[wdmaudiodev] Re: Fixed I/O to memory DMA

  • From: wade <wdawson61@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Tue, 10 Jun 2003 13:30:46 -0700 (PDT)

Hi Walter.  Thanks for the response.  I may have used the term "contiguous" 
ambiguously.  The destination memory doesn't need to be physically contiguous, 
in fact the desired destination is AVStream frames.  I was wondering if there 
was a DMA mode where the source of the DMA is an I/O port.  I have seen this 
sort of transfer supported by hardware in the past. 

Walter Oney <waltoney@xxxxxxxxxxxx> wrote:
wade wrote:
> Hi. I'm wondering if there exists a way to create DMA_ADAPTER from
> IoGetDmaAdapter() etc, that will read repeatedly from a fixed 16bit IO
> port and write to contiguous memory. (~ 64k per transfer) I guess you
> could create mega S/G mappings, but is this the way to do this?

If you're reading from an I/O port, it's not DMA. In that case, why
insist on contiguous memory?

Walter Oney, Consulting and Training
Basic and Advanced Driver Programming Seminars
Check out our schedule at http://www.oneysoft.com

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