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Date: Wed, 30 Jul 2008 09:00:58 -0700 (PDT)
From: Sanka Piyaratna <cesanka@yahoo.com>
Subject: PCIe device driver question
To: linux-kernel@vger.kernel.org
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Hi,

I am currently developing a PCIe data capture card hardware and the
device drivers to drive this. I have implemented DMA on the data
capture and the scatter-gather DMA is implemented in the hardware.  I
am testing this in an X86_64 architecture machine with 4 GB of RAM. I
am able to successfully dma data into any memory (dma) address >
0x0000_0001_0000_0000. However, my problem is to dma data to any
address less than this. When I try to DMA data to an address less than
0x0000_0001_0000_0000, the hardware device hangs indicating that the
address does not exist.

I have implemented the DMA mask to be full 64 bit and my hardware is
capable of transfering data to any address < 8TB. I am using kernel
version 2.6.23.11. 

Could you please let me know what I might be doing wrong?

Thanks and regards,

Sanka


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