Messages in this thread | | | Subject | Re: [parisc-linux] Untested port of parisc_device to generic device interface | Date | Wed, 13 Nov 2002 13:37:09 -0700 | From | Grant Grundler <> |
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"J.E.J. Bottomley" wrote: > Actually, I think dma_mask and consistent memory are orthogonal problems.
No. consistent memory needs to be reachable by the device as well. dma_mask constrains which memory pci_alloc_consistent() can use.
> dma_masks are used by the I/O subsystem to determine whether direct DMA to a > memory region containing an I/O buffer is possible or whether it has to be > bounced. Consistent memory is usually allocated for driver specific > transfers. The I/O subsystem doesn't usually require the actual I/O buffers > to be in consistent memory.
right.
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