9.1 Proposal: Power.

[Ian Daniher]

Hello all,
This is somewhat on-topic, as this code can be used to test the smoothness
of diming the backlight by editing SLP in the included code.
I originally wrote this as I'm planning on using an XO motherboard/screen as
an alarm clock, and will have the brightness set via some fancy HR=$(date
+%H) magic.

Questions and comments are appreciated.

<CODE>

FILE=/sys/class/backlight/dcon-bl/brightness
VAL=0
SLP=.1
while [ $VAL -lt 15 ]
do
        echo $VAL > $FILE
        echo $VAL
        VAL=`expr $VAL + 1`
        sleep $SLP
done
while [ $VAL -gt 0 ]
do
        echo $VAL > $FILE
        echo $VAL
        VAL=`expr $VAL - 1`
        sleep $SLP
done
echo "done"

<CODE />

Best,
-- 
Ian Daniher
--
OLPC Support Volunteer
OLPCinci Repair Center Coordinator

On Thu, Oct 23, 2008 at 4:45 PM, Jim Gettys <jg at laptop.org> wrote:

> How well we can do that isn't clear.
>
> We have 16 brightness levels, but we didn't think about making them
> logarithmic in response to correspond to the eye's behavior, so there
> are really fewer than that that are useful.
>
> Please experiment and see if it is helpful, of course...
>                      - Jim
>
> On Thu, 2008-10-23 at 10:14 -0400, Eben Eliason wrote:
> > I could be talking nonsense, and perhaps this would consume more power
> > than it saves, but if you were able to slowly dim the backlight over
> > the course of a minute or so, instead of waiting a minute and then
> > dropping it suddenly, we could prevent the sudden change which causes
> > a break in concentration.  (As long as the screen is bright enough to
> > be usable when dim, of course.)
> >
> > - Eben
> >
> >
> > On Wed, Oct 22, 2008 at 4:21 PM, Chris Ball <cjb at laptop.org> wrote:
> > > Hi,
> > >
> > >   > When running on battery with Energy Saver set to "Better Battery
> > >   > Life" (which sets "Automatically reduce the brightness of the
> > >   > display before display sleep") the backlight dims after 30 seconds.
> > >   > On AC with the equivalent setting it's 2 minutes, 30 seconds.  In
> > >   > each case the dimming time seems to be 50% of the time until the
> > >   > screen is turned off.  1 minute is the minimum time before display
> > >   > sleep.
> > >
> > > Thanks!  I was hoping someone would have numbers.  Our backlight dim
> > > currently happens fifty seconds after idleness starts, so we're
> > > definitely less aggressive than OS X already..
> > >
> > > - Chris.
> > > --
> > > Chris Ball   <cjb at laptop.org>
> > > _______________________________________________
> > > Devel mailing list
> > > Devel at lists.laptop.org
> > > http://lists.laptop.org/listinfo/devel
> > >
> > _______________________________________________
> > Devel mailing list
> > Devel at lists.laptop.org
> > http://lists.laptop.org/listinfo/devel
> --
> Jim Gettys <jg at laptop.org>
> One Laptop Per Child
>
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>
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