Hello, This RFC patch series is a first attempt at adding support for passing statistics data to userspace using a standard API. The two core requirements for statistics data capture is zero-copy and decoupling statistics buffers from images buffers, in order to make statistics data available to userspace as soon as they're captured. For those reasons the early consensus we have reached is to use a video device node with a buffer queue to pass statistics buffers using the V4L2 API. This patch series extends support for statistics data to the more generic concept of meta-data. It introduces a new video device type for meta-data, along with a new format type and a new buffer type. Patch 1/2 adds support for the meta-data video device type and contains documentation that explains the concept in more details. Patch 2/2 is an example of how a meta-data format can be defined and documented to support histogram data generated by the Renesas R-Car VSP histogram engine (HGO). Laurent Pinchart (2): v4l: Add meta-data video device type v4l: Define a pixel format for the R-Car VSP1 1-D histogram engine Documentation/DocBook/media/v4l/dev-meta.xml | 100 +++++++ .../DocBook/media/v4l/pixfmt-meta-vsp1-hgo.xml | 307 +++++++++++++++++++++ Documentation/DocBook/media/v4l/pixfmt.xml | 9 + Documentation/DocBook/media/v4l/v4l2.xml | 1 + drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 19 ++ drivers/media/v4l2-core/v4l2-dev.c | 21 +- drivers/media/v4l2-core/v4l2-ioctl.c | 40 +++ drivers/media/v4l2-core/videobuf2-v4l2.c | 3 + include/media/v4l2-dev.h | 3 +- include/media/v4l2-ioctl.h | 8 + include/uapi/linux/media.h | 2 + include/uapi/linux/videodev2.h | 17 ++ 12 files changed, 528 insertions(+), 2 deletions(-) create mode 100644 Documentation/DocBook/media/v4l/dev-meta.xml create mode 100644 Documentation/DocBook/media/v4l/pixfmt-meta-vsp1-hgo.xml -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
