[libcamera-devel] [PATCH v3 3/6] libcamera: camera_sensor: Default selection targets

[Laurent Pinchart]

Hi Jacopo,

Thank you for the patch.

On Wed, Dec 30, 2020 at 07:01:17PM +0100, Jacopo Mondi wrote:
> Support for the V4L2 selection API is optional in the CameraSensor
> class. Currently the properties registred by using values read

s/registred/registered/

> through that API are defaulted in several places (the Android camera HAL
> or the CameraSensor class).
> 
> In future support for the selection API will be made mandatory, but to

s/In future/In the future/

> give time to sensor drivers in all test platforms to be updated, provide
> a default for each of those properties, simplifying the creation of
> the camera sensor properties list and of CameraSensorInfo.
> 
> Provide a default size of [2592x2944] for the pixel array size and a
> default rectangle [16, 12, 2560, 1920] for the active area and analog
> crop rectangles.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  include/libcamera/internal/camera_sensor.h |  3 +
>  src/libcamera/camera_sensor.cpp            | 71 +++++++++-------------
>  2 files changed, 31 insertions(+), 43 deletions(-)
> 
> diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
> index aee10aa6e3c7..c2d620f05b65 100644
> --- a/include/libcamera/internal/camera_sensor.h
> +++ b/include/libcamera/internal/camera_sensor.h
> @@ -84,6 +84,9 @@ private:
>  	std::vector<unsigned int> mbusCodes_;
>  	std::vector<Size> sizes_;
>  
> +	Size pixelArraySize_;
> +	Rectangle activeAreaSize_;

It's not a size but a rectangle, I'd call this activeArea_.

> +
>  	ControlList properties_;
>  };
>  
> diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> index a1f1256bd6f4..2ce19a40b448 100644
> --- a/src/libcamera/camera_sensor.cpp
> +++ b/src/libcamera/camera_sensor.cpp
> @@ -31,6 +31,9 @@ namespace libcamera {
>  
>  LOG_DEFINE_CATEGORY(CameraSensor)
>  
> +static constexpr Size defaultPixelArraySize = { 2592, 1944 };
> +static constexpr Rectangle defaultActiveAreaSize = { 16, 12, 2560, 1920 };
> +
>  /**
>   * \struct CameraSensorInfo
>   * \brief Report the image sensor characteristics
> @@ -266,25 +269,35 @@ int CameraSensor::validateSensorDriver()
>  	 * but some properties and features, like constructing a
>  	 * CameraSensorInfo for the IPA module, won't be supported.
>  	 */
> +
>  	Rectangle rect;
>  	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_BOUNDS, &rect);
>  	if (ret) {
>  		LOG(CameraSensor, Info)
> -			<< "Failed to retrieve the readable pixel area size";
> +			<< "The PixelArraySize property has been defaulted to: "

s/to:/to/ (and same below). But do we actually need this change ? We
plan to revert it soon, isn't it better to keep talking about a failure
?

> +			<< defaultPixelArraySize.toString();
> +		rect.width = defaultPixelArraySize.width;
> +		rect.height = defaultPixelArraySize.height;
>  		err = -EINVAL;
>  	}
> +	pixelArraySize_.width = rect.width;
> +	pixelArraySize_.height = rect.height;
>  
>  	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &rect);

s/rect/activeAreaSize_/

>  	if (ret) {
>  		LOG(CameraSensor, Info)
> -			<< "Failed to retrieve the active pixel area size";
> +			<< "The PixelArraySize property has been defaulted to: "
> +			<< defaultActiveAreaSize.toString();
> +		rect = defaultActiveAreaSize;

		activeAreaSize_ = defaultActiveAreaSize;

>  		err = -EINVAL;
>  	}
> +	activeAreaSize_ = rect;

And drop this line.

>  
>  	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP, &rect);
>  	if (ret) {
>  		LOG(CameraSensor, Info)
> -			<< "Failed to retreive the sensor crop rectangle";

If this has been introduced in a previous patch in the series,
s/retreive/retrieve/.

> +			<< "The analog crop rectangle has been defaulted to: "
> +			<< defaultActiveAreaSize.toString();

This looks messy as there's no handling of the default here, only down
below.

>  		err = -EINVAL;
>  	}
>  
> @@ -378,30 +391,8 @@ int CameraSensor::initProperties()
>  	}
>  	properties_.set(properties::Rotation, propertyValue);
>  
> -	Rectangle bounds;
> -	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_BOUNDS, &bounds);
> -	if (!ret)
> -		properties_.set(properties::PixelArraySize, bounds.size());
> -	else
> -		LOG(CameraSensor, Debug)
> -			<< "PixelArraySize property not registered";
> -
> -	Rectangle crop;
> -	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &crop);
> -	if (!ret) {
> -		/*
> -		 * V4L2_SEL_TGT_CROP_DEFAULT and V4L2_SEL_TGT_CROP_BOUNDS are
> -		 * defined relatively to the sensor full pixel array size,
> -		 * while properties::PixelArrayActiveAreas is defined relatively
> -		 * to properties::PixelArraySize. Adjust it.
> -		 */
> -		crop.x -= bounds.x;
> -		crop.y -= bounds.y;
> -		properties_.set(properties::PixelArrayActiveAreas, { crop });
> -	} else {
> -		LOG(CameraSensor, Debug)
> -			<< "PixelArrayActiveAreas property not registered";
> -	}
> +	properties_.set(properties::PixelArraySize, pixelArraySize_);
> +	properties_.set(properties::PixelArrayActiveAreas, { activeAreaSize_ });

This is nice. Caching those two values is in my opinion the main feature
of this patch, it's worth mentioning it in the commit message.

>  
>  	/* Color filter array pattern, register only for RAW sensors. */
>  	for (const auto &format : formats_) {
> @@ -657,21 +648,15 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
>  {
>  	info->model = model();
>  
> -	/* Get the active area size. */
> -	Rectangle rect;
> -	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &rect);
> -	if (ret) {
> -		LOG(CameraSensor, Error) << "Failed to get the active area";
> -		return ret;
> -	}
> -	info->activeAreaSize = { rect.width, rect.height };
> +	/*
> +	 * The active area size is a static property, while the crop
> +	 * rectangle needs to be re-read as it changes per-mode.

s/changes per-mode/depends on the sensor configuration/

I'd like to avoid talking about sensor modes everywhere, a sensor mode
is an artificial limitation that we have to live with but that we should
still push against as much as possible. It shouldn't become a core
concept in the libcamera vocabulary.

> +	 */
> +	info->activeAreaSize = { activeAreaSize_.width, activeAreaSize_.height };
>  
> -	/* It's mandatory for the subdevice to report its crop rectangle. */
> -	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP, &info->analogCrop);
> -	if (ret) {
> -		LOG(CameraSensor, Error) << "Failed to get the crop rectangle";
> -		return ret;
> -	}
> +	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP, &info->analogCrop);
> +	if (ret)
> +		info->analogCrop = defaultActiveAreaSize;

As this already causes an error, and we want to turn it into a fatal
error soon, how about dropping this change and the corresponding one in
CameraSensor::validateSensorDriver() ?

>  
>  	/*
>  	 * CameraSensorInfo::analogCrop::x and CameraSensorInfo::analogCrop::y
> @@ -680,8 +665,8 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
>  	 *
>  	 * Compensate it by subtracting the active areas offset.

While at it you could write s/areas/area/ (s/areas/area's/ ?).

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

>  	 */
> -	info->analogCrop.x -= rect.x;
> -	info->analogCrop.y -= rect.y;
> +	info->analogCrop.x -= activeAreaSize_.x;
> +	info->analogCrop.y -= activeAreaSize_.y;
>  
>  	/* The bit depth and image size depend on the currently applied format. */
>  	V4L2SubdeviceFormat format{};

-- 
Regards,

Laurent Pinchart