My laptop is Lenovo thinkpad T420, I only use the discrete graphic. So, I
install the nvidia drivers from rpmfusion, and the /etc/X11/xorg.conf file is below:

# RPM Fusion - nvidia-xorg.conf
Section "Device"
Identifier "Videocard0"
Driver "nvidia"
Option "RegistryDwords" "EnableBrightnessControl=1"

before yesterday's updates everything works ok, I can adjust the LCD brightness with fn+ keys, but after updates, fn+ keys don't work any more.
But, I can adjust the birghtness by doing below:

echo 9 > /sys/class/backlight/acpi_video0/brightness

I don't know what happened, is there a bug in updates introduce this problem.

Thank you!

---------- Post added at 01:24 AM ---------- Previous post was at 12:55 AM ----------

I remember that after updating something like Dbus, the fn+keys don't work anymore. Is the bug of dbus introduce this problem.