Messages in this thread | | | Date | Wed, 22 Feb 2006 14:14:34 -0600 | From | Corey Minyard <> | Subject | Re: Problem with NETIF_F_HIGHDMA |
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Arjan van de Ven wrote:
>On Wed, 2006-02-22 at 12:47 -0600, Corey Minyard wrote: > > >>I was looking at a problem with a new system we are trying to get up and >>running. It has a 32-bit only PCI network device, but is a 64-bit >>(x86_64) system. Looking at the code for NETIF_F_HIGHDMA (which, when >>not set on a PCI network device, means that it cannot do 64-bit >>accesses) in net/core/dev.c, it seems wrong to me. >> >>It is dependent on HIGHMEM, but HIGHMEM has nothing to do with 32/64 bit >>accesses. On 64-bit systems, HIGHMEM is not set, thus the network code >>will pass any address (including those >32bits) to the driver. Plus, >>highmem on 32-bit systems may very well be 32-bit accessible, possibly >>resulting in unecessary copies. AFAICT, the current code will only work >>with i386 and PAE and is sub-optim >> >> > >you use the PCI mapping api right? if you do that then there's no >problem, after pci mapping the addresses will be in the lower address >range perfectly fine.... > > Ah, cool, physical memory remapping. Then the problem lies elsewhere. Thanks.
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