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From: Neo on 11 Apr 2008 01:58
Hi,

1. I am very much confused about USB Multi Interface, MultiFunction,
Compound and Composite Devices. Can anyone please Clarify me the
difference.

2. I am writing a USB Bus Enumerator, i mean something similar to the
Host Controller Driver.
so, i wanted to invalidate the undelying devices to the OS. Now, i am
arised to a point, how to detect Multi Interface Devices.
i thought the device with multiple interfaces is a Multi interface
device, but i have couple of devices with me which are multiple
interfaces(2No's) but it is a single interface device. when i connect
it to the standard host controller it detects as single interface
device and the usbccgp.sys is NOT loaded. Here my question is how do i
detect whether or not the device is a Multi Interface device.

Thanks and Regards,
Neo
From: Neo on 15 Apr 2008 07:23
Hi,

i have figured out something, please confirm it.

Question : How do i detect whether or not the device is a Multi
Interface device.
Answer : Number of Interfaces are greater than 1 then it is a
MultiFunction Device.
But, i have found some of the devices having more than one interface
but the Windows Standard HC Showing them as Single Function Device.

So, i have debugged furthur and arrived to a conclusion that,
The Device Having more than one interface is MF Device.
But, though the device having Multiple Interface but with same Class,
Protocol, Sub Class is Single Function Device.

That means multiple interface devices having different Class,
SubClass, Protocol are only MultiFunction DEvice, otherwise it's
single function device.

please confirm it !

Thanks and Regards,
Neo
From: chris.aseltine on 15 Apr 2008 11:05
On Apr 15, 6:23 am, Neo <rksandi...(a)gmail.com> wrote:

> Question : How do i detect whether or not the device is a Multi
> Interface device.
> Answer : Number of Interfaces are greater than 1 then it is a
> MultiFunction Device.

Nope. Hint: you changed the term in your answer from what it was in
your question.

> But, i have found some of the devices having more than one interface
> but the Windows Standard HC Showing them as Single Function Device.

Yep..

> So, i have debugged furthur and arrived to a conclusion that,
> The Device Having more than one interface is MF Device.
> But, though the device having Multiple Interface but with same Class,
> Protocol, Sub Class is Single Function Device.

Typically, multi-function devices have class/subclass/protocol of
0x00. Which is a special case of "they are all the same", I suppose.
From: Neo on 16 Apr 2008 01:22
Sorry, i Apologise for my mistake.
i should have checked thoroughly before postin it into the group. i
apologise for my mistake.

My question was :

Question : How do i detect whether or not the device is a Multi
Function device.
Answer : Number of Interfaces are greater than 1 then it is a
MultiFunction Device.
But, i have found some of the devices having more than one interface
but the Windows Standard HC Showing them as Single Function Device.

Regards,
Neo

From: chris.aseltine on 16 Apr 2008 09:30
On Apr 16, 12:22 am, Neo <rksandi...(a)gmail.com> wrote:

> Question : How do i detect whether or not the device is a Multi
> Function device.

This is how the Microsoft drivers do it:

http://msdn2.microsoft.com/en-us/library/aa476434.aspx
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