Re: network devices don't handle pci_dma_mapping_error()'s

On Thu, Dec 07, 2006 at 11:48:14AM +0530, Amit S. Kale wrote:

On the x86_64 boxes that don't feature iommu functionality (because the 
motherboard disables it or because Linux can't handle it) Linux bounce buffer 
framework automatically comes into picture. Could we have the same framework 
take over when IOMMU space is over? I don't think this is possible with 
present code, though. We probably can have fallback_dma_ops in addition to 
dma_ops.

In the general case, no - some platforms (including x86-64 on IBM's
high end servers!) have an isolation capable IOMMU, which means all
DMA mappings need to go through it, so a general mechanism to cope
with DMA mappings running out is still needed.

Cheers,
Muli