Hi,
On Wed, Dec 14, 2011 at 11:34 PM, Sakari Ailus <sakari.ailus@xxxxxx> wrote:
>> + case VIDIOC_G_FD_RESULT:
>> + {
>> + struct v4l2_fd_result *fr = arg;
>> +
>> + if (!ops->vidioc_g_fd_result)
>> + break;
>> +
>> + ret = ops->vidioc_g_fd_result(file, fh, fr);
>> +
>> + dbgarg(cmd, "index=%d", fr->buf_index);
>> + break;
>> + }
>> + case VIDIOC_G_FD_COUNT:
>> + {
>> + struct v4l2_fd_count *fc = arg;
>> +
>> + if (!ops->vidioc_g_fd_count)
>> + break;
>> +
>> + ret = ops->vidioc_g_fd_count(file, fh, fc);
>> +
>> + dbgarg(cmd, "index=%d", fc->buf_index);
>> + break;
>> + }
>
> The patch description tells these ioctls may be called between... what? I'd
In fact, these ioctls should be called after return from poll.
> think such information could be better provided as events.
Yes, I still think so, but the length of returned data is variant, also
event has the 64 byte length's limitation.
> How is face detection enabled or disabled?
Currently, streaming on will trigger detection enabling, and streaming off
will trigger detection disabling.
>
> Could you detect other objects than faces?
The -v2 has been extended to detect objects, not limited to faces.
> Would events be large enough to deliver you the necessary data? We could
Looks like event(64 bytes) is not large enough to deliver the data.
> also consider delivering the information as a data structure on a separate
> plane.
Could you let me know how to do it?
>> +/**
>> + * struct v4l2_fd_result - VIDIOC_G_FD_RESULT argument
>> + * @buf_index: entry, index of v4l2_buffer for face detection
>> + * @face_cnt: return, how many faces detected from the @buf_index
>> + * @fd: return, result of faces' detection
>> + */
>> +struct v4l2_fd_result {
>> + __u32 buf_index;
>> + __u32 face_cnt;
>> + __u32 reserved[6];
>> + struct v4l2_fd_detection *fd;
>
> Aligning structure sizes to a power of two is considered to be a good
> practice.
There are many changes on these structure in -v2.
thanks,
--
Ming Lei
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