[Libdlo] [PATCH] udlfb: Restrict device id match on composite devices

[Andrew Kephart]

On Thu, 2010-12-09 at 14:28 -0800, Bernie Thompson wrote: 
> Hi Andrew,
> 
> Thanks for submitting this patch!
> 

> [some text deleted]

> Can you say what hardware you're using?  Is this one of the
> DisplayLink HDMI designs with integrated audio?

Not exactly; it's the Imation Link product, which doesn't use the
DL-integrated audio, but does expose the on-board audio as a secondary
interface in the overall composite.

> 
> > I'm not sure if this is entirely the correct solution, but it seems to
> > work.
> 
> Yes, this area is very tricky. We need to think about a number of
> DisplayLink USB 2.0 design variations (normal, composite with HID or
> audio+HID, and multi-configuration for the purposes of driver install
> off of flash), plus we have the unknowns of USB 3.0 devices arriving
> in coming months.
> 

Absolutely.  My biggest concern would be a DL-based composite device
that may appear with a non-DL interface that happens to be
vendor-specific as well (like integrated ethernet or some DL-specific
controller).  It looks like the official Windows drivers just assume
that the first interface is DL, and the rest are not, but that's just my
observation.  

> > What do you folks think?
> 
> First blush, I think this is a safe change, and I assume something
> like this is needed for the HDMI graphics+audio solutions. I'd be
> interested if anyone else see any problems.  Of course, this doesn't
> solve our USB 3.0/DL next-gen vs. generic VID match dilemmas.
> 
> I'll run the change with some of the DisplayLink hardware variants I
> have here.  If no red flags come up, I expect we'll take this patch
> and get it pushed downstream into the kernel.
> 

Thanks!

-andrew

> Again, thank you!
> Bernie
> http://plugable.com/
> 
> [original text deleted]