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SubjectRe: [PATCH v2 1/5] media/v4l2-ctrls: volatiles should not generate CH_VALUE
Date
Hi Ricardo,

Thank you for the patch, and sorry for the late review (so late that the patch
has already been merged).

On Friday 20 March 2015 14:30:46 Ricardo Ribalda Delgado wrote:
> Volatile controls should not generate CH_VALUE events.

What's the rationale for that ? I would actually expect the value change
events to be more useful for volatile controls than non-volatile controls.
Volatile controls can have their value changed by the hardware without
software intervention, and it makes sense to me to report that to userspace.

> Set has_changed to false to prevent this happening.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
> v2: By Sakari Ailus <sakari.ailus@linux.intel.com>
>
> Fix CodeStyle (sorry :S)
> drivers/media/v4l2-core/v4l2-ctrls.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> b/drivers/media/v4l2-core/v4l2-ctrls.c index 45c5b47..2ebc33e 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -1609,6 +1609,15 @@ static int cluster_changed(struct v4l2_ctrl *master)
>
> if (ctrl == NULL)
> continue;
> + /*
> + * Set has_changed to false to avoid generating
> + * the event V4L2_EVENT_CTRL_CH_VALUE
> + */
> + if (ctrl->flags & V4L2_CTRL_FLAG_VOLATILE) {
> + ctrl->has_changed = false;
> + continue;
> + }
> +
> for (idx = 0; !ctrl_changed && idx < ctrl->elems; idx++)
> ctrl_changed = !ctrl->type_ops->equal(ctrl, idx,
> ctrl->p_cur, ctrl->p_new);

--
Regards,

Laurent Pinchart



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