Re: PCIe device driver question

[Robert Hancock]

V.Radhakrishnan wrote:
> > > 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.
>
> How can you DMA "successfully" into this address which is > 4 GB when
> you have only 4 GB RAM ? Or am I missing something ?

The MMIO and other reserved memory space at the top of the 32-bit memory 
space will cause the top part of memory to be relocated above 4GB.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/