The screen auto brightness has always bothered me. I love the convenience of using it but it simply doesn't work like I believe it should.
For example. At night while laying in bed in a completely dark room I'd expect the screen to dim to it's lowest setting. When in actuality it does not, and it always seems to bright. On the other hand when I'm outside in direct sunlight I'd like for the brightness to be at 100%. Again this doesn't appear to be the case.
So what's the issue here? Is there a dev out there who has found a better solution?
I agree with you on this one. The automatic brightness on the EVO is just silly. Its lowest is 25%, by the way. There should be a way to choose what you want the minimum/maximum brightness to be :\
I've seen this question before, some time ago, but still no solution. I've seen someone say use total screen control trial (free in market) and tweak the filter settings to essentially do the dimming value you want.
blakeboys said:
I've seen this question before, some time ago, but still no solution. I've seen someone say use total screen control trial (free in market) and tweak the filter settings to essentially do the dimming value you want.
Click to expand...
Click to collapse
I have been searching and searching for an answer to this. I don't want to have to use third party programs if I could just change the thresholds myself.
In Calkulins rom he says he lowered the maximum auto brightness to save on battery, and this question has been asked there, with no answer (except for the usual "just use this program to do it").
Someone has to know where the settings for this are. I'm getting more advanced at dealing with apk's, jars, etc... But I haven't been able to find which one controls this. Build.prop has some brightness settings in it, but it's just the default setting when not using auto-brightness (I think).
Anybody ?!?!?!?!?!?!?!?!?
I know it's possible, because Cyanogenmod has the option to tweak the levels in CM Settings.
I just know I've seen an app here on xda, but don't remember what it was.
plainjane said:
I know it's possible, because Cyanogenmod has the option to tweak the levels in CM Settings.
I just know I've seen an app here on xda, but don't remember what it was.
Click to expand...
Click to collapse
I know it must be here too but but searching comes up with nothing new. I've tried autobrightness, auto-brightness, with min and max levels, thresholds, custom settings and every other search I could think of.
Maybe I'm leaving out the one keyword that would finnd it... lol
http://forum.xda-developers.com/showthread.php?t=901540 he had some settings for it he might be able to help
Sent from my unrEVOked using xda app
roscoenr said:
http://forum.xda-developers.com/showthread.php?t=901540 he had some settings for it he might be able to help
Sent from my unrEVOked using xda app
Click to expand...
Click to collapse
Thanks for looking, but unfortunately I've been there already. It basically allows you to toggle between auto brightness and a variety of static levels, but doesn't affect the min and max of auto brightness when you are in that mode.
I'm trying to be able to leave the phone in auto brightness mode all the time and just have the screen get to it's max available brightness when I'm in a bright area, and minimum available brightness in a dark area.
fgr said:
I know it must be here too but but searching comes up with nothing new. I've tried autobrightness, auto-brightness, with min and max levels, thresholds, custom settings and every other search I could think of.
Maybe I'm leaving out the one keyword that would finnd it... lol
Click to expand...
Click to collapse
I did a quick search too, but I couldn't come up with what I saw before. I remember thinking "neat, but I don't need that because it's built into the Rom". It's driving me nuts now too :/
You could always contact one of the devs from CM & find out what files need to be edited.
Basically it sucks. It actually drives to crazy so I just don't use it anymore. When I am on tapa I put the background to black so it's a bit easier on the eyes when I am laying in bed going through the forums before sleep
Related
I was wondering if there is anyway to lower the brightness of the display even further than the lowest setting on Andriod. I realized I used the phone a lot in the dark ( i take long walks at night) and the lowest setting is still too bright for my eyes.
Anyone know an app or someway of lowering the brightness even further?
thanks in advance.
have you try an application filter screen, it is available on market...
fajarep said:
have you try an application filter screen, it is available on market...
Click to expand...
Click to collapse
O man Thank You so much. This makes my daily walks while reading the news a lot more enjoyable.
sure, no problem, i love that application too, but can't find a way how to enabled it automatically each time restart
So as everyone knows our brilliant screen and auto brightness eat batteries like candy. Many people, understandably, disable auto brightness to conserve battery life. I haven't gone that far yet as I do use my phone in many different environments and enjoy the dynamic brightness. With that said auto brightness does set the brightness unnecessarily high.
Would it be possible to adjust auto brightness so that it still functions but sets brightness 10-20% (or a user specified value) lower than normally?
I'm not sure this would save as much battery as statically setting the brightness (is it the "auto" adjustment that drains battery or the brightness it sets it at?) but I'm sure it would be better than stock auto brightness.
You cannot do this from stock rom to my knowledge, but I'm sure there is a custom rom that will allow you to do this. You might have to search around a bit though.
I wrote an app that allows you to set custom auto brightness behaviour. You can check out the free version here.
Cyb3rGlitch said:
I wrote an app that allows you to set custom auto brightness behaviour. You can check out the free version here.
Click to expand...
Click to collapse
Cool, question: will this actually reduce battery usage or possibly cause more by enabling so many extra features?
If you're willing to rebuild android from source you could try changing device/samsung/tuna/overlay/frameworks/base/core/res/res/values/config.xml to have a more subtle brightness adjustment.
Or maybe running yet another app is easier in the meantime... But maybe someone who builds custom roms might want to hack at it...
The juice defender app has a schedule for brightness i believe, So it will come on automatic during the times frames you set..good luck
textshell said:
If you're willing to rebuild android from source you could try changing device/samsung/tuna/overlay/frameworks/base/core/res/res/values/config.xml to have a more subtle brightness adjustment.
Or maybe running yet another app is easier in the meantime... But maybe someone who builds custom roms might want to hack at it...
Click to expand...
Click to collapse
Ah thanks that's what I was looking for. You can't mod this file directly without rebuilding from source? Would be cool to be able to apply this to any ROM.
Sent from my Galaxy Nexus using XDA App
wish777 said:
The juice defender app has a schedule for brightness i believe, So it will come on automatic during the times frames you set..good luck
Click to expand...
Click to collapse
Thanks, not exactly what I was looking for though. It has to be more dynamic than a hard schedule.
Sent from my Galaxy Nexus using XDA App
Editing default auto brightness levels was a Cyanogen 7 feature. If it hasn't yet been added into CM9, it'll eventually get there.
Sent from my Galaxy Nexus using Tapatalk
phishie said:
Ah thanks that's what I was looking for. You can't mod this file directly without rebuilding from source? Would be cool to be able to apply this to any ROM.
Click to expand...
Click to collapse
Seems this thread has figured out a lot more about this http://forum.xda-developers.com/showthread.php?t=1377410
I don't know how easy it is to patch the existing apk. Seems possible.
Cyb3rGlitch said:
I wrote an app that allows you to set custom auto brightness behaviour. You can check out the free version here.
Click to expand...
Click to collapse
Sounds good, unfortunately useless in free version and I have no card to buy payed one
pesho00 said:
Sounds good, unfortunately useless in free version and I have no card to buy payed one
Click to expand...
Click to collapse
Why is it useless? I have been playing with it since yesterday and really like it, much better than system auto brightness. I don't really feel it's missing anything it the free version though I'm pretty sure I'll buy it just to support the developer. Very nice app.
pascanu said:
Why is it useless? I have been playing with it since yesterday and really like it, much better than system auto brightness. I don't really feel it's missing anything it the free version though I'm pretty sure I'll buy it just to support the developer. Very nice app.
Click to expand...
Click to collapse
Same here, it is a very nice app! I love how I can customize the brightness to match my environment and needs.
In my case, I selected "auto brightness inly on wake" in Lux Auto Brightness and it is draining battery. I paid for it but I am going to uninstall it.
Please Vito, let us know how to improve battery with Lux configurations. Thaks
While I can't provide any input on Lux, I also wrote an custom auto brightness application which can be found on Market here.
The market version isn't really good on Gnex though, you may just contact me and I'll send you the last dev version, it is now alright. I myself have a GNex and now it's alright. It would take me about 2 weeks till I'll be able to update Market version, most likely - there are enough things to add.
Screen Dimmer
The minimum screen brightness is too damn bright to use in the dark.
Run the app, click "Load" next to "n5dim", change your brightness to the minimum (and then up a bit and back down) and notice how much dimmer it is.
The brightness at all other levels stay the same.
Source: https://github.com/mzhou/n5dim
Fast Charge
This works by setting the registers on the bq24192 charger chip to allow as much input current (from USB/AC) as possible, as well as allowing as high a charge current as possible (to the battery).
From limited tests I've performed in the past, this actually isn't enough to get faster charging, so further investigation will be needed, though your testing will be much appreciated.
It will take effect on the first time you plug in after clicking "Load". If you're already plugged in, you need to unplug and replug for it to take effect.
Source: https://github.com/mzhou/n5charge
General
To use either of these, you need any kernel which supports modules (CONFIG_MODULES=y).
I've attached (modules_boot.img) a stock kernel with the config changed to support modules.
modules_441_boot.img is for 4.4.1, while modules_boot.img is for 4.4.0.
Does this dim further than setting '1' in /sys/devices/mdp.0/qcom,mdss_fb_primary.160/leds/lcd-backlight?
(Also I noticed your CSE email, a fellow UNSW student?)
Cyb3rGlitch said:
Does this dim further than setting '1' in /sys/devices/mdp.0/qcom,mdss_fb_primary.160/leds/lcd-backlight?
(Also I noticed your CSE email, a fellow UNSW student?)
Click to expand...
Click to collapse
Yes. Dragging the brightness slider to the minimum already sets 1 there.
There's values hard coded in the platform data to internally restrict the value to a minimum of 5 (but that's of little consequence).
The main gain is is from the "full scale current" (you can find an explanation in the datasheet for lm3630) which has been hard coded to 18 in the platform data. Bringing it down to 0 makes a huge difference.
(sup)
Nice work! I wonder why they limited it. Possibly to stop people putting their phone into an unusable state during the day?
Cyb3rGlitch said:
Nice work! I wonder why they limited it. Possibly to stop people putting their phone into an unusable state during the day?
Click to expand...
Click to collapse
I've done it to myself many times when I did this to my old phone.
Also updated the attachment in the OP to be compatible with more kernels.
Tested working on Franco.
Very cool! :good:
AWESOME! Is there maybe a mod like this for the NN7 (new nexus 7 )
Is there any advantage to this method over using an app like lux?
Sent from my Nexus 5 using XDA Premium 4 mobile app
adzjwarner said:
Is there any advantage to this method over using an app like lux?
Sent from my Nexus 5 using XDA Premium 4 mobile app
Click to expand...
Click to collapse
No app will be able to get the backlight this dark.
I'm not sure what Lux does, but if it modifies the colours to produce a darkening effect, then the contrast will be very bad.
adzjwarner said:
Is there any advantage to this method over using an app like lux?
Sent from my Nexus 5 using XDA Premium 4 mobile app
Click to expand...
Click to collapse
Hey there, I'm actually the developer of Lux. The main purpose of Lux is to replace your auto brightness system without the need for root access. That being said, there's no reason why this neat kernel module couldn't be added to a root plugin for Lux.
Cyb3rGlitch said:
Hey there, I'm actually the developer of Lux. The main purpose of Lux is to replace your auto brightness system without the need for root access. That being said, there's no reason why this neat kernel module couldn't be added to a root plugin for Lux.
Click to expand...
Click to collapse
Ah cool.
I tried out Lux and I'm not sure if it's a limitation in the free version, but it only sets the backlight brightness (/sys/class/leds/lcd-backlight/brightness) to a minimum of 10 before it starts doing colour adjustment instead.
My module treats the value 1 as special for making the backlight super dark. Dragging Android's built in brightness slider uses the full range of values 1-225 inclusive.
There's no reason it couldn't just map the full 1-255 to a wider range, but I initially wanted to lean towards keeping things as stock as possible.
arararagi said:
Ah cool.
I tried out Lux and I'm not sure if it's a limitation in the free version, but it only sets the backlight brightness (/sys/class/leds/lcd-backlight/brightness) to a minimum of 10 before it starts doing colour adjustment instead.
My module treats the value 1 as special for making the backlight super dark. Dragging Android's built in brightness slider uses the full range of values 1-225 inclusive.
There's no reason it couldn't just map the full 1-255 to a wider range, but I initially wanted to lean towards keeping things as stock as possible.
Click to expand...
Click to collapse
It does that because some devices do silly things near 0 like putting the device to sleep. You can change the minimum brightness in settings to 1 which should fix this (although I suspect it might round 0.01*255 to 2. I'll have to check my codebase).
Cyb3rGlitch said:
It does that because some devices do silly things near 0 like putting the device to sleep. You can change the minimum brightness in settings to 1 which should fix this (although I suspect it might round 0.01*255 to 2. I'll have to check my codebase).
Click to expand...
Click to collapse
Somehow overlooked that when I was skimming the settings. (And it does round to 2 ).
I could make 2 or anything less than 5 special so that Lux users can benefit. Or maybe just make it configurable with a parameter at insmod time...
arararagi said:
Somehow overlooked that when I was skimming the settings. (And it does round to 2 ).
I could make 2 or anything less than 5 special so that Lux users can benefit. Or maybe just make it configurable with a parameter at insmod time...
Click to expand...
Click to collapse
Whatever you feel works best. A parameter sounds like the most flexible solution though.
This is exactly what I was looking for!
Could I get a bit more explanation of how to install this though? Do I flash the kernel in recovery and then run the command from a shell on my phone, or on my computer?
Thanks for making this.
Sent from my Nexus 5 using xda app-developers app
I'll be watching this thread intently. I currently use lux as well.
rockingondrums said:
I'll be watching this thread intently. I currently use lux as well.
Click to expand...
Click to collapse
Ditto!
Sent from my Nexus 5 using XDA Premium 4 mobile app
Nelsocracy said:
This is exactly what I was looking for!
Could I get a bit more explanation of how to install this though? Do I flash the kernel in recovery and then run the command from a shell on my phone, or on my computer?
Thanks for making this.
Sent from my Nexus 5 using xda app-developers app
Click to expand...
Click to collapse
Flash the kernel in whatever normal way you choose.
Extract and copy n5din.ko to your phone.
Use root and put it in /data so that apps with SD card access can't mess with it.
Run "insmod /data/n5dim.ko" on your phone. This can be with a terminal emulator or adb or script manager.
I'm probably gonna be making more modules so I might make an app to simplify the process.
Cyb3rGlitch said:
Hey there, I'm actually the developer of Lux. The main purpose of Lux is to replace your auto brightness system without the need for root access. That being said, there's no reason why this neat kernel module couldn't be added to a root plugin for Lux.
Click to expand...
Click to collapse
OhHai! Big fan of the app, it's saved my eyes when internetting in bed for many many months now! (Though I probably should just not internet at night)
I'll leave the plugin stuff to somebody who knows how to do that and rejoice when(if) it happens. :good:
arararagi said:
Flash the kernel in whatever normal way you choose.
Extract and copy n5din.ko to your phone.
Use root and put it in /data so that apps with SD card access can't mess with it.
Run "insmod /data/n5dim.ko" on your phone. This can be with a terminal emulator or adb or script manager.
I'm probably gonna be making more modules so I might make an app to simplify the process.
Click to expand...
Click to collapse
That worked perfectly, thanks.
This is really dim! I'm impressed. If you ever decide to modify it like you mentioned earlier so that the full brightness adjustment was available I'd be interested. It would be useful to have access to all the brightness levels between yours and the ordinary minimum brightness.
Sent from my Nexus 5 using xda app-developers app
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%
Someone asked me why I did this!
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).
Awesome, didn't know windows could be modded to do this! On a more related note, isn't the update interval a bit too high? 30x faster than normal seems a bit excessive and the battery drain would be very much more. If it is not too much trouble, could you perhaps make a version that updates every 1 second? This way people can download whichever one suits them best.
Thanks
version 1sec
It is not the refresh rate of the sensor, but the time between changes in display brightness because of lighting conditions.
This parameter does not affect the battery consumption.
However, to keep you happy I attach the version by 1 second.
Tell me if the curve satisfy you in different light conditions.
Thank you, going to try it out now. What do you mean it is the time between changes of brightness? Shouldn't the brightness only change when the sensor detects it? Or is this a filtering via an average for the time period method?
Going to try out both of them to see the differences. Will report back here.
Back!: guess I understand what you are saying, the timing is just the gap between the different brightness levels, not the sensor reading. Sorry for the confusion caused.
I found the 1 sec one to not have a wide enough brightness range, but your original 0.1 sec one works perfectly. Using it now!
Thanks again!
Yes, is the time to change between the different levels of brightness.
1 sec or 0.1 sec, the luminosity curve is the same.
Just for curiosity on what hardware you have tested?
I'm using it on a surface rt. But now I notice in the dark, I can't manually increase brightness anymore. I didn't backup my registry either, but its okay.
Edit: I can edit the brightness manually if I disable the auto brightness under settings
more light night
My intent was never to touch the brightness bar!
In this version, setting the bar more than about 25%, I raised slightly the minimum brightness
antys86 said:
Yes, is the time to change between the different levels of brightness.
1 sec or 0.1 sec, the luminosity curve is the same.
Just for curiosity on what hardware you have tested?
Click to expand...
Click to collapse
im using your original version on the Asus T100 and am loving it. Thanks!
I'm happy for you. However, work in progress for a new version.
does this work for laptops as well or just hand-help devices??
Nitro Lopez said:
does this work for laptops as well or just hand-help devices??
Click to expand...
Click to collapse
only if your laptop already has the adaptive brightness feature, check your display settings.
bountygiver said:
only if your laptop already has the adaptive brightness feature, check your display settings.
Click to expand...
Click to collapse
it does.. thanks for the quick reply..:good:
Nitro Lopez said:
does this work for laptops as well or just hand-help devices??
Click to expand...
Click to collapse
Works with all desktop, notebook, tablet in any version of windows 8. Obviously if you have a built-in light sensor recognized by windows
.Hey guys i been using this on the surfaxe pro 2 and i forgot to backup the defualt reg, i have no problems with it , i just wanted to compare wich i like the best, any chance any of you have the default reg backed uo.. thanks in advance
nalrodriguez said:
.Hey guys i been using this on the surfaxe pro 2 and i forgot to backup the defualt reg, i have no problems with it , i just wanted to compare wich i like the best, any chance any of you have the default reg backed uo.. thanks in advance
Click to expand...
Click to collapse
On surface 1 just delete the ALRPoints key for the default curve value, on surface 2 I think is the same.
nalrodriguez said:
.Hey guys i been using this on the surfaxe pro 2 and i forgot to backup the defualt reg, i have no problems with it , i just wanted to compare wich i like the best, any chance any of you have the default reg backed uo.. thanks in advance
Click to expand...
Click to collapse
Here you go
I made a backup before deploying it on my Surface 2 Pro..
Since I applied it just now, I will need to test it before giving comments on how good it works for me..
aaron.helin said:
Here you go
I made a backup before deploying it on my Surface 2 Pro..
Since I applied it just now, I will need to test it before giving comments on how good it works for me..
Click to expand...
Click to collapse
Also doing the restore of your backup, you must delete the key "ALRpoints".
This is the right backup
antys86 said:
Also doing the restore of your backup, you must delete the key "ALRpoints".
This is the right backup
Click to expand...
Click to collapse
ok, thanks for the finishing touch ?
antys86 said:
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%
Click to expand...
Click to collapse
Thanks antys86, I'm using just your ALRPoints values (the morelightnight version) on my Dell Venue 8 Pro, and finally auto brightness is usable! Brightness needs to be set at 100% for me though.
Hi,
is there any way to change brightness to lower level? My previous phone, Xperia Mini, could decrease brightness to absolute black (I didn't need it, but still...). But my Xperia M is still pretty shining in dark even in the lowest level. It burns my eyes. All I could find were some stupid filters. Is there any better solution (root or not, I don't care).
Thanks.
dave_lister said:
Hi,
is there any way to change brightness to lower level? My previous phone, Xperia Mini, could decrease brightness to absolute black (I didn't need it, but still...). But my Xperia M is still pretty shining in dark even in the lowest level. It burns my eyes. All I could find were some stupid filters. Is there any better solution (root or not, I don't care).
Thanks.
Click to expand...
Click to collapse
Click
Gravitybox has some brightness abilities to reassign lux-brightness pairs. Don't know if it can go under normal brightness though...
FindYanot: That's exactly what I don't want. I want something on HW level (lower led (or what they use) intensity), not just transparent black layer.
KoenGo: Do you think, it can work? I don't have root yet (I want do it, if I find solution), so I can't try.
Nobody faced this problem? Everyone is happy with light intensity?
Yes it's too much but if you lower that level screen will probably start flickering which is much more annoying than just too bright screen. This is common, hw related issue that can be found on other devices with low quality lcd.
I'm trying but it's kinda hard to tell if there's any difference since you have to reboot after applying new minimum. I would say there isn't much difference. I'll retry in the dark some time.
Doesn't crash or flicker or anything though, so that's the good news
Personally, I would not root just for this and just use the filters. What is your problem with them? That it uses more battery than a hardware method would, or just that it's impractical? In the second case, lux might be worth looking into. I've never tried it myself since it isn't free, I just use the filter u hate
Tried it in the dark and I believe there is a difference, although very small (barely noticeable) and imho definitely not worth rooting and installing framework.
OK. That's bad, but thanks for your time
Well I rooted my phone and I tried gravitybox and I don't think there is a difference. But still thanks.
My setup now is that I can (de)activate the filter app by swiping over the navigationbar. It's still a filter so it doesn't prolong battery life or anything, but it is a convenient way to enable or disable it.
If you would ever come across something better, please let us know
dave_lister said:
is there any way to change brightness to lower level?
Click to expand...
Click to collapse
Yes, but you need root.
Execute in Terminal or run attached file as script via Root Explorer / GScript:
Code:
#!/system/bin/sh
su
echo 5 > /sys/class/leds/wled/brightness
Minimal stock value 27, we change it to 5 or any other you want.
Maximum value: 255
Bug: backlight will be flickering.
Thank you. It really works! (I rewrite it manually without any script or terminal)
Just one thing. The brightness file is used for current state and when I change intensity in options (or select auto), it's rewritten. So, is there any way to change minimum level permanently (minimum on bar or 0 lux = 5 or something instead of stock 27)? Or is it possible to make some shortcut to rewrite the file with one click? Or use some tasker for it?
But it doesn't matter much. Even this way, without any shortcuts, is awesome. I'll test it in night, but even now (during a day), I can see a difference.
dave_lister said:
So, is there any way to change minimum level permanently
Click to expand...
Click to collapse
Yes, but only by editing file in kernel, it requires recompiling.
Then pulled slider to the left will set really minimal value.
Here commit from ElixER kernel for 4.1.2, originally this trick comes from there.
dave_lister said:
Or is it possible to make some shortcut to rewrite the file with one click? Or use some tasker for it?
Click to expand...
Click to collapse
Yes, GScript app, as far I know can create shortcuts.
Or in Tasker create task with only one action "Run shell" (tick Root) and then create shortcut in launcher.
iks8 said:
screen will probably start flickering which is much more annoying than just too bright screen. This is common, hw related issue that can be found on other devices with low quality lcd.
Click to expand...
Click to collapse
Always was interesting what exactly causing this flickering at hardware side. Led's controller?
Please can you provide any information and example devices with same issue?
Bonoboo said:
Always was interesting what exactly causing this flickering at hardware side. Led's controller?
Please can you provide any information and example devices with same issue?
Click to expand...
Click to collapse
For example galaxy tab 2 (I have one), on the lowest brightnes level it flicker a lot (especially annoying when it's displays white surface), my sister's asus memo pad 7 hd has this issue too but less noticible. Yes, it's somehow related to device's power managment, in galaxy tab 2 forum people saies that it's flicers more when wifi signal is low so as I understand: low signal -> device need more power for wifi -> device gives less power for leds -> screen is more flickering but I could be wrong since I'm almost total electroinc noob I will test that later
p.s.
This issue is really common, even s4 has this problem according to this https://www.youtube.com/watch?v=5yZaQRr76f8 So Sony has done good move with setting so high the lowest brightnes level (at least this hides unusable levels). Really my eyes hurt when I'm using my gtab2 at night although xperia does the same thing but in different way xD
Tested your method and at least in my device, the LED flickering was barely noticeable and only appeared when I set very low values (like 1). Setting as 3 and onwards gives zero flickering here (or I'm just blind, not noticing it)...
You're right. Values about 3, 4, 5 are quite ok.
I made the GSscript shortcut and I¨m finally happy.
I think the flickering is caused by pwr regulation with low frequency. But I'm not electrician either.