Hi Hans,
On Saturday 28 August 2010 13:14:18 Hans Verkuil wrote:
> On Friday, August 20, 2010 17:29:10 Laurent Pinchart wrote:
[snip]
> > +/**
> > + * media_entity_remote_pad - Locate the pad at the remote end of a link
> > + * @entity: Local entity
> > + * @pad: Pad at the local end of the link
> > + *
> > + * Search for a remote pad connected to the given pad by iterating over
> > all
> > + * links originating or terminating at that pad until an active link is
> > found.
> > + *
> > + * Return a pointer to the pad at the remote end of the first found
> > active link,
> > + * or NULL if no active link has been found.
> > + */
> > +struct media_pad *media_entity_remote_pad(struct media_pad *pad)
> > +{
> > + unsigned int i;
> > +
> > + for (i = 0; i < pad->entity->num_links; i++) {
> > + struct media_link *link = &pad->entity->links[i];
> > +
> > + if (!(link->flags & MEDIA_LINK_FLAG_ACTIVE))
> > + continue;
> > +
> > + if (link->source == pad)
> > + return link->sink;
> > +
> > + if (link->sink == pad)
> > + return link->source;
> > + }
> > +
> > + return NULL;
> > +
> > +}
>
> Why is this needed? Esp. since there can be multiple active remote pads if
> you have multiple active outgoing links. Something this function doesn't
> deal with.
The function is meant to be used when only one of the links can be active.
It's most useful to find the entity connected to a given input pad, as input
pads can't be connected by multiple simultaneously active links.
[snip]
> This patch made me wonder about something else: how is power management
> handled for immutable links? They are by definition active, so they should
> be powered on automatically as well. I'm not sure whether that happens
> right now.
Links are not powered, entities are. Whether a link is immutable or not
doesn't make much of a difference, it will just always be considered as
active.
--
Regards,
Laurent Pinchart
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