Re: struct page to 36 (or 64) bit bus address?

Gerd Knorr (kraxel@bytesex.org)
Sat, 11 Aug 2001 09:09:02 +0200

On Fri, Aug 10, 2001 at 02:58:36PM -0700, David S. Miller wrote:
>
> I'm using the patch below (pulled out of Jens Axboe's bio
> patches, i386 only).
>
> Are you sure you aren't missing anything in this patch? For example,
> one can't use the patch you've provided for 64-bit DMA unless the
> dma_addr_t type is made larger.

It only allows to use the full 32 bit address range for DMA. Without
the patch I'm limited to direct mapped memory (i.e. < ~900MB on i386).
With the patch highmem below 4GB can be used too.

Jens's bio patches don't have support for 64-bit DMA (at least not the
version I've used to build that patch). Because the bt848/878 chips
are 32-bit devices only I havn't even tried to fix that...

Gerd

-- 
Damn lot people confuse usability and eye-candy.
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