Hi Jacek,
On Thu, Nov 24, 2016 at 03:00:46PM +0100, Jacek Anaszewski wrote:
> Hi Sakari,
>
> Thanks for the review.
It's taken way too long. :-( My apologies for that.
> On 11/24/2016 01:40 PM, Sakari Ailus wrote:
> >Hi Jacek,
> >
> >On Wed, Oct 12, 2016 at 04:35:18PM +0200, Jacek Anaszewski wrote:
> >>Add a new graph helper useful for discovering video pipeline.
> >>
> >>Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
> >>Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> >>---
> >> utils/media-ctl/libmediactl.c | 21 +++++++++++++++++++++
> >> utils/media-ctl/mediactl.h | 15 +++++++++++++++
> >> 2 files changed, 36 insertions(+)
> >>
> >>diff --git a/utils/media-ctl/libmediactl.c b/utils/media-ctl/libmediactl.c
> >>index 91ed003..155b65f 100644
> >>--- a/utils/media-ctl/libmediactl.c
> >>+++ b/utils/media-ctl/libmediactl.c
> >>@@ -36,6 +36,7 @@
> >> #include <unistd.h>
> >>
> >> #include <linux/media.h>
> >>+#include <linux/kdev_t.h>
> >
> >Is there something that needs this one in the patch?
>
> MAJOR and MINOR macros.
Ok.
>
> >
> >> #include <linux/videodev2.h>
> >>
> >> #include "mediactl.h"
> >>@@ -172,6 +173,26 @@ const struct media_entity_desc *media_entity_get_info(struct media_entity *entit
> >> return &entity->info;
> >> }
> >>
> >>+int media_entity_get_backlinks(struct media_entity *entity,
> >>+ struct media_link **backlinks,
> >>+ unsigned int *num_backlinks)
> >>+{
> >>+ unsigned int num_bklinks = 0;
> >>+ int i;
> >>+
> >>+ if (entity == NULL || backlinks == NULL || num_backlinks == NULL)
> >>+ return -EINVAL;
> >>+
> >
> >If you have an interface that accesses a memory buffer of unknown size, you
> >need to verify that the user has provided a buffer large enough.
> >
> >How about using the num_backlinks argument to provide the maximum size to
> >the function, and passing the actual number to the user, the latter of which
> >you already do?
>
> Sounds reasonable.
>
> >Alternatively, an iterator style API could be nice as well. Up to you.
>
> It would probably need an addition of some generic infrastructure.
> I suppose that there is no such a feature in v4l-utils?
You basically need to store a value for the framework to tell which entity
is being worked on. So nothing too fancy.
I guess Laurent would prefer the current interface but I let him answer
that.
--
Regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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