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| author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2010-03-07 19:04:59 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-03-22 08:53:12 +0100 |
| commit | 503c3d829eaf48837dd5bff5d97ad66369bb955a (patch) | |
| tree | 9c14ed9561c5ffca07909e53d5ae0e52cdf5f99e /include/media | |
| parent | [media] media: Entity graph traversal (diff) | |
| download | linux-503c3d829eaf48837dd5bff5d97ad66369bb955a.tar.xz linux-503c3d829eaf48837dd5bff5d97ad66369bb955a.zip | |
[media] media: Entity use count
Due to the wide differences between drivers regarding power management
needs, the media controller does not implement power management.
However, the media_entity structure includes a use_count field that
media drivers can use to track the number of users of every entity for
power management needs.
The use_count field is owned by media drivers and must not be touched by
entity drivers. Access to the field must be protected by the media
device graph_mutex lock.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'include/media')
| -rw-r--r-- | include/media/media-device.h | 4 | ||||
| -rw-r--r-- | include/media/media-entity.h | 9 |
2 files changed, 13 insertions, 0 deletions
diff --git a/include/media/media-device.h b/include/media/media-device.h index a8390fe87e83..5d2bff4fc9e0 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -25,6 +25,7 @@ #include <linux/device.h> #include <linux/list.h> +#include <linux/mutex.h> #include <linux/spinlock.h> #include <media/media-devnode.h> @@ -42,6 +43,7 @@ * @entity_id: ID of the next entity to be registered * @entities: List of registered entities * @lock: Entities list lock + * @graph_mutex: Entities graph operation lock * * This structure represents an abstract high-level media device. It allows easy * access to entities and provides basic media device-level support. The @@ -69,6 +71,8 @@ struct media_device { /* Protects the entities list */ spinlock_t lock; + /* Serializes graph operations. */ + struct mutex graph_mutex; }; /* media_devnode to media_device */ diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 28f61f6ee549..a9b31d98e3c6 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -81,6 +81,12 @@ struct media_entity { struct media_pad *pads; /* Pads array (num_pads elements) */ struct media_link *links; /* Links array (max_links elements)*/ + /* Reference counts must never be negative, but are signed integers on + * purpose: a simple WARN_ON(<0) check can be used to detect reference + * count bugs that would make them negative. + */ + int use_count; /* Use count for the entity. */ + union { /* Node specifications */ struct { @@ -129,6 +135,9 @@ void media_entity_cleanup(struct media_entity *entity); int media_entity_create_link(struct media_entity *source, u16 source_pad, struct media_entity *sink, u16 sink_pad, u32 flags); +struct media_entity *media_entity_get(struct media_entity *entity); +void media_entity_put(struct media_entity *entity); + void media_entity_graph_walk_start(struct media_entity_graph *graph, struct media_entity *entity); struct media_entity * |