.0
>>
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> 

-- 
Regards
--
Kieran