[libcamera-devel] [PATCH v2 2/2] libcamera: Introduce V4L2Device base class

Kieran Bingham kieran.bingham at ideasonboard.com
Wed Jun 12 15:51:46 CEST 2019


Oh and,

On 12/06/2019 14:50, Kieran Bingham wrote:
> Hi Jacopo,
> 
> On 12/06/2019 14:38, Jacopo Mondi wrote:
>> he V4L2 devices and subdevices share a few common operations,like
> 
> s/he/The/
> 
>> opening and closing a device node, and perform IOCTLs on the device.
>>
>> With the forthcoming introduction of support for V4L2 controls, the
>> quantity of shared code will drastically increase, as the control
>> implementation is identical for the two.
>>
>> To maximize code re-use and avoid duplications, provide a V4L2Device
>> base class which groups the common operations and members.
>>
>> The newly introduced base class provides methods to open/close a device
>> node, access the file descriptor, and perform IOCTLs on the device.
>>
>> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> 
> Thank you - this is much easier to review now :-D
> 
> 
> A few comments below:

With comments addressed as you see fit,

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>


> 
>> ---
>>  src/libcamera/include/v4l2_device.h      |  36 ++++++
>>  src/libcamera/include/v4l2_subdevice.h   |   6 +-
>>  src/libcamera/include/v4l2_videodevice.h |   5 +-
>>  src/libcamera/meson.build                |   2 +
>>  src/libcamera/v4l2_device.cpp            | 148 +++++++++++++++++++++++
>>  src/libcamera/v4l2_subdevice.cpp         |  66 +++-------
>>  src/libcamera/v4l2_videodevice.cpp       |  68 ++++-------
>>  7 files changed, 227 insertions(+), 104 deletions(-)
>>  create mode 100644 src/libcamera/include/v4l2_device.h
>>  create mode 100644 src/libcamera/v4l2_device.cpp
>>
>> diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
>> new file mode 100644
>> index 000000000000..584a570a4703
>> --- /dev/null
>> +++ b/src/libcamera/include/v4l2_device.h
>> @@ -0,0 +1,36 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2019, Google Inc.
>> + *
>> + * v4l2_device.h - Common base for V4L2 video devices and subdevices
>> + */
>> +#ifndef __LIBCAMERA_V4L2_DEVICE_H__
>> +#define __LIBCAMERA_V4L2_DEVICE_H__
>> +
>> +#include <string>
>> +
>> +namespace libcamera {
>> +
>> +class V4L2Device
>> +{
>> +public:
>> +	virtual ~V4L2Device() { close(); }
>> +
>> +protected:
>> +	V4L2Device();
>> +
>> +	int fd() { return fd_; }
>> +
>> +	int open(const std::string &pathname, unsigned int flags);
>> +	int close();
>> +	bool isOpen() const;
>> +
>> +	int ioctl(unsigned long request, void *argp);
>> +
>> +private:
>> +	int fd_;
>> +};
>> +
>> +} /* namespace libcamera */
>> +
>> +#endif /* __LIBCAMERA_V4L2_DEVICE_H__ */
>> diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
>> index 3e4e5107aebe..a34b719f8c52 100644
>> --- a/src/libcamera/include/v4l2_subdevice.h
>> +++ b/src/libcamera/include/v4l2_subdevice.h
>> @@ -16,6 +16,7 @@
>>  #include "formats.h"
>>  #include "log.h"
>>  #include "media_object.h"
>> +#include "v4l2_device.h"
>>  
>>  namespace libcamera {
>>  
>> @@ -28,7 +29,7 @@ struct V4L2SubdeviceFormat {
>>  	const std::string toString() const;
>>  };
>>  
>> -class V4L2Subdevice : protected Loggable
>> +class V4L2Subdevice : public V4L2Device, protected Loggable
>>  {
>>  public:
>>  	explicit V4L2Subdevice(const MediaEntity *entity);
>> @@ -37,8 +38,6 @@ public:
>>  	~V4L2Subdevice();
>>  
>>  	int open();
>> -	bool isOpen() const;
>> -	void close();
>>  
>>  	const MediaEntity *entity() const { return entity_; }
>>  
>> @@ -64,7 +63,6 @@ private:
>>  			 Rectangle *rect);
>>  
>>  	const MediaEntity *entity_;
>> -	int fd_;
>>  };
>>  
>>  } /* namespace libcamera */
>> diff --git a/src/libcamera/include/v4l2_videodevice.h b/src/libcamera/include/v4l2_videodevice.h
>> index 6ecdb64e5f3c..15a83635b9bf 100644
>> --- a/src/libcamera/include/v4l2_videodevice.h
>> +++ b/src/libcamera/include/v4l2_videodevice.h
>> @@ -17,6 +17,7 @@
>>  #include <libcamera/signal.h>
>>  
>>  #include "log.h"
>> +#include "v4l2_device.h"
>>  
>>  namespace libcamera {
>>  
>> @@ -111,7 +112,7 @@ public:
>>  	const std::string toString() const;
>>  };
>>  
>> -class V4L2VideoDevice : protected Loggable
>> +class V4L2VideoDevice : public V4L2Device, protected Loggable
>>  {
>>  public:
>>  	explicit V4L2VideoDevice(const std::string &deviceNode);
>> @@ -122,7 +123,6 @@ public:
>>  	V4L2VideoDevice &operator=(const V4L2VideoDevice &) = delete;
>>  
>>  	int open();
>> -	bool isOpen() const;
>>  	void close();
>>  
>>  	const char *driverName() const { return caps_.driver(); }
>> @@ -167,7 +167,6 @@ private:
>>  	void bufferAvailable(EventNotifier *notifier);
>>  
>>  	std::string deviceNode_;
>> -	int fd_;
>>  	V4L2Capability caps_;
>>  
>>  	enum v4l2_buf_type bufferType_;
>> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
>> index 15ab53b1abbe..f26ad5b2dc57 100644
>> --- a/src/libcamera/meson.build
>> +++ b/src/libcamera/meson.build
>> @@ -23,6 +23,7 @@ libcamera_sources = files([
>>      'stream.cpp',
>>      'timer.cpp',
>>      'utils.cpp',
>> +    'v4l2_device.cpp',
>>      'v4l2_subdevice.cpp',
>>      'v4l2_videodevice.cpp',
>>  ])
>> @@ -41,6 +42,7 @@ libcamera_headers = files([
>>      'include/media_object.h',
>>      'include/pipeline_handler.h',
>>      'include/utils.h',
>> +    'include/v4l2_device.h',
>>      'include/v4l2_subdevice.h',
>>      'include/v4l2_videodevice.h',
>>  ])
>> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
>> new file mode 100644
>> index 000000000000..f89b2a2982ba
>> --- /dev/null
>> +++ b/src/libcamera/v4l2_device.cpp
>> @@ -0,0 +1,148 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2019, Google Inc.
>> + *
>> + * v4l2_device.cpp - Common base for V4L2 devices and subdevices
>> + */
>> +
>> +#include "v4l2_device.h"
>> +
>> +#include <fcntl.h>
>> +#include <string.h>
>> +#include <sys/ioctl.h>
>> +#include <unistd.h>
>> +
>> +#include "log.h"
>> +
>> +/**
>> + * \file v4l2_device.h
>> + * \brief Common base for V4L2 devices and subdevices
>> + */
>> +
>> +namespace libcamera {
>> +
>> +LOG_DEFINE_CATEGORY(V4L2)
>> +
>> +/**
>> + * \class V4L2Device
>> + * \brief Base class for V4L2Videodev and V4L2Subdev
>> + *
>> + * The V4L2Device class groups together the methods and fields common to
>> + * both V4L2Videodev and V4L2Subdev, and provide a base class which
>> + * provides methods to open and close the device node associated with the
>> + * device and to perform IOCTL system calls on it.
>> + *
>> + * The V4L2Device class cannot be instantiated directly, as its constructor
>> + * is protected. Users should use instead one the derived classes to model
>> + * either a V4L2 video device or a V4L2 subdevice.
>> + */
>> +
>> +/**
>> + * \brief Construct a V4L2Device
>> + *
>> + * The V4L2Device constructor is protected and can only be accessed by the
>> + * V4L2Videodev and V4L2Subdev derived classes.
>> + *
>> + * Initialize the file descriptor to -1.
>> + */
>> +V4L2Device::V4L2Device()
>> +	: fd_(-1)
>> +{
>> +}
>> +
>> +/**
>> + * \fn V4L2Device::fd()
>> + * \brief Retrieve the V4L2 device file descriptor
>> + * \return The V4L2 device file descriptor, -1 if the device node is not open
>> + */
>> +
>> +/**
>> + * \brief Open a V4L2 device node
>> + * \param pathname The filesystem path of the device node to open
>> + * \param flags Access mode flags
>> + *
>> + * Initialize the file descriptor, which was initially set to -1.
>> + *
>> + * \return 0 on success or a negative error code otherwise
>> + */
>> +int V4L2Device::open(const std::string &pathname, unsigned int flags)
>> +{
>> +	if (isOpen()) {
>> +		LOG(V4L2, Error) << "Device already open";
>> +		return -EBUSY;
>> +	}
>> +
>> +	int ret = ::open(pathname.c_str(), flags);
>> +	if (ret < 0) {
>> +		ret = -errno;
>> +		LOG(V4L2, Error) << "Failed to open V4L2 device: "
>> +				 << strerror(-ret);
>> +		return ret;
>> +	}
>> +
>> +	fd_ = ret;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * \brief Close the device node
>> + *
>> + * Reset the file descriptor to -1
>> + *
>> + * \return 0 on success or a negative error code otherwise
>> + */
>> +int V4L2Device::close()
>> +{
>> +	if (fd_ < 0)
>> +		return 0;
>> +
>> +	int ret = ::close(fd_);
>> +	if (ret < 0) {
>> +		ret = -errno;
>> +		LOG(V4L2, Error) << "Failed to close V4L2 device: "
>> +				 << strerror(-ret);
>> +		return ret;
>> +	}
>> +
>> +	fd_ = -1;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * \brief Check if the V4L2 device node is open
>> + * \return True if the V4L2 device node is open, false otherwise
>> + */
>> +bool V4L2Device::isOpen() const
>> +{
>> +	return fd_ != -1;
>> +}
>> +
>> +/**
>> + * \brief Perform an IOCTL system call on the device node
>> + * \param request The IOCTL request code
>> + * \param argp A poiunter to the IOCTL argument
> 
> 
> s/poiunter/pointer/
> 
> 
>> + * \return 0 on success or a negative error code otherwise
>> + */
>> +int V4L2Device::ioctl(unsigned long request, void *argp)
>> +{
>> +	/*
>> +	 * Printing out an error message is usually better performed
>> +	 * in the caller, which can provide more context.
>> +	 */
>> +	if (::ioctl(fd_, request, argp) < 0)
>> +		return -errno;
> 
> I /really/ like this ... but note how many of the call sites for
> V4L2Device::ioctl() still work with the -errno fuss, which should now
> just deal directly with 'ret' where it's used.
> 
> 'man ioctl' states:
> 
> RETURN VALUE
>        Usually,  on  success zero is returned.  A few ioctl() requests
>        use the return value as an output parameter and return a
>        nonnegative value on success.  On error, -1 is returned, and
>        errno is set appropriately.
> 
> 
> I really like simplifying the -1, errno check pattern that is
> everywhere. But do we need to be sure we'll never need the return code
> of the ioctl?
> 
> (I don't think we do - and we /could/ have a different call for that if
> necessary)
> 
> 
> 
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * \var V4L2Device::fd_
>> + * \brief The V4L2 device node file descriptor
>> + *
>> + * The file descriptor is initialized to -1 and reset to this value once
>> + * the device node gets closed.
>> + */
>> +
>> +} /* namespace libcamera */
>> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
>> index 6681c1920065..b1e5f559b944 100644
>> --- a/src/libcamera/v4l2_subdevice.cpp
>> +++ b/src/libcamera/v4l2_subdevice.cpp
>> @@ -29,7 +29,7 @@
>>  
>>  namespace libcamera {
>>  
>> -LOG_DEFINE_CATEGORY(V4L2Subdev)
>> +LOG_DECLARE_CATEGORY(V4L2)
>>  
>>  /**
>>   * \struct V4L2SubdeviceFormat
>> @@ -102,7 +102,7 @@ const std::string V4L2SubdeviceFormat::toString() const
>>   * path
>>   */
>>  V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
>> -	: entity_(entity), fd_(-1)
>> +	: V4L2Device(), entity_(entity)
>>  {
>>  }
>>  
>> @@ -117,45 +117,7 @@ V4L2Subdevice::~V4L2Subdevice()
>>   */
>>  int V4L2Subdevice::open()
>>  {
>> -	int ret;
>> -
>> -	if (isOpen()) {
>> -		LOG(V4L2Subdev, Error) << "Device already open";
>> -		return -EBUSY;
>> -	}
>> -
>> -	ret = ::open(entity_->deviceNode().c_str(), O_RDWR);
>> -	if (ret < 0) {
>> -		ret = -errno;
>> -		LOG(V4L2Subdev, Error)
>> -			<< "Failed to open V4L2 subdevice '"
>> -			<< entity_->deviceNode() << "': " << strerror(-ret);
>> -		return ret;
>> -	}
>> -	fd_ = ret;
>> -
>> -	return 0;
>> -}
>> -
>> -/**
>> - * \brief Check if the subdevice is open
>> - * \return True if the subdevice is open, false otherwise
>> - */
>> -bool V4L2Subdevice::isOpen() const
>> -{
>> -	return fd_ != -1;
>> -}
>> -
>> -/**
>> - * \brief Close the subdevice, releasing any resources acquired by open()
>> - */
>> -void V4L2Subdevice::close()
>> -{
>> -	if (!isOpen())
>> -		return;
>> -
>> -	::close(fd_);
>> -	fd_ = -1;
>> +	return V4L2Device::open(entity_->deviceNode(), O_RDWR);
>>  }
>>  
>>  /**
>> @@ -207,7 +169,7 @@ FormatEnum V4L2Subdevice::formats(unsigned int pad)
>>  	int ret;
>>  
>>  	if (pad >= entity_->pads().size()) {
>> -		LOG(V4L2Subdev, Error) << "Invalid pad: " << pad;
>> +		LOG(V4L2, Error) << "Invalid pad: " << pad;
>>  		return formatMap;
>>  	}
>>  
>> @@ -215,7 +177,7 @@ FormatEnum V4L2Subdevice::formats(unsigned int pad)
>>  	mbusEnum.index = 0;
>>  	mbusEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>>  	while (true) {
>> -		ret = ioctl(fd_, VIDIOC_SUBDEV_ENUM_MBUS_CODE, &mbusEnum);
>> +		ret = ioctl(VIDIOC_SUBDEV_ENUM_MBUS_CODE, &mbusEnum);
>>  		if (ret)
>>  			break;
>>  
>> @@ -229,7 +191,7 @@ FormatEnum V4L2Subdevice::formats(unsigned int pad)
>>  
>>  	if (ret && (errno != EINVAL && errno != ENOTTY)) {
>>  		ret = -errno;
>> -		LOG(V4L2Subdev, Error)
>> +		LOG(V4L2, Error)
>>  			<< "Unable to enumerate formats on pad " << pad
>>  			<< ": " << strerror(-ret);
>>  		formatMap.clear();
>> @@ -250,10 +212,10 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
>>  	subdevFmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>>  	subdevFmt.pad = pad;
>>  
>> -	int ret = ioctl(fd_, VIDIOC_SUBDEV_G_FMT, &subdevFmt);
>> +	int ret = ioctl(VIDIOC_SUBDEV_G_FMT, &subdevFmt);
>>  	if (ret) {
>>  		ret = -errno;
>> -		LOG(V4L2Subdev, Error)
>> +		LOG(V4L2, Error)
>>  			<< "Unable to get format on pad " << pad
>>  			<< ": " << strerror(-ret);
>>  		return ret;
>> @@ -286,10 +248,10 @@ int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format)
>>  	subdevFmt.format.height = format->size.height;
>>  	subdevFmt.format.code = format->mbus_code;
>>  
>> -	int ret = ioctl(fd_, VIDIOC_SUBDEV_S_FMT, &subdevFmt);
>> +	int ret = ioctl(VIDIOC_SUBDEV_S_FMT, &subdevFmt);
>>  	if (ret) {
>>  		ret = -errno;
>> -		LOG(V4L2Subdev, Error)
>> +		LOG(V4L2, Error)
>>  			<< "Unable to set format on pad " << pad
>>  			<< ": " << strerror(-ret);
>>  		return ret;
>> @@ -339,7 +301,7 @@ int V4L2Subdevice::enumPadSizes(unsigned int pad,unsigned int code,
>>  	sizeEnum.code = code;
>>  	sizeEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>>  	while (true) {
>> -		ret = ioctl(fd_, VIDIOC_SUBDEV_ENUM_FRAME_SIZE, &sizeEnum);
>> +		ret = ioctl(VIDIOC_SUBDEV_ENUM_FRAME_SIZE, &sizeEnum);
>>  		if (ret)
>>  			break;
>>  
>> @@ -351,7 +313,7 @@ int V4L2Subdevice::enumPadSizes(unsigned int pad,unsigned int code,
>>  
>>  	if (ret && (errno != EINVAL && errno != ENOTTY)) {
>>  		ret = -errno;
>> -		LOG(V4L2Subdev, Error)
>> +		LOG(V4L2, Error)
>>  			<< "Unable to enumerate sizes on pad " << pad
>>  			<< ": " << strerror(-ret);
>>  		sizes->clear();
>> @@ -377,10 +339,10 @@ int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
>>  	sel.r.width = rect->w;
>>  	sel.r.height = rect->h;
>>  
>> -	int ret = ioctl(fd_, VIDIOC_SUBDEV_S_SELECTION, &sel);
>> +	int ret = ioctl(VIDIOC_SUBDEV_S_SELECTION, &sel);
>>  	if (ret < 0) {
>>  		ret = -errno;
>> -		LOG(V4L2Subdev, Error)
>> +		LOG(V4L2, Error)
>>  			<< "Unable to set rectangle " << target << " on pad "
>>  			<< pad << ": " << strerror(-ret);
>>  		return ret;
>> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
>> index 8957cf8f97d3..14e711d5dde3 100644
>> --- a/src/libcamera/v4l2_videodevice.cpp
>> +++ b/src/libcamera/v4l2_videodevice.cpp
>> @@ -30,7 +30,7 @@
>>   */
>>  namespace libcamera {
>>  
>> -LOG_DEFINE_CATEGORY(V4L2)
>> +LOG_DECLARE_CATEGORY(V4L2)
>>  
>>  /**
>>   * \struct V4L2Capability
>> @@ -270,7 +270,7 @@ const std::string V4L2DeviceFormat::toString() const
>>   * \param[in] deviceNode The file-system path to the video device node
>>   */
>>  V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
>> -	: deviceNode_(deviceNode), fd_(-1), bufferPool_(nullptr),
>> +	: V4L2Device(), deviceNode_(deviceNode), bufferPool_(nullptr),
>>  	  queuedBuffersCount_(0), fdEvent_(nullptr)
>>  {
>>  	/*
>> @@ -305,21 +305,11 @@ int V4L2VideoDevice::open()
>>  {
>>  	int ret;
>>  
>> -	if (isOpen()) {
>> -		LOG(V4L2, Error) << "Device already open";
>> -		return -EBUSY;
>> -	}
>> -
>> -	ret = ::open(deviceNode_.c_str(), O_RDWR | O_NONBLOCK);
>> -	if (ret < 0) {
>> -		ret = -errno;
>> -		LOG(V4L2, Error)
>> -			<< "Failed to open V4L2 device: " << strerror(-ret);
>> +	ret = V4L2Device::open(deviceNode_, O_RDWR | O_NONBLOCK);
>> +	if (ret < 0)
>>  		return ret;
>> -	}
>> -	fd_ = ret;
>>  
>> -	ret = ioctl(fd_, VIDIOC_QUERYCAP, &caps_);
>> +	ret = ioctl(VIDIOC_QUERYCAP, &caps_);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>> @@ -342,20 +332,20 @@ int V4L2VideoDevice::open()
>>  	 * (POLLIN), and write notifications for OUTPUT devices (POLLOUT).
>>  	 */
>>  	if (caps_.isVideoCapture()) {
>> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Read);
>> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Read);
>>  		bufferType_ = caps_.isMultiplanar()
>>  			    ? V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE
>>  			    : V4L2_BUF_TYPE_VIDEO_CAPTURE;
>>  	} else if (caps_.isVideoOutput()) {
>> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Write);
>> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Write);
>>  		bufferType_ = caps_.isMultiplanar()
>>  			    ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE
>>  			    : V4L2_BUF_TYPE_VIDEO_OUTPUT;
>>  	} else if (caps_.isMetaCapture()) {
>> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Read);
>> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Read);
>>  		bufferType_ = V4L2_BUF_TYPE_META_CAPTURE;
>>  	} else if (caps_.isMetaOutput()) {
>> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Write);
>> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Write);
>>  		bufferType_ = V4L2_BUF_TYPE_META_OUTPUT;
>>  	} else {
>>  		LOG(V4L2, Error) << "Device is not a supported type";
>> @@ -368,28 +358,16 @@ int V4L2VideoDevice::open()
>>  	return 0;
>>  }
>>  
>> -/**
>> - * \brief Check if device is successfully opened
>> - * \return True if the device is open, false otherwise
>> - */
>> -bool V4L2VideoDevice::isOpen() const
>> -{
>> -	return fd_ != -1;
>> -}
>> -
>>  /**
>>   * \brief Close the device, releasing any resources acquired by open()
>>   */
>>  void V4L2VideoDevice::close()
>>  {
>> -	if (fd_ < 0)
>> +	if (fd() < 0)
>>  		return;
>>  
>>  	releaseBuffers();
>>  	delete fdEvent_;
>> -
>> -	::close(fd_);
>> -	fd_ = -1;
>>  }
>>  
>>  /**
>> @@ -462,7 +440,7 @@ int V4L2VideoDevice::getFormatMeta(V4L2DeviceFormat *format)
>>  	int ret;
>>  
>>  	v4l2Format.type = bufferType_;
>> -	ret = ioctl(fd_, VIDIOC_G_FMT, &v4l2Format);
>> +	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
> 
> 
> I really like that ioctl now knows about the FD internally and thus is
> simpler :)
> 
> "do this action with this structure..."
> 
> 
>>  	if (ret) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
> 
> This is an example of things that I think should now be:
> 
> ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
> if (ret) {
> 	LOG(V4L2, Error) << "Unable to get format: " << strerror(ret);
> 	...
> }
> 
> That probably applies to all uses of V4L2Device::ioctl()
> 
> 
>> @@ -488,7 +466,7 @@ int V4L2VideoDevice::setFormatMeta(V4L2DeviceFormat *format)
>>  	v4l2Format.type = bufferType_;
>>  	pix->dataformat = format->fourcc;
>>  	pix->buffersize = format->planes[0].size;
>> -	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
>> +	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
>>  	if (ret) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
>> @@ -516,7 +494,7 @@ int V4L2VideoDevice::getFormatMultiplane(V4L2DeviceFormat *format)
>>  	int ret;
>>  
>>  	v4l2Format.type = bufferType_;
>> -	ret = ioctl(fd_, VIDIOC_G_FMT, &v4l2Format);
>> +	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
>>  	if (ret) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
>> @@ -554,7 +532,7 @@ int V4L2VideoDevice::setFormatMultiplane(V4L2DeviceFormat *format)
>>  		pix->plane_fmt[i].sizeimage = format->planes[i].size;
>>  	}
>>  
>> -	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
>> +	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
>>  	if (ret) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
>> @@ -584,7 +562,7 @@ int V4L2VideoDevice::getFormatSingleplane(V4L2DeviceFormat *format)
>>  	int ret;
>>  
>>  	v4l2Format.type = bufferType_;
>> -	ret = ioctl(fd_, VIDIOC_G_FMT, &v4l2Format);
>> +	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
>>  	if (ret) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
>> @@ -613,7 +591,7 @@ int V4L2VideoDevice::setFormatSingleplane(V4L2DeviceFormat *format)
>>  	pix->pixelformat = format->fourcc;
>>  	pix->bytesperline = format->planes[0].bpl;
>>  	pix->field = V4L2_FIELD_NONE;
>> -	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
>> +	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
>>  	if (ret) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
>> @@ -643,7 +621,7 @@ int V4L2VideoDevice::requestBuffers(unsigned int count)
>>  	rb.type = bufferType_;
>>  	rb.memory = memoryType_;
>>  
>> -	ret = ioctl(fd_, VIDIOC_REQBUFS, &rb);
>> +	ret = ioctl(VIDIOC_REQBUFS, &rb);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>> @@ -695,7 +673,7 @@ int V4L2VideoDevice::exportBuffers(BufferPool *pool)
>>  		buf.length = VIDEO_MAX_PLANES;
>>  		buf.m.planes = planes;
>>  
>> -		ret = ioctl(fd_, VIDIOC_QUERYBUF, &buf);
>> +		ret = ioctl(VIDIOC_QUERYBUF, &buf);
>>  		if (ret < 0) {
>>  			ret = -errno;
>>  			LOG(V4L2, Error)
>> @@ -748,7 +726,7 @@ int V4L2VideoDevice::createPlane(Buffer *buffer, unsigned int planeIndex,
>>  	expbuf.plane = planeIndex;
>>  	expbuf.flags = O_RDWR;
>>  
>> -	ret = ioctl(fd_, VIDIOC_EXPBUF, &expbuf);
>> +	ret = ioctl(VIDIOC_EXPBUF, &expbuf);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>> @@ -855,7 +833,7 @@ int V4L2VideoDevice::queueBuffer(Buffer *buffer)
>>  
>>  	LOG(V4L2, Debug) << "Queueing buffer " << buf.index;
>>  
>> -	ret = ioctl(fd_, VIDIOC_QBUF, &buf);
>> +	ret = ioctl(VIDIOC_QBUF, &buf);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>> @@ -892,7 +870,7 @@ Buffer *V4L2VideoDevice::dequeueBuffer()
>>  		buf.m.planes = planes;
>>  	}
>>  
>> -	ret = ioctl(fd_, VIDIOC_DQBUF, &buf);
>> +	ret = ioctl(VIDIOC_DQBUF, &buf);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>> @@ -952,7 +930,7 @@ int V4L2VideoDevice::streamOn()
>>  {
>>  	int ret;
>>  
>> -	ret = ioctl(fd_, VIDIOC_STREAMON, &bufferType_);
>> +	ret = ioctl(VIDIOC_STREAMON, &bufferType_);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>> @@ -975,7 +953,7 @@ int V4L2VideoDevice::streamOff()
>>  {
>>  	int ret;
>>  
>> -	ret = ioctl(fd_, VIDIOC_STREAMOFF, &bufferType_);
>> +	ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
>>  	if (ret < 0) {
>>  		ret = -errno;
>>  		LOG(V4L2, Error)
>>
> 

-- 
Regards
--
Kieran


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