.fdi files and HAL

Jono Bacon jono at jonobacon.org
Mon Jun 7 11:52:34 PDT 2004

Joe Shaw wrote:
> On Mon, 2004-06-07 at 01:44 +0100, Jono Bacon wrote:
>>I am really intrigued by the concept of .fdi files and how a 
>>collaborative network of contributors could allow .fdi files to be 
>>created for a vast range of devices. I am still quite new to HAL, and I 
>>read through the specification properly tonight, but I have a few 
>>questions I hope you can answer.
> I think a network of contributors would be wonderful.  It's badly
> needed, as those of us doing the development on HAL have such a small
> subset of all those devices out there.

I might be able to create some form of web interface to this. It would
be great if people could use a web form that automatically generated the
XML. The challenge would be testing the files and ensuring that they
work well. It would also be cool if regular people could find
instructions on how to find the relevent hardware information to fill
the form in.

> Er, I'm not totally sure I understand the question.  Right now only a
> single FDI can match a device, so it needs to be rather specific.  In
> general I think that the FDI files should:

What I meant was - if a device is detected and HAL can figure out a
particular property, does it matter that the FDI overrides that property
with the same value. It seems that we only need FDI files for devices
that have properties that cannot be detected, but it seems that it would
be a good idea if *every* device could have an FDI file to explicitly
state properties, even if some of them can be detected.

> I think the spec will be a decent reference point once it's updated.
> Beyond that, example FDI files and maybe a tutorial would also be
> helpful.  But for the time being there's little info, and you'd probably
> have to refer to the source code. :(

The XML seems to be fairly strightforward, I was just curious how I find
the value for the different properties. Some of these things are obvious
- I know my camera is a camera for example, but I suspect I may need to
prod some devices to get information about them.

Also, is *every* device uniquely identifiable by its PCI/USB product_id?
As an example, my webcam is a Terratec TerraCAM USB with the product_id
42257, but would other cams with the OV511 chipset have the same product_id?


Jono Bacon - http://www.jonobacon.org/
Writer / Journalist / Consultant / Developer

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