Messages in this thread | | | Date | Wed, 30 Jul 2008 16:47:18 +0100 | From | Alan Cox <> | Subject | Re: PCIe device driver question |
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On Wed, 30 Jul 2008 09:00:58 -0700 (PDT) Sanka Piyaratna <cesanka@yahoo.com> wrote:
> 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.
Assuming the failures are in the range 640K-1MB then I would imagine your bridge doesn't permit transfers via DMA to the ISA hole.
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