Can't Adjust LCD Backlight on Laptop

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jcs
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Can't Adjust LCD Backlight on Laptop

Post by jcs »

All of the function hotkeys I have tested work out of the box except for my backlight controls. Even those appear to work (I can scale the brightness status bar that appears in the top right-hand corner + and -) but the brightness remains at 100% regardless of what level I select.

I have tried xbacklight -set * with the same results. I can adjust the numerical value but the physical brightness of my screen is unaffected.

Any suggestions would be appreciated. I have an Acer Aspire Timeline 4810TZ.

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lagagnon
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Re: Can't Adjust LCD Backlight on Laptop

Post by lagagnon »


uilenspiegel
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Re: Can't Adjust LCD Backlight on Laptop

Post by uilenspiegel »

I'm running mint gloria on an old Dell Latitude C640, but I had the same problem --- brightness was stuck at100%, and neither power settings nor brightness slider affect the actual level of brightness at all.

So I followed the link supplied by lagagnon above, and tried the various things there; I was able to download xbacklight, but the actual commands to set up the backlight control failed.

However I found another clever trick elsewhere in the forum (I've lost track of it now or I'd link) that works great for me:

1. switch to terminal with CTRL-ALT-F1
2. use your laptop's normal brightness keys to adjust brightness --- they will work now
3. switch back out of terminal with CTRL-ALT-F7

I suspect that this will work for a lot of different hardware. Good luck ---

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hernando
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Re: Can't Adjust LCD Backlight on Laptop

Post by hernando »

The solution brought by lagagnon is the best one.

Code: Select all

xrandr --output LVDS --set BACKLIGHT_CONTROL native
To make this run on every restart:
You have to go to System > Preferences > Startup Application Preferences.
Then Click on add. For the name, call it Screen Brightness (or anything you want) and put the code under command. The restart and check if it worked.
The only thing I noticed is that if you leave the laptop without doing anything for a while, the screen start to darken, like starting the energy saver. After to touch any key, the brightness does not return to original brightness.

kate
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Re: Can't Adjust LCD Backlight on Laptop

Post by kate »

hernando wrote:The solution brought by lagagnon is the best one.

Code: Select all

xrandr --output LVDS --set BACKLIGHT_CONTROL native
To make this run on every restart:
You have to go to System > Preferences > Startup Application Preferences.
Then Click on add. For the name, call it Screen Brightness (or anything you want) and put the code under command. The restart and check if it worked.
The only thing I noticed is that if you leave the laptop without doing anything for a while, the screen start to darken, like starting the energy saver. After to touch any key, the brightness does not return to original brightness.
This didn't work for me... any other suggestions?
(Dell Studio 15 Series)

uilenspiegel
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Re: Can't Adjust LCD Backlight on Laptop

Post by uilenspiegel »

kate wrote:
hernando wrote:The solution brought by lagagnon is the best one.
This didn't work for me... any other suggestions?
(Dell Studio 15 Series)
Kate,

Did you try the workaround I suggested above?

1. switch to terminal with CTRL-ALT-F1
2. use your laptop's normal brightness keys to adjust brightness --- they will work now
3. switch back out of terminal with CTRL-ALT-F7

It's not a solution in the sense of getting all your keys to work like they do in windows, but it gets you past the practical problem of not being able to dim/brighten your screen.

kate
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Re: Can't Adjust LCD Backlight on Laptop

Post by kate »

I tried that but I couldn't get the CTRL ALT F1 to cooperate. It gave me a whiny message about configuration and then when I tried to do it again to get the message, it just does a weird little flash at the very top of the screen and then no change. =/

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hernando
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Re: Can't Adjust LCD Backlight on Laptop

Post by hernando »

I'm afraid that this solution is not working for Mint 8.... I just installed it, and this is the first thing I tried with no success.... :(
Let's keep looking around for a solution.

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lagagnon
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Re: Can't Adjust LCD Backlight on Laptop

Post by lagagnon »

Right click on panel, Add to Panel, Brightness Applet - I know it doesn't solve your keyboard problem but hey, it works!

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hernando
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Re: Can't Adjust LCD Backlight on Laptop

Post by hernando »

Didn't work for me... :(
At full brightness my battery drain very fast...

guitar player
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Re: Can't Adjust LCD Backlight on Laptop

Post by guitar player »

Here is the solution that worked for me, it is the third post http://wwww.ubuntuforums.org/showthread.php?t=1311491

kate
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Re: Can't Adjust LCD Backlight on Laptop

Post by kate »

guitar player wrote:Here is the solution that worked for me, it is the third post http://wwww.ubuntuforums.org/showthread.php?t=1311491
OMG! It worked!!! It WORKED!!!!
And then I rebooted again and now it isnt working! =/

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hernando
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Re: Can't Adjust LCD Backlight on Laptop

Post by hernando »

I finally tested the last solution and it really worked for me, even after rebooting !
No screen flickering, still playing videos as before...
So, I can say this solved my problem.

I have an Acer Timeline 4810 TZ with Mint 8 Helena.
kate wrote:
guitar player wrote:Here is the solution that worked for me, it is the third post http://wwww.ubuntuforums.org/showthread.php?t=1311491
OMG! It worked!!! It WORKED!!!!
And then I rebooted again and now it isnt working! =/
Thank you Guitar Player!

soryuu
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Re: Can't Adjust LCD Backlight on Laptop

Post by soryuu »

BEFORE BECOMING DISCOURAGED, TRY GUITAR PLAYER'S SOLUTION. IT WORKED FOR ME!!

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hernando
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Freeze when adjusting LCD Backlight on Laptop

Post by hernando »

Hi, I'm using Ubuntu 10.04 (gnome) and when adjusting the Brightness (with Compiz enabled), the computer totally freezes ! Totally !
If I disable Compiz to No Effects, then it work, but not very smoothly... at least I can adjust brightnes without freezing the machine.

In Mint 9, this has happened to anyone?
Do you know of a Fix besides disabling Compiz?

I have an Acer 4810TZ.

Thanks!

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