Re: [RFC] Simple userspace interface for PCI drivers

[Andi Kleen]

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.

Then it should hopefully just work.

-Andi
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