You might have answered this already but is your device on 32 or 64 bit bus. If it is on a 32 bit bus, does it do 64 bit addressing?
–Mark Cariddi
OSR Open Systems Resources, Inc.
-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@neurologica.com
Sent: Thursday, November 04, 2010 11:42 AM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] limitations on DMA transfer size?
Thank you for the help - though I don’t think I will be buying microsoft right yet
One reason we went to 64 bit platform was to defeat these memory limitations. Win7-64 seems to be giving me the same limitation that XP has…
I am not giving up yet. There must be something I can look at. Any suggestions???
Peter, your statement
“given that you have a 64-bit, device that does scatter/gather, I’m a bit surprised you’re seeing this limit”
leads me to believe that others have defeated this - now I need to find out what is different b/t theirs and mine…
Is there any clue from the fact that I specify an 8 byte param (size_t) to WDF_DMA_ENABLER_CONFIG_INIT(), but when I ask for that param back via WdfDmaEnablerGetMaximumLength(), it gives me the param back with the top 4 bytes chopped off… I mean, my understanding is that WdfDmaEnablerGetMaximumLength() gives me what I told it, and WdfDmaEnablerGetFragmentLength() gives me the Windows adjusted value.
(I am building in Win7 x64 Checked Build Environment…)
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