[wdmaudiodev] Re: WaveCyclic vs WavePCI for HD Audio
- From: "Cheng-mean Liu (SOCCER)" <soccerl@xxxxxxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Mon, 30 Mar 2009 10:49:45 -0700
For HD Audio solution, you want to use WaveRT port, which has the benefits of
both WavePCI and WavePCI - without redundant data copy and mapping and
unmapping hassels.
Thanks
Cheng-mean Liu
Microsoft
This posting is provided "AS IS" with no warranties, and confers no
rights.
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Preston
Sent: Saturday, March 28, 2009 11:59 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] WaveCyclic vs WavePCI for HD Audio
I've seen lots of discussions on WavePCI vs WaveCyclic but nothing specifically
references HD Audio since both seem to have been available long before HD Audio
existed .
I know that the HD Audio DDI
document<http://download.microsoft.com/download/e/b/a/eba1050f-a31d-436b-9281-92cdfeae4b45/HDAudioDdi11.doc>
from Microsoft stated that the HD Audio sample driver was written using
WaveCyclic. However based on reading the documentation WavePCI seems to be seen
as the more effecient choice, but a bit trickier to implement. I did see
another
post<//www.freelists.org/post/wdmaudiodev/Problem-about-GetMapping-ReleaseMapping-in-WavePCI,12>
on here that if states if implemented correctly, WavePCI doesn't yield much
better results than WaveCyclic:
"There should be no difference in audio quality between WaveCyclic and WavePci.
... The IRP handling between the two models is essentially the same, with the
main difference that in the case of WavePci we hand you the page mappings from
the mapped IRP buffer and in WaveCyclic we copy the data from the IRP buffer
into your cyclic buffer based on your indication of DMA position with a DPC
that is scheduled whenever you notify us."
it seems like WaveCyclic would the reasonable choice for development, does
anyone have reccomendations on this?
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