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>
---
I have a control that tells the user when there has been a external trigger
overrun. (Trigger while processing old image). This is a volatile control.
The user writes 0 to the control, to ack the error condition, and clear the
hardware flag.
Unfortunately, it only works one time, because the next time the user writes
a zero to the control cluster_changed returns false.
I think on volatile controls it is safer to run s_ctrl twice than missing a
valid s_ctrl.
I know I am abusing a bit the API for this :P, but I also believe that the
semantic here is a bit confusing.
drivers/media/v4l2-core/v4l2-ctrls.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 45c5b47..3d0c7f4 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1605,7 +1605,7 @@ static int cluster_changed(struct v4l2_ctrl *master)
for (i = 0; i < master->ncontrols; i++) {
struct v4l2_ctrl *ctrl = master->cluster[i];
- bool ctrl_changed = false;
+ bool ctrl_changed = ctrl->flags & V4L2_CTRL_FLAG_VOLATILE;
if (ctrl == NULL)
continue;
--
2.1.4
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