Hi HeungJun, On Monday 14 March 2011 08:02:01 Kim, HeungJun wrote: > Hi Laurent, > > I heard of that there was a chance between you and Sylwester telling about > the menu entries focus, and so after that, probably this menu style of the > patch I sent, need to be more upgraded. So, can you tell me the kind or > sequence of the UVC device breifly? > > I guess the word *AUTO* at the UVC device means doing focus continuously, > not once or one time. That's correct. In the UVC context, auto focus means CAF and manual focus means... well, manual focus :-) > But, at the sensors I used the *AUTO* focus means doing focus once, on the > other hand *CONTINUOUS* means doing continuously. So, we need to be clear > terms about focus. > > At the sensor I used, the focus needs 3 kinds of commands: > 1) setting mode > > : it makes the lens initial position for each AF(Normal, Continuous, > : Night mode Focus, etc), > > and set the AF status Idle. > 2) execute AF > > : doing the move of the lens > > 3) read AF status > > : checking the lens status(Focus failed, Focus success, Idle, Busy) > > and do the proper jobs. > > I don't know uvc case well, so, If you share about this, it can be help. What bothers me with your auto-focus implementation is that the user might want to perform auto-focus several times. Let's imagine this use case: 1. The user points the camera (webcam, cellphone camera, digital camera, it doesn't matter) at an object. 2. The user presses a button to perform singleshot auto-focus (it can be a physical button or a button on the camera screen, once again it doesn't matter). 3. The application sets the focus control to AUTO. 4. The driver and device perform auto-focus once. The lens is moved so that the object is in focus. 5. The user points the camera at another object. 6. The user presses a button to perform singleshot auto-focus. 7. The applications sets the focus control to AUTO. As the focus control value was already AUTO, nothing is done. This is clearly broken. That's why we need a V4L2 button control in addition to the menu control. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
