.fdi files and HAL

Joe Shaw joeshaw at novell.com
Mon Jun 7 11:24:31 PDT 2004

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.

>  - Is it preferable to have an .fdi file for *every* device. I know that 
> the spec says that many devices can be determined from device 
> information, but is an .fdi better for overriding that information and 
> providing concrete information on the device?

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:

        * Fill in anything missing from HAL's detection.  Things like
        adding the "camera" capability when it can't be autodetected
        (see fdi/20freedesktop/canon-digital-ixus-v.fdi) or setting the
        media type of a flash card reader to "flash-card" (see
        fdi/20freedesktop/lexar-media-cf-reader.fdi).  I'm going to
        write one for my wireless card so that I don't have to keep
        seeing "Unknown Device" every time. :)
        * Override any incorrect or unclear information.  For example, I
        have a 6-in-1 flash card reader, but all 4 of the bays show up
        as "STORAGE DEVICE".  It'd be much nicer if they were described
        by the type of media in each bay.  There's an example of this
        one, actually, for a 6-in-1 that David has.  See
        * I thought I had a third thing, but I forget it now.

>  - Is the plan to be able to download .fdi files on the fly from the 
> net? I saw the Fedora Hardware Project which seems to be a non-starter 
> from my initial googling.

I think that was the blue sky idea, but there hasn't really been much
thought about it as far as I know.

>  - What is the best method of creating .fdi files? I don't mean how to 
> write XML, I mean, how do I find the most detailed information to write 
> the key-value pairs for the .fdi files?

Well, ideally we would have a simple little python tool or something for
doing the XML editing as well, but... :)

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. :(


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