[wdmaudiodev] Re: Usb Audio Driver
- From: "DJ Sisolak" <dsisolak@xxxxxxxxxxxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Wed, 16 Jul 2003 13:08:09 -0700
Hello Jerry,
1) The USBAudio driver supports overlapped IO on any and all requests.
It is the responsibility of the application to use it this way.
(Requests to the device itself are necessarily serial due to the nature
of the bus.)
3) The request to do a "GET_MEM" or a "SET_MEM" needs a target object.
Therefore it is necessary to open the filter for the IOCTL to address to
do this. It would not be necessary to open a pin or address this to a
particular topology node though.
Thanks,
DJ Sisolak
Microsoft Corp.
This posting is provided "AS IS" with no warranties, and confers no
rights.
-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Jerry Evans
Sent: Wednesday, July 16, 2003 12:20 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Usb Audio Driver
Hi DJ
Thanks.
> 1) Not sure what you are after. Being that the driver is KS based, it
is
> impossible to get away from the KS style ...
Apologies. I'm not sure of the division of responsibilities here :-))
How about this:
HANDLE handle = OpenFile(\\.\\usbgadget")
WriteFile(...)
OLVERLAPPED ol
ReadFile(...,&ol);
i.e. now the device can be treated as a file and as it will do
overlapped IO
might actually be rather efficient. It would certainly *enormously*
simplify
non-time critical transfers. This gets well away from the (IMHO) overly
complex filter graph stuff.
> There is the mixer API to address any audio device, though I
> can see where that might fall short for addressing all possible
> properties.
Interesting. Can you elucidate ?
> 2) I will make measurements on the driver and stack once the new
driver
> is complete.
Sounds good.
> 3) The USB Audio specification allows for a "SET_MEM" and "GET_MEM"
> request to the device.
In principle it sounds good. What would the API be ? Do I have to go
thru
all the Pin stuff ? Could I go a DeviceIOControl(SET_MEM) if you see
what I
mean ?
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