Hi Guennadi,
On Friday 01 April 2011 10:13:02 Guennadi Liakhovetski wrote:
> A possibility to preallocate and initialise buffers of different sizes
> in V4L2 is required for an efficient implementation of asnapshot mode.
> This patch adds three new ioctl()s: VIDIOC_CREATE_BUFS,
> VIDIOC_DESTROY_BUFS, and VIDIOC_SUBMIT_BUF and defines respective data
> structures.
[snip]
> diff --git a/drivers/media/video/v4l2-ioctl.c
> b/drivers/media/video/v4l2-ioctl.c index a01ed39..b80a211 100644
> --- a/drivers/media/video/v4l2-ioctl.c
> +++ b/drivers/media/video/v4l2-ioctl.c
[snip]
> @@ -2184,6 +2187,46 @@ static long __video_do_ioctl(struct file *file,
> dbgarg(cmd, "type=0x%8.8x", sub->type);
> break;
> }
> + case VIDIOC_CREATE_BUFS:
> + {
> + struct v4l2_create_buffers *create = arg;
> +
> + if (!ops->vidioc_create_bufs)
> + break;
> + ret = check_fmt(ops, create->format.type);
> + if (ret)
> + break;
> +
> + if (create->size)
> + CLEAR_AFTER_FIELD(create, count);
Why only when create->size is > 0 ?
> + ret = ops->vidioc_create_bufs(file, fh, create);
> +
> + dbgarg(cmd, "count=%d\n", create->count);
> + break;
> + }
> + case VIDIOC_DESTROY_BUFS:
> + {
> + struct v4l2_buffer_span *span = arg;
> +
> + if (!ops->vidioc_destroy_bufs)
> + break;
> +
> + ret = ops->vidioc_destroy_bufs(file, fh, span);
> +
> + dbgarg(cmd, "count=%d", span->count);
> + break;
> + }
> + case VIDIOC_SUBMIT_BUF:
> + {
> + unsigned int *i = arg;
> +
> + if (!ops->vidioc_submit_buf)
> + break;
> + ret = ops->vidioc_submit_buf(file, fh, *i);
> + dbgarg(cmd, "index=%d", *i);
> + break;
> + }
> default:
> {
> bool valid_prio = true;
> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> index aa6c393..b6ef46e 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -1847,6 +1847,26 @@ struct v4l2_dbg_chip_ident {
> __u32 revision; /* chip revision, chip specific */
> } __attribute__ ((packed));
>
> +/* VIDIOC_DESTROY_BUFS */
> +struct v4l2_buffer_span {
> + __u32 index; /* output: buffers index...index + count - 1 have been
> created */ + __u32 count;
> + __u32 reserved[2];
> +};
> +
> +/* struct v4l2_createbuffers::flags */
> +#define V4L2_BUFFER_FLAG_NO_CACHE_INVALIDATE (1 << 0)
Shouldn't cache management be handled at submit/qbuf time instead of being a
buffer property ?
> +/* VIDIOC_CREATE_BUFS */
> +struct v4l2_create_buffers {
> + __u32 index; /* output: buffers index...index + count - 1 have been
> created */ + __u32 count;
> + __u32 flags; /* V4L2_BUFFER_FLAG_* */
> + enum v4l2_memory memory;
> + __u32 size; /* Explicit size, e.g., for compressed streams */
> + struct v4l2_format format; /* "type" is used always, the rest if size
==
> 0 */ +};
You need reserved fields here.
> +
> /*
> * I O C T L C O D E S F O R V I D E O D E V I C E S
> *
> @@ -1937,6 +1957,10 @@ struct v4l2_dbg_chip_ident {
> #define VIDIOC_SUBSCRIBE_EVENT _IOW('V', 90, struct
> v4l2_event_subscription) #define VIDIOC_UNSUBSCRIBE_EVENT _IOW('V', 91,
> struct v4l2_event_subscription)
>
> +#define VIDIOC_CREATE_BUFS _IOWR('V', 92, struct v4l2_create_buffers)
> +#define VIDIOC_DESTROY_BUFS _IOWR('V', 93, struct v4l2_buffer_span)
Just throwing an idea in here, what about using the same structure for both
ioctls ? Or even a single ioctl for both create and destroy, like we do with
REQBUFS ?
> +#define VIDIOC_SUBMIT_BUF _IOW('V', 94, int)
> +
> /* Reminder: when adding new ioctls please add support for them to
> drivers/media/video/v4l2-compat-ioctl32.c as well! */
>
[snip]
--
Regards,
Laurent Pinchart
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