Lower 1MB & DMA

NTDEV
1

Is there any chance that Windows XP or Vista will allocate a buffer
for DMA from the lower MB?
The BIOS doesn’t mark the whole region as reserved.

Thanks in advance!

2

You’d need to call MmAllocateContiguousMemory and specify your maximum physical address. Depending on the size of the buffer you want and where you are in the boot cycle you might get it.

-p

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of David Pilger
Sent: Thursday, November 29, 2007 2:49 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Lower 1MB & DMA

Is there any chance that Windows XP or Vista will allocate a buffer
for DMA from the lower MB?
The BIOS doesn’t mark the whole region as reserved.

Thanks in advance!

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