Seems that the poperty is not enough as the NC10 doesn't have a proper acpi-backend to support it, if i understand that correctly?
What i don't understand is, from the changelog:
Matthias Hopf (7):
Add HP Mini 5101 to quirks list.
Add BACKLIGHT property support in KMS case.
Don't ignore backlight level change to the same level.
Add get_property support.
Use "Backlight" as backlight brightness property.
Don't set backlight level if going on->on.
Add new backlight driver "samsung".