[libcamera-devel] [PATCH v4 04/21] libcamera: V4L2VideoDevice: Add tryFormat

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Wed, Jul 08, 2020 at 10:44:00PM +0900, Paul Elder wrote:
> Add tryFormat and its variations (meta, single-plane, multi-plane) to
> V4L2VideoDevice.
> 
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> ---
> Changes in v4:
> - merge tryFormat{Meta,Multiplane,SinglePlane} into setFormat with a
>   flag
> 
> New in v3
> ---
>  include/libcamera/internal/v4l2_videodevice.h |  7 +--
>  src/libcamera/v4l2_videodevice.cpp            | 50 ++++++++++++++-----
>  2 files changed, 42 insertions(+), 15 deletions(-)
> 
> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
> index 4d21f5a..fb4c0aa 100644
> --- a/include/libcamera/internal/v4l2_videodevice.h
> +++ b/include/libcamera/internal/v4l2_videodevice.h
> @@ -186,6 +186,7 @@ public:
>  	const V4L2Capability &caps() const { return caps_; }
>  
>  	int getFormat(V4L2DeviceFormat *format);
> +	int tryFormat(V4L2DeviceFormat *format);
>  	int setFormat(V4L2DeviceFormat *format);
>  	std::map<V4L2PixelFormat, std::vector<SizeRange>> formats(uint32_t code = 0);
>  
> @@ -217,13 +218,13 @@ protected:
>  
>  private:
>  	int getFormatMeta(V4L2DeviceFormat *format);
> -	int setFormatMeta(V4L2DeviceFormat *format);
> +	int trySetFormatMeta(V4L2DeviceFormat *format, bool set);
>  
>  	int getFormatMultiplane(V4L2DeviceFormat *format);
> -	int setFormatMultiplane(V4L2DeviceFormat *format);
> +	int trySetFormatMultiplane(V4L2DeviceFormat *format, bool set);
>  
>  	int getFormatSingleplane(V4L2DeviceFormat *format);
> -	int setFormatSingleplane(V4L2DeviceFormat *format);
> +	int trySetFormatSingleplane(V4L2DeviceFormat *format, bool set);
>  
>  	std::vector<V4L2PixelFormat> enumPixelformats(uint32_t code);
>  	std::vector<SizeRange> enumSizes(V4L2PixelFormat pixelFormat);
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index 3614b2e..16c78b6 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -723,6 +723,26 @@ int V4L2VideoDevice::getFormat(V4L2DeviceFormat *format)
>  		return getFormatSingleplane(format);
>  }
>  
> +/**
> + * \brief Try an image format on the V4L2 video device
> + * \param[inout] format The image format to test applicability to the video device
> + *
> + * Try the supplied \a format on the video device without applying it, returning
> + * the format that would be applied. This is equivalent to setFormat(), except
> + * that the device configuration is not changed.
> + *
> + * \return 0 on success or a negative error code otherwise
> + */
> +int V4L2VideoDevice::tryFormat(V4L2DeviceFormat *format)
> +{
> +	if (caps_.isMeta())
> +		return trySetFormatMeta(format, false);
> +	else if (caps_.isMultiplanar())
> +		return trySetFormatMultiplane(format, false);
> +	else
> +		return trySetFormatSingleplane(format, false);
> +}
> +
>  /**
>   * \brief Configure an image format on the V4L2 video device
>   * \param[inout] format The image format to apply to the video device
> @@ -735,11 +755,11 @@ int V4L2VideoDevice::getFormat(V4L2DeviceFormat *format)
>  int V4L2VideoDevice::setFormat(V4L2DeviceFormat *format)
>  {
>  	if (caps_.isMeta())
> -		return setFormatMeta(format);
> +		return trySetFormatMeta(format, true);
>  	else if (caps_.isMultiplanar())
> -		return setFormatMultiplane(format);
> +		return trySetFormatMultiplane(format, true);
>  	else
> -		return setFormatSingleplane(format);
> +		return trySetFormatSingleplane(format, true);
>  }
>  
>  int V4L2VideoDevice::getFormatMeta(V4L2DeviceFormat *format)
> @@ -765,7 +785,7 @@ int V4L2VideoDevice::getFormatMeta(V4L2DeviceFormat *format)
>  	return 0;
>  }
>  
> -int V4L2VideoDevice::setFormatMeta(V4L2DeviceFormat *format)
> +int V4L2VideoDevice::trySetFormatMeta(V4L2DeviceFormat *format, bool set)
>  {
>  	struct v4l2_format v4l2Format = {};
>  	struct v4l2_meta_format *pix = &v4l2Format.fmt.meta;
> @@ -774,9 +794,11 @@ int V4L2VideoDevice::setFormatMeta(V4L2DeviceFormat *format)
>  	v4l2Format.type = bufferType_;
>  	pix->dataformat = format->fourcc;
>  	pix->buffersize = format->planes[0].size;
> -	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
> +	ret = ioctl((set ? VIDIOC_S_FMT : VIDIOC_TRY_FMT), &v4l2Format);

No need for the extra parentheses. Same in the next two functions.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

>  	if (ret) {
> -		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
> +		LOG(V4L2, Error)
> +			<< "Unable to " << (set ? "set" : "try")
> +			<< " format: " << strerror(-ret);
>  		return ret;
>  	}
>  
> @@ -820,7 +842,7 @@ int V4L2VideoDevice::getFormatMultiplane(V4L2DeviceFormat *format)
>  	return 0;
>  }
>  
> -int V4L2VideoDevice::setFormatMultiplane(V4L2DeviceFormat *format)
> +int V4L2VideoDevice::trySetFormatMultiplane(V4L2DeviceFormat *format, bool set)
>  {
>  	struct v4l2_format v4l2Format = {};
>  	struct v4l2_pix_format_mplane *pix = &v4l2Format.fmt.pix_mp;
> @@ -838,9 +860,11 @@ int V4L2VideoDevice::setFormatMultiplane(V4L2DeviceFormat *format)
>  		pix->plane_fmt[i].sizeimage = format->planes[i].size;
>  	}
>  
> -	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
> +	ret = ioctl((set ? VIDIOC_S_FMT : VIDIOC_TRY_FMT), &v4l2Format);
>  	if (ret) {
> -		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
> +		LOG(V4L2, Error)
> +			<< "Unable to " << (set ? "set" : "try")
> +			<< " format: " << strerror(-ret);
>  		return ret;
>  	}
>  
> @@ -883,7 +907,7 @@ int V4L2VideoDevice::getFormatSingleplane(V4L2DeviceFormat *format)
>  	return 0;
>  }
>  
> -int V4L2VideoDevice::setFormatSingleplane(V4L2DeviceFormat *format)
> +int V4L2VideoDevice::trySetFormatSingleplane(V4L2DeviceFormat *format, bool set)
>  {
>  	struct v4l2_format v4l2Format = {};
>  	struct v4l2_pix_format *pix = &v4l2Format.fmt.pix;
> @@ -895,9 +919,11 @@ int V4L2VideoDevice::setFormatSingleplane(V4L2DeviceFormat *format)
>  	pix->pixelformat = format->fourcc;
>  	pix->bytesperline = format->planes[0].bpl;
>  	pix->field = V4L2_FIELD_NONE;
> -	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
> +	ret = ioctl((set ? VIDIOC_S_FMT : VIDIOC_TRY_FMT), &v4l2Format);
>  	if (ret) {
> -		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
> +		LOG(V4L2, Error)
> +			<< "Unable to " << (set ? "set" : "try")
> +			<< " format: " << strerror(-ret);
>  		return ret;
>  	}
>  

-- 
Regards,

Laurent Pinchart