Auto backlight management?

[Jordan Crouse]

On 24/04/08 22:10 -0700, david at lang.hm wrote:
> On Fri, 25 Apr 2008, Eben Eliason wrote:
> 
> > On Thu, Apr 24, 2008 at 10:43 PM, John Watlington <wad at laptop.org> wrote:
> >>
> >>  Bert misread the spec.  When the backlight is switched off, the screen
> >>  automatically switches to B&W mode.   Why would you want to take
> >>  that out of the control of the user ?
> >
> > I'm working on mockups for a "screen device" (in the Frame) which will
> > include a brightness slider and an independent checkbox for color/b&w
> > mode, so that these can be managed directly by the user at their
> > discretion.  It's clear to me that it would be quite useful to have a
> > bright backlight AND black & white mode for reading a book at night,
> > for instance, and this isn't possible in the current UI.
> 
> I used to think the same thing, but I learned it's not possible in the 
> current hardware.
> 
> this is the one drawback to the fantasic screen, any light from the 
> backlight that gets through is colored by the screen. it can be made to 
> appear white by allowing all three colors through, but it's still colored.
> 
> this means that you can't get high resolution mode with the backlight on.

No part of that is true.  The behavior you describe is a myth, 
kept alive by people who misinterpet the display specification.

You can turn on monochrome mode at any time. Try it yourself:
echo "1" > /sys/devices/platform/dcon/output

Boom - there you go.   Monochrome for your pleasure.

Jordan

-- 
Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.