Xubuntu LTS 14.04 Toshiba Satellite - No Brightness control

[kotelyan]

Just installed Xubuntu LTS 14.04 on the new Toshiba Satellite C75D-B.
Running Xfce.
Brightness control is not working.
Slider control on Brightness Plugin moves, but does not result in any brightness change. it looks like it is at maximum.

I checked this thread <http://ubuntuforums.org/showthread.php?t=2216428&page=2>, but it seems like my case is different.

cat /sys/class/backlight/acpi_video0/brightness

shows that moving the slide does change the value in the file.

[tgalati4]

Install acpitool. Open a terminal:


sudo apt-get install acpitool



-l x Set LCD brightness level to x, where x is in the range 0..7. Works only on Toshiba and IBM Thinkpad laptops. Requires write access to
/proc/acpi/tochiba/lcd or /proc/acpi/ibm/brightness
Illegal values for x will result in the value being set to either 0 or 7.


Try using:


sudo acpitool -l 7
sudo acpitool -l 3

It's possible that you just need read access to the LED state variable:


sudo chmod 777 /sys/class/backlight/acpi_video0/brightness

[kotelyan]

I have tried that. acpitools was installed already, but I re-installed it just in case. It Didn't help.
I am getting the message that file /proc/acpi/tochiba/lcd does not exist.

I can write into /sys/class/backlight/acpi_video0/brightness
and in fact, when I move the slide in Brightness Plugin - the value does indeed change.

[kotelyan]

Thanks, acpitool was already installed, I re-installed it just in case, here is what I get:
sudo acpitool -l 7
Could not open file : /proc/acpi/toshiba/lcd
You must have write access to /proc/acpi/toshiba/lcd to change the LCD brightness level.
Or ensure yourself you are running a kernel with Toshiba ACPI support enabled.

It turns out there is a folder /proc/acpi, but no such file - /proc/acpi/toshiba/lcd :-(

ls /proc/acpi
ac_adapter battery button toshiba wakeup