On a T61 I have 16 steps (0 to 15) all accessible under Fluxbox, and less (but bigger) under KDE or XFCE.
It seems that both KDE and XFCE make "big steps" in grouping it somehow.
But you can set it yourself in a terminal or xterm, e.g.
Code:
bash-4.2# pwd
/sys/class/backlight/acpi_video0
bash-4.2# ls
actual_brightness bl_power brightness device max_brightness power subsystem type uevent
bash-4.2# cat max_brightness
15
bash-4.2# cat brightness
3
bash-4.2# echo 10 > brightness
bash-4.2# cat brightness
10
bash-4.2#
The exact directory differ upon models, there is a /proc interface also but which could be deprecated.
To know more, read /usr/src/linux-3.2.23/Documentation/laptops/thinkpad-acpi.txt
PS You can set some parameters when loading the driver, see the documentation and (as root) "modinfo thinkad-acpi" for a summary.
