[libcamera-devel] [PATCH] libcamera: pipeline: uvcvideo: add warning if no default video device is found

[Laurent Pinchart]

Hi Niklas,

Thank you for the patch.

On Sun, Jan 27, 2019 at 01:52:06AM +0100, Niklas Söderlund wrote:
> If for any reason a default video device is not found in the media graph
> the creation of the UVC pipeline silently failed. This is not optimal
> when debugging problems with the pipeline, add a warning to notify the
> user of the issue.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
>  src/libcamera/pipeline/uvcvideo.cpp | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
> index c51e8bc1f2c2bf25..4ae179d24709c856 100644
> --- a/src/libcamera/pipeline/uvcvideo.cpp
> +++ b/src/libcamera/pipeline/uvcvideo.cpp
> @@ -8,12 +8,15 @@
>  #include <libcamera/camera.h>
>  
>  #include "device_enumerator.h"
> +#include "log.h"
>  #include "media_device.h"
>  #include "pipeline_handler.h"
>  #include "v4l2_device.h"
>  
>  namespace libcamera {
>  
> +LOG_DEFINE_CATEGORY(UVC)
> +
>  class PipelineHandlerUVC : public PipelineHandler
>  {
>  public:
> @@ -60,6 +63,9 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
>  	}
>  
>  	if (!video_ || video_->open()) {
> +		if (!video_)
> +			LOG(UVC, Warning) << "Could not find a default video device";

I'd make it an error, as it's quite fatal. I think we should also log a
message in the video_->open() failure case, as that's equally fatal (the
permissions denied case is especially important).

> +
>  		media_->release();
>  		return false;
>  	}

-- 
Regards,

Laurent Pinchart