Linux Fedora 19 NVidia Brightness setting

NVidia in Fedora 14 is unable to bet set via GNOME desktop. The workaround was
# echo 5 > /sys/class/backlight/acpi_video0/brightness
And to retained the setting, simply add the command line in the /etc/rc.local

Now I am in Fedora 19 64bit with kernel updated and NVidia installed. The boot
parameter already set to acpi_mode=vendor. Attempting the same workaround but
The result is not like the expected. Right after the # echo 5 > ... The brightness stays
at 10, nothing happen.

Accidentally suspend (standby) my laptop session and resume runs the new
brightness setting. So the conclusion is that the brightness setting will take
effect if you somehow shutdown the display and turn it back on. The way that
I know is to pm-suspend or going to standby mode.

Hope it helps.