[Sugar-devel] automatic backlight control
pgf at laptop.org
Wed Nov 23 09:17:37 EST 2011
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.
> 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?
where can i find some colored text on the laptop?
> 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.
> 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.
> 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"
> > forster at ozonline.com.au wrote:
> > > The shift from colour to monochrome is noticable and would be annoying if
> > > happened a lot, for example as clouds pass, trees and people move.
> > >
> > > If the hysterisis, the difference between cutin and cutout brightness is
> > > the change in mode will happen a lot less frequently and not be annoying.
> > >
> > > I would like to try it switching automatically to monochrome but with
> > > hysterisis.
> > >
> > > I'll wait to try OS12
> > you may be in a better position to play with this, geographically
> > speaking, than i am -- we're running low on sunlight these days.
> > the hysteresis is currently hard-coded in powerd -- you'll find it in
> > the function ambient_adjust_init(). it only gets set once, though, so
> > after powerd starts, you can change the limits directly and they
> > should take effect immediately.
> > additionally, to cause auto-monochrome to happen, uncomment the
> > obvious lines at the end of set_brightness() and brightness_ramp().
> > paul
> > >
> > > Tony
> > > _______________________________________________
> > > Devel mailing list
> > > Devel at lists.laptop.org
> > > http://lists.laptop.org/listinfo/devel
> > =---------------------
> > paul fox, pgf at laptop.org
> > _______________________________________________
> > Sugar-devel mailing list
> > Sugar-devel at lists.sugarlabs.org
> > http://lists.sugarlabs.org/listinfo/sugar-devel
> > _____________________________________________________
> > This mail has been virus scanned by Australia On Line
> > see http://www.australiaonline.net.au/mailscanning
paul fox, pgf at laptop.org
More information about the Sugar-devel