Disabling add-ons in the presence of a generic control device

[Matthew Garrett]

We currently have backlight control addons for a couple of systems 
(Apple and Dell spring to mind). Over time, these platforms are gaining 
kernel support for the backlight control - either through the vendor 
adding generic ACPI video support or through hardware specific drivers 
being written. I'm not quite clear on the cleanest way of doing this 
with the fdi format, though. It needs to handle two cases:

1) The kernel driver is loaded before hal. The addon needs to never be 
started in this case.
2) The kernel driver is loaded after hal. The addon needs to be stopped.

Anyone have any thoughts on the best way to achieve this?

-- 
Matthew Garrett | mjg59 at srcf.ucam.org