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[media] v4l2-controls.txt: update to latest v4l2-ctrl.c changes 

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2011-05-27 08:53:37 -03:00 committed by Mauro Carvalho Chehab
parent ddac5c1079
commit 78866efe8a
1 changed files with 4 additions and 9 deletions
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13
Documentation/video4linux/v4l2-controls.txt
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@ -277,16 +277,13 @@ implement g_volatile_ctrl like this:
{
switch (ctrl->id) {
case V4L2_CID_BRIGHTNESS:
ctrl->cur.val = read_reg(0x123);
ctrl->val = read_reg(0x123);
break;
}
}
The 'new value' union is not used in g_volatile_ctrl. In general controls
that need to implement g_volatile_ctrl are read-only controls.
Note that if one or more controls in a control cluster are marked as volatile,
then all the controls in the cluster are seen as volatile.
Note that you use the 'new value' union as well in g_volatile_ctrl. In general
controls that need to implement g_volatile_ctrl are read-only controls.
To mark a control as volatile you have to set the is_volatile flag:
@ -636,9 +633,7 @@ button controls are write-only controls.
-EINVAL as the spec says.
5) The spec does not mention what should happen when you try to set/get a
control class controls. ivtv currently returns -EINVAL (indicating that the
control ID does not exist) while the framework will return -EACCES, which
makes more sense.
control class controls. The framework will return -EACCES.
Proposals for Extensions