Messages in this thread | | | Date | Tue, 05 Mar 2002 17:13:33 -0800 (PST) | Subject | Re: Does kmalloc always return address below 4GB? | From | "David S. Miller" <> |
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From: "Adam J. Richter" <adam@yggdrasil.com> Date: Tue, 5 Mar 2002 09:08:20 -0800
Steffen Persvold writes: >I know pci_map_single (and _sg) will >use bounce buffers on platforms without an IOMMU [...]
For a moment I thought that must be the point that I was missing, but I don't see any such bounce buffer support in linux-2.5.6-pre2/include/asm-i386/pci.h or arch/i386/kernel/pci-dma.c. I do not see how this is currently implemented on x86 systems with >4GB of RAM.
You won't get HIGHMEM pages in your driver unless you are using 2.5.x and tell the scsi layer you are capable to DMA to/from HIGHMEM pages.
Similarly for networking drivers, and setting NETIF_F_HIGHDMA in the net device feature flags. - 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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