Changing brightness does not work in Ubuntu 11.10 after upgrading.

[khosro]

khosro@khosro-laptop:~$ ls /sys/class/backlight/sony
actual_brightness  brightness      power      type
bl_power           max_brightness  subsystem  uevent
khosro@khosro-laptop:~$ echo 5 | sudo tee /sys/class/backlight/sony/brightness
[sudo] password for khosro: 
5
khosro@khosro-laptop:~$ 
khosro@khosro-laptop:~$ 
echo 9 | sudo tee /sys/class/backlight/sony/brightness
9
tee: /sys/class/backlight/sony/brightness: Invalid argument
khosro@khosro-laptop:~$

I do not really know where the problem is?It seems every configuration is OK,but i can not increase or decrease brightness.
I am really confusing.

[matt_symes]

Hi

I have to say i am not sure what the problem is either in this case. If writing to sysfs blacklight brightness is not working then it may be a bigger problem.

Let's see if anybody else has any other ideas.

An upgrade as opposed to a fresh install can be problematic.

Kind regards

[khosro]

Thanks matt_symes for your help.
I remember i had the same issue after upgrading from 10.10 to 11.04,but one of benefit of 11.04 was that we could use Ubuntu classic rather than Unity.I remember that in Ubuntu classic i uninstalled NVIDIA accelerated graphic drivers and then brightness worked and i could increase and decrease brightness via fn+(f5/f6).But it seems Ubuntu Unity needs NVIDIA accelerated graphic drivers to run properly,so that i can not do the same in Ubuntu 11.10.
So that due to this issue and some other issues(such as suspending Ubuntu does not work any more) that i discovered using Ubuntu Unity after upgrading to Ubuntu 11.10 , maybe in future i can not use Ubuntu for my development environment and all of my work,and i really disappointed now,i am not sure but maybe i must again migrate to Windows

Khosro.

[khosro]

Hello,
I am sure the brightness problem is related to NVIDIA graphic driver that Ubuntu installed it after upgrading.Because after uninstalling NVIDIA graphic driver and install GNOME Desktop environment(Ubuntu classic) ,and log in in Ubuntu classic ,increasing and decreasing brightness works.
I do not know why brightness problem related to NVIDIA graphic driver?
I would be appreciate if any one can help me.

Khosro.

[matt_symes]

Hi

Hello,
I am sure the brightness problem is related to NVIDIA graphic driver that Ubuntu installed it after upgrading.Because after uninstalling NVIDIA graphic driver and install GNOME Desktop environment(Ubuntu classic) ,and log in in Ubuntu classic ,increasing and decreasing brightness works.
I do not know why brightness problem related to NVIDIA graphic driver?
I would be appreciate if any one can help me.

Khosro.

This is interesting and may be due to an incompatibility between the nvidia driver and the sony video ACPI platform driver.

This is only a suggestion and may not work but it's worth a try.

Reinstall the nvidia driver.

Open a terminal and type

sudo nano /etc/default/grub

Look for the lines that say

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

and change to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=video"

Run

sudo update-grub

and reboot your PC.

What we are trying to do here is use the standard ACPI video.ko driver and not sonys platform driver.

I don't know if this will work but it's worth the 5 minutes to give it a go.

Kind regards

[khosro]

Hello matt_symes,
I test it,but it does not work.

Khosro.

[daniel.t.miles]

After searching in other places, I found a solution that solved this problem for me. In your /etc/X11/xorg.conf file, find the "Default Device" section and add the EnableBrightnessControl line. After I restarted X (sudo service lightdm restart ... apparently ubuntu 11.10 doesn't use GDM anymore), my FN-key brightness controls worked just fine.

Section “Device”
Identifier “Default Device”
Option “NoLogo” “True”
Option “RegistryDwords” “EnableBrightnessControl=1″
EndSection

[khosro]

Hello Daniel ,
I have upgraded from Ubuntu 11.04 to 11.10.And as i said in one of my last post,i had the same problem in 11.04,and i solved it by uninstalling NVIDIA driver.
Any way,after upgrading to 11.10,there is not any file named xorg.conf in /etc/X11 folder,only files with following name exist:

"xorg.conf.backup" "cursors","xorg.conf.dist-upgrade-201111041549","default-display-manager" ,"xorg.conf.failsafe".

And also ,i remember that i have test your solution in Ubuntu 11.04,but it did not work,and still there is a line that i have inserted in xorg.conf(In Ubuntu 11.04) ,and it seems xorg.conf file in Ubuntu 11.04 renamed to xorg.conf.backup during upgrade to 11.10.
And the following lines reside in xorg.conf.backup :

Section "Device"
	Identifier	"Default Device"
	Option	"NoLogo"	"True"
#	Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

Khosro.

[khosro]

Hi,
I think the following links are related to my problem.
I am not sure whether this comment is true http://www.techrepublic.com/forum/di...351775-3527078.This comment is in this article http://www.techrepublic.com/blog/ope...x-desktop/3226.

Khosro.

[fernandodabadia]

Hello Daniel ,
I have upgraded from Ubuntu 11.04 to 11.10.And as i said in one of my last post,i had the same problem in 11.04,and i solved it by uninstalling NVIDIA driver.
Any way,after upgrading to 11.10,there is not any file named xorg.conf in /etc/X11 folder,only files with following name exist:

"xorg.conf.backup" "cursors","xorg.conf.dist-upgrade-201111041549","default-display-manager" ,"xorg.conf.failsafe".

And also ,i remember that i have test your solution in Ubuntu 11.04,but it did not work,and still there is a line that i have inserted in xorg.conf(In Ubuntu 11.04) ,and it seems xorg.conf file in Ubuntu 11.04 renamed to xorg.conf.backup during upgrade to 11.10.
And the following lines reside in xorg.conf.backup :

Section "Device"
	Identifier	"Default Device"
	Option	"NoLogo"	"True"
#	Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

Khosro.

Hi Khosro.

Thank you so much. It worked so fine. I just changed de section. In my case I added the Option "RegistryDwords" "EnableBrightnessControl=1" in section "Screen".