[SOLVED TEMPORARILY] Mageia 2 - Laptop Brightness is Full

[Tommylee567]

Hi friends,
I really like this distro and have installed the DVD x64 bit version of Mageia 2.
Running on a laptop.

I will jot down the specs of the laptop.

HP DV-6107tx
Intel 2630QM i7 (Sandy Bridge)
640 GB HDD
4 GB RAM
Hybrid gfx: Intel Video gfx & AMD Radeon 6770M
15" wide screen LCD

Do i need to give more info? pls notify that too. I would be happy to help

My problem is simple, i have brightness in full that i can't reduce or adjust. I have used many distros in the past months but none helped. (they all had the same problem)
I'm supposed to adjust the file at /sys/class/backlight/intel_backlight/actual_brightness ----and as intel_backlight i have other two folders as well, acpi_video0 & acpi_video1.


After much time i have installed the Radeon drivers and now the system switches cards well. and i have no heating issues and everything is running stable. But this brightness thing is full i can't get it to dim at a good level.

I searched the forums but no one had problem like i have. So please kindly suggest some ideas.


Thank you!
Tim

[doktor5000]

Which desktop environment are you using?

[Tommylee567]

At present im using KDE. I have all the other desktops also installed. (but they all have the same problem with brightness)

[yankee495]

I have a Toshiba Laptop and it does not allow dimming the back light either. I use the function + F5/F6 to adjust it.

But it does appear Mageia does not have software control over it. I can't remember if 2010.2 did or not.

Running Mageia 2 & KDE.

[Tommylee567]

@yankee495
It seems like its something with the kernel or some other hardware matter. Cause i have used, Suse, Fedora, PCLinuxOS, Puppy, Archbang, Chakra, Porteus, Frugalware, Mint, Comice OS (Pear OS) and all of them have the brightness problem. It is a virus with all of linux and not for a specific distro i think.
I have to adjust the brightness file everytime but i have no permission to do so in Mageia.

Take a look at this post:
http://www.linuxquestions.org/questions ... ost4615780

It solved the brightness problem but not the script. i could not run it well.
We gotta bypass this issue of doing it manually and get it right like running a desktop machine.

Thanks y'all
Tim

[doktor5000]

Please, guys don't mix this altogether. Mostly every laptop vendor has his own custom implemetation and oddities about backlight control and hotkeys handling, and the support under linux greatly varies from working properly out-of-the-box to not working at all/hard to accomplish. In general the best idea is to search for the model of your laptop + backlight + linux and you will most often find wiki pages that describe the problem and give solution or forum threads which often give solutions and describe particular problems with some vendors implementation.

Please keep this structured, if you mix your issues together i won't be able to help you with your problems, i just don't have the time to divide all the individual problems from every thread. That's why there is the golden rule "One problem per thread".

So please guys, can you give a clear statement about the status quo of your problems?

[Tommylee567]

@doktor5000
Im sorry. My problem is on post #1.
Also, for now can you guide me to update the number on actual_brightness file? I tried to open it using vim or leafpad with su permission. but it opens read only.
If you can guide that i can open the file and put the number 250 instead of 4882 for full brightness. I tried it in Pear OS (Ubuntu base) and it worked. but have to edit the file everytime i got to linux.
For now the problem wont be solved so please guide me to manually edit the file.

File is at
/sys/class/backlight/intel_backlight
and the file name is actual_brightness

Thanks!
Tim

[doktor5000]

Actually that's no real file you're trying to edit, /sys and /proc are only pseudo-"filesystems" or directory/file hierarchies. /sys contains al kernel settings, which can be directly changed at runtime, and /proc contains process and system informations.

You can just do an

Code: Select all

echo 250 > /sys/class/backlight/intel_backlight/actual_brightness

as root which writes 250 as the setting in that "file" which is just a representation of the current kernel setting, so you can directly change it on-the-fly. Does it work?

[Tommylee567]

hi Doc,
thanks for the reply.
I was sleeping by the time you posted here. so sorry.
echo 250 brings up permission denied message. Im on SU. and that did not work. that is why i asked why it said permission denied.
any ideas?

Code: Select all

[root@localhost tim]# echo 250 > /sys/class/backlight/intel_backlight/actual_brightness
bash: /sys/class/backlight/intel_backlight/actual_brightness: Permission denied
[root@localhost tim]#


Thanks!

[doktor5000]

Well, maybe you try to change the wrong setting?
For example for me it's /sys/class/backlight/acpi_video0/brightness

Code: Select all

find /sys -name "*bright*"

should show you all occurrences of "bright" below /sys, just try with all those who are from the backlight itself.

[Tommylee567]

Bro, all the links i checked i got permission denied.
Ain't lettin me in!!

I tried everything through as su and says permission denied....
any suggestions?

Thanks!

[Tommylee567]

Solved!

Solution:
I dont know whether this did the job or something else. but i will explain. i added my user group to root and video in the MCC/user (just tick it off).
then i
echo 250 > /sys/class/backlight/intel_backlight/brightness
Notice it is not actual or max brightness, but only the brightness file. and the above command works.
now, how to add it to rc local so it will do it everytime automatically?

Thanks!

I have marked it solved temporarily cause this is not a permanent solution yet

[doktor5000]

I dont know whether this did the job or something else. but i will explain. i added my user group to root and video in the MCC/user (just tick it off).

Please remove at least the membership of root group, as rc.local (see below) is executed as root.

now, how to add it to rc local so it will do it everytime automatically?

Well, just append it there using some text editor as root?

Or you could also do it via

Code: Select all

echo "echo 250 > /sys/class/backlight/intel_backlight/brightness" >> /etc/rc.d/rc.local

[Tommylee567]

Ok i will try it Doc.
I'm just not sure it worked because i added root to the tim group. Not sure. Will try it out

Thank you!
Regards

[doktor5000]

I'm just not sure it worked because i added root to the tim group. Not sure.

If you added the user root to the group tim, than you done it even the wrong way around