Messages in this thread | | | Date | Wed, 25 May 2011 21:21:21 +0100 | From | Daniel Haid <> | Subject | Re: Question about iommu on x86 64 and ra deon driver. |
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> Only if you allow 3GB or less in the machine. So you would have to do > mem=3G as well. > > The reason is that (and you can see that yourself by looking at the > E820), is that 1GB is actually _above_ the 4GB.
Just another question on this one:
Why can a driver not simply ask for DMA-capable memory, is this not what memory zones are for?
So if a driver wants to do DMA it requests DMA-memory and gets it from the lower than 4GB address space.
But for some reason it is not done like this, why?
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