You are not logged in.

#1 2010-02-27 13:14:10

xCrucialDudex
Member
Registered: 2007-08-19
Posts: 144

Brightness resets

This is something that plagues many users as I've seen but I haven't been able to find a compelling explanation of this issue as well as a solution.

The problem is that a brightness level resets several times during the start up of my laptop (Samsung R-20 X001). It starts with 100% level of brightness and then when init starts it drops to a minimum. If I use Fn keys to set brightness level back to 100% it stays at this level only until I log into KDE. Starting KDM doesn't seem to affect a brightness level but then when logging in and KDE is loading up a workspace the brightness level resets yet again. So, I have to manually (Fn keys) set it back to 100%.

These are the actions that cause a brightness reset:
- changing a Power Profile through either Battery Monitor applet or Battery Monitor Settings in KDE;
- switching to any VC (Ctrl+ALT+F1-F6): an interesting detail to note here is that VC brightness level is at exactly the same value as I set it manually via Fn keys, while going back to X (Alt+F7) always results in lowest level of brightness;
- Resuming from Suspend to RAM results in lowest level of brightness.

It seems I can adjust brightness levels via /proc and /sys but only by decreasing a brightness level. I haven't been able to increase a brightness level by echoing corresponding values into either of these files.

I don't have laptop-mode installed, I do have cpufrequtils and pm-utils installed. This is a very annoying issue that requires an often attendance. Has anybody figured out a way to take control over these brightness levels resets?

Last edited by xCrucialDudex (2010-02-27 13:15:16)

Offline

#2 2011-07-01 06:28:26

Shark
Member
From: /dev/zero
Registered: 2011-02-28
Posts: 684

Re: Brightness resets

Hi

I have the same problem. Have you by any chance solved the problem and if you did what is the solution.


If you have built castles in the air, your work need not be lost; that is where they should be. Now put foundations under them.
Henry David Thoreau

Registered Linux User: #559057

Offline

#3 2011-07-03 06:11:30

xCrucialDudex
Member
Registered: 2007-08-19
Posts: 144

Re: Brightness resets

Shark wrote:

Hi

I have the same problem. Have you by any chance solved the problem and if you did what is the solution.

No, I still experience the described behavior neutral

Offline

#4 2011-07-13 20:57:32

ulit
Member
Registered: 2011-07-13
Posts: 2

Re: Brightness resets

Check if value in /proc/acpi/video/VGA/LCD/brightness (or equivalent in your system - use 'find') has been modified after performing one of the actions you mentioned. If not, write a script which will overwrite the value from /proc/acpi/video/VGA/LCD/brightness with the actual value at, for example, 1-second intervals. Similar idea helped me with a problem with reseting brightness level after reopening the lid.

Offline

Board footer

Powered by FluxBB