On Tuesday, January 25, 2011 21:36:59 Hans de Goede wrote:
> Hi,
>
> On 01/23/2011 05:13 PM, Hans Verkuil wrote:
> > On Sunday, January 23, 2011 16:15:03 Hans de Goede wrote:
>
> <snip>
>
> >> This is what the UVC spec for example mandates and what the current UVC
> >> driver
> >> does. Combining this with an app which honors the update and the read only
> >> flag (try gtk-v4l), results in a nice experience. User enables auto
> >> exposure
> >> -> exposure control gets grayed out, put exposure back manual -> control
> >> is ungrayed.
> >>
> >> So this new auto_cluster behavior would be a behavioral change (for both
> >> the
> >> uvc driver and several gspca drivers), and more over an unwanted one IMHO
> >> setting one control should not change another as a side effect.
> >
> > Actually, I've been converting a whole list of subdev drivers recently
> > (soc_camera,
> > ov7670) and they all behaved like this. So I didn't change anything.
>
> Hmm, interesting.
>
> > There is nothing preventing other drivers from doing something different.
> >
> > That said, changing the behavior to your proposal may not be such a bad
> > idea.
>
> Yes and AFAIK this is what we agreed on when we discussed auto control a
> couple of months ago.
>
> > But then I need the OK from all driver authors involved, since this would
> > mean a change of behavior for them.
> >
> > The good news is that once they use the new framework function I only need
> > to change what that function does and I don't need to change any of those
> > drivers.
> >
> > So I will proceed for now by converting those drivers to use this new
> > function,
> > and at the same time I can contact the authors and ask what their opinion is
> > of this change. I'm hoping for more feedback as well from what others think.
> >
>
> Yes, contacting the authors to discuss this further sounds like a good idea.
>
> > BTW, if I understand the gspca code correctly then it seems that if an e.g.
> > autogain control is set to 1, then the gain control effectively disappears.
> > I think queryctrl will just never return it. That can't be right.
>
> Erm, it should not disappear, but just get disabled. But this may have
> (accidentally) changed with the drivers which were converted to the new
> control framework.
gspca doesn't use the control framework at all. Or are you talking about a
gspca-internal change in control handling?
> Anyways, we should discuss this with involved driver
> authors and agree on a standard way to handle this. Once we have agreement
> on how to handle this converting the drivers should be relatively easy.
Yes, I'll continue working on this.
Regards,
Hans
--
Hans Verkuil - video4linux developer - sponsored by Cisco
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