RADEONFB_BACKLIGHT_MAX
param->max = RADEONFB_BACKLIGHT_MAX;
level = RADEONFB_BACKLIGHT_MAX - level;
else if (level >= RADEONFB_BACKLIGHT_MAX)
level = RADEONFB_BACKLIGHT_MAX;
rlevel = RADEONFB_BACKLIGHT_MAX - level;
level = uimin(RADEONFB_BACKLIGHT_MAX, level + 5);