On 01/28/2016 09:43 AM, Mauro Carvalho Chehab wrote:

Em Wed,  6 Jan 2016 13:27:12 -0700
Shuah Khan [off-list ref] escreveu:

quoted

Implements enable_source and disable_source handlers for other
drivers (v4l2-core, dvb-core, and ALSA) to use to check for
tuner connected to the decoder and activate the link if tuner
is free, and deactivate and free the tuner when it is no longer
needed.

Signed-off-by: Shuah Khan <redacted>
---
 drivers/media/usb/au0828/au0828-core.c | 148 +++++++++++++++++++++++++++++++++
 drivers/media/usb/au0828/au0828.h      |   2 +
 2 files changed, 150 insertions(+)

diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
index a15a61a..f8d2db3 100644
--- a/drivers/media/usb/au0828/au0828-core.c
+++ b/drivers/media/usb/au0828/au0828-core.c

@@ -370,6 +370,150 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
 	return 0;
 }
 
+static int au0828_enable_source(struct media_entity *entity,
+				struct media_pipeline *pipe)
+{

The best would be to put those enable source stuff at the core, in a way
that other drivers could share it.

Hans and I discussed this at the Media Summit in Finland.
It will be very difficult to make this work in a generic
way. Besides, bridge driver knows the hardware it has and
it would make sense for it to implement enable and disable
source handlers.

Not sure about the implementation, as this requires testing ;)
Did you consider the cases where the source connector is S-Video
or Composite?

I think you asked this question on another patch and Devin
responded to that thread. Let's discuss it there.

thanks,
-- Shuah

quoted

+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_entity  *source;
+	struct media_entity *sink;
+	struct media_link *link, *found_link = NULL;
+	int ret = 0;
+	struct media_device *mdev = entity->graph_obj.mdev;
+	struct au0828_dev *dev;
+
+	if (!mdev)
+		return -ENODEV;
+
+	/* for Audio and Video entities, source is the decoder */
+	mutex_lock(&mdev->graph_mutex);
+
+	dev = mdev->source_priv;
+	if (!dev->tuner || !dev->decoder) {
+		ret = -ENODEV;
+		goto end;
+	}
+
+	/*
+	 * For Audio and V4L2 entity, find the link to which decoder
+	 * is the sink. Look for an active link between decoder and
+	 * tuner, if one exists, nothing to do. If not, look for any
+	 * active links between tuner and any other entity. If one
+	 * exists, tuner is busy. If tuner is free, setup link and
+	 * start pipeline from source (tuner).
+	 * For DVB FE entity, the source for the link is the tuner.
+	 * Check if tuner is available and setup link and start
+	 * pipeline.
+	*/
+	if (entity->function != MEDIA_ENT_F_DTV_DEMOD)
+		sink = dev->decoder;
+	else
+		sink = entity;
+
+	/* Is an active link between sink and tuner */
+	if (dev->active_link) {
+		if (dev->active_link->sink->entity == sink &&
+		    dev->active_link->source->entity == dev->tuner) {
+			ret = 0;
+			goto end;
+		} else {
+			ret = -EBUSY;
+			goto end;
+		}
+	}
+
+	list_for_each_entry(link, &sink->links, list) {
+		/* Check sink, and source */
+		if (link->sink->entity == sink &&
+		    link->source->entity == dev->tuner) {
+			found_link = link;
+			break;
+		}
+	}
+
+	if (!found_link) {
+		ret = -ENODEV;
+		goto end;
+	}
+
+	/* activate link between source and sink and start pipeline */
+	source = found_link->source->entity;
+	ret = __media_entity_setup_link(found_link, MEDIA_LNK_FL_ENABLED);
+	if (ret) {
+		pr_err(
+			"Activate tuner link %s->%s. Error %d\n",
+			source->name, sink->name, ret);
+		goto end;
+	}
+
+	ret = __media_entity_pipeline_start(entity, pipe);
+	if (ret) {
+		pr_err("Start Pipeline: %s->%s Error %d\n",
+			source->name, entity->name, ret);
+		ret = __media_entity_setup_link(found_link, 0);
+		pr_err("Deactive link Error %d\n", ret);
+		goto end;
+	}
+	/*
+	 * save active link and active link owner to avoid audio
+	 * deactivating video owned link from disable_source and
+	 * vice versa
+	*/
+	dev->active_link = found_link;
+	dev->active_link_owner = entity;
+end:
+	mutex_unlock(&mdev->graph_mutex);
+	pr_debug("au0828_enable_source() end %s %d %d\n",
+		entity->name, entity->function, ret);
+	return ret;
+#endif
+	return 0;
+}
+
+static void au0828_disable_source(struct media_entity *entity)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_entity *sink;
+	int ret = 0;
+	struct media_device *mdev = entity->graph_obj.mdev;
+	struct au0828_dev *dev;
+
+	if (!mdev)
+		return;
+
+	mutex_lock(&mdev->graph_mutex);
+	dev = mdev->source_priv;
+	if (!dev->tuner || !dev->decoder || !dev->active_link) {
+		ret = -ENODEV;
+		goto end;
+	}
+
+	if (entity->function != MEDIA_ENT_F_DTV_DEMOD)
+		sink = dev->decoder;
+	else
+		sink = entity;
+
+	/* link is active - stop pipeline from source (tuner) */
+	if (dev->active_link && dev->active_link->sink->entity == sink &&
+	    dev->active_link->source->entity == dev->tuner) {
+		/*
+		 * prevent video from deactivating link when audio
+		 * has active pipeline
+		*/
+		if (dev->active_link_owner != entity)
+			goto end;
+		__media_entity_pipeline_stop(entity);
+		ret = __media_entity_setup_link(dev->active_link, 0);
+		if (ret)
+			pr_err("Deactive link Error %d\n", ret);
+		dev->active_link = NULL;
+		dev->active_link_owner = NULL;
+	}
+
+end:
+	mutex_unlock(&mdev->graph_mutex);
+#endif
+}
+
 static int au0828_media_device_register(struct au0828_dev *dev,
 					struct usb_device *udev)
 {

@@ -400,6 +544,10 @@ static int au0828_media_device_register(struct au0828_dev *dev,
 			ret);
 		return ret;
 	}
+	/* set enable_source */
+	dev->media_dev->source_priv = (void *) dev;
+	dev->media_dev->enable_source = au0828_enable_source;
+	dev->media_dev->disable_source = au0828_disable_source;
 #endif
 	return 0;
 }

diff --git a/drivers/media/usb/au0828/au0828.h b/drivers/media/usb/au0828/au0828.h
index cfb6d58..3707664 100644
--- a/drivers/media/usb/au0828/au0828.h
+++ b/drivers/media/usb/au0828/au0828.h

@@ -289,6 +289,8 @@ struct au0828_dev {
 	bool vdev_linked;
 	bool vbi_linked;
 	bool audio_capture_linked;
+	struct media_link *active_link;
+	struct media_entity *active_link_owner;
 #endif
 };
 

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978