Messages in this thread | | | Date | Mon, 07 Jul 2003 19:14:38 -0700 (PDT) | Subject | Re: [RFC] block layer support for DMA IOMMU bypass mode II | From | "David S. Miller" <> |
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From: Andi Kleen <ak@suse.de> Date: Thu, 3 Jul 2003 23:24:15 +0200
But of course it doesn't help much in practice because all the interesting block devices support DAC anyways and the IOMMU is disabled for that.
Platform dependant. SAC DMA transfers are faster on sparc64 so we only allow the device to specify a 32-bit DMA mask successfully.
And actually, I would recommend other platforms that have a IOMMU do this too (unless there is some other reason not to) since virtual merging causes less scatter-gather entries to be used in the device and thus you can stuff more requests into it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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