On Tue, Oct 05, 2004 at 05:32:26PM +0200, Michael S. Tsirkin wrote: > > The argument about IOMMU resources seems to be an argument > > in favor of letting the consumer handle allocation. > > Are you saying consumer shall play with IOMMU?
Yes, if "play with" means something above the HCA driver deals with DMA mappings. > But then > PCI addresses of memory will change each time consumer > does this and you wont be able to use your default region? Are regions defined by physical (DMA) or virtual addresses? In any case, a "default region" implies a long term DMA mapping. Documentation/DMA-mapping.txt is pretty clear that "streaming" DMA mappings are only intended for transient use - ie map something, do the DMA, then unmap. "Coherent" DMA mappings are intended to live longer periods but only for control structures like descriptor rings or other shared data. Linux tries to be "stingy" with DMA mappings because they are a scarce resource on some platforms. hth, grant _______________________________________________ openib-general mailing list [EMAIL PROTECTED] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
