This problem has been solved, our email servers having been a little laggy
for the last few days sorry…
It turned out that it was a problem setting up the physical base address on
a 64k block boundary
using a micro… please refer to the previous mails
Regards
James
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Tim Roberts
Sent: 08 November 2005 17:04
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] My [Free/Release] Build Driver doesn’t function
correctly!
James Dunning wrote:
I have noticed that my PCI device driver doesn’t function correctly under
the Free Build configuration. When I try to read data from the device
using
ReadFile, it returns successfully however nothing is written to the User
Buffer?
…
I suspect that the DMA operation is working correctly, writing data from
the
onboard memory to system physical addresses. but how can I prove this? how
is it possible probe the physical addresses from the scattergather table to
ensure data is actually there? Ideally it would be nice to probe the
physical memory during the read completion routine prior to calling
ReadAdapter->DmaOperations->PutScatterGatherList… However I am not quite
sure how to do this.
DbgPrint is one way.
I am wondering whether there’s a problem with windows is not copying the
DMA’s data written to system’s physical memory to the user’s virtual memory
(I am not sure how the windows virtual memory manager works)
None of us can answer this question unless you show us the code in your
ReadFile handler.
The Windows virtual memory manager does not get involved in DMA. It’s
entirely up to you. Are you locking the user’s buffer into kernel space
and using that for the DMA, or are you using a common buffer and then
copying to the user’s buffer?
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
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