Hi Sakari,
On Sunday 15 January 2012 16:40:56 Sakari Ailus wrote:
> Laurent Pinchart wrote:
> > On Saturday 14 January 2012 20:33:36 Sakari Ailus wrote:
> >> Signed-off-by: Sakari Ailus<sakari.ailus@xxxxxx>
> >> ---
> >>
> >> src/mediactl.c | 9 +++++++--
> >> src/mediactl.h | 4 +++-
> >> 2 files changed, 10 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/src/mediactl.c b/src/mediactl.c
> >> index 5b8c587..f62fcdf 100644
> >> --- a/src/mediactl.c
> >> +++ b/src/mediactl.c
> >> @@ -81,8 +81,13 @@ struct media_entity *media_get_entity_by_id(struct
> >> media_device *media, for (i = 0; i< media->entities_count; ++i) {
> >>
> >> struct media_entity *entity =&media->entities[i];
> >>
> >> - if (entity->info.id == id)
> >> - return entity;
> >> + if (!(id& MEDIA_ENT_ID_FLAG_NEXT)) {
> >> + if (entity->info.id == id)
> >> + return entity;
> >> + } else {
> >> + if (entity->info.id>= (id& ~MEDIA_ENT_ID_FLAG_NEXT)
> >> + return entity;
> >> + }
> >
> > Just one question that hasn't crossed my mind before, why do you need
> > this ? If you want to enumerate entities in an application you can just
> > iterate over media_device::entities.
>
> We do have the MEDIA_ENT_ID_FLAG_NEXT flag which is intended to help in
> entity enumeration. Currently the range of entity ids is contiguous in
> all practical implementation but will that always be the case, also in
> the future? A few things might break in the kernel if the range is
> non-contiguous as well, but that's still internal to the kernel.
>
> However, this is a user space library and if this interface change is
> not made, we essentially are making a promise that the entity ranges
> will always be contiguous.
I definitely don't want to make that promise, but what's the point in calling
media_get_entity_by_id() for entity enumeration instead of iterating over the
media_device::entities array ?
> I wouldn't as there's no need to do so.
>
> I you think about programmable hardware, entities there are logical
> rather than physical and their existence may be dependent on multiple
> factors.
--
Regards,
Laurent Pinchart
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