Screen Blanking or Headless GUIs to Save Battery?

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Hi, are there laptop independent means of permanently turning off the screen
when running on battery? How much battery life would I gain by doing so?

Better yet, does Vista or Linux (X and Gnome) support running the GUI
headless, such that the image is not drawn in the first place, and if done
smartly, all event handling related to drawing could be skipped to save the
CPU and battery. As long as keyboard focus handling and the accessibility
trees of the GUI work correctly, I'm quite happy without the GUi ever being
rendered on-screen, <smile>.

That is, I'm legally blind and use the GUi from the keyboard with a screen
reader speaking and Brailling what's going on, thus not needing the actual
screen, since I'm the only user of the machine. Though I SOMETIMES use HEAVY
magnification on desktop MACHINES, laptop screens are so hard to get very
close to ergonomically, that I wouldn't mind killing the output totally.

I've blanked my screen reader equipped Nokia phone's screen using brightness
1 and do find the battery lasting longer than with full brightness. So it
occurred to me to ask if screen blanking can be done for laptops, too., and
whether it is worth it if you're into hacks in the first place.

If brightness is not laptop independent, howabout laptop specifics? My
current laptop is the HP NX8220 I'm planning to run Ubuntu in after XP. I do
find the laptop specific keyboard based brightness adjustment doesn't go all
the way to blackness, though. My next laptop will be the Lenovo T61 largely
due to the keyboard and quiet operation, so any experiences related to its
screen brightness would be appreciated. I've read it has an app for
stretching the battery life in Vista, so could I possibly disable the screen
by tweaking that app's settings? I suppose Linux has more tweaking options,
such as dummy display drivers for X, if you do know what you're doing.
Vista's Aero has to be disabled for screen reader's anyway, as they hook GDI
calls at the driver level.

With kind regards Veli-Pekka Ttil
Accessibility, Apps and Coding plus Synths and Music:

Re: Screen Blanking or Headless GUIs to Save Battery?

Veli-Pekka Ttil typed on Sat, 12 Jul 2008 19:14:19 +0300:
Quoted text here. Click to load it

The easiest way to hack the laptop display to be permanently is to unhook
the LCD cable from the motherboard or the video card. I don't know if the
model you have will complain or not without a display and fail to boot?

Another thing that works great, but it requires an external monitor. Is to
fire up the laptop connected to the laptop and configure the laptop to use
the display. Once the OS is loaded, you can turn off the external monitor or
even pull the VGA cable off. Once you use Standby, hibernation, or power up
again, you usually have to repeat the process.

As for saving battery power with the display off. It does, but usually like
10 to 20% longer life. Which isn't that much if you ask me. I am using an
UMPC called an Asus EEE PC with an 10400mAh battery (this size can only be
found on eBay so far) which gives me 6 to 7 hours worth of battery power. I
dunno, maybe that gives you some ideas.

Windows XP Home SP2

Re: Screen Blanking or Headless GUIs to Save Battery?

BillW50 typed on Sat, 12 Jul 2008 12:36:22 -0500:
Quoted text here. Click to load it

If it helps, I just tried this with my Gateway MX6124 laptop. And it didn't
complain at all that I had the LCD disconnected from the laptop. Boy is this
laptop light without the top half. It wouldn't be bad to leave it this way
except that the WiFi antenna is glued in the top half and running without
it, range is terrible. Just barely 10 feet. LOL

Windows XP Home SP2 - 10400mAh

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