On Sat, Mar 11, 2017 at 12:31:24PM -0800, Steve Longerbeam wrote:

On 03/11/2017 05:41 AM, Sakari Ailus wrote:

quoted

Hi Steve,

On Thu, Mar 09, 2017 at 08:52:58PM -0800, Steve Longerbeam wrote:

quoted

If the pads on both sides of a link specify a frame interval, then
those frame intervals should match. Create the exported function
v4l2_subdev_link_validate_frame_interval() to verify this. This
function can be called in a subdevice's media_entity_operations
or v4l2_subdev_pad_ops link_validate callbacks.

Signed-off-by: Steve Longerbeam <redacted>

If your only goal is to configure frame dropping on a sub-device, I suggest
to implement s_frame_interval() on the pads of that sub-device only. The
frames are then dropped according to the configured frame rates between the
sink and source pads. Say, configuring sink for 1/30 s and source 1/15 would
drop half of the incoming frames.

Considering that supporting specific frame interval on most sub-devices adds
no value or is not the interface through which it the frame rate configured,
I think it is overkill to change the link validation to expect otherwise.

Well, while I think this function might still have validity in the future, I
do agree with you that a subdev that has no control over
frame rate has no business implementing the get|set ops.

In the imx-media subdevs, the only one that can affect frame rate (via
frame skipping) is the CSI. So I'll go ahead and remove the
[gs]_frame_interval ops from the others. I can remove this patch as
a result.

Agreed.

-- 
Sakari Ailus
e-mail: sakari.ailus at iki.fi	XMPP: sailus at retiisi.org.uk