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| author | Ricardo Ribalda <ricardo.ribalda@gmail.com> | 2015-03-20 15:13:14 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2015-04-08 11:35:16 +0200 |
| commit | acd2b672b45e557829c1f080e46457586aab9d74 (patch) | |
| tree | 9dc5ba94ea6425877edd6f94e254010f938b7ba7 /Documentation/DocBook | |
| parent | [media] media/v4l2-ctrls: Always execute EXECUTE_ON_WRITE ctrls (diff) | |
| download | linux-acd2b672b45e557829c1f080e46457586aab9d74.tar.xz linux-acd2b672b45e557829c1f080e46457586aab9d74.zip | |
[media] media/Documentation: New flag EXECUTE_ON_WRITE
Document new flag V4L2_CTRL_FLAG_EXECUTE_ON_WRITE, and the new behavior
of CH_VALUE event on VOLATILE controls.
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'Documentation/DocBook')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-dqevent.xml | 6 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-queryctrl.xml | 12 |
2 files changed, 14 insertions, 4 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml index a31eea07d455..50ccd33948c1 100644 --- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml @@ -425,9 +425,9 @@ <entry><constant>V4L2_EVENT_CTRL_CH_VALUE</constant></entry> <entry>0x0001</entry> <entry>This control event was triggered because the value of the control - changed. Special case: if a button control is pressed, then this - event is sent as well, even though there is not explicit value - associated with a button control.</entry> + changed. Special cases: Volatile controls do no generate this event; + If a control has the <constant>V4L2_CTRL_FLAG_EXECUTE_ON_WRITE</constant> + flag set, then this event is sent as well, regardless its value.</entry> </row> <row> <entry><constant>V4L2_EVENT_CTRL_CH_FLAGS</constant></entry> diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml index 2bd98fd7a4e5..dc83ad70f8dc 100644 --- a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml +++ b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml @@ -600,7 +600,9 @@ writing a value will cause the device to carry out a given action changes continuously. A typical example would be the current gain value if the device is in auto-gain mode. In such a case the hardware calculates the gain value based on the lighting conditions which can change over time. Note that setting a new value for -a volatile control will have no effect. The new value will just be ignored.</entry> +a volatile control will have no effect and no <constant>V4L2_EVENT_CTRL_CH_VALUE</constant> +will be sent, unless the <constant>V4L2_CTRL_FLAG_EXECUTE_ON_WRITE</constant> flag +(see below) is also set. Otherwise the new value will just be ignored.</entry> </row> <row> <entry><constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant></entry> @@ -610,6 +612,14 @@ using one of the pointer fields of &v4l2-ext-control;. This flag is set for cont that are an array, string, or have a compound type. In all cases you have to set a pointer to memory containing the payload of the control.</entry> </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_EXECUTE_ON_WRITE</constant></entry> + <entry>0x0200</entry> + <entry>The value provided to the control will be propagated to the driver +even if remains constant. This is required when the control represents an action +on the hardware. For example: clearing an error flag or triggering the flash. All the +controls of the type <constant>V4L2_CTRL_TYPE_BUTTON</constant> have this flag set.</entry> + </row> </tbody> </tgroup> </table> |