[wdmaudiodev] Re: Vista APOs: new API calls for locking memory?

  • From: "Andrew Wheeler" <AWheeler@xxxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Thu, 20 Apr 2006 11:16:12 -0500

Thoughts, anyone?  Or is this an RTFM question, and I'm just not looking
in the right place?

For initial dev can I get away with using, say, VirtualAlloc?  I'm
alright with the occasional audio hiccup due to a page miss, but clearly
this wouldn't work at all if the APO processing truly runs at a higher
priority than the virtual memory management.  Requesting nonpageable
memory from the driver would be doable, but just more time for what is
essentially throw-away code.


Thanks,

-andrew  


-----Original Message-----
From: Andrew Wheeler 
Sent: Tuesday, April 18, 2006 1:08 PM
To: 'wdmaudiodev@xxxxxxxxxxxxx'
Subject: RE: [wdmaudiodev] Re: Vista APOs: new API calls for locking
memory?

Alrighty.  In the meantime, any suggestions on work-arounds?  I could
have my driver allocate memory for the APOs, but are you guys aware of
anything simpler?  From the MSDN docs VirtualLock looks viable, but I've
found a number of usenet postings that say that the memory can actually
be paged out as the process loses context.  


Thanks for any thoughts/suggestions,

-andrew

-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] 
Sent: Tuesday, April 18, 2006 12:47 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Vista APOs: new API calls for locking memory?

Yes, that text is erroneous and a different method is being worked on.

Sorry for the inconvenience.

Sincerely,

Hakon Strande
PM Integrated, Internal, External, and Wireless Audio Devices
MediaTech/DMD/Windows Client/Microsoft

-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] 
Sent: Tuesday, April 18, 2006 8:18 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Vista APOs: new API calls for locking memory?

Hey there,

The SysFx document on developing APOs states:

        All code and data in the process path must be 
        nonpageable. The Windows Vista SDK contains a 
        new code- and memory-locking API that is useful 
        for this purpose. For details, see Nturtl.h.    


I'm having a hard time finding documentation on these new memory-locking
functions or the above-mentioned header, and the sample APO doesn't
allocate any memory.  Does anyone have pointers to these new functions,
documentation, and/or sample code? 

Thanks,

-andrew
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