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.
-Corey
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