[PATCH 0/2] media: stm32: correct s_stream calls in dcmi & st-mipid02

[PATCH 0/2] media: stm32: correct s_stream calls in dcmi & st-mipid02

[Alain Volmat]

Currently the stm32 dcmi driver is calling s_stream to all subdevs until
reaching the sensor subdev.  This serie corrects this by having a subdev
only calling s_stream on its source subdev.

Alain Volmat (2):
  media: i2c: st_mipid02: cascade s_stream call to the source subdev
  media: stm32: dcmi: only call s_stream on the source subdev

 drivers/media/i2c/st-mipid02.c               | 11 ++++
 drivers/media/platform/st/stm32/stm32-dcmi.c | 63 +++++---------------
 2 files changed, 25 insertions(+), 49 deletions(-)

-- 
2.25.1

[PATCH 1/2] media: i2c: st_mipid02: cascade s_stream call to the source subdev

[Alain Volmat]

Cascade the s_stream call to the source subdev whenever the bridge
streaming is enable / disabled.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
---
 drivers/media/i2c/st-mipid02.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/media/i2c/st-mipid02.c b/drivers/media/i2c/st-mipid02.c
index 906553a28676..703d2f06f552 100644
--- a/drivers/media/i2c/st-mipid02.c
+++ b/drivers/media/i2c/st-mipid02.c
@@ -547,6 +547,13 @@ static int mipid02_stream_disable(struct mipid02_dev *bridge)
 	struct i2c_client *client = bridge->i2c_client;
 	int ret;
 
+	if (!bridge->s_subdev)
+		goto error;
+
+	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 0);
+	if (ret)
+		goto error;
+
 	/* Disable all lanes */
 	ret = mipid02_write_reg(bridge, MIPID02_CLK_LANE_REG1, 0);
 	if (ret)
@@ -633,6 +640,10 @@ static int mipid02_stream_enable(struct mipid02_dev *bridge)
 	if (ret)
 		goto error;
 
+	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 1);
+	if (ret)
+		goto error;
+
 	return 0;
 
 error:
-- 
2.25.1

[PATCH 2/2] media: stm32: dcmi: only call s_stream on the source subdev

[Alain Volmat]

Avoid calling s_stream on each subdev until reaching the sensor and
instead call s_stream on the source subdev only (which will in turn
do whatever needed to start the stream).

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
---
 drivers/media/platform/st/stm32/stm32-dcmi.c | 63 +++++---------------
 1 file changed, 14 insertions(+), 49 deletions(-)

diff --git a/drivers/media/platform/st/stm32/stm32-dcmi.c b/drivers/media/platform/st/stm32/stm32-dcmi.c
index dad6e22e4ce4..ac8a5031dce6 100644
--- a/drivers/media/platform/st/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/st/stm32/stm32-dcmi.c
@@ -134,6 +134,7 @@ struct stm32_dcmi {
 	struct video_device		*vdev;
 	struct v4l2_async_notifier	notifier;
 	struct v4l2_subdev		*source;
+	struct v4l2_subdev		*s_subdev;
 	struct v4l2_format		fmt;
 	struct v4l2_rect		crop;
 	bool				do_crop;
@@ -692,51 +693,6 @@ static int dcmi_pipeline_s_fmt(struct stm32_dcmi *dcmi,
 	return 0;
 }
 
-static int dcmi_pipeline_s_stream(struct stm32_dcmi *dcmi, int state)
-{
-	struct media_entity *entity = &dcmi->vdev->entity;
-	struct v4l2_subdev *subdev;
-	struct media_pad *pad;
-	int ret;
-
-	/* Start/stop all entities within pipeline */
-	while (1) {
-		pad = &entity->pads[0];
-		if (!(pad->flags & MEDIA_PAD_FL_SINK))
-			break;
-
-		pad = media_pad_remote_pad_first(pad);
-		if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
-			break;
-
-		entity = pad->entity;
-		subdev = media_entity_to_v4l2_subdev(entity);
-
-		ret = v4l2_subdev_call(subdev, video, s_stream, state);
-		if (ret < 0 && ret != -ENOIOCTLCMD) {
-			dev_err(dcmi->dev, "%s: \"%s\" failed to %s streaming (%d)\n",
-				__func__, subdev->name,
-				state ? "start" : "stop", ret);
-			return ret;
-		}
-
-		dev_dbg(dcmi->dev, "\"%s\" is %s\n",
-			subdev->name, state ? "started" : "stopped");
-	}
-
-	return 0;
-}
-
-static int dcmi_pipeline_start(struct stm32_dcmi *dcmi)
-{
-	return dcmi_pipeline_s_stream(dcmi, 1);
-}
-
-static void dcmi_pipeline_stop(struct stm32_dcmi *dcmi)
-{
-	dcmi_pipeline_s_stream(dcmi, 0);
-}
-
 static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
 {
 	struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
@@ -758,9 +714,12 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
 		goto err_pm_put;
 	}
 
-	ret = dcmi_pipeline_start(dcmi);
-	if (ret)
+	ret = v4l2_subdev_call(dcmi->s_subdev, video, s_stream, 1);
+	if (ret < 0) {
+		dev_err(dcmi->dev, "%s: Failed to start source subdev, error (%d)\n",
+			__func__, ret);
 		goto err_media_pipeline_stop;
+	}
 
 	spin_lock_irq(&dcmi->irqlock);
 
@@ -862,7 +821,7 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
 	return 0;
 
 err_pipeline_stop:
-	dcmi_pipeline_stop(dcmi);
+	v4l2_subdev_call(dcmi->s_subdev, video, s_stream, 0);
 
 err_media_pipeline_stop:
 	video_device_pipeline_stop(dcmi->vdev);
@@ -889,8 +848,12 @@ static void dcmi_stop_streaming(struct vb2_queue *vq)
 {
 	struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
 	struct dcmi_buf *buf, *node;
+	int ret;
 
-	dcmi_pipeline_stop(dcmi);
+	ret = v4l2_subdev_call(dcmi->s_subdev, video, s_stream, 0);
+	if (ret < 0)
+		dev_err(dcmi->dev, "%s: Failed to stop source subdev, error (%d)\n",
+			__func__, ret);
 
 	video_device_pipeline_stop(dcmi->vdev);
 
@@ -1876,6 +1839,8 @@ static int dcmi_graph_notify_bound(struct v4l2_async_notifier *notifier,
 		dev_dbg(dcmi->dev, "DCMI is now linked to \"%s\"\n",
 			subdev->name);
 
+	dcmi->s_subdev = subdev;
+
 	return ret;
 }
 
-- 
2.25.1

Re: [PATCH 1/2] media: i2c: st_mipid02: cascade s_stream call to the source subdev

[Benjamin Mugnier]

Hi Alain,

Thank you for your patch. LGTM.

Reviewed-By: Benjamin Mugnier <benjamin.mugnier@foss.st.com>

On 7/11/23 14:32, Alain Volmat wrote:
> Cascade the s_stream call to the source subdev whenever the bridge
> streaming is enable / disabled.
> 
> Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
> ---
>  drivers/media/i2c/st-mipid02.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/media/i2c/st-mipid02.c b/drivers/media/i2c/st-mipid02.c
> index 906553a28676..703d2f06f552 100644
> --- a/drivers/media/i2c/st-mipid02.c
> +++ b/drivers/media/i2c/st-mipid02.c
> @@ -547,6 +547,13 @@ static int mipid02_stream_disable(struct mipid02_dev *bridge)
>  	struct i2c_client *client = bridge->i2c_client;
>  	int ret;
>  
> +	if (!bridge->s_subdev)
> +		goto error;
> +
> +	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 0);
> +	if (ret)
> +		goto error;
> +
>  	/* Disable all lanes */
>  	ret = mipid02_write_reg(bridge, MIPID02_CLK_LANE_REG1, 0);
>  	if (ret)
> @@ -633,6 +640,10 @@ static int mipid02_stream_enable(struct mipid02_dev *bridge)
>  	if (ret)
>  		goto error;
>  
> +	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 1);
> +	if (ret)
> +		goto error;
> +
>  	return 0;
>  
>  error:

-- 
Regards,

Benjamin

Re: [PATCH 1/2] media: i2c: st_mipid02: cascade s_stream call to the source subdev

[Hans Verkuil]

On 11/07/2023 14:32, Alain Volmat wrote:
> Cascade the s_stream call to the source subdev whenever the bridge
> streaming is enable / disabled.
> 
> Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
> ---
>  drivers/media/i2c/st-mipid02.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/media/i2c/st-mipid02.c b/drivers/media/i2c/st-mipid02.c
> index 906553a28676..703d2f06f552 100644
> --- a/drivers/media/i2c/st-mipid02.c
> +++ b/drivers/media/i2c/st-mipid02.c
> @@ -547,6 +547,13 @@ static int mipid02_stream_disable(struct mipid02_dev *bridge)
>  	struct i2c_client *client = bridge->i2c_client;
>  	int ret;
>  
> +	if (!bridge->s_subdev)
> +		goto error;

I'm getting this compiler warning:

media-git/drivers/media/i2c/st-mipid02.c: In function 'mipid02_stream_disable':
media-git/drivers/media/i2c/st-mipid02.c:568:12: warning: 'ret' may be used uninitialized [-Wmaybe-uninitialized]
  568 |         if (ret)
      |            ^
media-git/drivers/media/i2c/st-mipid02.c:548:13: note: 'ret' was declared here
  548 |         int ret;
      |             ^~~

I'm dropping this series, waiting for a v2.

Regards,

	Hans

> +
> +	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 0);
> +	if (ret)
> +		goto error;
> +
>  	/* Disable all lanes */
>  	ret = mipid02_write_reg(bridge, MIPID02_CLK_LANE_REG1, 0);
>  	if (ret)
> @@ -633,6 +640,10 @@ static int mipid02_stream_enable(struct mipid02_dev *bridge)
>  	if (ret)
>  		goto error;
>  
> +	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 1);
> +	if (ret)
> +		goto error;
> +
>  	return 0;
>  
>  error:

Re: [PATCH 1/2] media: i2c: st_mipid02: cascade s_stream call to the source subdev

[Alain Volmat]

Hi Hans,

On Wed, Jul 19, 2023 at 12:26:37PM +0200, Hans Verkuil wrote:
> On 11/07/2023 14:32, Alain Volmat wrote:
> > Cascade the s_stream call to the source subdev whenever the bridge
> > streaming is enable / disabled.
> > 
> > Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
> > ---
> >  drivers/media/i2c/st-mipid02.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/drivers/media/i2c/st-mipid02.c b/drivers/media/i2c/st-mipid02.c
> > index 906553a28676..703d2f06f552 100644
> > --- a/drivers/media/i2c/st-mipid02.c
> > +++ b/drivers/media/i2c/st-mipid02.c
> > @@ -547,6 +547,13 @@ static int mipid02_stream_disable(struct mipid02_dev *bridge)
> >  	struct i2c_client *client = bridge->i2c_client;
> >  	int ret;
> >  
> > +	if (!bridge->s_subdev)
> > +		goto error;
> 
> I'm getting this compiler warning:
> 
> media-git/drivers/media/i2c/st-mipid02.c: In function 'mipid02_stream_disable':
> media-git/drivers/media/i2c/st-mipid02.c:568:12: warning: 'ret' may be used uninitialized [-Wmaybe-uninitialized]
>   568 |         if (ret)
>       |            ^
> media-git/drivers/media/i2c/st-mipid02.c:548:13: note: 'ret' was declared here
>   548 |         int ret;
>       |             ^~~
> 
> I'm dropping this series, waiting for a v2.

Indeed, this was a real issue.  I added KCFLAGS=-Wmaybe-uninitialized
in my build command line to spot thoses issues from now on.

v2 posted with the fix.

> 
> Regards,
> 
> 	Hans

Regards,
Alain
> 
> > +
> > +	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 0);
> > +	if (ret)
> > +		goto error;
> > +
> >  	/* Disable all lanes */
> >  	ret = mipid02_write_reg(bridge, MIPID02_CLK_LANE_REG1, 0);
> >  	if (ret)
> > @@ -633,6 +640,10 @@ static int mipid02_stream_enable(struct mipid02_dev *bridge)
> >  	if (ret)
> >  		goto error;
> >  
> > +	ret = v4l2_subdev_call(bridge->s_subdev, video, s_stream, 1);
> > +	if (ret)
> > +		goto error;
> > +
> >  	return 0;
> >  
> >  error:
>