Unable to change the screen brightness (KDE 4 with VESA)


The brightness control keys are not working in my laptop.

System: Dell Inspiron15 3000 series
OS : FreeBSD 10.3
Driver : ATI Radeon R4 (Not supported)...using VESA

Tried several programs such as xbacklight, xbrightness etc, but no success.

Any suggestions?

I am using VESA as my graphics driver since my graphics card (AMD Kaveri - Sea Islands) is not supported in FreeBSD 10.3.

What are the limitations for VESA?

I know that there wont be any 3D acceleration support. But, for the moment I couldn't change the brightness of screen using the keys or by any software method (xbacklight, xbrightness etc). Is this due to VESA? Or something else??

(Already posted in System Hardware, but no replies yet).