[Q] Software control of LCD backlight?

[Hal V. Engel]

On Friday 10 August 2007 12:30, Alex Deucher wrote:
> On 8/10/07, Hal V. Engel <hvengel at astound.net> wrote:
snip
> > At some point most monitors will stop providing front panel controls and
> > require a software interface for making these adjustments.  Therefore in
> > the long run this functionality does belong somewhere in the X server and
> > I guess that RandR is as good a place as any.  But there will be
> > significant issues getting a good implementation of this in place. 
> > Personnaly I would like to see this sooner rather than later.
>
> I don't know anything much about the ddc/ci spec, but it would be
> pretty easy to expose the i2c interface for each output in randr.
> What's we'd do wtih that interface depends on what's needed for
> ddc/ci.
>
> Alex

Exposing the i2c interface is a first step and would allow for the addition of 
another library to specifcially support DDC/CI type monitor controls if it 
was decided that randr was not the right place for this.  I think another 
initial step down this path would be for someone who really knows about this 
stuff (for example someone from the ddccontrol team working with someone who 
works on X) to write a specification document for how monitor controls 
(DDC/CI and perhaps USB HID) would work in X.   That would give everyone a 
road map to follow.  

I would also like to see some hooks for USB HID Monitors and I think the 
monitor control library should encapsolate both DDC/CI and USB HID Monitor 
controls since these implement almost exactly the same functionality with the 
major difference being the low level communications protocol (i2c vs. USB 
HID).   This is not an area where I have much expertise but it is something 
that I am interested in becaue having this functionality available would be 
very helpful to my own OSS project.  So I want to do whatever I can to 
encourage this effort.

Hal