Accessing HID attributes from user mode

[Kurt Fankhauser]

I am trying to access the Vendor ID (VID) of the USB HID devices currently
attached to the computer. Under Windows 98 I use the HID GUID and calls
to SetupDiGetClassDevs(), SetupDiEnumDeviceInterfaces() and
SetupDiGetDeviceInterfaceDetail() to obtain a device path. Calling
CreateFile() with the device path returns a handle to the device which can
then be used to call HidD_GetAttributes() which returns the VID and PID of
the device.

This techinique does not work with Windows 2000 as the CreateFile()
function fails with an error code of "Access Denied". I believe this is
because the OS opens the keyboard and mouse devices with exclusive access.

Is there an alternate way to obtain the VIDs of the current HID devices?

[Doron Holan [MS]]

if you open the file without asking for read access, the create should
succeed and you should be able to use HidD_GetAttributes on either the
keyboard or mouse.

--
d

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"Kurt Fankhauser" <kf...@shell.pacifier.com> wrote in message
news:udggo8g...@corp.supernews.com...

[Adrian Taylor]

Fantastic! This is just what I needed to do to get a user-mode application
to use a GetFeature/SetFeature interface to my Windows2000 HID minidriver.

I had previously been trying to use the recommended way of creating a 2nd
top-level collection to do this. However, after a fortnight of banging my
head against a brick wall I found that the HIDClass parser does not allow 2
top-level collections in a single report descriptor, and that there is no
way of getting the HIDClass driver to accept 2 different report descriptors
(if this is even a viable alternative anyway).

My only question is : Is this solution a loop-hole that is likely to be sewn
up in a future service pack or OS update, or is it an entirely valid
approach that will stand forever?

Adrian.

"Doron Holan [MS]" <dor...@online.microsoft.com> wrote in message
news:3cd85c3d$1...@news.microsoft.com...

> if you open the file without asking for read access, the create should
> succeed and you should be able to use HidD_GetAttributes on either the
> keyboard or mouse.
>
> --
> d

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[Eliyas Yakub]

>I found that the HIDClass parser does not allow 2 top-level collections in
a single report descriptor

I don't think this is true. In the sample I sent you, look at the commented
report desc in the header file. That has both mouse report and a generic hid
report. Try using that. I'm sure it works because Kumar was doing the
initial testing with that.

-Eliyas

"Adrian Taylor" <adr...@not.here> wrote in message
news:abn39f$8ak$1...@news8.svr.pol.co.uk...

[Adrian Taylor]

I actually cut-and-pasted that commented-out report descriptor into my
mini-driver just to make sure : but the driver still got removed straight
away after returning it. I was half expecting it as I had tried this method
every-which-way before, but I thought your one might have just the right
settings or something. As a double check I removed the last part of the
descriptor (the 2nd top-level collection) and it was fine again.

What OS / service pack did you have it running on?

Adrian.

"Eliyas Yakub" <eli...@microsoft.com> wrote in message
news:oRQD8.30407$Po6....@rwcrnsc52.ops.asp.att.net...

> >I found that the HIDClass parser does not allow 2 top-level collections
in
> a single report descriptor
>
> I don't think this is true. In the sample I sent you, look at the
commented
> report desc in the header file. That has both mouse report and a generic
hid
> report. Try using that. I'm sure it works because Kumar was doing the
> initial testing with that.
>
> -Eliyas