On 01/23/2014 12:02 AM, Sylwester Nawrocki wrote:
> On 01/20/2014 01:45 PM, Hans Verkuil wrote:
>> From: Hans Verkuil<hans.verkuil@xxxxxxxxx>
>>
>> Add a new struct and ioctl to extend the amount of information you can
>> get for a control.
>>
>> It gives back a unit string, the range is now a s64 type, and the matrix
>> and element size can be reported through cols/rows/elem_size.
>>
>> Signed-off-by: Hans Verkuil<hans.verkuil@xxxxxxxxx>
>> ---
>> include/uapi/linux/videodev2.h | 30 ++++++++++++++++++++++++++++++
>> 1 file changed, 30 insertions(+)
>>
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 4d7782a..9e5b7d4 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -1272,6 +1272,34 @@ struct v4l2_queryctrl {
>> __u32 reserved[2];
>> };
>>
>> +/* Used in the VIDIOC_QUERY_EXT_CTRL ioctl for querying extended controls */
>> +struct v4l2_query_ext_ctrl {
>> + __u32 id;
>> + __u32 type;
>> + char name[32];
>> + char unit[32];
>
>> + union {
>> + __s64 val;
>> + __u32 reserved[4];
>> + } min;
>> + union {
>> + __s64 val;
>> + __u32 reserved[4];
>> + } max;
>> + union {
>> + __u64 val;
>> + __u32 reserved[4];
>> + } step;
>> + union {
>> + __s64 val;
>> + __u32 reserved[4];
>> + } def;
>
> Are these reserved[] arrays of any use ?
Excellent question. I'd like to know as well :-)
The idea is that if the type of the control is complex, then for certain types
it might still make sense to have a range. E.g. say that the type is v4l2_rect,
then you can define min/max/step/def v4l2_rect entries in the unions. Ditto
for a v4l2_fract (it would be nice to be able to specify the min/max allowed
scaling factors, for example).
The question is, am I over-engineering or is this the best idea since sliced
bread? Without the 'reserved' part this idea will be impossible to implement,
and I don't think it hurts to have it in.
>
>> + __u32 flags;
>> + __u32 cols, rows;
>
> nit: I would put them on separate lines and use full words.
Separate lines: no problem, but do I really have to write 'columns' in full? :-(
Regards,
Hans
>
>> + __u32 elem_size;
>> + __u32 reserved[17];
>> +};
>> +
>> /* Used in the VIDIOC_QUERYMENU ioctl for querying menu items */
>> struct v4l2_querymenu {
>> __u32 id;
>> @@ -1965,6 +1993,8 @@ struct v4l2_create_buffers {
>> Never use these in applications! */
>> #define VIDIOC_DBG_G_CHIP_INFO _IOWR('V', 102, struct v4l2_dbg_chip_info)
>>
>> +#define VIDIOC_QUERY_EXT_CTRL _IOWR('V', 103, struct v4l2_query_ext_ctrl)
>> +
>> /* Reminder: when adding new ioctls please add support for them to
>> drivers/media/video/v4l2-compat-ioctl32.c as well! */
>
> --
> Regards,
> Sylwester
>
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