Hi Sakari,
On 09/06/2013 07:10 PM, Sakari Ailus wrote:
On Fri, Sep 06, 2013 at 06:30:47PM +0200, Laurent Pinchart wrote:
On Wednesday 04 September 2013 03:09:42 Sakari Ailus wrote:
Do not allow streaming if a pad with MEDIA_PAD_FL_MUST_CONNECT flag is
connected by links that are all inactive.
This patch makes it possible to avoid drivers having to check for the most
common case of link state validation: a sink pad that must be connected.
Signed-off-by: Sakari Ailus<sakari.ailus@xxxxxx>
---
drivers/media/media-entity.c | 41> +++++++++++++++++++++++++++++++------
1 file changed, 34 insertions(+), 7 deletions(-)
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 2c286c3..567a171 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -235,6 +235,8 @@ __must_check int media_entity_pipeline_start(struct
media_entity *entity, media_entity_graph_walk_start(&graph, entity);
while ((entity = media_entity_graph_walk_next(&graph))) {
+ DECLARE_BITMAP(active, entity->num_pads);
+ DECLARE_BITMAP(has_no_links, entity->num_pads);
unsigned int i;
entity->stream_count++;
@@ -248,21 +250,46 @@ __must_check int media_entity_pipeline_start(struct
media_entity *entity, if (!entity->ops || !entity->ops->link_validate)
continue;
+ bitmap_zero(active, entity->num_pads);
+ bitmap_fill(has_no_links, entity->num_pads);
+
for (i = 0; i< entity->num_links; i++) {
struct media_link *link =&entity->links[i];
-
- /* Is this pad part of an enabled link? */
- if (!(link->flags& MEDIA_LNK_FL_ENABLED))
- continue;
-
- /* Are we the sink or not? */
- if (link->sink->entity != entity)
+ struct media_pad *pad = link->sink->entity == entity
+ ? link->sink : link->source;
+
+ /* Mark that a pad is connected by a link. */
+ bitmap_clear(has_no_links, pad->index, 1);
+
+ /*
+ * Pads that either do not need to connect or
+ * are connected through an enabled link are
+ * fine.
+ */
+ if (!(pad->flags& MEDIA_PAD_FL_MUST_CONNECT)
+ || link->flags& MEDIA_LNK_FL_ENABLED)
With the || moved on the previous line (here and below),
I agree with Laurent here, I feel such formatting with operator at end of
line is more common in the kernel. But that's certainly not something
I would be going to die for ;)
I'd like to claim the above is more clear and conforms to GNU coding
standards whereas the kernel CodingStyle doesn't suggest either way:
<URL:http://www.gnu.org/prep/standards/standards.html#Formatting>
I feel we've had this discussion before. :-)
I have to admit I disagree with Stallman's liberal use of parentheses and a
funny habit of having a space between a function name and the parentheses
enclosing its arguments. ;-)
Acked-by: Laurent Pinchart<laurent.pinchart@xxxxxxxxxxxxxxxx>
If that's fine with you there's no need to resent, I'll take the patch in my
tree with that modification.
I won't say no, but I would prefer getting an ack from someone else, too,
for the two first patches. A less permissive variant of this was dismissed
around a year ago, potentially perhaps there was no pressing need for that
kind of a change. The earlier set required all sink pads must have a
connected link (which indeed was too restrictive, I agree).
<URL:https://linuxtv.org/patch/15205/>
As seen in the fourth patch of this set, this makes it possible to avoid
another loop (done in the driver) over the pipeline, which was my motivation
for this patch --- so I think this is the right thing to do.
Other drivers could be changed the same way but I think this is up to the
driver authors. There could be other reasons for the pad to need connecting;
tha absence of the flag won't say there aren't.
Patches 1, 2 look good to me. Feel free to add my Acked-by for patch 1/4 and
Tested-by for 2/4.
I'm just wondering whether we shouldn't put something what you just said
above:
"There could be other reasons for the pad to need connecting;
the absence of the flag won't say there aren't."
in the DocBook, to make definition of the MEDIA_PAD_FL_MUST_CONNECT flags
more clear ?
--
Regards,
Sylwester
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
