Re: [PATCH 18/18] [media] dvbdev: Don't create indirect links

[Mauro Carvalho Chehab <mchehab@osg.samsung.com>]

Em Fri, 11 Sep 2015 17:48:19 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> On 09/06/2015 07:31 PM, Mauro Carvalho Chehab wrote:
> > Indirect links are those whose the interface indirectly controls
> 
> s/the//
> 
> > other functions.
> > 
> > There are two interfaces that have indirect controls at the DVB
> > side:
> > - the network interface, with also controls the demux;
> 
> s/with/which/
> 
> > - the DVR interface with also controls the demux.
> 
> ditto
> 
> > 
> > One could argue that the frontend control to the tuner is indirect.
> > Well, that's debateable. There's no way to create subdef interfaces
> 
> s/debateable/debatable/
> s/subdef/subdev/
> 
> > for tuner and demod, as those devices are tightly coupled. So, it
> > was decided that just one interface is the best to control both
> > entities, and there's no plan (or easy way) to decouple both. So,
> > the DVB frontend interface should link to both entities.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> 
> With the typos fixed:
> 
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Fixed, thanks.

> 
> Note: I am not convinced that the dvr->demux indirect link isn't needed, but
> it can be enabled later, so it's OK for me to keep it under #if 0 for now.

Yeah, I'm also not convinced if it would be worth to represent 
indirect links. That's why I opted to comment, instead of striping them.

> 
> Regards,
> 
> 	Hans
> 
> > 
> > diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c
> > index ea76fe54e0e4..e9f24c1479dd 100644
> > --- a/drivers/media/dvb-core/dvbdev.c
> > +++ b/drivers/media/dvb-core/dvbdev.c
> > @@ -619,7 +619,7 @@ int dvb_create_media_graph(struct dvb_adapter *adap)
> >  		}
> >  	}
> >  
> > -	/* Create indirect interface links for FE->tuner, DVR->demux and CA->ca */
> > +	/* Create interface links for FE->tuner, DVR->demux and CA->ca */
> >  	media_device_for_each_intf(intf, mdev) {
> >  		if (intf->type == MEDIA_INTF_T_DVB_CA && ca) {
> >  			link = media_create_intf_link(ca, intf,
> > @@ -634,13 +634,19 @@ int dvb_create_media_graph(struct dvb_adapter *adap)
> >  			if (!link)
> >  				return -ENOMEM;
> >  		}
> > -
> > +#if 0
> > +		/*
> > +		 * Indirect link - let's not create yet, as we don't know how
> > +		 *		   to handle indirect links, nor if this will
> > +		 *		   actually be needed.
> > +		 */
> >  		if (intf->type == MEDIA_INTF_T_DVB_DVR && demux) {
> >  			link = media_create_intf_link(demux, intf,
> >  						      MEDIA_LNK_FL_ENABLED);
> >  			if (!link)
> >  				return -ENOMEM;
> >  		}
> > +#endif
> >  		if (intf->type == MEDIA_INTF_T_DVB_DVR) {
> >  			ret = dvb_create_io_intf_links(adap, intf, DVR_TSOUT);
> >  			if (ret)
> > 
> 
>