Messages in this thread |  | | Date | Tue, 9 Jan 2001 08:27:49 -0800 | From | Tim Wright <> | Subject | Re: Confirmation request about new 2.4.x. kernel limits |
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On Tue, Jan 09, 2001 at 02:21:56PM +0200, Matti Aarnio wrote: [...] > > For IO on usual systems you have 32 bit address space PCI busmasters, > so those can access only the lowest 4GB of address space, and to have > a block of data in upper area, it needs to be "bounced", that is, CPU > must copy it. Linux 2.4.0 system doesn't support 64-bit PCI addresses > at 32-bit systems (not at 64-bit Alpha either, I recall.) > On the other hand, Alpha systems and SPARC systems have IOMMU hardware, > and we do support that (to some extent), but 32-bit intel world doesn't > have similar things. >
Hi Matti, you are correct in saying that ia32 systems don't have IOMMU hardware, but it's unfortunate that we don't support 64-bit PCI bus master cards, since they're inexpensive and fairly common now. For instance, the Qlogic ISP SCSI cards can do 64-bit addressing, as can many others. Has anybody taken a look at enabling this ?
Tim
-- Tim Wright - timw@splhi.com or timw@aracnet.com or twright@us.ibm.com IBM Linux Technology Center, Beaverton, Oregon "Nobody ever said I was charming, they said "Rimmer, you're a git!"" RD VI - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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