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Re: DART bad DMA behaviour?
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Re: DART bad DMA behaviour?



Josh de Cesare writes:
 > Andrew,
 > 	The DART is organized around 4K page.  So it give the page
 > number of the fault.  I'm guessing a bit about the answer to your
 > second question...
 > 	PCI-X allows a 64 bit address so the address on the bus would
 > be 0xdeadbeefcacababe.  HyperTransport only supports a 40 bit
 > address, so if it gets passed to the bus, the address there would be
 > 0xefcacababe.  Since this address is not from 0x0080000000 -
 > 0x00FFFFFFFF, it will not get passed back to HT and will go to the
 > DART.  The DART only supports a 31 bit address, so it will try to
 > find the mapping for the address 0x4acababe.  Assuming the page is
 > not mapped, the panic should talk about page 0x4acab.
 > 	Again this is all a guess as to what would happen.
 > 									Josh

BTW, thanks again for all your help.  It is wonderful to get an answer
like this.


Drew
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References: 
 >DART bad DMA behaviour? (From: Andrew Gallatin <email@hidden>)
 >Re: DART bad DMA behaviour? (From: Josh de Cesare <email@hidden>)
 >Re: DART bad DMA behaviour? (From: Andrew Gallatin <email@hidden>)
 >Re: DART bad DMA behaviour? (From: Josh de Cesare <email@hidden>)



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