Message-ID: <20160128143610.154ce103@recife.lan>
Date:	Thu, 28 Jan 2016 14:36:10 -0200
From:	Mauro Carvalho Chehab <mchehab@....samsung.com>
To:	Shuah Khan <shuahkh@....samsung.com>
Cc:	tiwai@...e.com, clemens@...isch.de, hans.verkuil@...co.com,
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	alsa-devel@...a-project.org
Subject: Re: [PATCH 20/31] media: au0828 change to register/unregister
 entity_notify hook

Em Wed,  6 Jan 2016 13:27:09 -0700
Shuah Khan <shuahkh@....samsung.com> escreveu:

> au0828 registers entity_notify hook to create media graph for
> the device. This handler runs whenvere a new entity gets added

typo: whenever.

> to the media device. It creates necessary links from video, vbi,
> and ALSA entities to decoder and links tuner and decoder entities.
> As this handler runs as entities get added, it has to maintain
> state on the links it already created. New fields are added to
> au0828_dev to keep this state information. entity_notify gets
> unregistered before media_device unregister.

Bty, please avoid long paragraphs at the patch description, 
and please try to be clearer on your patch descriptions... That
makes boring to read everything. :-;

> 
> Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
> ---
>  drivers/media/usb/au0828/au0828-core.c | 104 +++++++++++++++++++++++----------
>  drivers/media/usb/au0828/au0828.h      |   6 ++
>  2 files changed, 78 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
> index 6ef177c..a381660 100644
> --- a/drivers/media/usb/au0828/au0828-core.c
> +++ b/drivers/media/usb/au0828/au0828-core.c
> @@ -137,6 +137,8 @@ static void au0828_unregister_media_device(struct au0828_dev *dev)
>  #ifdef CONFIG_MEDIA_CONTROLLER
>  	if (dev->media_dev &&
>  		media_devnode_is_registered(&dev->media_dev->devnode)) {
> +		media_device_unregister_entity_notify(dev->media_dev,
> +						      &dev->entity_notify);
>  		media_device_unregister(dev->media_dev);
>  		media_device_cleanup(dev->media_dev);
>  		dev->media_dev = NULL;
> @@ -263,11 +265,16 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
>  	struct media_device *mdev = dev->media_dev;
>  	struct media_entity *entity;
>  	struct media_entity *tuner = NULL, *decoder = NULL;
> +	struct media_entity *audio_capture = NULL;
>  	int i, ret;
>  
>  	if (!mdev)
>  		return 0;
>  
> +	if (dev->tuner_linked && dev->vdev_linked && dev->vbi_linked &&
> +	    dev->audio_capture_linked)
> +		return 0;
> +
>  	media_device_for_each_entity(entity, mdev) {
>  		switch (entity->function) {
>  		case MEDIA_ENT_F_TUNER:
> @@ -276,6 +283,9 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
>  		case MEDIA_ENT_F_ATV_DECODER:
>  			decoder = entity;
>  			break;
> +		case MEDIA_ENT_F_AUDIO_CAPTURE:
> +			audio_capture = entity;
> +			break;
>  		}
>  	}
>  
> @@ -285,60 +295,77 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
>  	if (!decoder)
>  		return -EINVAL;
>  
> -	if (tuner) {
> +	if (tuner  && !dev->tuner_linked) {
> +		dev->tuner = tuner;
>  		ret = media_create_pad_link(tuner, TUNER_PAD_IF_OUTPUT,
>  					    decoder, 0,
>  					    MEDIA_LNK_FL_ENABLED);
>  		if (ret)
>  			return ret;
> +		dev->tuner_linked = 1;
>  	}
> -	if (dev->vdev.entity.graph_obj.mdev) {
> +	if (dev->vdev.entity.graph_obj.mdev && !dev->vdev_linked) {
>  		ret = media_create_pad_link(decoder, AU8522_PAD_VID_OUT,
>  					    &dev->vdev.entity, 0,
>  					    MEDIA_LNK_FL_ENABLED);
>  		if (ret)
>  			return ret;
> +		dev->vdev_linked = 1;
>  	}
> -	if (dev->vbi_dev.entity.graph_obj.mdev) {
> +	if (dev->vbi_dev.entity.graph_obj.mdev && !dev->vbi_linked) {
>  		ret = media_create_pad_link(decoder, AU8522_PAD_VBI_OUT,
>  					    &dev->vbi_dev.entity, 0,
>  					    MEDIA_LNK_FL_ENABLED);
>  		if (ret)
>  			return ret;
> -	}
> -
> -	for (i = 0; i < AU0828_MAX_INPUT; i++) {
> -		struct media_entity *ent = &dev->input_ent[i];
> +		dev->vbi_linked = 1;
>  
> -		if (!ent->graph_obj.mdev)
> -			continue;
> +		/*
> +		 * Input entities are registered before vbi entity,
> +		 * create graph nodes for them after vbi is created
> +		*/
> +		for (i = 0; i < AU0828_MAX_INPUT; i++) {
> +			struct media_entity *ent = &dev->input_ent[i];
>  
> -		if (AUVI_INPUT(i).type == AU0828_VMUX_UNDEFINED)
> -			break;
> +			if (!ent->graph_obj.mdev)
> +				continue;
>  
> -		switch (AUVI_INPUT(i).type) {
> -		case AU0828_VMUX_CABLE:
> -		case AU0828_VMUX_TELEVISION:
> -		case AU0828_VMUX_DVB:
> -			if (!tuner)
> +			if (AUVI_INPUT(i).type == AU0828_VMUX_UNDEFINED)
>  				break;
>  
> -			ret = media_create_pad_link(ent, 0, tuner,
> -						    TUNER_PAD_RF_INPUT,
> -						    MEDIA_LNK_FL_ENABLED);
> -			if (ret)
> -				return ret;
> -			break;
> -		case AU0828_VMUX_COMPOSITE:
> -		case AU0828_VMUX_SVIDEO:
> -		default: /* AU0828_VMUX_DEBUG */
> -			/* FIXME: fix the decoder PAD */
> -			ret = media_create_pad_link(ent, 0, decoder, 0, 0);
> -			if (ret)
> -				return ret;
> -			break;
> +			switch (AUVI_INPUT(i).type) {
> +			case AU0828_VMUX_CABLE:
> +			case AU0828_VMUX_TELEVISION:
> +			case AU0828_VMUX_DVB:
> +				if (!tuner)
> +					break;
> +
> +				ret = media_create_pad_link(ent, 0, tuner,
> +							TUNER_PAD_RF_INPUT,
> +							MEDIA_LNK_FL_ENABLED);
> +				if (ret)
> +					return ret;
> +				break;
> +			case AU0828_VMUX_COMPOSITE:
> +			case AU0828_VMUX_SVIDEO:
> +			default: /* AU0828_VMUX_DEBUG */
> +				/* FIXME: fix the decoder PAD */
> +				ret = media_create_pad_link(ent, 0, decoder,
> +							    0, 0);
> +				if (ret)
> +					return ret;
> +				break;
> +			}
>  		}
>  	}
> +	if (audio_capture && !dev->audio_capture_linked) {
> +		ret = media_create_pad_link(decoder, AU8522_PAD_AUDIO_OUT,
> +					    audio_capture, 0,
> +					    MEDIA_LNK_FL_ENABLED);
> +		if (ret)
> +			return ret;
> +		dev->audio_capture_linked = 1;
> +	}
>  #endif
>  	return 0;
>  }
> @@ -349,8 +376,10 @@ static int au0828_media_device_register(struct au0828_dev *dev,
>  #ifdef CONFIG_MEDIA_CONTROLLER
>  	int ret;
>  
> -	if (dev->media_dev &&
> -		!media_devnode_is_registered(&dev->media_dev->devnode)) {
> +	if (!dev->media_dev)
> +		return 0;
> +
> +	if (!media_devnode_is_registered(&dev->media_dev->devnode)) {
>  
>  		/* register media device */
>  		ret = media_device_register(dev->media_dev);
> @@ -360,6 +389,17 @@ static int au0828_media_device_register(struct au0828_dev *dev,
>  			return ret;
>  		}
>  	}
> +	/* register entity_notify callback */
> +	dev->entity_notify.notify_data = (void *) dev;
> +	dev->entity_notify.notify = (void *) au0828_create_media_graph;
> +	ret = media_device_register_entity_notify(dev->media_dev,
> +						  &dev->entity_notify);
> +	if (ret) {
> +		dev_err(&udev->dev,
> +			"Media Device register entity_notify Error: %d\n",
> +			ret);
> +		return ret;
> +	}
>  #endif
>  	return 0;
>  }
> diff --git a/drivers/media/usb/au0828/au0828.h b/drivers/media/usb/au0828/au0828.h
> index 8276072..cfb6d58 100644
> --- a/drivers/media/usb/au0828/au0828.h
> +++ b/drivers/media/usb/au0828/au0828.h
> @@ -283,6 +283,12 @@ struct au0828_dev {
>  	struct media_entity *decoder;
>  	struct media_entity input_ent[AU0828_MAX_INPUT];
>  	struct media_pad input_pad[AU0828_MAX_INPUT];
> +	struct media_entity_notify entity_notify;
> +	struct media_entity *tuner;
> +	bool tuner_linked;
> +	bool vdev_linked;
> +	bool vbi_linked;
> +	bool audio_capture_linked;

Hmm... now I understood why you did the changes on patch 13/31.

I see what you're doing, but not sure if this is a good idea
to have one bool for each possible device. On au0828, the
topology is actually simpler than on other devices, as it
currently supports a very few set of I2C devices, but on other
drivers, things can be messier.

See, for example, two graphs for em28xx-based devices:
	https://mchehab.fedorapeople.org/mc-next-gen/wintv_usb2.png
	https://mchehab.fedorapeople.org/mc-next-gen/hvr_950.png

On the first graph, the tuner is not connected directly to the
analog demod, but, instead, to two other elements:
	- tda9887 - for video
	- msp3400 - for audio

IMHO, the best way to handle graph setup is that each driver
should handle the links that belong only to them synchronously,
after creating/registering all the entities.

So, only the links between two drivers would be asynchronously
created. So, In the case of au0828:

- au0828 core will create the connector entities;

- I2C drivers will create their own entities;

- DVB core will create the DVB entities/interfaces;

- V4L core will create V4L interfaces and I/O entities;

- au0828 V4L driver will create all V4L links, after
  ensuring that the needed I2C drivers were bound;

- snd-usb-audio will create all ALSA-specific entities links;

The V4L->ALSA links will either be created by au0828-core,
via the notification handler.

With that in mind, I don't see any need to touch at
au0828_create_media_graph(). It will need an extra function
to handle the notification when ALSA gets registered
(or when the entities there are added, whatever works best).

Regards,
Mauro






>  #endif
>  };
>  

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