[libcamera-devel] [PATCH v3 09/16] libcamera: v4l2_device: Add enumeration of pixelformats and frame sizes

[Niklas Söderlund]

Hi Laurent,

Thanks for your feedback,

On 2019-06-19 02:07:27 +0300, Laurent Pinchart wrote:
> Hi Niklas,
> 
> Thank you for the patch.
> 
> On Sun, Jun 16, 2019 at 03:33:55PM +0200, Niklas Söderlund wrote:
> > Add methods to enumerate pixelformats and frame sizes from a v4l2
> > device. The interface is similar to how V4L2Subdevice enumerates mbus
> > codes and frame sizes.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> > ---
> >  src/libcamera/include/v4l2_device.h |   5 ++
> >  src/libcamera/v4l2_device.cpp       | 110 ++++++++++++++++++++++++++++
> >  2 files changed, 115 insertions(+)
> > 
> > diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> > index bdecc087fe5afae0..1a67850ac4c1088f 100644
> > --- a/src/libcamera/include/v4l2_device.h
> > +++ b/src/libcamera/include/v4l2_device.h
> > @@ -16,6 +16,7 @@
> >  #include <libcamera/geometry.h>
> >  #include <libcamera/signal.h>
> >  
> > +#include "formats.h"
> >  #include "log.h"
> >  
> >  namespace libcamera {
> > @@ -132,6 +133,7 @@ public:
> >  
> >  	int getFormat(V4L2DeviceFormat *format);
> >  	int setFormat(V4L2DeviceFormat *format);
> > +	ImageFormats formats();
> >  
> >  	int exportBuffers(BufferPool *pool);
> >  	int importBuffers(BufferPool *pool);
> > @@ -163,6 +165,9 @@ private:
> >  	int createPlane(Buffer *buffer, unsigned int plane,
> >  			unsigned int length);
> >  
> > +	std::vector<unsigned int> enumPixelformats();
> > +	std::vector<SizeRange> enumSizes(unsigned int pixelFormat);
> > +
> >  	Buffer *dequeueBuffer();
> >  	void bufferAvailable(EventNotifier *notifier);
> >  
> > diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> > index 0821bd75fb428766..96aa525025629697 100644
> > --- a/src/libcamera/v4l2_device.cpp
> > +++ b/src/libcamera/v4l2_device.cpp
> > @@ -634,6 +634,29 @@ int V4L2Device::setFormatSingleplane(V4L2DeviceFormat *format)
> >  	return 0;
> >  }
> >  
> > +/**
> > + * \brief Enumerate all pixel formats and frame sizes
> > + *
> > + * Enumerate all pixel formats and frame sizes supported by the video device.
> > + *
> > + * \return A list of the supported device formats
> > + */
> > +ImageFormats V4L2Device::formats()
> > +{
> > +	ImageFormats formats;
> > +
> > +	for (unsigned int pixelformat : enumPixelformats()) {
> > +		if (formats.addFormat(pixelformat, enumSizes(pixelformat))) {
> > +			LOG(V4L2, Error)
> > +				<< "Could not add sizes for pixel format "
> > +				<< pixelformat;
> > +			return {};
> > +		}
> 
> I think you should catch the error from enumSizes() and return {}. I
> would also extend the documentation a little bit, you can copy the one
> from the V4L2Subdevice class.

I agree that enumSizes() should have a error check and I added that for 
next version. About the documentation I'm not sure what you are asking, 
the V4L2Device::formats() documentation is already an adapted copy of 
V4L2Subdevice::formats().

I have addressed all other comments in this patch but I have not 
collected your tag until I understand what you are asking here ;-)

> 
> > +	}
> > +
> > +	return formats;
> > +}
> > +
> >  int V4L2Device::requestBuffers(unsigned int count)
> >  {
> >  	struct v4l2_requestbuffers rb = {};
> > @@ -763,6 +786,93 @@ int V4L2Device::createPlane(Buffer *buffer, unsigned int planeIndex,
> >  	return 0;
> >  }
> >  
> > +std::vector<unsigned int> V4L2Device::enumPixelformats()
> > +{
> > +	std::vector<unsigned int> formats;
> > +	int ret;
> > +
> > +	for (unsigned int index = 0; ; index++) {
> > +		struct v4l2_fmtdesc pixelformatEnum = {};
> > +		pixelformatEnum.index = index;
> > +		pixelformatEnum.type = bufferType_;
> > +
> > +		ret = ioctl(fd_, VIDIOC_ENUM_FMT, &pixelformatEnum);
> > +		if (ret)
> > +			break;
> > +
> > +		formats.push_back(pixelformatEnum.pixelformat);
> > +	}
> > +
> > +	if (ret && errno != EINVAL) {
> > +		ret = -errno;
> > +		LOG(V4L2, Error)
> > +			<< "Unable to enumerate pixelformats: "
> 
> s/pixelformats/pixel formats/
> 
> > +			<< strerror(-ret);
> > +		return {};
> > +	}
> > +
> > +	return formats;
> > +}
> > +
> > +std::vector<SizeRange> V4L2Device::enumSizes(unsigned int pixelFormat)
> > +{
> > +	std::vector<SizeRange> sizes;
> > +	int ret;
> > +
> > +	for (unsigned int index = 0;; index++) {
> > +		struct v4l2_frmsizeenum frameSize = {};
> > +		frameSize.index = index;
> > +		frameSize.pixel_format = pixelFormat;
> > +
> > +		ret = ioctl(fd_, VIDIOC_ENUM_FRAMESIZES, &frameSize);
> > +		if (ret)
> > +			break;
> > +
> > +		if (index != 0 &&
> > +		    frameSize.type != V4L2_FRMSIZE_TYPE_DISCRETE) {
> > +			LOG(V4L2, Error)
> > +				<< "Non-zero index for non discrete type";
> > +			return {};
> > +		}
> > +
> > +		switch (frameSize.type) {
> > +		case V4L2_FRMSIZE_TYPE_DISCRETE:
> > +			sizes.emplace_back(frameSize.discrete.width,
> > +					   frameSize.discrete.height);
> > +			break;
> > +		case V4L2_FRMSIZE_TYPE_CONTINUOUS:
> > +			sizes.emplace_back(frameSize.stepwise.min_width,
> > +					   frameSize.stepwise.min_height,
> > +					   frameSize.stepwise.max_width,
> > +					   frameSize.stepwise.max_height);
> > +			break;
> > +		case V4L2_FRMSIZE_TYPE_STEPWISE:
> > +			sizes.emplace_back(frameSize.stepwise.min_width,
> > +					   frameSize.stepwise.min_height,
> > +					   frameSize.stepwise.max_width,
> > +					   frameSize.stepwise.max_height,
> > +					   frameSize.stepwise.step_width,
> > +					   frameSize.stepwise.step_height);
> > +			break;
> > +		default:
> > +			LOG(V4L2, Error)
> > +				<< "Unknown VIDIOC_ENUM_FRAMESIZES type: "
> 
> Nit-picking, s/://
> 
> With these small issues fixed (and trusting your documentation skills
> for the formats() method),
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> > +				<< frameSize.type;
> > +			return {};
> > +		}
> > +	}
> > +
> > +	if (ret && errno != EINVAL) {
> > +		ret = -errno;
> > +		LOG(V4L2, Error)
> > +			<< "Unable to enumerate frame sizes: "
> > +			<< strerror(-ret);
> > +		return {};
> > +	}
> > +
> > +	return sizes;
> > +}
> > +
> >  /**
> >   * \brief Import the externally allocated \a pool of buffers
> >   * \param[in] pool BufferPool of buffers to import
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Regards,
Niklas Söderlund