[Sugar-devel] automatic backlight control

Paul Fox pgf at laptop.org
Mon Nov 28 11:36:20 EST 2011

martin wrote:
 > On Thu, Nov 24, 2011 at 10:09 AM, Paul Fox <pgf at laptop.org> wrote:
 > >  - hitting "brightness down" one more time when at level 0 will
 > >    switch to mono.  users that use auto-repeat to get there probably
 > >    won't see a difference.

as discussed on this thread on friday (i think), this part is no longer
right.  there will be no extra step to get to mono mode.  i.e., the
behavior of the keyboard controls will be unchanged.

 > ...
 > >  - sunlight-driven auto-turnoff will go all the way to 0, but won't
 > >    invoke mono mode.

this is (still) correct.

 > Great!
 > Does it "stick"? Or will the "auto-brighten" aspect of "auto-dimming"
 > kick in when a cloud comes over?

it doesn't stick currently.

if you dim (to any level) before auto-dimming happens (i.e., while
you're still inside), then auto-dim/auto-brighten will take you back
to the previous level that you set manually.

but if you manually dim while auto-dim is already in effect, your
manual change (which only caused a color --> mono switch, since the
backlight was already off) will be lost -- you'll be back in color
mode.  but since the backlight is now on, this is the correct

now, you could argue that it should go back to mono on the next
auto-dim, since that's what the user wanted last time, but that
argument would require patches to both powerd and olpc-brightness to
give it any teeth.  (it's complications like this which led me to try
and simplify the whole mechanism in the first place.)

so, currently, to get mono mode every time auto-dim happens, you
have to use ctrl-brightness-down to force mono mode always.


 > m
 > -- 
 >  martin.langhoff at gmail.com
 >  martin at laptop.org -- Software Architect - OLPC
 >  - ask interesting questions
 >  - don't get distracted with shiny stuff  - working code first
 >  - http://wiki.laptop.org/go/User:Martinlanghoff

 paul fox, pgf at laptop.org

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