Brightness

[kurci2]

Hi everyone!
I have a problem with Kubuntu 12.04
Brightness control doesn't work at all. I am waiting and searching for a fix for the last two months but nothing...

Fn+F6/F7 keys doesn't work and also that slider in power manager does nothing.

Does anyone have same problem, because i really like kde and dont want to switch...

Just for information: I have Toshiba a660 laptop with Nvidia m330 graphic card and i also have nvidia drivers installed.

Please help! =)

[Redblade20XX]

Try pushing this boot parameter:

acpi_backlight=vendor

See here on how to actually do it:
http://askubuntu.com/questions/19486...boot-parameter

Post what happens afterwards!

- Red

[kurci2]

Well, i have already done that, but nothing happened.
Everything remained just the same.

[kurci2]

i have just discovered something really weird today.
I found that tutorial: http://askubuntu.com/questions/57236...op/57610#57610

And when i run command:

ls /sys/class/backlight/*/brightness

i get two options:

/sys/class/backlight/acpi_video0/brightness
/sys/class/backlight/toshiba/brightness

Now, if i use command for example:

echo 5 | sudo tee /sys/class/backlight/acpi_video0/brightness

it changes my brightness, but if i use

echo 5 | sudo tee /sys/class/backlight/toshiba/brightness

nothing happens. Max value is 7.

So now i thing that my system uses wrong command... Is this possible?

[sideshowAnthony]

I had this problem with my Fujitsu Esprimo V6555 laptop, with nvidia graphics, and Ubuntu 12.04.

The solution was (and in detail for newbies reading this):

Press Ctrl + Alt + T to open the terminal

Type this to copy this file to your desktop as a safety measure

cp /etc/rc.local ~/Desktop/rc.local

Type this to edit the original file using gedit (is it gkedit on Kubuntu? I dunno).

sudo gedit /etc/rc.local

If you are asked for a password, enter the password of the root user.

When the editor opens add this line before 'exit 0'

echo 7 > /sys/class/backlight/acpi_video0/brightness

'7' is the brightness level. Save and close this file.

Now reboot your laptop.



If this causes problems, you can always undo the change by copying the file back:

 sudo cp ~/Desktop/rc.local /etc/rc.local

If you are asked for a password, enter the password of the root user.


Source: http://media3000.co.uk/2012/06/fujit...and-ubuntu-12/

[kurci2]

well that made no difference.
But i discovered that when change brightness using keyboard od power manager, it changes value in /sys/class/backlight/toshiba/brightness but as i sad nothing happens on computer.

So if i could make my computer to use acpi_video0 everything would work (i suppose...)

[Cheesemill]

Type this to edit the original file using gedit (is it gkedit on Kubuntu? I dunno).

sudo gedit /etc/rc.local

If you are asked for a password, enter the password of the root user.

Don't use sudo. You should always use gksudo for graphical applications.
Also the password you are asked for is your user password, there isn't a root password in Ubuntu.

[kurci2]

yes, i know that. but it does not help...
but don't forget that i have this problem on Kubuntu 12.04 (Ubuntu 12.04 works fine, i tried)
so command is:

gksudo kate /etc/rc.local

i think...

[kurci2]

I think the question is if it is possible to remove that "toshiba" folder in /sys/class/backlight/ and use acpi_video0 instead...

[kurci2]

i discovered also this:
Ubuntu 12.04 uses acpi_video0 to control brigtness
Kubuntu 12.04 uses toshiba in /sys/class/backlight/ to control brightness

In Ubuntu everything works, but in Kubuntu it does NOT.

How could i change Kubuntu to use acpi_video0??