A small update for the double backlight interface problem. It is possible to blacklist the sony one and keep sony-laptop module running. I found the solution to this post:
Create the file /etc/hal/fdi/preprobe/sony.fdi and paste the following text
<?xml version="1.0" encoding="UTF-8"?>
<!-- Ignore backlight interface created by sony_laptop
<match key="linux.sysfs_path" string="/sys/devices/virtual/backlight/sony">
<merge key="info.ignore" type="bool">true</merge>
Edit the string="/sys/devices/virtual/backlight/sony" to match your system. You can find it with lshal.
After you restart hal if you lshal you should see that the "linux.sysfs_path" string="/sys/devices/virtual/backlight/sony" is registered to a temp interface. After that gnome-power-manager can control the backlight of the vaio. Although kde4 powerdevil still cannot with the Fn keys.