Hi Tomasz,
Thanks for the patch.
On Tuesday 10 April 2012 15:10:35 Tomasz Stanislawski wrote:
> This patch adds extension to V4L2 api. It allow to export a mmap buffer as
> file descriptor. New ioctl VIDIOC_EXPBUF is added. It takes a buffer offset
> used by mmap and return a file descriptor on success.
>
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
This mostly looks good to me, except for the lack of documentation of course
:-)
> ---
> drivers/media/video/v4l2-compat-ioctl32.c | 1 +
> drivers/media/video/v4l2-ioctl.c | 7 +++++++
> include/linux/videodev2.h | 23 +++++++++++++++++++++++
> include/media/v4l2-ioctl.h | 2 ++
> 4 files changed, 33 insertions(+), 0 deletions(-)
[snip]
> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> index 38259bf..627e235 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -680,6 +680,28 @@ struct v4l2_buffer {
> #define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE 0x0800
> #define V4L2_BUF_FLAG_NO_CACHE_CLEAN 0x1000
>
> +/**
> + * struct v4l2_exportbuffer - export of video buffer as DMABUF file
> descriptor
> + *
> + * @fd: file descriptor associated with DMABUF (set by driver)
> + * @mem_offset: a "cookie" that is passed to mmap() as offset
I wouldn't mention mmap() here, as that's unrelated to the DMABUF exporter
API. Maybe something like
"buffer memory offset as returned by VIDIOC_QUERYBUF in struct
v4l2_buffer::m.offset (for single-plane formats) or v4l2_plane::m.offset (for
multi-planar formats)"
> + * @flags: flags for newly created file, currently only O_CLOEXEC is
> + * supported, refer to manual of open syscall for more details
> + *
> + * Contains data used for exporting a video buffer as DMABUF file
> + *descriptor. Uses the same 'cookie' as mmap() syscall.
The buffer is identified by a 'cookie' returned by VIDIOC_QUERYBUF (identical
to the cookie used to mmap() the buffer to userspace).
> All reserved fields
> +*must be set to zero. The field reserved0 is expected to become a structure
> + *'type' allowing an alternative layout of the structure content. Therefore
> + * this field should not be used for any other extensions.
> + */
> +struct v4l2_exportbuffer {
> + __u32 fd;
> + __u32 reserved0;
> + __u32 mem_offset;
> + __u32 flags;
> + __u32 reserved[12];
> +};
--
Regards,
Laurent Pinchart
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