Re: [PATCH v4 4/5] media: staging: rkisp1: cap: use v4l2_pipeline_stream_{enable,disable} helpers

[Tomasz Figa <tfiga@chromium.org>]

Hi Dafna,

On Fri, May 22, 2020 at 09:55:21AM +0200, Dafna Hirschfeld wrote:
> From: Helen Koike <helen.koike@collabora.com>
> 
> Use v4l2_pipeline_stream_{enable,disable} to call .s_stream()
> subdevice callbacks through the pipeline.
> Those helpers are called only if the other capture is not streaming.
> 
> If the other capture is streaming then he already did that for us
> so we call s_stream only on the resizer that is connected to the
> capture node.
> 
> Signed-off-by: Helen Koike <helen.koike@collabora.com>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> ---
>  drivers/staging/media/rkisp1/rkisp1-capture.c | 104 ++++++------------
>  1 file changed, 32 insertions(+), 72 deletions(-)
> 

Thank you for the patch. Please see my comments inline.

[snip]
> +static int rkisp1_s_stream_subdev(struct rkisp1_capture *cap, int enable)
> +{
> +	struct rkisp1_device *rkisp1 = cap->rkisp1;
> +	struct rkisp1_capture *other = &rkisp1->capture_devs[cap->id ^ 1];
> +	int ret;
> +
> +	/*
> +	 * if the other capture is already streaming then we only need to
> +	 * call s_stream of our reszier
> +	 */
> +	if (other->is_streaming) {
> +		struct v4l2_subdev *rsz_sd  = &rkisp1->resizer_devs[cap->id].sd;
> +
> +		ret = v4l2_subdev_call(rsz_sd, video, s_stream, enable);
> +		if (ret && ret != -ENOIOCTLCMD)
> +			dev_err(rkisp1->dev,
> +				"stream %s resizer '%s' failed (%d)\n",
> +				enable ? "on" : "off", rsz_sd->name, ret);

Do we need this special case? Wouldn't v4l2_pipeline_stream_*() simply
increment reference counters for the other entities?

> +	} else {
> +		if (enable)
> +			ret = v4l2_pipeline_stream_enable(&cap->vnode.vdev);
> +		else
> +			ret = v4l2_pipeline_stream_disable(&cap->vnode.vdev);

I wonder if this doesn't ask for just making the helper
v4l2_pipeline_s_stream(..., int enable).

Best regards,
Tomasz