[PATCH 7/9] libcamera: v4l2_subdevice: Add stream support to get/set functions
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Feb 28 12:24:23 CET 2024
On Wed, Feb 28, 2024 at 12:18:47PM +0100, Jacopo Mondi wrote:
> On Wed, Feb 28, 2024 at 12:51:19PM +0200, Laurent Pinchart wrote:
> > On Tue, Feb 27, 2024 at 05:48:35PM +0100, Jacopo Mondi wrote:
> > > On Tue, Feb 27, 2024 at 04:09:51PM +0200, Laurent Pinchart wrote:
> > > > Extend the V4L2Subdevice API with stream support for the functions that
> > > > get and set formats and selection rectangles. Add a Stream structure to
> > > > identify a subdev pad and stream, and use it to extend the V4L2Subdevice
> > > > functions that get and set formats and selection rectangles with stream
> > > > support.
> > > >
> > > > To preserve the existing pad-based API, implement overloaded functions
> > > > that wrap the new stream-based API. This allows callers that are not
> > > > stream-aware to use a simpler pad-based API, instead of having to
> > > > explicitly set the stream number to 0 in all API calls.
> > > >
> > > > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > > > ---
> > > > include/libcamera/internal/v4l2_subdevice.h | 41 +++-
> > > > src/libcamera/v4l2_subdevice.cpp | 232 ++++++++++++++------
> > > > 2 files changed, 202 insertions(+), 71 deletions(-)
> > > >
> > > > diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
> > > > index 1115cfa55594..65003394a984 100644
> > > > --- a/include/libcamera/internal/v4l2_subdevice.h
> > > > +++ b/include/libcamera/internal/v4l2_subdevice.h
> > > > @@ -80,6 +80,11 @@ public:
> > > > ActiveFormat = V4L2_SUBDEV_FORMAT_ACTIVE,
> > > > };
> > > >
> > > > + struct Stream {
> > > > + unsigned int pad;
> > > > + unsigned int stream;
> > > > + };
> > > > +
> > > > class Routing : public std::vector<struct v4l2_subdev_route>
> > > > {
> > > > public:
> > > > @@ -93,17 +98,39 @@ public:
> > > >
> > > > const MediaEntity *entity() const { return entity_; }
> > > >
> > > > - int getSelection(unsigned int pad, unsigned int target,
> > > > + int getSelection(const Stream &stream, unsigned int target,
> > > > Rectangle *rect);
> > > > - int setSelection(unsigned int pad, unsigned int target,
> > > > + int getSelection(unsigned int pad, unsigned int target, Rectangle *rect)
> > > > + {
> > > > + return getSelection({ pad, 0 }, target, rect);
> > > > + }
> > > > + int setSelection(const Stream &stream, unsigned int target,
> > > > Rectangle *rect);
> > > > + int setSelection(unsigned int pad, unsigned int target, Rectangle *rect)
> > > > + {
> > > > + return setSelection({ pad, 0 }, target, rect);
> > > > + }
> > > >
> > > > - Formats formats(unsigned int pad);
> > > > + Formats formats(const Stream &stream);
> > > > + Formats formats(unsigned int pad)
> > > > + {
> > > > + return formats({ pad, 0 });
> > > > + }
> > > >
> > > > + int getFormat(const Stream &stream, V4L2SubdeviceFormat *format,
> > > > + Whence whence = ActiveFormat);
> > > > int getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > + Whence whence = ActiveFormat)
> > > > + {
> > > > + return getFormat({ pad, 0 }, format, whence);
> > > > + }
> > > > + int setFormat(const Stream &stream, V4L2SubdeviceFormat *format,
> > > > Whence whence = ActiveFormat);
> > > > int setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > - Whence whence = ActiveFormat);
> > > > + Whence whence = ActiveFormat)
> > > > + {
> > > > + return setFormat({ pad, 0 }, format, whence);
> > > > + }
> > > >
> > > > int getRouting(Routing *routing, Whence whence = ActiveFormat);
> > > > int setRouting(Routing *routing, Whence whence = ActiveFormat);
> > > > @@ -123,8 +150,8 @@ private:
> > > > std::optional<ColorSpace>
> > > > toColorSpace(const v4l2_mbus_framefmt &format) const;
> > > >
> > > > - std::vector<unsigned int> enumPadCodes(unsigned int pad);
> > > > - std::vector<SizeRange> enumPadSizes(unsigned int pad,
> > > > + std::vector<unsigned int> enumPadCodes(const Stream &stream);
> > > > + std::vector<SizeRange> enumPadSizes(const Stream &stream,
> > > > unsigned int code);
> > > >
> > > > const MediaEntity *entity_;
> > > > @@ -133,4 +160,6 @@ private:
> > > > struct V4L2SubdeviceCapability caps_;
> > > > };
> > > >
> > > > +std::ostream &operator<<(std::ostream &out, const V4L2Subdevice::Stream &stream);
> > > > +
> > > > } /* namespace libcamera */
> > > > diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> > > > index 19ddecf714c6..efe8b0f793e9 100644
> > > > --- a/src/libcamera/v4l2_subdevice.cpp
> > > > +++ b/src/libcamera/v4l2_subdevice.cpp
> > > > @@ -814,6 +814,35 @@ std::ostream &operator<<(std::ostream &out, const V4L2SubdeviceFormat &f)
> > > > * \brief The format operation applies to TRY formats
> > > > */
> > > >
> > > > +/**
> > > > + * \class V4L2Subdevice::Stream
> > > > + * \brief V4L2 subdevice stream
> > > > + *
> > > > + * This class identifies a subdev stream, by bundling the pad number with the
> > > > + * stream number. It is used in all stream-aware functions of the V4L2Subdevice
> > > > + * class to identify the stream the functions operate on.
> > > > + *
> > > > + * \var V4L2Subdevice::Stream::pad
> > > > + * \brief The 0-indexed pad number
> > > > + *
> > > > + * \var V4L2Subdevice::Stream::stream
> > > > + * \brief The stream number
> > > > + */
> > > > +
> > > > +/**
> > > > + * \brief Insert a text representation of a V4L2Subdevice::Stream into an
> > > > + * output stream
> > >
> > > What is the alignment rule when we break \brief ? I see different ones
> > > being used in this patch
> >
> > Good question :-) Let's decide. Does anybody have a preference between
> >
> > * \brief Insert a text representation of a V4L2Subdevice::Stream into an
> > * output stream
> >
> > (single tab after the '*', no space)
> >
> > and
> >
> > * \brief Insert a text representation of a V4L2Subdevice::Stream into an
> > * output stream
> >
> > (single space after the '*')
> >
>
> My vote for the second option, but whatever, really
>
> > ?
> >
> > > > + * \param[in] out The output stream
> > > > + * \param[in] stream The V4L2Subdevice::Stream
> > > > + * \return The output stream \a out
> > > > + */
> > > > +std::ostream &operator<<(std::ostream &out, const V4L2Subdevice::Stream &stream)
> > > > +{
> > > > + out << stream.pad << "/" << stream.stream;
> > > > +
> > > > + return out;
> > > > +}
> > > > +
> > > > /**
> > > > * \class V4L2Subdevice::Routing
> > > > * \brief V4L2 subdevice routing table
> > > > @@ -879,7 +908,10 @@ int V4L2Subdevice::open()
> > > > return ret;
> > > > }
> > > >
> > > > - /* If the subdev supports streams, enable the streams API. */
> > > > + /*
> > > > + * If the subdev supports streams, enable the streams API, and retrieve
> > > > + * and cache the routing table.
> > >
> > > Does it happen in this patch ?
> >
> > Indeed not. I was planning to do so and then didn't. I'll drop the
> > comment change.
> >
> > > > + */
> > > > if (caps_.hasStreams()) {
> > > > struct v4l2_subdev_client_capability clientCaps{};
> > > > clientCaps.capabilities = V4L2_SUBDEV_CLIENT_CAP_STREAMS;
> > > > @@ -905,7 +937,7 @@ int V4L2Subdevice::open()
> > > >
> > > > /**
> > > > * \brief Get selection rectangle \a rect for \a target
> > > > - * \param[in] pad The 0-indexed pad number the rectangle is retrieved from
> > > > + * \param[in] stream The stream the rectangle is retrieved from
> > > > * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
> > > > * \param[out] rect The retrieved selection rectangle
> > > > *
> > > > @@ -913,13 +945,14 @@ int V4L2Subdevice::open()
> > > > *
> > > > * \return 0 on success or a negative error code otherwise
> > > > */
> > > > -int V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
> > > > +int V4L2Subdevice::getSelection(const Stream &stream, unsigned int target,
> > > > Rectangle *rect)
> > > > {
> > > > struct v4l2_subdev_selection sel = {};
> > > >
> > > > sel.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> > > > - sel.pad = pad;
> > > > + sel.pad = stream.pad;
> > > > + sel.stream = stream.stream;
> > > > sel.target = target;
> > > > sel.flags = 0;
> > > >
> > > > @@ -927,7 +960,8 @@ int V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
> > > > if (ret < 0) {
> > > > LOG(V4L2, Error)
> > > > << "Unable to get rectangle " << target << " on pad "
> > > > - << pad << ": " << strerror(-ret);
> > > > + << stream.pad << "/" << stream.stream << ": "
> > >
> > > Can't you use operator<<(Stream) ?
> >
> > I'll fix it, and below too.
> >
> > > > + << strerror(-ret);
> > > > return ret;
> > > > }
> > > >
> > > > @@ -939,9 +973,20 @@ int V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
> > > > return 0;
> > > > }
> > > >
> > > > +/**
> > > > + * \fn V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
> > > > + * Rectangle *rect)
> > > > + * \brief Get selection rectangle \a rect for \a target
> > > > + * \param[in] pad The 0-indexed pad number the rectangle is retrieved from
> > > > + * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
> > > > + * \param[out] rect The retrieved selection rectangle
> > > > + *
> > > > + * \return 0 on success or a negative error code otherwise
> > > > + */
> > > > +
> > > > /**
> > > > * \brief Set selection rectangle \a rect for \a target
> > > > - * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
> > > > + * \param[in] stream The stream the rectangle is to be applied to
> > > > * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
> > > > * \param[inout] rect The selection rectangle to be applied
> > > > *
> > > > @@ -949,13 +994,14 @@ int V4L2Subdevice::getSelection(unsigned int pad, unsigned int target,
> > > > *
> > > > * \return 0 on success or a negative error code otherwise
> > > > */
> > > > -int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> > > > +int V4L2Subdevice::setSelection(const Stream &stream, unsigned int target,
> > > > Rectangle *rect)
> > > > {
> > > > struct v4l2_subdev_selection sel = {};
> > > >
> > > > sel.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> > > > - sel.pad = pad;
> > > > + sel.pad = stream.pad;
> > > > + sel.stream = stream.stream;
> > > > sel.target = target;
> > > > sel.flags = 0;
> > > >
> > > > @@ -968,7 +1014,8 @@ int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> > > > if (ret < 0) {
> > > > LOG(V4L2, Error)
> > > > << "Unable to set rectangle " << target << " on pad "
> > > > - << pad << ": " << strerror(-ret);
> > > > + << stream.pad << "/" << stream.stream << ": "
> > >
> > > ditto
> > >
> > > > + << strerror(-ret);
> > > > return ret;
> > > > }
> > > >
> > > > @@ -979,26 +1026,40 @@ int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> > > >
> > > > return 0;
> > > > }
> > > > +
> > > > /**
> > > > - * \brief Enumerate all media bus codes and frame sizes on a \a pad
> > > > - * \param[in] pad The 0-indexed pad number to enumerate formats on
> > > > + * \fn V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> > > > + * Rectangle *rect)
> > > > + * \brief Set selection rectangle \a rect for \a target
> > > > + * \param[in] pad The 0-indexed pad number the rectangle is to be applied to
> > > > + * \param[in] target The selection target defined by the V4L2_SEL_TGT_* flags
> > > > + * \param[inout] rect The selection rectangle to be applied
> > > > + *
> > > > + * \todo Define a V4L2SelectionTarget enum for the selection target
> > > > + *
> > > > + * \return 0 on success or a negative error code otherwise
> > > > + */
> > > > +
> > > > +/**
> > > > + * \brief Enumerate all media bus codes and frame sizes on a \a stream
> > > > + * \param[in] stream The stream to enumerate formats for
> > > > *
> > > > * Enumerate all media bus codes and frame sizes supported by the subdevice on
> > > > - * a \a pad.
> > > > + * a \a stream.
> > > > *
> > > > * \return A list of the supported device formats
> > > > */
> > > > -V4L2Subdevice::Formats V4L2Subdevice::formats(unsigned int pad)
> > > > +V4L2Subdevice::Formats V4L2Subdevice::formats(const Stream &stream)
> > > > {
> > > > Formats formats;
> > > >
> > > > - if (pad >= entity_->pads().size()) {
> > > > - LOG(V4L2, Error) << "Invalid pad: " << pad;
> > > > + if (stream.pad >= entity_->pads().size()) {
> > > > + LOG(V4L2, Error) << "Invalid pad: " << stream.pad;
> > > > return {};
> > > > }
> > > >
> > > > - for (unsigned int code : enumPadCodes(pad)) {
> > > > - std::vector<SizeRange> sizes = enumPadSizes(pad, code);
> > > > + for (unsigned int code : enumPadCodes(stream)) {
> > > > + std::vector<SizeRange> sizes = enumPadSizes(stream, code);
> > > > if (sizes.empty())
> > > > return {};
> > > >
> > > > @@ -1006,7 +1067,7 @@ V4L2Subdevice::Formats V4L2Subdevice::formats(unsigned int pad)
> > > > if (!inserted.second) {
> > > > LOG(V4L2, Error)
> > > > << "Could not add sizes for media bus code "
> > > > - << code << " on pad " << pad;
> > > > + << code << " on pad " << stream.pad;
> > > > return {};
> > > > }
> > > > }
> > > > @@ -1014,6 +1075,17 @@ V4L2Subdevice::Formats V4L2Subdevice::formats(unsigned int pad)
> > > > return formats;
> > > > }
> > > >
> > > > +/**
> > > > + * \fn V4L2Subdevice::formats(unsigned int pad)
> > > > + * \brief Enumerate all media bus codes and frame sizes on a \a pad
> > > > + * \param[in] pad The 0-indexed pad number to enumerate formats on
> > > > + *
> > > > + * Enumerate all media bus codes and frame sizes supported by the subdevice on
> > > > + * a \a pad
> > > > + *
> > > > + * \return A list of the supported device formats
> > > > + */
> > > > +
> > > > std::optional<ColorSpace> V4L2Subdevice::toColorSpace(const v4l2_mbus_framefmt &format) const
> > > > {
> > > > /*
> > > > @@ -1045,25 +1117,26 @@ std::optional<ColorSpace> V4L2Subdevice::toColorSpace(const v4l2_mbus_framefmt &
> > > > }
> > > >
> > > > /**
> > > > - * \brief Retrieve the image format set on one of the V4L2 subdevice pads
> > > > - * \param[in] pad The 0-indexed pad number the format is to be retrieved from
> > > > + * \brief Retrieve the image format set on one of the V4L2 subdevice streams
> > > > + * \param[in] stream The stream the format is to be retrieved from
> > > > * \param[out] format The image bus format
> > > > * \param[in] whence The format to get, \ref V4L2Subdevice::ActiveFormat
> > > > * "ActiveFormat" or \ref V4L2Subdevice::TryFormat "TryFormat"
> > > > * \return 0 on success or a negative error code otherwise
> > > > */
> > > > -int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > +int V4L2Subdevice::getFormat(const Stream &stream, V4L2SubdeviceFormat *format,
> > > > Whence whence)
> > > > {
> > > > struct v4l2_subdev_format subdevFmt = {};
> > > > subdevFmt.which = whence;
> > > > - subdevFmt.pad = pad;
> > > > + subdevFmt.pad = stream.pad;
> > > > + subdevFmt.stream = stream.stream;
> > > >
> > > > int ret = ioctl(VIDIOC_SUBDEV_G_FMT, &subdevFmt);
> > > > if (ret) {
> > > > LOG(V4L2, Error)
> > > > - << "Unable to get format on pad " << pad
> > > > - << ": " << strerror(-ret);
> > > > + << "Unable to get format on pad " << stream.pad << "/"
> > > > + << stream.stream << ": " << strerror(-ret);
> > > > return ret;
> > > > }
> > > >
> > > > @@ -1076,6 +1149,66 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > }
> > > >
> > > > /**
> > > > + * \fn V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > + * Whence whence)
> > > > + * \brief Retrieve the image format set on one of the V4L2 subdevice pads
> > > > + * \param[in] pad The 0-indexed pad number the format is to be retrieved from
> > > > + * \param[out] format The image bus format
> > > > + * \param[in] whence The format to get, \ref V4L2Subdevice::ActiveFormat
> > > > + * "ActiveFormat" or \ref V4L2Subdevice::TryFormat "TryFormat"
> > > > + * \return 0 on success or a negative error code otherwise
> > > > + */
> > > > +
> > > > +/**
> > > > + * \brief Set an image format on one of the V4L2 subdevice pads
> > > > + * \param[in] stream The stream the format is to be applied to
> > > > + * \param[inout] format The image bus format to apply to the stream
> > > > + * \param[in] whence The format to set, \ref V4L2Subdevice::ActiveFormat
> > > > + * "ActiveFormat" or \ref V4L2Subdevice::TryFormat "TryFormat"
> > > > + *
> > > > + * Apply the requested image format to the desired stream and return the
> > > > + * actually applied format parameters, as getFormat() would do.
> > > > + *
> > > > + * \return 0 on success or a negative error code otherwise
> > > > + */
> > > > +int V4L2Subdevice::setFormat(const Stream &stream, V4L2SubdeviceFormat *format,
> > > > + Whence whence)
> > > > +{
> > > > + struct v4l2_subdev_format subdevFmt = {};
> > > > + subdevFmt.which = whence;
> > > > + subdevFmt.pad = stream.pad;
> > > > + subdevFmt.stream = stream.stream;
> > > > + subdevFmt.format.width = format->size.width;
> > > > + subdevFmt.format.height = format->size.height;
> > > > + subdevFmt.format.code = format->code;
> > > > + subdevFmt.format.field = V4L2_FIELD_NONE;
> > > > + if (format->colorSpace) {
> > > > + fromColorSpace(format->colorSpace, subdevFmt.format);
> > > > +
> > > > + /* The CSC flag is only applicable to source pads. */
> > > > + if (entity_->pads()[stream.pad]->flags() & MEDIA_PAD_FL_SOURCE)
> > > > + subdevFmt.format.flags |= V4L2_MBUS_FRAMEFMT_SET_CSC;
> > > > + }
> > > > +
> > > > + int ret = ioctl(VIDIOC_SUBDEV_S_FMT, &subdevFmt);
> > > > + if (ret) {
> > > > + LOG(V4L2, Error)
> > > > + << "Unable to set format on pad " << stream.pad << "/"
> > > > + << stream.stream << ": " << strerror(-ret);
> > > > + return ret;
> > > > + }
> > > > +
> > > > + format->size.width = subdevFmt.format.width;
> > > > + format->size.height = subdevFmt.format.height;
> > > > + format->code = subdevFmt.format.code;
> > > > + format->colorSpace = toColorSpace(subdevFmt.format);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/**
> > > > + * \fn V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > + * Whence whence)
> > > > * \brief Set an image format on one of the V4L2 subdevice pads
> > > > * \param[in] pad The 0-indexed pad number the format is to be applied to
> > > > * \param[inout] format The image bus format to apply to the subdevice's pad
> > > > @@ -1087,39 +1220,6 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > *
> > > > * \return 0 on success or a negative error code otherwise
> > > > */
> > > > -int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> > > > - Whence whence)
> > > > -{
> > > > - struct v4l2_subdev_format subdevFmt = {};
> > > > - subdevFmt.which = whence;
> > > > - subdevFmt.pad = pad;
> > > > - subdevFmt.format.width = format->size.width;
> > > > - subdevFmt.format.height = format->size.height;
> > > > - subdevFmt.format.code = format->code;
> > > > - subdevFmt.format.field = V4L2_FIELD_NONE;
> > > > - if (format->colorSpace) {
> > > > - fromColorSpace(format->colorSpace, subdevFmt.format);
> > > > -
> > > > - /* The CSC flag is only applicable to source pads. */
> > > > - if (entity_->pads()[pad]->flags() & MEDIA_PAD_FL_SOURCE)
> > > > - subdevFmt.format.flags |= V4L2_MBUS_FRAMEFMT_SET_CSC;
> > > > - }
> > > > -
> > > > - int ret = ioctl(VIDIOC_SUBDEV_S_FMT, &subdevFmt);
> > > > - if (ret) {
> > > > - LOG(V4L2, Error)
> > > > - << "Unable to set format on pad " << pad
> > > > - << ": " << strerror(-ret);
> > > > - return ret;
> > > > - }
> > > > -
> > > > - format->size.width = subdevFmt.format.width;
> > > > - format->size.height = subdevFmt.format.height;
> > > > - format->code = subdevFmt.format.code;
> > > > - format->colorSpace = toColorSpace(subdevFmt.format);
> > > > -
> > > > - return 0;
> > > > -}
> > > >
> > > > /**
> > > > * \brief Retrieve the subdevice's internal routing table
> > > > @@ -1282,14 +1382,15 @@ std::string V4L2Subdevice::logPrefix() const
> > > > return "'" + entity_->name() + "'";
> > > > }
> > > >
> > > > -std::vector<unsigned int> V4L2Subdevice::enumPadCodes(unsigned int pad)
> > > > +std::vector<unsigned int> V4L2Subdevice::enumPadCodes(const Stream &stream)
> > > > {
> > > > std::vector<unsigned int> codes;
> > > > int ret;
> > > >
> > > > for (unsigned int index = 0; ; index++) {
> > > > struct v4l2_subdev_mbus_code_enum mbusEnum = {};
> > > > - mbusEnum.pad = pad;
> > > > + mbusEnum.pad = stream.pad;
> > > > + mbusEnum.stream = stream.stream;
> > > > mbusEnum.index = index;
> > > > mbusEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> > > >
> > > > @@ -1302,15 +1403,15 @@ std::vector<unsigned int> V4L2Subdevice::enumPadCodes(unsigned int pad)
> > > >
> > > > if (ret < 0 && ret != -EINVAL) {
> > > > LOG(V4L2, Error)
> > > > - << "Unable to enumerate formats on pad " << pad
> > > > - << ": " << strerror(-ret);
> > > > + << "Unable to enumerate formats on pad " << stream.pad
> > > > + << "/" << stream.stream << ": " << strerror(-ret);
> > > > return {};
> > > > }
> > > >
> > > > return codes;
> > > > }
> > > >
> > > > -std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
> > > > +std::vector<SizeRange> V4L2Subdevice::enumPadSizes(const Stream &stream,
> > > > unsigned int code)
> > > > {
> > > > std::vector<SizeRange> sizes;
> > > > @@ -1319,7 +1420,8 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
> > > > for (unsigned int index = 0;; index++) {
> > > > struct v4l2_subdev_frame_size_enum sizeEnum = {};
> > > > sizeEnum.index = index;
> > > > - sizeEnum.pad = pad;
> > > > + sizeEnum.pad = stream.pad;
> > > > + sizeEnum.stream = stream.stream;
> > > > sizeEnum.code = code;
> > > > sizeEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> > > >
> > > > @@ -1333,8 +1435,8 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
> > > >
> > > > if (ret < 0 && ret != -EINVAL && ret != -ENOTTY) {
> > > > LOG(V4L2, Error)
> > > > - << "Unable to enumerate sizes on pad " << pad
> > > > - << ": " << strerror(-ret);
> > > > + << "Unable to enumerate sizes on pad " << stream.pad
> > > > + << "/" << stream.stream << ": " << strerror(-ret);
> > > > return {};
> > >
> > > The only question I have is if we should allow the V4L2Subdevice API
> > > to expose a pad-only interface or we should bite the bullet and move
> > > it to use Stream. The reason is that, a open() time
> > >
> > > /* If the subdev supports streams, enable the streams API. */
> > > if (caps_.hasStreams()) {
> > > struct v4l2_subdev_client_capability clientCaps{};
> > > clientCaps.capabilities = V4L2_SUBDEV_CLIENT_CAP_STREAMS;
> > >
> > > ret = ioctl(VIDIOC_SUBDEV_S_CLIENT_CAP, &clientCaps);
> > >
> > > And allowing users to use the pad-based API would make stream == 0
> > > implicitly. It's a lot of work though, not sure it's worth it ?
> >
> > Most devices don't use streams, that's why I decided to overload the
> > get/set functions and offer users a pad-based interface and a
> > stream-based interface. It's low-maintenance on the V4L2Subdevice side
> > (at least for now), and allows callers that deal with stream-unaware
> > devices only not to have to specify the stream number. I think the code
>
> That's my concern, not having to specify the stream number would
> default it to 0 on devices which are stream aware, as we enable the
> stream API at open() time unconditionally, and if the kernel drivers
> gets updated to use streams and the libcamera support doesn't this
> might cause unexpected issues. However, even if we make Stream usage
> mandatory, the existing implementations would have to use 0 anyway, so
> this probably doesn't make any practical difference ?
Drivers are supposed to preserve backward-compatibility. For instance, a
sensor driver that grows support for embedded data streams should use
stream 0 as the image stream. I don't think it would thus make any
practical difference.
> > gets more readable that way.
> >
> > > > }
> > > >
--
Regards,
Laurent Pinchart
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