Re: [PATCH v3 1/2] media: v4l2-ctrls: Add V4L2_CID_NOTIFY_GAIN_XXX controls

[Sakari Ailus <sakari.ailus@iki.fi>]

On Thu, Aug 05, 2021 at 06:49:33PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Thu, Aug 05, 2021 at 06:40:42PM +0300, Sakari Ailus wrote:
> > On Thu, Aug 05, 2021 at 06:22:32PM +0300, Laurent Pinchart wrote:
> > > On Thu, Jul 22, 2021 at 01:12:48PM +0100, David Plowman wrote:
> > > > We add new controls, one for each of the four usual Bayer channels:
> > > > 
> > > > V4L2_CID_NOTIFY_GAIN_RED
> > > > V4L2_CID_NOTIFY_GAIN_GREENR
> > > > V4L2_CID_NOTIFY_GAIN_BLUE
> > > > V4L2_CID_NOTIFY_GAIN_GREENB
> > > 
> > > This will effectively limit the API to Bayer patterns. I wonder if we
> > > should instead implement it as a single array control, with one element
> > > per CFA component.
> > 
> > There are other raw patterns, too. Supporting them would likely require one
> > or a few more controls.
> > 
> > That said, as the values change often it's more efficient to use a single
> > control. But each colour combination (not each pattern) would require its
> > own control in this case, eventually requiring more controls.
> 
> I'm not sure to follow you. My idea is to define a single control, with
> a number of elements that depends on the pattern being used, and the
> order specified in the native sensor pattern. I don't think each colour
> combination would then require its own control.

Ah, I guess that would work, too. Then we'll need to define what kind of
pixel orders are supported for that single control (and for which formats).

-- 
Sakari Ailus