Hi to all.
it happens that I'm unable to change the brightness of my screen.
Impossible at the moment for me to find the original cause.

Sometimes I'm able to change it by Fn+Left/Right arrows to respectively reduce and increase brightness. Some other times I'm not able to do it, but in turn my laptop hangs or snaps. In those cases, most of the times I should only reboot brutally.

Also, I'm not able to change the brightness properly through the power management applet on the task bar. If i just move the slide bar and click on "apply" nothing happens. If I reduce it through Fn+Left arrow key then sliding the bar just set the brightness to the maximum value, even if the bar is not slid to the right end.

Is it a hardware/driver problem? Please find the lspci | grep Graphics result below:
Code:
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
Thanks,
regards.