On Fri, Aug 21, 2009 at 2:09 AM, Ronny Brendel<[email protected]> wrote: > According to the spec it is """A control which performs an action when set. > Drivers must ignore the value passed with VIDIOC_S_CTRL and return an EINVAL > error code on a VIDIOC_G_CTRL attempt.""" > > I don't get what this means. It is no boolean. It has no effect, and you > cannot > set it? I am probably missing something. Please help. >
Hi, This exactly what I wondered several months ago :-) Recalling the memory back then, the answer was that the button type is just a command to trigger some functionality which doesn't care about parameters because that is actually not necessary. For instance, "adjusting white balance" button in digital camera could be a good example which is performing adjustment of white balance for one time and no need for any kind of parameter for this but needs to be triggered. Cheers, Nate -- = DongSoo, Nathaniel Kim Engineer Mobile S/W Platform Lab. Digital Media & Communications R&D Centre Samsung Electronics CO., LTD. e-mail : [email protected] [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
