Re: [PATCH 1/2] media/v4l2-ctrls: Always run s_ctrl on volatile ctrls

From: Hans Verkuil
Date: Tue Feb 17 2015 - 09:49:05 EST


On 02/17/2015 03:41 PM, Ricardo Ribalda Delgado wrote:
> Volatile controls can change their value outside the v4l-ctrl framework.
> We should ignore the cached written value of the ctrl when evaluating if
> we should run s_ctrl.
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-ctrls.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 45c5b47..693a473 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -1609,6 +1609,12 @@ static int cluster_changed(struct v4l2_ctrl *master)
>
> if (ctrl == NULL)
> continue;
> +
> + if (ctrl->flags & V4L2_CTRL_FLAG_VOLATILE) {
> + changed = true;

You need to explicitly set 'ctrl->has_changed = false;' here.

And a comment why it is set to false (to prevent sending the event) is
needed as well since it would look a bit weird otherwise.

Regards,

Hans

> + continue;
> + }
> +
> for (idx = 0; !ctrl_changed && idx < ctrl->elems; idx++)
> ctrl_changed = !ctrl->type_ops->equal(ctrl, idx,
> ctrl->p_cur, ctrl->p_new);
>

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