thanks alot Doron !!
-----Original Message-----
From: Doron Holan [mailto:xxxxx@windows.microsoft.com]
Sent: Thursday, June 20, 2002 4:23 PM
To: NT Developers Interest List
Subject: [ntdev] RE: How to write Lower Filter driver for USB Audio De
vice
- I would load as a lower filter to usbaudio, so you can trap all URB
traffic between usbaudio and the core stack - you send the fake descriptors in response to the appropriate URBs,
take a close look at _URB_CONTROL_DESCRIPTOR_REQUEST with types
USB_DEVICE_DESCRIPTOR_TYPE, USB_CONFIGURATION_DESCRIPTOR_TYPE, and
USB_INTERFACE_DESCRIPTOR_TYPE. Note that I am not basing this on
usbaudio’s code, rather general usb device driver setup. - no, if you fake things out correctly, there is no need to be a bus
driver
You will also need to trap the following URBs if I follow your device
layout
URB_FUNCTION_SELECT_CONFIGURATION
And/or
URB_FUNCTION_SELECT_INTERFACE
URB_FUNCTION_ISOCH_TRANSFER
And perhaps others. You can easily monitor all URBs going by (by
filling out your own internal device control routine, looking at the URB
header) and build up what you need by trial and error.
I think you have a bit of a difficult road ahead of you, good luck.
d
-----Original Message-----
From: Deevi, Srinivasa [mailto:xxxxx@microtune.com]
Sent: Wednesday, June 19, 2002 7:13 PM
To: NT Developers Interest List
Subject: [ntdev] RE: How to write Lower Filter driver for USB Audio De
vice
Hi all
Doron , thanks for the reply.
I am clear about what USB audio spec wants . Our hardware has a single
interface for both ISO IN and OUT . but as per the spec , we need two
interfaces to connect the speaker and microphone . My doubts are 1. When
should I load the filter ( ? ) driver ( which emulates what USB audio
driver wants ) ? 2. How and when can I send the fake descriptors to USB
audio driver ? 3. Do I need to develop the multifunction driver for this
?
those are my doubts.
thanks in advance
srinivasa
-----Original Message-----
From: Doron Holan [mailto:xxxxx@windows.microsoft.com]
Sent: Wednesday, June 19, 2002 6:32 PM
To: NT Developers Interest List
Subject: [ntdev] RE: How to write Lower Filter driver for USB Audio De
vice
I would first start off with the USB audio specification, I am pretty
sure it describes the various isoch interfaces which the usb audio
driver uses to play audio.
If your device doesn’t conform to the interfaces described, you will
have to return fake descriptors to usbaudio’s requests and then also map
select config (and select interface b/c usbaudio will pick the most
appropriate interface for the given sound) as well. If the number and
types of pipe handles are the same, you should be OK, otherwise you will
have to spoof those as well, catching each ISOCH read and write,
inserting your own handles and converting them back when you are done.
Overall, depending on your hardware design, this might not be that
trivial.
d
-----Original Message-----
From: Deevi, Srinivasa [mailto:xxxxx@microtune.com]
Sent: Wednesday, June 19, 2002 6:14 PM
To: NT Developers Interest List
Subject: [ntdev] RE: How to write Lower Filter driver for USB Audio De
vice
Hi all
Scott , thanks for your reply. Are you pointing to the Multifunction
example ? I am still looking into the examples to find an answer .
I think that I don’t have proper idea of how to simulate what USB Audio
device driver wants . Can anybody point me some resources ? How can I
map the present hardware to what USB audio device driver wants ? Do I
need develop the driver like a bus driver which sits on USB hub ?
Thanks in advance
srinivasa
-----Original Message-----
From: Peter Scott [mailto:xxxxx@KernelDrivers.com]
Sent: Wednesday, June 19, 2002 4:39 PM
To: NT Developers Interest List
Subject: [ntdev] RE: How to write Lower Filter driver for USB Audio
Device
Check out the examples given with the “Programming the Windows Driver
Model” by Oney. It has a driver example I have inserted into various
levels of the USB Audio stack down to just above the USB hub.
Pete
Peter Scott
xxxxx@KernelDrivers.com
http://www.KernelDrivers.com
>-----Original Message-----
>From: xxxxx@lists.osr.com [mailto:bounce-ntdev-
>xxxxx@lists.osr.com] On Behalf Of Deevi, Srinivasa
>Sent: Wednesday, June 19, 2002 4:22 PM
>To: NT Developers Interest List
>Subject: [ntdev] How to write Lower Filter driver for USB Audio Device
>
>Hi all
>
>I wanted to use Microsoft USB audio device driver for our device , but
our
>hardware configuration is little different than what is expected by
the MS
>USB audio driver . I want to develop a lower filter driver to map the
MS
>Usb
>audio driver to our hardware . Can anbody tell me whether this is
possible
>or not ? If possible suggest me a way to develop this ?
>
>thanks in advance
>srinivasa
>
>—
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