Re: [PATCH 1/3] add feedback LED control

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On Sunday 28 February 2010 20:38:00 Németh Márton wrote:
> Jean-Francois Moine wrote:
> > On Sun, 28 Feb 2010 08:55:04 +0100
> > 
> > Németh Márton <nm127@xxxxxxxxxxx> wrote:
> >> On some webcams a feedback LED can be found. This LED usually shows
> >> the state of streaming mode: this is the "Auto" mode. The LED can
> >> be programmed to constantly switched off state (e.g. for power saving
> >> reasons, preview mode) or on state (e.g. the application shows motion
> >> detection or "on-air").
> > 
> > Hi,
> > 
> > There may be many LEDs on the webcams. One LED may be used for
> > the streaming state, Some other ones may be used to give more light in
> > dark rooms. One webcam, the microscope 093a:050f, has a top and a bottom
> > lights/illuminators; an other one, the MSI StarCam 370i 0c45:60c0, has
> > an infra-red light.
> > 
> > That's why I proposed to have bit fields in the control value to switch
> > on/off each LED.
> 
> With a bitfield on and off state can be specified. What about the "auto"
> mode? Should two bits grouped together to have auto, on and off state? Is
> there already a similar control?

I don't like the bitfield either. As stated in my previous mail, we can have 
more than 3 states, so using 2 bits per LED will simply not scale.

> Is the brightness of the background light LEDs adjustable or are they just
> on/off? If yes, then maybe the feedback LEDs and the background light LEDs
> should be treated as different kind.

I think there should indeed be a different control for the background LEDs. 
Still, there could be more than one feedback LED.

-- 
Regards,

Laurent Pinchart
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