[wdmaudiodev] Re: sAPO must be real-time compatible
- From: "Andrew Sha......" <universalkludge@xxxxxxxxxxx>
- To: wdmaudiodev wdmaudiodev <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Fri, 9 Jul 2010 17:18:55 -0500
Thank you
It looks like DeviceIoControl w/ overlapped I/O +
GetOverlappedResult(..bWait=FALSE) is the way to go and upon
ERROR_IO_INCOMPLETE returned just fail processing
Date: Fri, 9 Jul 2010 14:45:45 -0700
From: timr@xxxxxxxxx
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: sAPO must be real-time compatible
Andrew Sha...... wrote:
"All methods that are members of real-time interfaces must be implemented as
non-blocking. They should not block, use paged memory, or call any blocking
system routines. Note that most system routines are blocking"
This is most probably means that any kind of WaitXXX function should NOT be
called explicitly or implicitly; so DeviceIoControl should be fine to use
providing that a called driver completes a request synchronously
Do I miss / misinterpret something?
You can only call a Wait function if you specify a timeout of 0, which means it
checks and returns immediately telling you whether the event has completed. If
you need to call DeviceIoControl, you should use overlapped I/O so that you can
continue processing and handle the results later.
On the other hand, if you need to process the data and the processing is going
to take time, what alternative do you have? ;)
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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