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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2010-03-07 19:04:59 +0100
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-03-22 08:53:12 +0100
commit503c3d829eaf48837dd5bff5d97ad66369bb955a (patch)
tree9c14ed9561c5ffca07909e53d5ae0e52cdf5f99e /include/media/media-device.h
parent[media] media: Entity graph traversal (diff)
downloadlinux-503c3d829eaf48837dd5bff5d97ad66369bb955a.tar.xz
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[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/media-device.h')
-rw-r--r--include/media/media-device.h4
1 files changed, 4 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 */