Screen brightness suddenly changed

Support & Help Requests
#1

All of a sudden, my screen brightness goes down.

It never did it before.

I tried Brightness Controller v2.2, but it does not work.

Can someone help me?

Thanks.

#2

Hi Fixit,
Have you tried something easy like Power manager brightness applet in panel?
How much your screen low brightness? Do you configure AC and battery preferences unchecking do not attenuate brightness?

#3

There is no power manager applet.

Yes to your 2nd question.

#4

I think @Tim means this applet :

image

#5

Thanks Olek, that is. :slightly_smiling_face:

#6

Maybe try somewhere here :

┌─[✗]─[olek@apbook04u]─[/usr/share/icons]
└──╼ $cat /sys/class/backlight/intel_backlight/actual_brightness 
76

I'm trying to overwrite but :

bash: /sys/class/backlight/intel_backlight/brightness: Permission denied for me

Edit :
sudo -s
cd /sys/class/backlight/intel_backlight
echo 100 > brightness

Try it out :slight_smile:

#7

I installed the applet.

But when I adjusted the slider, nothing happened.

#8

I use a LG 32LK330 32" LCD TV as my monitor.

I have /sys/class/backlight/acpi_video0/brightness

It's value is 50.

Do I change it to 100?

#9

The brightness control is designed to adjust the brightness of a laptop screen or other built-in monitor. I don't think it will control an external monitor or TV used as a monitor. I suspect that the "50" represents that the internal screen is set at 50%.

#10

Well, my brightness used to be bright.

But as of a few hours ago something happened that broke my "brightness."

:frowning:

#11

So the issue is visible on your LG TV display right ? and not on a laptop display ?

Maybe the problem is with the TV. Do you have a other machine to try plug it to the TV to see if the problem persist ?

Good luck :slight_smile:

#12

I do not have another monitor to check.

When I move my mouse, the screen gets brighter.

Then a little later, it gets dimmer?

I tried restoring a image, but no change.

Thanks for your help.

#13

Hi back @fixit7
Are you able to boot a liveCD to get sure it's not a hardware issue on your TV ?

1 Like
#14

I found some picture adjustments on the TV itself.

After the adjustments, the brightness was restored.

1 Like
#15

Hi,

I'm running dual boot (Windows 8 and Mate). I had this problem also: screen very dim. I simply restarted into Windows OS then maxed out my brightness. Logged back into Mate and now I have full brightness as well.

#16

I suggest you to test my script to adjust the brightness:

1 Like