[libcamera-devel] [PATCH] libcamera: pipeline: simple: enable mplane devices using contiguous memory

[Niklas Söderlund]

Hello Andrey,

Thanks for your patch.

On 2020-10-07 10:54:57 +0300, Andrey Konovalov wrote:
> The current simple pipeline handler refuses to work with capture devices
> which have V4L2_CAP_VIDEO_CAPTURE_MPLANE flag set in the device capabilities
> field. This is too restrictive, as devices supporting the multi-planar API
> can be using contiguous memory for semi-planar and planar formats, and this
> would just work without any changes to libcamera.
> 
> Drop the guard against MPLANE devices, and replace it with the check of
> the number of planes in the format the simple pipeline handler is going to
> use for capture. This will let MPLANE devices which don't use non-contiguous
> memory for frame buffers to work with the simple pipeline handler.

I wonder if the check should not be moved to SimpleCameraData::init() 
where the formats_ array is built. The array contains all supported 
formats of the camera and excluding mplaner formats from it will make it 
not show up at all for applications. Also validate() would Adjust if any 
format is asked for that is not in the formats_ array.

> 
> Signed-off-by: Andrey Konovalov <andrey.konovalov at linaro.org>
> ---
>  src/libcamera/pipeline/simple/simple.cpp | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index 10223a9b..8dc23623 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -592,6 +592,12 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
>  	if (ret)
>  		return ret;
>  
> +	if (captureFormat.planesCount != 1) {
> +		LOG(SimplePipeline, Error)
> +			<<  "Planar formats using non-contiguous memory not supported";
> +		return -EINVAL;
> +	}
> +
>  	if (captureFormat.fourcc != videoFormat ||
>  	    captureFormat.size != pipeConfig.captureSize) {
>  		LOG(SimplePipeline, Error)
> @@ -845,12 +851,6 @@ V4L2VideoDevice *SimplePipelineHandler::video(const MediaEntity *entity)
>  	if (video->open() < 0)
>  		return nullptr;
>  
> -	if (video->caps().isMultiplanar()) {
> -		LOG(SimplePipeline, Error)
> -			<< "V4L2 multiplanar devices are not supported";
> -		return nullptr;
> -	}
> -
>  	video->bufferReady.connect(this, &SimplePipelineHandler::bufferReady);
>  
>  	auto element = videos_.emplace(entity, std::move(video));
> -- 
> 2.17.1
> 
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-- 
Regards,
Niklas Söderlund