On 11/29/2011 07:58 PM, Laurent Pinchart wrote: > On Tuesday 29 November 2011 19:30:25 Hans Verkuil wrote: >> On Tuesday, November 29, 2011 19:10:39 Laurent Pinchart wrote: >>> On Tuesday 29 November 2011 17:40:10 Sylwester Nawrocki wrote: >>>> On 11/29/2011 12:08 PM, Hans Verkuil wrote: >>>>> On Monday 28 November 2011 14:02:49 Sylwester Nawrocki wrote: >>>>>> On 11/28/2011 01:39 PM, Hans Verkuil wrote: >>>>>>> On Monday 28 November 2011 13:13:32 Sylwester Nawrocki wrote: >>>>>>>> On 11/28/2011 12:38 PM, Hans Verkuil wrote: >>>>>>>>> On Friday 25 November 2011 16:39:31 Sylwester Nawrocki wrote: >>>>> Here is a patch that updates the range. It also sends a control event >>>>> telling any listener that the range has changed. Tested with vivi and >>>>> a modified v4l2-ctl. >>>>> >>>>> The only thing missing is a DocBook entry for that new event flag and >>>>> perhaps some more documentation in places. >>>>> >>>>> Let me know how this works for you, and if it is really needed, then >>>>> I can add it to the control framework. >>>> >>>> Thanks for your work, it's very appreciated. >>>> >>>> I've tested the patch with s5p-fimc and it works well. I just didn't >>>> check the event part yet. >>>> >>>> I spoke to Kamil as in the past he considered the control range >>>> updating at the codec driver. But since separate controls are used for >>>> different encoding standards, this is not needed it any more. >>>> >>>> Nevertheless I have at least two use cases, for the alpha control and >>>> for the image sensor driver. In case of the camera sensor, different >>>> device revisions may have different step and maximum value for some >>>> controls, depending on firmware. >>>> By using v4l2_ctrl_range_update() I don't need to invoke lengthy sensor >>>> start-up procedure just to find out properties of some controls. >>> >>> Wouldn't it be confusing for applications to start with a range and have >>> it updated at runtime ? >> >> Good question. It was a nice exercise creating the range_update() function >> and it works well, but it this something we want to do? > > I think that being able to modify the range is a very useful functionality. > It's just that in this case the sensor would start with a default range and > switch to another based on the model. It would be better if we could start > with the right range from the start. > >> If we do, then we should mark such controls with a flag (_VOLATILE_RANGE or >> something like that) so apps know that the range isn't fixed. >> >> I think that when it comes to apps writing or reading such a control >> directly it isn't a problem. But for applications that automatically >> generate control panels (xawtv et al) it is rather complex to support such >> things.
Hans, are you going to carry on with the control range update patches ? I'd like to push the alpha colour control for v3.3 but it depends on the controls framework updates now. Another use case for control range update would be with an auto-exposure metering spot location controls. An available range for x and y coordinates would depend on selected pixel resolution. If we would have created two controls for (x, y) their range would depend on pixel (width, height) respectively. So when a new format is set such controls would need to get their range updated. -- Thanks, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
