[Sugar-devel] automatic backlight control
pgf at laptop.org
Wed Nov 23 14:58:20 EST 2011
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
> > 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.
paul fox, pgf at laptop.org
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