Database Info

Set brightness even lower to increase battery

Hi all,
i just want to suggest looking at a possibility of having the minimum brightness set to even lower than it is allowed now: to increase battery capacity.
this is possible with:
# echo 8 > /sys/devices/platform/trout-backlight.0/leds/lcd-backlight/brightness
but the problem is the change isn't permanent.
somehow after the screen is off and is turned on again the os sets the brightness back.
yes, even the minimum brightness in the settings is still higher than this.
thanks

This would be very helpful.
I've seen my brightness at -2% in Usefull Switchers before, so it's do-able I'd think.

How can you dim the screen further?

Hey Everyone,
As has been mentioned many times in other threads:
1) The LCD is often the biggest battery drainer
2) The 'minimum' setting of the brightness setting is still needlessly bright.
It certainly can be pushed further down for dim/night/dark settings.
3) Certain apps "dim" the screen but are just changing the color, not the backlight. So while useful they still aren't helping your battery.
Following some tips from a different android phone, I found this file:
/sys/devices/platform_/nov_cabc.0/leds/lcd-backlight/brightness
Which appears to contain the current 'brightness #' of the LCD backlight.
Using the normal Brightness slider, the value changes from 30 - 255, with 255 being the brightest. So this clearly could be reduced further.
Setting 'Screen Filter' to 50% brightness has no effect on the value.
Here's something interesting:
Assume the screen is already set at lowest brightness.
When I use 'Widgetsoid' to set brightness to '1', the screen dims slightly, then brightens back up. The 'brightness' file gets set to 20.
'widgetsoid 20' feels the same as 'min brightness 30'. - I wonder if Android is enforcing minimum backlight?
Anyway, thought that would be interesting to note. I'm going to download some other screen dimmer apps and see what they do.
- Frank

I found this online which is very interesting reading:
http://www.scribd.com/doc/35972886/An-Analysis-of-Power-Consumption-in-a-Smart-Phone
At '30' they said the display consumed 7.8 mW, while at 255 it consumed 414 (!!!)
Various apps coud push the value to 20 - tasker, adjbrightness.
Tasker tries to set it lower but as with widgetsoid, you can see the screen get forced back up to 20.
adjbrightness can "set" it lower than 20, but the entire screen blacks out, even at 19. Remember where the other buttons are so you can restore brightness!
- Frank

Whoa, thanks for the information. That pretty insane but its an apparently in the Market: Screen Filter, saves a helluva lot of battery.
Edit: Nevermind, Frank shut me up LOL.
Sent from my HTC Glacier using XDA App

I read a thread that said that the stock rom just doesn't allow setting it that low.
Ah well
- Frank

ChodTheWacko said:
I read a thread that said that the stock rom just doesn't allow setting it that low.
Ah well
- Frank
Click to expand...
Click to collapse
Can you set it lower in other roms - like cm7?

netter123 said:
Can you set it lower in other roms - like cm7?
Click to expand...
Click to collapse
I've been playing with CM7 which has some nice features for customizing the auto-brightness settings as well as the "dim" value which seems to be the lowest value the screen will go to and what it gets set to when the screen dims before shutting off after a timeout.
For the Dim setting in CM7, the default is 20. The next highest setting in the picker is 18. I believe it goes down to 0 or 1. When set to 18 or lower the screen blanks out completely when dimmed. Depending on how you test this, you may have a problem getting the screen back, so be careful you know where your widget button is on the screen to bring it back... 20 seems to be the lowest value. However, while dim, in a very dark room it could certainly be even dimmer so I don't know why lower values don't work.
I've also found the light detector doesn't seem to detect a continuum of light levels. It seems to be quantized at particular values, so there's a pretty hard limit on how fine you can set the auto brightness levels since the lowest light reading it seems to take is not very sensitive. It can't seem to distinguish between a fully darkened room and a dimly lit room, so setting the lowest value automatically makes the screen too dark to be comfortable in many environments, but then too bright for a really dark room. I don't know if this is an issue with the ROM software or a hardware limitation of the sensor. I've set my lowest auto setting to 40 which seems to work well, then I manually switch it to the dim value (20) if I'm in the dark.

[R&D] Settings Screen Brightness API Issue

I am writing an application that changes the brightness, and I noticed that the Skyrocket does not return the proper values.
Using the Settings class if I call:
Settings.System.getInt(resolver,Settings.System.SCREEN_BRIGHTNESS);
25 is returned the first time regardless of the system brightness. If I call it again, then the proper value is returned.
Can you guys confirm or deny this issue? I've tested on another phone and emulator, which work as documented.

wrong thread somehow. wat.

My screen doesn't keep it's brightness settings when I use another program besides the built-in brightness changer in the Settings menu. If I set it low and I lock it, it always comes back up to full brightness after I turn it back on. Weird.

Seems that the T989 t-mo variant has the same issue with CM7's display tweaking utilities. Something in the hardware seems to always make it come back on at a hardcoded predefined brightness.

Hi,
As I recall from poking around the kernel source, there are some routines that intercept the value passed from the ROM and tweak it a bit before actually applying it to the screen.
Take a look at ./drivers/video/msm/lcdc_ld9040.c in the kernel source, IIRC there are some hardcoded values in here that might be resulting in your reading of 25 (I think there is a minimum value of 24 set somewhere in there, been a while since I looked)

Too high brightness?

Is there a way to lower the brightness of the screen, lower than the Low setting? At the Low brightness, its still to high to use in the dark.
Any reg hack or something?

Bump, anyone?

If you use the adaptive lighting (automatic adjustment), it should be pretty dim in a dark room.
If that's not enough, there are probably regisrty settings that control the brightness at each level, but you'll need to find them and figure out how to modify them.
I suggest starting with the Registry Tweaks thread on the dev & hacking sub-forum. Somebody may have discovered it already. Search is your friend!

GoodDayToDie said:
If you use the adaptive lighting (automatic adjustment), it should be pretty dim in a dark room.
If that's not enough, there are probably regisrty settings that control the brightness at each level, but you'll need to find them and figure out how to modify them.
I suggest starting with the Registry Tweaks thread on the dev & hacking sub-forum. Somebody may have discovered it already. Search is your friend!
Click to expand...
Click to collapse
I did search, I'll see again, btw, I am using adaptive lightning, and it hurts my eyes. but on manual setting set to low, it's convenient, thx for the reply

wish there was a lower setting as well.
I notice right before the screen auto turns off after 30 seconds, it dims slightly lower than it can be set to via settings.

Did anyone found the registry to change for the brightness?

Fix adaptive brightness (windows rt/8)

I customized a luminosity curve for my surface rt, just edit the registry keys.
Download extract and run the attached .reg file and confirm the insertion of the Keys, then reboot the system.
Alert to make a backup of the old keys if you want to restore the previous state.
This change is compatible with all windows 8 but I have tested only on the surface.
Adaptive brightness varies proportionally to the user manual brightness, I suggest to manually adjust the brightness bar to about 20%, if you place the bar at 0 the brightness will be minimal with no automatic adaptation.
Appreciated thanks
New version v2
New improved version.
Try it and tell me if it's okay.
In the zip you will find the normal version and one with more brightness in the dark
I suggest to manually adjust the brightness bar to about 25%

So you have a fix, that's great. But to what? You didn't state what the problem is. Neither did you way what you are doing differently over the default values. Why would me, or anybody else for that matter, want do download this?

Amax said:
So you have a fix, that's great. But to what? You didn't state what the problem is. Neither did you way what you are doing differently over the default values. Why would me, or anybody else for that matter, want do download this?
Click to expand...
Click to collapse
In my surface the luminosity curve does not satisfy me.
The display seemed to have only three levels of brightness, setting an average value (ie on the desk in the room in the morning) adaptivity did not fit values ​​for low-light (night) and lots of light, that is to say the brightness in the dark was not a minimum making it annoying for the view and unnecessary consumption of battery, instead with shaded light levels brightness became easily maximum, with again a waste of battery.
This forced me to move often the brightness bar manually, but now with my calibration does not touch more because it adapts automatically to any light condition.
Also the adaptation of brightness occurred after 3 seconds by the change of light, whereas now changes instantly in 0,1 seconds (100ms).

I like it a lot, just what I was looking for.
I use mostly in low light conditions my surface so it is very useful.
Just one remark: it is too sensitive so it is changing screen brightness very quickly even when I just touching the upper part of the screen and making a little shade on the light sensor...
So I think instead of 1 msec. would be better 3 msec.
Would you please and make a 3. version of the settings with 3 msec.?

Alapar said:
I like it a lot, just what I was looking for.
I use mostly in low light conditions my surface so it is very useful.
Just one remark: it is too sensitive so it is changing screen brightness very quickly even when I just touching the upper part of the screen and making a little shade on the light sensor...
So I think instead of 1 msec. would be better 3 msec.
Would you please and make a 3. version of the settings with 3 msec.?
Click to expand...
Click to collapse
100ms not 1ms! However, this file will change only the time in 300ms

antys86 said:
100ms not 1ms! However, this file will change only the time in 300ms
Click to expand...
Click to collapse
You are right, 100 ms. I was in a hurry. Thanks for the fast response and update

Your v2 seems to be working fine for me. Before applying it I could really tell when my surface was adjusting the screen, after applying it the transitions seems smoother and less abrupt.
I have been looking for documentation about how all of these things really work and the closest thing i could find was this link http://superuser.com/questions/644538/customize-adaptative-brightness-in-windows-8
but they seem to be using a different registry location than what you are and different registry names
regardless your settings seem to work immediately after restarting the sensor service