diff options
author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2010-03-07 13:04:59 -0500 |
---|---|---|
committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-03-22 03:53:12 -0400 |
commit | 503c3d829eaf48837dd5bff5d97ad66369bb955a (patch) | |
tree | 9c14ed9561c5ffca07909e53d5ae0e52cdf5f99e /Documentation | |
parent | a5ccc48a7c48610e7f92fa599406738d69195d51 (diff) |
[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 'Documentation')
-rw-r--r-- | Documentation/media-framework.txt | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index ab17f33ddedc..78ae02095372 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt | |||
@@ -258,3 +258,16 @@ When the graph traversal is complete the function will return NULL. | |||
258 | 258 | ||
259 | Graph traversal can be interrupted at any moment. No cleanup function call is | 259 | Graph traversal can be interrupted at any moment. No cleanup function call is |
260 | required and the graph structure can be freed normally. | 260 | required and the graph structure can be freed normally. |
261 | |||
262 | |||
263 | Use count and power handling | ||
264 | ---------------------------- | ||
265 | |||
266 | Due to the wide differences between drivers regarding power management needs, | ||
267 | the media controller does not implement power management. However, the | ||
268 | media_entity structure includes a use_count field that media drivers can use to | ||
269 | track the number of users of every entity for power management needs. | ||
270 | |||
271 | The use_count field is owned by media drivers and must not be touched by entity | ||
272 | drivers. Access to the field must be protected by the media device graph_mutex | ||
273 | lock. | ||