[Sugar-devel] automatic backlight control

[Paul Fox]

forster at ozonline.com.au wrote:
 > > forster at ozonline.com.au wrote:
 > >  > Thanks Paul
 > > 
 > > thanks for testing!
 > > 
 > >  > 
 > >  > The logic appears to be buggy, see #11487:  XO-1.75 OS12 backlight
 > >  > is off when you come back inside
 > > 
 > > okay, more testing is needed.  as you noted, it's quite hard to tell
 > > when it's on and off.  i'll see if i can come up with an indicator,
 > > on the display or on the LEDs, which will help during debug.
 > 
 > Its not too hard to write a TurtleArt program which continuously prints the 
 > brightness sensor and the screen brightness, there is a block for the 
 > brightness sensor and sample python code 'sensor.py' for the screen bightness

oh, of course.  thx.

 > 
 > > 
 > >  > 
 > >  > As it stands, neither the monochrome nor colour modes are OK in
 > >  > full sunlight.  The colour mode causes a significant loss of
 > >  > resolution for reading small black text and even more resolution
 > >  > loss with coloured text.
 > > 
 > > to clarify -- neither of these issues is caused by the auto-turnoff,
 > > but they might suggest that one or the other modes is a better target
 > > in full sun -- is that what you're saying?
 > 
 > The loss of resolution in full sunlight results from disabling the monochrome 
 > mode, disabled for both manual and automatic triggering in OS12

you were complaining about the visuals for both mono and color mode,
and i was just verifying that you didn't think those visuals were
powerd's fault.  it's in a different mode now (color), but you don't
seem to think monochrome mode would be any better.  this is what's
confusing me.

 > 
 > > 
 > > where can i find some colored text on the laptop?
 > 
 > I am not sure what you are asking, links in webpages is one example, you can 
 > create coloured text in Write
 > 
 > > 
 > >  > 
 > >  > With the monochrome mode, the shadow of your hands as you type is
 > >  > enough to switch mode which is quite distracting
 > > 
 > > the color/mono selection shouldn't have affect on how much light
 > > causes the mode switch.
 > 
 > no it doesn't, what are you saying?

why did you say "with the monochrome mode, ..."?

 > 
 > > 
 > >  > 
 > >  > The cutin cutout settings are 50 (bright)and 80 (dark).  It does
 > >  > not seem worth raising the 80 figure because there is still visible
 > >  > colour information at 70.  The 50 figure could be lowered, direct
 > >  > sunlight is 5-10, so I tried 15, this still could give mode
 > >  > switching from your hands' shadow in direct sunlight.
 > > 
 > > how can you tell the switch has occurred, if you're in full sunlight?
 > > i honestly can't tell when it's happened.
 > 
 > I am running a Turtleart program to interrogate the sensor and screen brightness
 > 
 > > 
 > >  > 
 > >  > What I suggest is that the backlight not switch off unless you have
 > >  > been in the sun for (eg) 5 minutes, but switch back on immediately
 > >  > in the dark.  I don't have the coding skills or I would have tried
 > >  > it out.
 > >  > 
 > >  > For anybody who wants to try it powerd is at /usr/sbin/power
 > >  > 
 > >  > the brightness settings are at line1853 monochrome is commented out
 > >  > at lines 1764 &1793
 > >  > 
 > >  > uncommenting these lines reenables monochrome in response to the
 > >  > sensor but surprisingly not the control keys
 > > 
 > > i don't follow -- the code in powerd currently has (or should have) no
 > > effect on how the brightness keys work.  they're handled by
 > > olpc-brightness.  so they should continue doing what they were doing
 > > before you modified those lines to reenable "zero brightness gives mono"
 > > behavior.
 > 
 > The brightness keys no longer give monochrome at zero brightness. 
 > You must have coded that somewhere in powerd?  Line 1793 looked
 > like it was going to be the culprit.

no, i coded it in /usr/bin/olpc-brightness.  the code in powerd is there
for suspend dimming, and now, auto-backlight turnoff.

thanks,
paul
=---------------------
 paul fox, pgf at laptop.org