Re: [PATCH] [media] davinci: vpfe: Add documentation

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Saturday 01 September 2012 19:11:56 Sakari Ailus wrote:
> Hi Prabhakar,
> 
> On Sat, Sep 01, 2012 at 08:23:58PM +0530, Prabhakar Lad wrote:
> > On Sat, Sep 1, 2012 at 7:52 PM, Laurent Pinchart
> > 
> > <laurent.pinchart@ideasonboard.com> wrote:
> > > Hi Sakari,
> > > 
> > > On Saturday 01 September 2012 12:57:07 Sakari Ailus wrote:
> > >> On Wed, Aug 29, 2012 at 08:11:50PM +0530, Prabhakar Lad wrote:
> > > [snip]
> > > 
> > >> > For test pattern you meant control to enable/disable it ?
> > >> 
> > >> There are two approaches I can think of.
> > >> 
> > >> One is a menu control which can be used to choose the test pattern (or
> > >> disable it). The control could be standardised but the menu items would
> > >> have to be hardware-specific since the test patterns themselves are
> > >> not standardised.
> > > 
> > > Agreed. The test patterns themselves are highly hardware-specific.
> > > 
> > > From personal experience with sensors, most devices implement a small,
> > > fixed set of test patterns that can be exposed through a menu control.
> > > However, some devices also implement more "configurable" test patterns.
> > > For instance the MT9V032 can generate horizontal, vertical or diagonal
> > > test patterns, or a uniform grey test pattern with a user-configurable
> > > value. This would then require two controls.
> > 
> > two controls I didn't get it ? When we have menu itself with a list of
> > standard patterns why would two controls be required ?
> 
> Two are not required. A single menu control will do.

That's correct, in this case a single menu control will do. We would only need 
multiple controls if the device exposes test pattern parameters, as in the 
MT9V032 sensor example.

-- 
Regards,

Laurent Pinchart