sudo apt-get install laptop-mode-tools
Laptop-mode-tools also has a very premitive gui where a module can
be checked/unchecked to enable/disable power management for a specific
section of your system.
If the file is found using any of the above two ways (in my case, it
was “/sys/class/backlight/intel_backlight/brightness”), then the process
is pretty straightforward from there. The value inside the
BRIGHTNESS_OUPUT file is the max value for brightness. Anything between 0
and the max value can be chosen as the min value. I had to update the
below values in the /etc/laptop-mode/conf.d/lcd-brightness.conf file (opened with root priviledge):
<min-value> and <max-value> need to be updated with the chosen min and max brightness value where as /sys/class/backlight/intel_backlight/brightness needs to be changed with the actual BRIGHTNESS_VALUE found.
In case of Toshiba laptops, the author of the tool says to use the
command “toshset” with the -lcd or -inten command. Read the toshset(1)
manual page for more information on the parameters for this command. If
you use this command, set BRIGHTNESS_OUTPUT to “/dev/null”.