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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.

[Kernel Module] Backlight: Lower Brightness (Useful at Night)

(dev only for now, you need to know how to install/load a kernel module by hand/write a init.d script for it)
Hi,
I was annoyed by the too bright backlight especially at night. Even the lowest (non-zero) setting was too bright for me (see my thread in general section).
Thanks to irfanbagus BCM-TWEAK which I could easily adapt here's kernel module to lower the lowest brightness. This means that only the former lowest mode is changed to an even lower brightness, the other modes remain the same.
I've attached a kernel module for this incl. source (based on irfanbagus' source, say thanks to him ).
After loading this module you can simply use the system backlight setter to dim the backlight. In case it was already set to lowest brightness, simply increase the brightness and then decrease it again to apply the updated mode.
This doesn't work with GO Launcher's setting widget's backlight setter and probably also not with other 3rd party backlight setters.
If you test it, please report.
More details about backlight/brightness (see aat1401_bl.c in kernel source if you're interested):
- brightness level is a value in [0,255] (most apps map this to [0,100]%)
- in fact there're just about 25 different brightness levels which a stored in a table, each entry has a 'level' and a 'tune_level' value
- the tune_level (>0) determines the brightness: low level low brightness, high level high brightness
- there's a "lowest" level (30) but only the system setter respects this. This level's tune_level is changed by my kernel module to 1 instead of 2
- system's brightness setter allows no level below 30 thus my mod works good with it
- other setters allow levels below 30 and here is the problem:
The responsible module for setting the backlight brightness looks at the level value in [0,255]. If it's below 30 then a default tune_level of 2 is used.
The GO Launcher widget probably simply sets the level to 0.
I don't know a way to change this default tune_level in a already compiled/running kernel.
So if you want to use another setter, make sure to choose level 30 or about 12% because then my updated tune_level will be used. Usually 12% should map to level 30. If not, I can't help you. Use system setter instead.
Btw to switch backlight off (warning, not recommended) you can use the direct way: echo 0 > /sys/class/backlight/aat1401-backlight/brightness

Found a widget which allows custom brightness values and works fine with my mod: Brightness Widget - Backlight!
Tested with this settings: 30,1,150,255

i am using switch pro widget..range from
0% ----> 100%

ronnieryan said:
i am using switch pro widget..range from
0% ----> 100%
Click to expand...
Click to collapse
0% = no backlight?
Anyway, with my mod you'd have the lowest brightness at 12%.

mikstev said:
0% = no backlight?
Anyway, with my mod you'd have the lowest brightness at 12%.
Click to expand...
Click to collapse
yes, 0% no backlight, but its so inconvenient ..10% is better

Interesting, I'll have a look.
Edit: As far as I see this widget doesn't require root. Even if it could disable backlight (I'm not sure if this is possible) its lowest non-zero brightness is higher than with my mod.

how can i use this sir?

nakawanaoki said:
how can i use this sir?
Click to expand...
Click to collapse
1. Copy the .ko file to /system/lib/modules
2. Set the file permissions to 644
3. Install the module via insmod bl_brightness-tweak.ko (you can also use a init.d script for this, you can adapt the one I uploaded in the droidwall thread)

I am not sure why,
but on trying to turn off screen with "echo 0" it is only get darker, but not completely off.
Is there any way to really turn of screen ?
Thank you,
Ranchu

POCO F2 PRO LOS / Crdroid Decreasing min brightness using livedisplay and Tasker

As some of you already running custom roms are aware, the minimum brightness currently possible in LOS roms ( Pixel experience, Crdroid, LOS) is far too high to be used at night.
Yesterday i figured out that by decreasing RGB values in LiveDisplay ( Settings->Display->LiveDisplay->ColorCalibration) from default 100% to 10% ( lowest possible) i could achieve similar minimum brightness as with my previous phone which i measured at under 1 nits.
Here is the problem: It's a PITA to go through decreasing and increasing values each time you want to decrease the brightness. I have tried multiple solutions but it seems that the only viable one is trough use of Tasker. Here is the catch. I have little experience with its programming language and its UI is confusing at best. Is there anybody here that has experience with tasker and wants to help me with this? My current best approach ( dunno if each part even works yet)
CASE IF BELOW 5% brightness
THEN set Livedisplay RGB to 10%
IF ABOVE 5% brightness
THEN set Livedisplay RGB to 100%
Or just make a widget toggle.

Question 12s ultra LTPO problem (refresh rate) in EU ROM

I think the LTPO2 is not working properly on eu rom currently im on last update 13.0.11 and i can see that the refresh rate is not going to 1fps in main menu or in settings, the frames going only low to 90fps in Facebook and i think this draining a lot of battery. Could you check on your phones how it is, go in developer settings and enable "show refresh rate" to see do you have this problem as well and if there is any solution for that, thanks

mititko123 said:
I think the LTPO2 is not working properly on eu rom currently im on last update 13.0.11 and i can see that the refresh rate is not going to 1fps in main menu or in settings, the frames going only low to 90fps in Facebook and i think this draining a lot of battery. Could you check on your phones how it is, go in developer settings and enable "show refresh rate" to see do you have this problem as well and if there is any solution for that, thanks
Click to expand...
Click to collapse
Adjust brightness.
Screen in FHD+ 60Hz
Minimum brightness: stay at 60
Brightness in the middle: goes to 30
Maximum brightness: goes to 10
With any other settings, the minimum reached is 10.
Surely a particular scenario is needed to reach 1.
You were going to 1 with the stock rom?
https://xiaomi.eu/community/threads...-rate-not-working-correctly.61079/post-650620

NOSS8 said:
Adjust brightness.
Screen in FHD+ 60Hz
Minimum brightness: stay at 60
Brightness in the middle: goes to 30
Maximum brightness: goes to 10
With any other settings, the minimum reached is 10.
Surely a particular scenario is needed to reach 1.
You were going to 1 with the stock rom?
https://xiaomi.eu/community/threads...-rate-not-working-correctly.61079/post-650620
Click to expand...
Click to collapse
Thank you for information, i have never used the phone with stock CH ROM, but now i have realised the brightest is the main thing as well, thanks and it works alright