Re: [Intel IOMMU][patch 8/8] Preserve some Virtual Address when devices cannot address entire range.

Alan Cox
2007-04-24T23:19:18Z

On Tue, 24 Apr 2007 14:50:26 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:

> From: Ashok Raj <ashok.raj@intel.com>
> Date: Tue, 24 Apr 2007 14:38:35 -0700
>
> > Its not clear if we have a very generic device breakage.. most devices
> > on these platforms are going to be more recent, (except maybe some
> > legacy fd)...
>
> I'm not so sure, there are some "modern" sound cards that have
> a 31-bit DMA addressing limitation because they use the 31st
> bit as a status bit in their DMA descriptors :-)

The sound stuff is going away bit by bit thankfully, but the 30bit DMA
limit is present on some more demented wireless chips still.

Alan