On Tue, Sep 06, 2011 at 01:03:57PM +0000, Bastian Hecht wrote:
> Hello Sakari,
>
> 2011/9/6 Sakari Ailus <sakari.ai...@iki.fi>:
> > On Tue, Sep 06, 2011 at 09:35:24AM +0000, Bastian Hecht wrote:
> >> Hello Sakari,
> >>
> >> 2011/9/6 Sakari Ailus <sakari.ai...@iki.fi>:
> >> > On Tue, Sep 06, 2011 at 09:01:15AM +0000, Bastian Hecht wrote:
> >> >> 2011/9/6 Sakari Ailus <sakari.ai...@iki.fi>:
> >> >> > On Tue, Sep 06, 2011 at 07:56:40AM +0000, Bastian Hecht wrote:
> >> >> >> Hello Sakari!
> >> >> >
> >> >> > Hi Bastian,
> >> >> >
> >> >> >> 2011/9/6 Sakari Ailus <sakari.ai...@iki.fi>:
> >> >> >> > Hi Bastian,
> >> >> >> >
> >> >> >> > On Mon, Sep 05, 2011 at 09:32:55AM +0000, Bastian Hecht wrote:
> >> >> >> >> 2011/9/1 Sakari Ailus <sakari.ai...@iki.fi>:
> >> >> >> >> > On Thu, Sep 01, 2011 at 11:14:08AM +0200, Sylwester Nawrocki
> >> >> >> >> > wrote:
> >> >> >> >> >> Hi Sakari,
> >> >> >> >> >>
> >> >> >> >> >> On 09/01/2011 10:47 AM, Sakari Ailus wrote:
> >> >> >> >> >> > On Thu, Sep 01, 2011 at 09:15:20AM +0200, Guennadi
> >> >> >> >> >> > Liakhovetski wrote:
> >> >> >> >> >> >> On Thu, 1 Sep 2011, Sakari Ailus wrote:
> >> >> >> >> >> >>
> >> >> >> >> >> >>> On Wed, Aug 31, 2011 at 03:27:49PM +0000, Bastian Hecht
> >> >> >> >> >> >>> wrote:
> >> >> >> >> >> >>>> 2011/8/28 Laurent Pinchart
> >> >> >> >> >> >>>> <laurent.pinch...@ideasonboard.com>:
> >> >> >> >> >> >>> [clip]
> >> >> >> >> >> >>>>> If I'm not mistaken V4L2_CID_PRIVATE_BASE is deprecated.
> >> >> >> >> >> >>>>
> >> >> >> >> >> >>>> I checked at http://v4l2spec.bytesex.org/spec/x542.htm,
> >> >> >> >> >> >>>> googled
> >> >> >> >> >> >>>> "V4L2_CID_PRIVATE_BASE deprecated" and read
> >> >> >> >> >> >>>> Documentation/feature-removal-schedule.txt. I couldn't
> >> >> >> >> >> >>>> find anything.
> >> >> >> >> >> >>>
> >> >> >> >> >> >>> Hmm. Did you happen to check when that has been written? :)
> >> >> >> >> >> >>>
> >> >> >> >> >> >>> Please use this one instead:
> >> >> >> >> >> >>>
> >> >> >> >> >> >>> <URL:http://hverkuil.home.xs4all.nl/spec/media.html>
> >> >> >> >> >> >>
> >> >> >> >> >> >> "Drivers can also implement their own custom controls using
> >> >> >> >> >> >> V4L2_CID_PRIVATE_BASE and higher values."
> >> >> >> >> >> >>
> >> >> >> >> >> >> Which specific location describes V4L2_CID_PRIVATE_BASE
> >> >> >> >> >> >> differently there?
> >> >> >> >> >> >
> >> >> >> >> >> > That was a general comment, not related to the private base.
> >> >> >> >> >> > There's no
> >> >> >> >> >> > use for a three-year-old spec as a reference!
> >> >> >> >> >> >
> >> >> >> >> >> > The control framework does not support private controls, for
> >> >> >> >> >> > example. The
> >> >> >> >> >> > controls should be put to their own class in videodev2.h
> >> >> >> >> >> > nowadays, that's my
> >> >> >> >> >> > understanding. Cc Hans.
> >> >> >> >> >>
> >> >> >> >> >> Is this really the case that we close the door for private
> >> >> >> >> >> controls in
> >> >> >> >> >> the mainline kernel ? Or am I misunderstanding something ?
> >> >> >> >> >> How about v4l2_ctrl_new_custom() ?
> >> >> >> >> >>
> >> >> >> >> >> What if there are controls applicable to single driver only ?
> >> >> >> >> >> Do we really want to have plenty of such in videodev2.h ?
> >> >> >> >> >
> >> >> >> >> > We have some of those already in videodev2.h. I'm not certain
> >> >> >> >> > if I'm happy
> >> >> >> >> > with this myself, considering e.g. that we could get a few
> >> >> >> >> > truckloads of
> >> >> >> >> > only camera lens hardware specific controls in the near future.
> >> >> >> >>
> >> >> >> >> So in my case (as these are controls that might be used by others
> >> >> >> >> too)
> >> >> >> >> I should add something like
> >> >> >> >>
> >> >> >> >> #define V4L2_CID_BLUE_SATURATION
> >> >> >> >> (V4L2_CID_CAMERA_CLASS_BASE+19)
> >> >> >> >> #define V4L2_CID_RED_SATURATION
> >> >> >> >> (V4L2_CID_CAMERA_CLASS_BASE+20)
> >> >> >> >
> >> >> >> > What do these two controls do? Do they control gain or something
> >> >> >> > else?
> >> >> >>
> >> >> >> Hmm. Maybe I named them a bit unsharp. It is the U Saturation and V
> >> >> >> Saturation. To me it looks like turning up the saturation in HSV
> >> >> >> space, but only for either the blue or the red channel. This would
> >> >> >> correspond to V4L2_CID_{RED,BLUE}_BALANCE when I read the docs. They
> >> >> >> say it is "{Red,Blue} chroma balance".
> >> >> >>
> >> >> >> I have other controls for that I used V4L2_CID_{RED,BLUE}_BALANCE.
> >> >> >> These are gains. So in fact I should swap them in my code and the
> >> >> >> remaining question is, how to name the red and blue gain controls.
> >> >> >
> >> >> > I think Laurent had a similar issue in his Aptina sensor driver. In my
> >> >> > opinion we need a class for low level controls such as the gain ones.
> >> >> > Do I
> >> >> > understand correctly they control the red and blue pixel gain in the
> >> >> > sensor
> >> >> > pixel matrix? Do you also have gain controls for the two greens?
> >> >>
> >> >> Yes, I assume that this is done there. Either in the analog circuit by
> >> >> decreasing the preload or digitally then. Don't know exactly. There
> >> >> are registers for the green pixels as well. As I used the
> >> >> V4L2_CID_{RED,BLUE}_BALANCE controls and there was no
> >> >> V4L2_CID_GREEN_BALANCE, I just skipped green as one can
> >> >> increase/decrease the global gain and get an arbitrary mix as well.
> >> >>
> >> >> So for these gain settings we should add these?
> >> >> V4L2_CID_RED_GAIN
> >> >> V4L2_CID_BLUE_GAIN
> >> >> V4L2_CID_GREEN_GAIN
> >> >
> >> > Do you have two or just one green gains? In all sensors I've seen there
> >> > are
> >> > two.
> >>
> >> No, here is only one.
> >
> > It is a raw bayer sensor, isn't it?
> >
> >> > I think I could send an RFC on this to the list and cc you and Laurent.
> >>
> >> Ok fine, thanks! But hmmm - what do I do with my driver in the
> >> meantime actually? Stall the upstream process or remove my controls
> >> temporarily - or is there a better way?
> >
> > It is also possible to expose these controls just for this sensor, but I
> > would wait a little bit if that's okay for you. Your sensor driver isn't the
> > only one depending on these new controls --- Laurent also has one.
> >
> > I don't think this should take too long, but I can't promise that. :-)
> >
> > If you want the driver to mainline fast, then you could also submit it
> > without these controls implemented, and implement them in another patch when
> > the controls have been standardised.
>
> Ok, thanks for the info. I'll try it this way: I'll post an
> [PATCH/RFC] with the final version except the right control names for
> gain and chroma balance. So when this rfc gets through, I can simply
> change names and am done.
Sounds good to me.
> >> >> >> >> #define V4L2_CID_GRAY_SCALE_IMAGE
> >> >> >> >> (V4L2_CID_CAMERA_CLASS_BASE+21)
> >> >> >> >
> >> >> >> > V4L2_CID_COLOR_KILLER looks like something which would fit for the
> >> >> >> > purpose.
> >> >> >>
> >> >> >> Oh great! So I just take this.
> >> >> >>
> >> >> >> >> #define V4L2_CID_SOLARIZE_EFFECT
> >> >> >> >> (V4L2_CID_CAMERA_CLASS_BASE+22)
> >> >> >> >
> >> >> >> > Sounds interesting for a sensor. I wonder if this would fall under
> >> >> >> > a menu
> >> >> >> > control, V4L2_CID_COLORFX.
> >> >> >>
> >> >> >> When I read the the possible enums for V4L2_CID_COLORFX, it indeed
> >> >> >> sounds very much like my solarize effect should be added there too. I
> >> >> >> found V4L2_COLORFX_BW there, too. Isn't that a duplicate of the color
> >> >> >> killer control then?
> >> >> >
> >> >> > In my opinion V4L2_CID_COLORFX should never be implemented in drivers
> >> >> > for
> >> >> > which the hardware doesn't implement these effects in a
> >> >> > non-parametrisable
> >> >> > way. This control was originally added for the OMAP 3 ISP driver but
> >> >> > the
> >> >> > driver never implemented it.
> >> >>
> >> >> Your triple negation (never, doesn't, non-) is quite tricky xD
> >> >> If I get it right, you say that one should not use V4L2_CID_COLORFX
> >> >> for hardware with parametrisable effects.
> >> >
> >> > Yes. I could have written that in a more clear way. ;-)
> >>
> >> After starring dazzled for 2 minutes on it, I realized at some point
> >> that formal logic is your friend ;)
> >>
> >> >> My BW and Solarize effects are non-parametrisable and they can be
> >> >> turned on together (which makes not so much sense though - but these
> >> >> fun-effects like "solarize" aren't here to make sense, I guess :-) ).
> >> >
> >> > Good.
> >> >
> >> > The OMAP 3 ISP actually provides a way to set gamma tables, any effects
> >> > implemented using them are more or less use case specific. There are also
> >> > other uses for those same gamma tables, making a driver implementation
> >> > for
> >> > effects using them non-functional in practice.
> >>
> >> Ok I see. Luckily (for me) in my sensor it is binary on/off only.
> >>
> >> >> > I think you have a valid case using this control. I think the main
> >> >> > difference between the two is that V4L2_COLORFX_BW is something that
> >> >> > you
> >> >> > can't use with other effects while V4L2_CID_COLOR_KILLER can be used
> >> >> > with
> >> >> > any of the effects.
> >> >>
> >> >> > Based on your original proposal the black/white should stay as a
> >> >> > separate
> >> >> > control but the solarise should be configurable through
> >> >> > V4L2_CID_COLORFX
> >> >> > menu control. So it boils down to the question whether you can use
> >> >> > them at
> >> >> > the same time.
> >> >>
> >> >> I can - so it is still working to enable V4L2_COLORFX_BW and
> >> >> V4L2_CID_COLORFX with a new enum value, right? Is that the way to go
> >> >> now?
> >> >
> >> > That's my opinion, yes.
> >>
> >> So I will post an additional patch for videodev2.h with
> >> enum v4l2_colorfx {
> >> ...
> >> V4L2_COLORFX_SOLARIZE = 10,
> >> };
> >
> > That's correct. I think the COLORFX hasn't been very well documented so far,
> > but it should be. I don't think many know what the solarize effect would do.
> > :-) I think the patch should also add that. The user control documentation
> > may be found in Documentation/DocBook/media/v4l/controls.xml .
> >
> > Cheers,
>
> In fact, I had no idea as well, but wikipedia teached me :)
> So I will prepare a documentation patch as well.
> http://en.wikipedia.org/wiki/Solarisation
Nice. I didn't know that. :-)
--
Sakari Ailus
e-mail: sakari.ai...@iki.fi jabber/XMPP/Gmail: sai...@retiisi.org.uk
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