Messages in this thread | | | Date | Thu, 24 Jun 2004 09:39:27 -0500 | From | Terence Ripperda <> | Subject | Re: 32-bit dma allocations on 64-bit platforms |
| |
correct. I checked with my contacts here on the PCI express requirements. Apparently the spec says "A PCI Express Endpoint operating as the Requester of a Memory Transaction is required to be capable of generating addresses greater than 4GB", but my contact claims this is a "soft" requirement.
but even if all PCI-X and PCI-E devices properly addressed the full 64-bits, legacy 32-bit PCI devices can be plugged into the motherboards as well. my Intel em64t boards have mostly PCI-X, but 1 PCI slot and my amd x86_64 have all PCI slots (aside from the main PCI-E slot).
also, at least one motherboard manufacturer claims PCI-E + AGP, but the AGP is really just an AGP form-factor slot on the PCI bus.
Thanks, Terence
On Thu, Jun 24, 2004 at 06:48:07AM -0700, jbarnes@engr.sgi.com wrote: > On Thursday, June 24, 2004 2:18 am, Arjan van de Ven wrote: > > What is the problem again, can't the driver us the dynamic pci mapping > > API which does allow more memory to be mapped even on crippled > machines > > without iommu ? > > And isn't this a problem that will vanish since PCI Express and PCI X > > both *require* support for 64 bit addressing, so all higher speed > cards > > are going to be ok in principle ? > > Well, PCI-X may require it, but there certainly are PCI-X devices that > don't > do 64 bit addressing, or if they do, it's a crippled implementation > (e.g. top > 32 bits have to be constant). > > Jesse - 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/
| |