On Wed, Sep 24, 2008 at 8:24 PM, George Spelvin <linux@xxxxxxxxxxx> wrote: > Just a little followup... I currently have the machine with 8 GB RAM, > all 4 SB600 channels populated, and 64-bit DMA enabled, operating in > production. No problems so far. > > Q: Does the fact that I'm using the GART IOMMU mean that I'm not really using > 64-bit DMA at all? If pci_dev->dma_mask has more bits set than the highest physical memory address, then the GART will not be used for that device. See "need_iommu()" in arch/x86/kernel/pci-gart_64.c and how that's used in gart_map_single(). My assumption is libata will not override something the PCI device driver sets. hth, grant -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
