Re: [RFC] Simple userspace interface for PCI drivers

From: Greg KH
Date: Fri Sep 01 2006 - 14:21:19 EST


On Thu, Aug 31, 2006 at 03:49:10PM +0200, Andi Kleen wrote:
> Matt Porter <mporter@xxxxxxxxxxxxxxxxx> writes:
> >
> > What about portable access to the PCI DMA API from userspace?
>
> We'll definitely need this for X11 anyways. Currently it is not
> possible to run the standard X server with a IOMMU that isolates
> the graphics card because it has no way to get at the GPU MMIO
> registers then.
>
> My long-term plan was to integrate it in /sys/bus/pci mmaps
> (together with PAT etc.). When you mmap it there the kernel
> allocates a DMA mapping and then frees it on unmap.

That sounds very reasonable, looking forward to it.

thanks,

greg k-h
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