Re: Question about iommu on x86_64 and radeon driver.

[Konrad Rzeszutek Wilk]

On Tue, May 31, 2011 at 08:57:39PM +0100, Daniel Haid wrote:
> Just another question, the problem seems to be an issue with
> 
> swiotlb=force
> 
> and I assume that without "force" DMA with addresses that
> already are below 4GB should be handled without any
> bounce-buffer, and with "force" everything goes through
> the bounce-buffer, is this correct?
> 
> Now I have a VIA chipset where the IOMMU does not work, so
> swiotlb is activated, but is it activated in force mode or
> in normal mode? How can I find out?

Look in the source code. I somehow assumed it would activate it
but maybe it isn't. And the problem you have is related to
something else?
> 
> If it is activated in force mode, maybe the problem will
> go away in normal mode?

<nods> Should.
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